The Fox & Cone

Cone Ha100 20 15 OIII B CROP

After the fun of December and January provided by the wide choice of exciting DSO objects, February affords a worthy finale to the winter season, in particular within the constellation Monoceros.  After successfully imaging the Rosette Nebula on 9th February, a few days later I was able to move on to another nearby HII-region in the Milky Way, with equally good results.  Surprisingly it’s been just over 3-years since I last imaged the same part of the sky just before Christmas 2014, on that occasion with an unmodded Cannon 700D DSLR.  Now armed with the more capable ZWO1600MM-Cool camera and narrowband filters, the potential for raising the bar was good and the results did not disappoint.

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Of foremost interest this time was NGC 2264, which officially describes the Cone Nebula and Christmas Tree Cluster but also includes the Snowflake Cluster and Fox Fur Nebula, all set within a large HII-region.  Individually each object is towards the limit of my equipment’s resolution but taken all together makes for an interesting combination when encompassed inside the 2.65o x 2.00o field-of-view.  Like the Rosette I chose to image in narrowband, with a total integration time of 90 minutes; again using 300 second subs at Unity gain proved to be very effective – I suspect that only more subs rather than longer exposures would lead to a better outcome but that will have to wait until I’ve sorted how to plate solve, watch this space!

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I’ve recently been experimenting in Photoshop using star masks and related sharpening and contrast enhancement methods, which for the first time I applied when processing these images to great effect.   Being an HII-region the overall image area is dominated by Ha-light and the processed Ha-subs resulted in a very exciting image at this wavelength, with many subtleties revealed throughout (see below).  On the other hand OIII and especially SII wavelengths are much less prevalent, from which it would seem  that a higher ratio of those subs would be required to better tease out detail at those wavelengths.  Notwithstanding, the resulting Ha-OIII-OIII Bi-Colour image has turned out well (top of the page), with all the aforementioned objects showing clearly.

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The signature object of this image is probably the Cone Nebula.  New stars are forming within a cone shaped dark molecular cloud, itself sculpted by strong stellar winds. However, I consider the Fox Fur Nebula (Sharpless-273) to be the bigger imaging challenge, which I’m therefore pleased to say is starting to show well in these images.  The name derives from the rich, fur-like texture of the nebula which is also shaped by stellar winds; reckon The Fox & Cone would make a good pub name! Below:  Cone Nebula & Christmas Tree Cluster Ha-OIII-OIII before colour mapping.

Cone Ha100 20 15 OIII A crop

But there’s more. A series of stars form an inverted outline shape of the so-called Christmas Tree Cluster above the Cone Nebula (see image above), with the conspicuously bright 15 Monocerotis at its base made of a massive variable star system.  And finally, somewhat off piste, lurking in the top right corner of the main image is NGC 2261 or Hubble’s Variable Nebula.  Discovered by Edwin Hubble in 1949, the nebula is illuminated by the unseen R Monocerotis star and forms a small but distinct bright triangular area.

All-in-all this is a great part of the February sky for imaging.  There’s still more to discover and I won’t leave it as long as 3-years before going back again, with the objectives of increasing integration time and possible addition of RGB subs to enhance the colour potential.

IMAGING DETAILS
Object Fox  & Cone Nebulae  NGC 2264 + Hubble’s Variable Nebula NGC  2261     
Constellation Monoceros
Distance 2,700 light-years
Size Approx. 54’ x 37’
Apparent Magnitude +3.9
 
Scope  William Optics GT81 + Focal Reducer FL 382mm  f4.72
Mount SW AZ-EQ6 GT + EQASCOM computer control
Guiding William Optics 50mm guide scope
  + Starlight Xpress Lodestar X2 guide camera & PHD2 control
Camera ZWO1600MM-Cool (mono)   CMOS sensor
  FOV 2.65o x 2.0o    Resolution 2.05”/pix   Max. image size 4,656 x 3,520 pix   
EFW ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters 
Capture & Processing Astro Photography Tool,  Deep Sky Stacker & Photoshop CS2
Exposures 12 x 300 sec Ha, 6 x 300 sec  OIII   (Total time: 90 minutes)
  @ 139 Gain  21 Offset @ -20oC  
Calibration 5 x 300 sec Darks  20 x 1/4000 sec Bias  10 x Flats Ha, OIII & SII @ ADU 25,000  
Location & Darkness Fairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5
Date & Time 11th February 2018 @ 21.00h
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Reflections – 2017

Following some important developments, I think it’s fair to say that the past year has hopefully marked an appreciable turning point for my astrophotography.  Reflections is a summary of my astronomy last year, in particular astrophotography, as well as some thoughts about how I hope to progress in the 2018.

I’m again pleased that there is continuing interest in Watch This space (Man) – A personal discovery of the Universe through astronomy and astrophotography.  This is a personal journey and I’m glad to see there is also regular activity in many of the older blogs, which altogether illustrate what I expect many others have experienced during their own personal journeys? For those starting out or with related interests, I hope they will find these pieces interesting, instructive and perhaps even inspiring; it’s not an easy hobby but when it works – it usually does with patience, perseverance and help from the wider community –  the experience is  very rewarding, often exciting and mostly fun.

I’m aware that many of my blogs can sometimes be on the long side, that’s because I want to thoroughly document and discuss the matters rather than superficially comment on them.  However, I am mindful that from time-to-time there are issues that can best be covered in a more concise manner or just events that speak for themselves and can therefore be brief, for which purpose I have now introduced the AstroBites section.  Unfortunately, despite the best of intentions, I’ve so far only used this item occasionally but hopefully will rectify the situation next year.

I’m always tinkering with the website, so even if you’re a regular visitor take a look around from time-to-time.  There is a photo gallery but for a simpler view of some of my better images I’ve recently added a FLICKR album, which is accessible from the Gallery menu.  The sharp eyed may also note that in response to new imaging techniques, I have changed the image and technical details summary for each picture; I find this information invaluable when looking at other astrophotographer’s images, as it can be very helpful when starting out in general or when using similar equipment or imaging the same object for the first time.

Once again the site attracted much interest from all corners of the world, which are summarised in the map below.  Please do get in touch if you have and relevant thoughts, queries or just to say – hello – contact details are in the ABOUT section of the main menu.

WTSM Heat Map

Reflections Crop

JANUARY TO MARCH

After overcoming some major technical problems that almost brought my nascent hobby to a premature end in 2016, I felt I needed to consider what would be the best way forwards thereafter.  My initial inclination was a larger telescope in order to get at those faint fuzzies but most of all I just wanted better quality images.  In the past this would inevitably result in acquiring a CCD mono camera and all that means in terms of very exacting technical issues and very long exposures, neither of which I was prepared to take on, or at least only to a degree – life’s too short and the UK weather too cloudy!

However, during the latter part of 2016 something of a game changer was emerging in the world of astrophotography and after following developments online for a few months, I was persuaded that the new ZWO1600MM-Cool mono camera could also give me what I wanted, without many of the issues of a conventional CCD camera.  As a result I purchased the aforesaid camera and matching x8 EFW just before Christmas in 2016  and eagerly awaited clear skies in the New Year.  Unfortunately it wasn’t that simple – now there’s a surprise!

The crucial benefits of the new CMOS based ZWO camera are three-fold: (i) very low read noise and high sensitivity achieved with, (ii) relatively short exposures – sometimes as little as 30 to 60 seconds, (iii) larger field-of-view compared to a CCD. Wow!  Unfortunately there was still much to sort out, notably the image train, image capture and processing, all of which differ considerably from a DSLR camera.  Notwithstanding, eventually first light (see image below) was achieved in March and it was immediately obvious that this was going to fulfil my astrophotography dreams and more for now – hopefully!

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Rosette Nebula in Ha | William Optics GT81 + ZWO ASI 1600MM-Cool & 0.80 focal reducer guided | 15 x 180 secs + darks & bias calibration Gain 300, Offset 10 | 21st March 2017

Using mostly narrowband filters – more on that later – I was initially able to obtain some exciting and very promising images of classic HII-region objects just before they disappeared over the western horizon; thereafter followed weeks of frustration whilst I waited for other suitable objects to appear – timing is everything.  The ZWO1600 camera is very good for most deep sky objects, nebulae, galaxies and globular clusters but with the William Optics GT81 the combination is best suited to larger targets.  As a result by late winter and early spring, when smaller objects such as galaxies dominate the night sky, it became necessary to find something else to do for the next few months.

Aurora Borealis Northern Norway February 2017 I’ve previously worked north of the Arctic Circle in Sweden and Russia but in February I took a more relaxed ferry trip along the west and north coast of Norway from Bergen to Kirkenes, close to the Russian border.  Given the time of year it was of course very cold and the nights long but the ship was comfortable and the scenery spectacular.  However, once north of Tromsø the real show began in the form of the Aurora Borealis AKA the Northern Lights.  This natural light show lived up to expectations and with some difficulty I managed to obtain numerous images of the spectacle – the problem being imaging from a moving ship in severe cold, which with wind chill was well below -20oC – but it was worth it and made for an exciting end to my winter astrophotography.

No Date Type* Object Name
1 20/01/17 DSLR M45 Pleiades
2 20/01/17 N NGC 2244 Rosette Nebula
3 22/01/17 DSLR M45 Pleiades
4 22/01/17 N IC 434 Horsehead & Flame Nebula
5 21/03/17 N NGC 2244 Rosette Nebula
6 21/03/17 B M65 Leo Triplet
7 24/03/17 B NGC 4874 Coma Cluster
8 25/03/17 N M42 Orion Nebula
9 27/03/17 N IC 434 Horsehead Nebula

Record of quarterly photographic images taken in 2017

*Type: DSLR colour, B Broadband LRGB, N Narrowband Ha-OIII-SII, V Video

APRIL TO JUNE

The period from April until the end of July can be a frustrating time of the year for astronomers, except those with an interest and the equipment for solar imaging.  Other than just giving up for a while, the secret is to abandon normal pursuits and just make the best of whats on offer, which is exactly what I did this year.  After limited success  attempting some of the larger galaxies in early Spring, I moved on to webcam imaging Jupiter and Saturn, insofar as is possible with my small telescope.  At about this time I also managed to capture the comet C/2015 V2 (Johnson), my second one after previously imaging C/2014 Q2 Comet Lovejoy in early 2015.  As I had not attempted such objects for more than two years and was more than a bit rusty with the different imaging and processing techniques, the results were varied but is was still good fun, which I hope to repeat in 2018 depending on what’s around at the time.

I also used the much improved weather and extra spare time afforded to go over the basics of my mount-telescope-computer set-up: balance, leads, equipment alignment, computer updates etc.  I inspected and replaced some old cables, wherever possible using cold-resistant silicon leads.  Following last year’s catastrophic camera power lead failure, I am now aware of the damage that cold can do to cables and pay greater attention in order to avoid repeating such problems.  I was also aware that with the change to the ZWO camera and using autoguiding routinely there had been a noticeable increase in cables, which I therefore tidied and strapped with Velcro bands to restrict unnecessary movement and snagging.

IMG_20170324_194502542 (Medium) The overall impact of these changes has transformed my working practices, making set-up and dismantling quicker, more efficient and more effective, itself a huge improvement.  In addition, I’ve also been able to move the mount and image capture controls indoors, which being more convenient and comfortable has made operating conditions and results much better.  Astrophotography inevitably becomes more complex and working in a warm environment with access to a cup of tea really does improve the outcome when working, in particular when resolving problems.  Given the significant benefits achieved from this housekeeping, in the future I intend to repeat this exercise each summer – it really pays off.

Veil SHO GxCcropHub

Eastern Veil Nebula in SHO – for Will| 21st June 2017

Notwithstanding these virtues, by June I was eager to start imaging again with the ZWO1600MM-Cool and with good weather and some very late nights I was able to obtain a few narrowband subs of the Eagle and North America nebulae.  To my surprise on the morning of 21st June I even briefly managed to image the Eastern Veil Nebula in narrowband; who would have thought imaging the Veil on the Summer Solstice?  Once again the results of just a few subs from the new camera continued to show great promise.

No Date Type* Object Name / Type
10 02/04/17 B NGC 2903 Galaxy
11 02/04/17 B M61 Galaxy
12 18/04/17 B NGC 4438 Markarian’s Chain
13 14/0517 V Jupiter Video Sequence
14 25/05/17 V Jupiter Video Sequence
15 26/05/17 DSLR Comet C/2015 V2
16 11/06/17 V Saturn Video Sequence
17 14/06/17 V Jupiter Video Sequence
18 19/06/16 N M20 Eagle Nebula
20 20/06/17 N NGC 7000 North America Nebula
21 21/06/17 N NGC 6992 Eastern Veil Nebula

JULY TO SEPTEMBER

After a taste of the ZWO1600MM-Cool at the start of the year and briefly around the Summer Solstice, the end of July finally brought the return of astronomical darkness, more suitable DSO targets and at last the opportunity to get serious with narrowband and broadband imaging.  Combined with some exceptionally good weather and clear skies this period was very productive and successful.  Without plate solving the maximum imaging time I can achieve at the moment is about two hours before or after the Meridian but using a high Gain of 300, 180 second exposures and autoguiding, for the first time I was able to get some very decent subs of various nebulae – now it was really getting exciting!

At the time of purchase I wavered between the ZWO EFW x5 filter or the soon to be released alternative x8 version and in the end waited for the larger version, together with the matched LRGB, Ha, OIII and SII filter bundle.  There were initial problems controlling the EFW and camera, inevitably resolved after some time with a new driver code but in the end the x8 EFW and camera have proved to be an excellent combination.  I have especially found narrowband imaging to be a revelation and when possible have so far mostly concentrated on this technique; its use when the Moon is about is an added and somewhat pleasing bonus.  The detail shown in Ha-subs can often be quite spectacular and for the best results I’ve discovered that more aggressive stretching is needed.

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To my surprise, I’ve so far found LRGB broadband imaging more difficult than expected, both to capture and in post-processing.  It’s apparent that Gain and Offset settings are more critical than narrowband, perhaps because such objects tend to be brighter, with more contrast and often greater complexity?  I had been looking forwards to imaging the Andromeda Galaxy in LRGB and as is often the case with M31, first thought that my subs were overblown.  However, after dialling down Gain, Offset and exposure time the alternative result was even more disappointing.  It was instructive that by returning to the original data and applying greater care during processing, I was able to tease a good image from the subs after all.

No Date Type* Object Name / Type
22 27/07/17 N M20 Trifid Nebula
23 31/07/17 N NGC 6960 Western Veil Nebula
        & Pickering’s Triangle
24 10/08/17 N IC 5070 Pelican Nebula
25 11/08/17 N IC 1318 SADR Region
26 11/08/17 N NGC 6888 Crescent Nebula
27 13/08/17 DSLR Perseids  
28 19/08/17 N NGC 6995/ NGC 6992 Eastern (Bat) Veil Nebula
29 20/08/17 B M15 Globular Cluster
30 27/08/17 N NGC 7000 North America Nebula
31 28/08/17 B M31 Andromeda Galaxy
32 28/08/17 B M33 Pinwheel Galaxy
33 15/09/17 DSLR Milky Way  

OCTOBER TO DECEMBER

From the experience of the new camera to-date I had arrived at two critical questions:

  • What are ‘right’ Gain and Offset settings?
  • What are the ‘best’ methods for LRGB imaging and post-processing?

Imaging during the final quarter then turned out to be something of a mixed bag trying to answer these questions.

I have a general feel about Gain, Offset and the related ADU values but if I’m honest despite reading around the subject I’m still mainly in the dark – no pun intended!  Such are the new challenges posed for all by the features of the ZWO1600MM-Cool it seems to me that even after 12 months the jury remains out over the answer to the first question – so it’s not just me!

The manufacturer provides value guidelines but based on experience, three schools of thought seem to have emerged from users:

  • Use Unity Gain 139 setting and vary exposure times – longer for nebulae, shorter for brighter objects such as M31;
  • Use low Gain for bright objects and higher Gain for faint objects + short and longer exposures, mindful of achieving a relevant ADU level across the resulting sub;
  • Use very high Gain and take lots and lots of short to moderate exposures.

I’m still experimenting with each of these techniques but increasingly lean towards higher Gain and varied exposure times of between 60” and 300”.  I have certainly found that lower Gain and short exposures didn’t work well for me when applied to the Andromeda Galaxy and California Nebula.

One issue when taking shorter exposures with the ZWO camera compared to a CCD is that many more subs are required, which inevitably needs very large storage and processing memory requirements – it’s a small price to pay for such quality and other advantages.  My laptop was already well specced for processing, with an Intel i7 64 bit chip 16GB RAM and to store the extra data I purchased a 4Tb external hard disc at a very reasonable cost = problem solved.

Picture saved with settings embedded.Like most people M42 has long been one of my favourites but like M31 I’m still struggling achieve a decent broadband image with the new camera and M45 is a similar problem; there’s nothing wrong with the camera, I just haven’t mastered the technique required yet.  However  narrowband images of M42, the Horsehead and Monkey Head nebulae all worked well at my standard default used of Gain 300 and Offset 10.

In preparation for further experimentation, at the beginning of  November I took time to compile a more comprehensive calibration library at various Gain, Offset and exposure settings.  Like most CCD cameras the new ZWO camera incorporates cooling to -45oC below ambient in order to reduce noise that is associated with all photoelectric sensors; I have been using the camera at a nominal temperature of -20oC.  By having such control it is therefore possible to obtain the aforementioned calibration frames irrespective of the ambient temperature and at any time.  Since June I’d already been successfully using another calibration set which has saved considerable time during each imaging session, unlike DSLR imaging which generally has to be undertaken at the same time + every time to ensure the same conditions.

Passing Shot: I’m posting Reflections later than usual this year having just returned from a protracted trip to New Zealand over the Christmas and New Year period.  The night sky down under was spectacular and I managed some good widefield imaging using a basic DSLR and tripod set-up; more on astronomy in New Zealand at a later date – Watch This Space Man! In the meantime below is a taster of the results taken whilst staying at my daughter and son-in-law’s house in Ohaupo, North Island.  Other than the beautiful Milky Way itself, note the Southern Cross just above the roof line and especially the large and Small Magellanic Clouds.

IMG_9984 (Large)

No Date Type Object Name / Type
34 12/10/17 B M31 Andromeda Galaxy
35 13/10/17 N NGC 1499 California Nebula
36 28/10/17 B NGC 2174 Monkey Head Nebula
37 28/10/17 B IC 434 Horsehead Nebula
38 30/10/17 B M45 Pleiades
39 30/10/17 B M42 Orion Nebula
40 01/11/17 N NGC 1499 California Nebula
41 13/11/17 DSLR Jupiter-Venus Conjunction
42 25/11/17 B NGC 1333 Reflection Nebula / Perseus
43 26/11/17 N NGC 2264 Cone Nebula

  ETCETERA

Once again my astronomy year was often shaped by other events and related matters.  Throughout the first quarter I completed an online MOOC course at Edinburgh University on the Higgs Boson and Particle Physics hosted by a wide variety of relevant experts, including no less than Peter Higgs himself.  It’s relevance to astronomy only came right at the end but was well worth waiting for.  Based on the theories of particle physics, the Higgs Boson, scalar fields and inflation, cosmologist Professor John Peacock ably demonstrated:

  • There was no Big Bang;
  • The existence of a multiverse – of which our Universe is but a part.

Intuitively I’ve long wondered about such possibilities and Professor Peacock’s lectures were by far the most convincing case I have seen for such a model.  Of course the implications of these conclusions are  profound and I’ve continued to think about this for the rest of the year.

As previously reviewed, for two weeks in February it was my good fortune to sail along the Norwegian coastline on the Richard With, flagship of the Hurtigruten ferry line.  At this time of the year it was very, very cold being mostly north of the Arctic Circle and the weather can be rough at times but overall the journey was outstanding.  Like most, my personal goal was to see and image the Aurora Borealis, which I was successful in doing on a number of evenings.  However, it’s got to be said that such imaging from a moving ship at -20C is both difficult and very uncomfortable.  Whilst I was pleased with the photographs, next time I’d prefer to be on land, where it should be so much easier.

Inspired both by the aforementioned trip and meeting a fellow geologist on board the Richard With who worked as a guest speaker on other cruises, I subsequently attended an audition to lecture myself on astrophotography.  Whilst my talk was successful and I was chosen to join the agency’s list of speakers, I have yet to be asked to join a cruise.

Favourite Images

With only a few exceptions, the outcome of my astrophotography in 2017 reflects the transition that took place from DSLR to the ZWO1600MM-Cool mono CMOS sensor camera.  The new camera has in every sense been a game changer and the resulting images have shown just how much colour and detail can be achieved in both broadband and especially narrowband.  Some of my personal favourites taken during the year are shown below, in no particular order:

Aurora Borealis-2 Northern Norway February 2017

LRGB1 GXCrop

NGC 2244 SHO Final1

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SHO Final

Eastern Veil Nebula detail in Bicolour 19th August 2017

Western Veil Nebula (Witch's Broom & Pickerings Triangle) in Ha-OIII Bicolour July 2017.jpg

MiIky Way Isle of Purbeck Dorset September 2017

M31 FINAL

CalCrop FINAL

SHO2 FINAL

Cygnus Wall BiCol FINAL

Above Images (from top-to-bottom): Aurora Borealis off Norwegian Coast – DSLR; Leo Triplet – LRGB; Rosette Nebula – SHO; Flame & Horsehead Nebulae – Ha; Eastern Veil Nebula – SHO; Eastern Veil Detail – Bi-Colour; Western Veil Nebula & Pickering Triangle – Bi-Colour; Milky Way from Isle of Purbeck, Dorset – DSLR; Andromeda Galaxy – LRGB; California Nebula – form left-to-right, Ha-SHO-Bi-Colour; North America Nebula – SHO; Cygnus Wall – Bi-Colour 

Round-up & goals for 2017

Since resolving a number of critical issues in 2016 and finally getting to grips with autoguiding, I’m pleased to say the basic processes worked very well in 2017.  In addition to improvements in the set-up, being able to operate from indoors has greatly improved both working conditions and the results.  Not surprisingly my astrophotography last year was dominated by learning and using the new camera.  Whilst the experience of DSLR imaging and related matters was helpful, I was surprised at just how different working with a mono camera, filters and especially processing has been by comparison and I’m still learning.  Some of the minutiae can be very important and are frustratingly easy to miss but, with the assistance of those ever helpful astronomers online and perseverance the results are really starting to show in my work.

RECORD CARD – 2017

 

Goal Specifics / Results Outcome
Improve processing After some set-backs now successfully processing FITS files in DSS and compiling broadband and narrowband images in Photoshop – all very different to DSLR RAW! Noticeable improvements using more complex techniques in PS.

  MUCH BETTER

 

Expand & Improve Widefield Imaging For the first time I obtained some decent images of the Milky Way but otherwise barely used the Vixen Polarie and did not make it to any other dark sky sites – disappointing.   FAILED

 

Start LRGB  imaging Now using the ZWO1600MM-Cool mono camera + EFW with LRGB & Ha- OIII- SII filters with good narrowband and varied broadband results.   GETTING           THERE

 

I think it helps to set some goals for the forthcoming year, so here goes:

  • Improve processing – more: Despite some noticeable improvements in 2017 there’s always more to learn whichever software is being used. I aspire to working with PixInsight or the newly acclaimed APP but will likely persevere with various more advanced Photoshop techniques.
  • Expand widefield imaging: First – use the Vixen Polarie as had been intended last year to obtain nightscape images at UK dark-site locations. Second – look at ways of using a widefield set-up with the mount.  Having previously failed I’m hoping to be more successful in 2018.
  • Improve broadband and narrowband imaging: In considering how to progress in 2016, I came to the conclusion that the next step should be a move to a mono camera rather than a larger telescope. This has turned out to be a great decision but it’s still early days.  There’s plenty more to learn and finesse but most of all after nearly a year’s learning and experimentation it’s clear that I need to improve one matter above all – increased integration time and this means learning plate solving.  I’ve been very happy using Astro Photography Tool (APT) for FITS image capture, scheduling and filter control (the APT Forum has been very helpful), but I also own the much praised Sequence Generator Pro (SGP) and might switch or at least give it a try in 2018.

I’m very pleased to say 2017 was a very good year for astrophotography, perhaps my best yet, which was especially defined by two positive developments:

  • In general the equipment set-up was much better after some long overdue changes and in particular operating from indoors, once all the basics are completed. With a good basic starting set-up and alignment of the guidescope-autoguiding camera with the main OTA, I’m often able to just quickly refresh EQASCOM alignment models directly from the computer = no more crawling around on the ground in the dark, or at least very little!
  • Although it’s still early days and despite my reservations over the complexity (which is true) of using a mono camera and filters, it’s revolutionised and revitalised my imaging and therefore proved very worthwhile. It is a lot of fun and the improvement of my images has been both exciting and very fulfilling.

You can’t ask for more than that and holds much promise for the coming year, which I hope to record in WTSM’s Reflections at the end of 2018.

Watch this space!

POSTSCRIPT

The ones that got away:  Imaged but not seen in WTSM this year (warts and all)

NGC 2174 281017

Pleiades 301017

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M15 Crop 200817

Above Images (from top-to-bottom): M42 Bi-Colour, Ha & SHO; Monkey Head Nebula Bi-Colour; Crescent Nebula SHO & Bi-Colour; Pleiades LRGB; Sadr Region Ha; M15 Globular Cluster LRGB    

Eastern Promise

SHO Final

Eastern Veil Nebula NGC 6992 & NGC 6995 in SHO narrowband*

The East traditionally evokes connotations of the exotic and a promise of excitement.  This year the late Summer delivered plenty such opportunity for astrophotography combined with long, warm and clear nights, making for a productive and very enjoyable time.  Furthermore, this being the first year I’ve owned the mono ZWO1600MM-Cool camera, I’m mostly revisiting objects previously imaged with a modded DSLR and as a result am discovering details of hidden interest and beauty within the new images; on this occasion the object of my desire was the Eastern Veil Nebula in the Cygnus constellation.

Desperate to start re-imaging suitable targets with the ZWO camera, I briefly flirted with the Eastern Veil on the morning of the summer solstice this year.  But with limited darkness of any sort and coming just before dawn, imaging time was very limited.  I was still pleased with the result which bode well for longer, darker night conditions with the potential for extended imaging time.  In June I was only able to capture 18 minutes of Ha and 9 minutes each of OII and SII wavelengths, compared this time with a whopping 30 minutes for each!  OK it’s still quite short and for a standard CCD camera might only amount to one or two subs but given the unique sensitivity of the ZWO1600 operating at -20oC – itself a game changer in so many ways – the additional integration time achieved resulted in much more detailed and dramatic images than before.

Bicolour FINAL

Eastern Veil Nebula in Ha-OIII BiColour*

For the moment I’m very pleased with the outcome but it’s obvious that greater imaging time holds the prospect of even better images – although such improvements are likely to be less dramatic and more incremental in nature.  Due to practical limitations at this site I’m limited to about 2-hours dedicated imaging time each side of the Meridian and will only be able to increase the integration time beyond this barrier by using plate solving, thus enabling meridian flips during a session or cumulative imaging of the same object over different nights.  With plenty to learn and enjoy with the ZWO1600 camera, plus Orion already reappearing over the eastern horizon – my personal favourite, this is unlikely to occur before next year.  In the meantime, the Eastern Veil points towards a very promising future – Watch This Space!

NGC 6992 Bicolour The Eastern Veil Nebula detail in Ha-OIII BiColour*

Bicolour FINAL BAT

The Bat Nebula IC 1340 detail in Ha-OIII Bicolour*

IMAGING DETAILS*
Object Eastern Veil Nebula   AKA Caldwell 33      NGC 6995, NGC 6992 & IC1340   
Constellation Cygnus
Distance 1,470 light-years
Size Approx. 80’  vs Total Veil Nebula 3o
Apparent Magnitude +7.0
Scope  William Optics GT81 + Focal Reducer FL 382mm  f4.72
Mount SW AZ-EQ6 GT + EQASCOM computer control
Guiding William Optics 50mm guide scope
+ Starlight Xpress Lodestar X2 guide camera & PHD2 control
Camera ZWO1600MM-Cool (mono)   CMOS sensor 
FOV 2.65o x 2.0o   Resolution 2.05″/pix  Max. image size 4,656 x 3,520 pix
EFW ZWOx8 & ZWO LRGB Ha OIII SII 7nm filters 
Capture & Processing Astro Photography Tool,  Deep Sky Stacker & Photoshop CS2
Exposures 10 x 180 sec Ha, OIII & SII  (Total time: 90 minutes)
@ 300 Gain 10 Offset @ -20oC  
Calibration 5 x 180 sec Darks 10 x 1/4000 sec Bias 10 x Flats Ha, OIII & SII  
Location Fairvale Observatory – Redhill – Surrey – UK
Date & Time 19th August 2017 @ 22.38h

 

Pelican Brief

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Located 3o west of the star Deneb in the Cygnus constellation, the North America Nebula is an emission nebula spanning some 50 light-years across, which contains numerous areas of astronomical interest that form some excellent imaging targets.  In the past I’ve usually concentrated on the ‘continent’ of North America itself but on this occasion moved my attention off the ‘east coast’ in search of the distinctive Pelican Nebula – it really does look like a pelican!

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North American Nebula (left) & Pelican Nebula | WO GT 81 & modded-Canon 550D | 2015

Separated from its neighbour by a molecular cloud of dark dust, the dominant HII region of the Pelican Nebula responds well to Ha imaging and I therefore sought to capture the ‘bird’ in this and other narrowband wavelengths.  Detail within the main cloud is further highlighted as a result of ionization from within created by young star formation, making for some pleasing and often spectacular effects.

Whilst image capture went well I was concerned by the outcome of stretching the Ha-image after stacking; the stacked image in DSS looked bright and detailed but after using Levels in Photoshop to establish the dark and light points the resulting image was somewhat dull in appearance and without the finer detail I had previously seen in DSS.  Responses to a question on the SGL Forum post made it clear that I needed to be bolder when stretching in order to achieve the desired result; I am further persuaded that I’ve been too timid with such processing techniques in the past and may need to revisit and reprocess some older data when time permits.

Pelican Images 10th August 2017 in order below:  

Ha – Bicolour – SHO narrowband

WO GT81 & ZWO1600MM-Cool + x0.80 focal reducer | 180 sec Gain 300 Offset 10 @ -20C 

10xHa + 10xOIII + 5x SII + full calibration    

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I went on to process the full narrowband data in both SHO and Bicolour, with interesting results.  The aforementioned assessment of linear stretching resulted in a much improved Ha-image, which subsequently impacted positively on the final compiled image.  However, there’s still much to consider when processing the combined channels, in particular in narrowband.

Some aspects of manipulation used during processing can have a material impact on the final image and I’ve long been concerned whether the resulting astrophotography presents a factual representation – in the case of narrowband the answer must surely be no.  Depending on the quality of data capture, detail and structure will usually be accurately recorded but subsequent ‘playing’ with the colour channels is most likely to produce a final image that is pleasing aesthetically to the photographer rather than factual; in the case of narrowband the colours available will be correctly determined by the respective filter wavelengths but there is no definitive measure of what actual colour should be in the final image.

RGB2crop (Large)In this case the Ha-image of The Pelican that was obtained demonstrated the significant improvements that can be achieved with the CMOS based ZWO1600MM-Cool camera compared to a DSLR.  I’m still learning about processing and in particular, with the plethora of options available when using LRGB and narrowband subs the issues have now escalated exponentially.  Notwithstanding the aforementioned issues I’m very pleased with my ‘new’ bird The Pelican Nebula.

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The Dutch Gadget

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I have just finished reading J.L. Heilbron’s biographical tome on Galileo, which though very interesting I found a difficult book and somewhat academic in style.  In 1609 Galileo became aware of a Dutch spectacle maker’s device that made distant objects appear closer.  He subsequently became known for developing the so-called ‘Dutch Gadget’ into what we now know as the refracting telescope and moreover, applying its use to understanding the Solar System with the discovery of Jupiter’s four largest moons, confirmation of the phases of Venus and the observation and analysis of sunspots; the word telescope was subsequently coined in 1611 from the Greek tele “far” and skopein “to look or see” i.e. far-seeing.  In so doing he also helped to confirm the then controversial truth of the heliocentric astronomical model, whereby the Earth and planets orbit the Sun.  Against this background it is no surprise that Galileo is today much revered by mankind and has become known as the father of observational astronomy.

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Drawn into the complexity of obtaining images of the Solar System and beyond, it is the curse of astrophotography that we inevitably neglect observing the spectacle itself.  Notwithstanding, I am sure that Galileo would understand the power and beauty of today’s astrophotography, which in its own way is producing a quantum leap in our understanding of the Universe comparable to the impact of the original application of the telescope.

This summer the Solar System will hopefully provide both good observational and astrophotography opportunities here at Fairvale Observatory: Jupiter, Saturn, Comet C/2015 V2 (Johnson), the Perseids meteor shower and the Sun – sadly though I will not witness next month’s solar eclipse which takes place mainly over North America.  During recent summer months the lack of astronomical darkness, short nights and absence of DSOs has frustratingly continued to limit potential imaging targets for my new ZWO 1600MM-Cool camera but utilising a period of good weather there have recently been a few fleeting opportunities just before dawn related to the appearance of the summer arm of the Milky Way on the eastern horizon.

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NGC 7000 The North America & Pelican Nebulae WO GT81 + modded Canon EOS 550D + FF | 30 x 120 secs @ ISO 1,600 + calibration | 19th September 2015

I first imaged the North America Nebula (NGC 7000) in 2014 and have since returned each year to image the nebula or its various parts using a DSLR camera.  Being a very large Ha-object the nebula is an ideal target for the ZWO1600MM-cool camera and I have been anxiously waiting its arrival again this year.  On this occasion, early on the morning of the summer solstice, high in the sky and 90o east the nebula was only just visible from my location, being very close to the roof-edge of my house!  Consisting of just six Ha-frames plus three OIII and SII taken just before dawn broke, the resulting image was never going to be my best but is nonetheless interesting in SHO format and quite different to previous DSLR images.

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North America Nebula in Ha-OIII Bicolour

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North America Nebula in SHO

At the other extreme, located low on the southern horizon and only briefly visible as it passed between the trees at the end of my garden is the Eagle Nebula AKA M16, home of the Pillars of Creation.  At 7-arcminutes in size and an apparent magnitude of +6.0, the nebula is at the lower end of possible for my set-up and at some 27o altitude with just 40-minutes imaging time between the trees it was a challenging target.  Notwithstanding, I’m pleased with the Ha and SHO narrowband images obtained, which quite clearly show the Pillars too.

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M16 Eagel Nebula in SHO: William Optics GT81 & ZWO1600MM- Cool & Field Flattener | 6 x 180sec Ha, x3 OIII, x3 SII Gain 300 Offset 10 + full calibration | 21st June 2017

As astronomical darkness is now slowly returning and with clear skies and weather permitting, I hope to attempt longer imaging sessions of both these and other targets during the rest if the summer and into autumn – I might even get to see M16 again as it eventually emerges from the other side of the trees!  Thanks to the development of the Dutch Gadget and modern cameras it is now possible for amateur astronomers to image such spectacular objects – I’m sure Galileo would be impressed and highly approve.

Brave New World

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In my quest to understand astronomy and in particular the big picture, I have just successfully completed another MOOC course at the University of Edinburgh on the Higgs Boson and particle physics.  From earlier studies which included the Special Theory of Relativity and the Universe, the next step was obvious: moving from the very big to the very small in order to better grasp where we might be with the elusive unified theory and I was not disappointed. An added bonus to the course was the participation of Professor Peter Higgs himself, in which he discussed how he had arrived at his conclusions and the development of subsequent matters that led to the actual discovery of the Higgs Boson at the Large Hadron Collider in Cern, Switzerland in 2012; watching and listening to him speak felt like having a personal chat with Einstein and was quite a privilege!

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A chat with Professor Peter Higgs!

Frankly I found the nature of the subject very difficult and at times bewildering but its potential impact on astronomy was finally something of an epiphany for me.  The Higgs and related items results in two profound results:

  • There was no Big Bang.
  • The existence of a multiverse, of which our Universe is but a part.

I am not sufficiently able to articulate how these conclusions are arrived at nor is this the place, but when the full content of particle theory, the Higgs, General Relativity are applied to cosmology, the aforementioned outcome is, like all good science, simple and beautiful – click here for lecture notes Higgsmooc part1  + Higgsmooc part2  and accompanying presentations 7.11_Quantum Vacuum_& Cosmology + 7.12_The HB_scalarfieldsand inflation.

I’m pleased to say there have also been other breakthroughs for me since achieving first light with the ZWO 1600MM-Cool CMOS camera.  I am still at the experimental stage and with the spectacle of the winter sky rapidly departing, suitable objects are much more limited, with the few remaining HII objects low and very far to the west of the early evening sky.  However, before the Milky Way disappeared completely I managed to obtain some useful imaging experience by targeting some old favourites.

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Passing Shots: Orion & Rosette Nebulae

Having already battled a number of issues with the new camera – basic LRGB image capture, using Astro Astronomy Tools, achieving focus, guiding, alignment, processing and post-processing – for the moment everything has come together, including some warmer nights and clear skies.  Over a few evenings I therefore undertook imaging in LRGB as well as Ha, OIII and SII, with some excellent results that augur well for the future.

The camera’s sensitivity and ability to image at short exposures enables much less imaging time than conventionally used with CCD cameras – one of the reasons I decided to purchase this camera.  In addition, shorter exposures make perfect alignment and tracking less important, though still a desirable set-up.  The downside is it produces a prodigious number of images, which leads to a somewhat challenging processing burden – but it’s worth it.

Despite my DSLR experience, CCD processing and especially post-processing, is significantly more complex.  I was surprised to find only one decent online video on LRGB processing by Rankin Studio, without which the task would have been even more difficult and taken much longer to learn – thanks David.  Ironically I have found narrowband processing easier, probably because there are just less filters and resulting image sets required, however, the restricted wavelength also provides whole new opportunities that I’ve already started to exploit.

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Orion Nebula + M43 & Running Man Nebulae in Ha: William Optics GT 81 & ZWO 1600MM-Cool + x0.80 field flattener | 15 x 180sec Gain 139 Offset 21 @ -18C & full calibration | 25th March 2017

Just before they disappear from our night sky until next winter I was fortunate to be able to image both the Horsehead and Orion nebulae, everyone’s favourites and I’m no exception.  With limited time available in the early evening sky it was only possible to capture a limited number of images before it moved outside my view in the west but even with these few images the power of the camera has already become self-evident.

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Horsehead Nebula in Ha: William Optics GT81 & ZWO 1600MM-Cool + x0.80 field flattener | 19 x 180 secs Gain 139 Offset 21 @ -18C & full calibration | 27th March 2017

Given the need to use less filters and thus less time I have started out with narrowband imaging – as a completely new medium for me that holds great promise aesthetically and scientifically, I was also keen to give it a try and on this occasion used Ha and OIII.  Having sorted an earlier problem with the EFW managing the filters is a breeze and can easily be automatically sequenced in the APT capture software.  Notwithstanding, as previously indicated image capture is really only just the start – though good data is always the key to the final image – and processing and post-processing is both complex and takes considerable time.

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Orion Nebula in bi-colour: Ha red channel + OIII green and blue channels

On this occasion the individual Ha subs are themselves very revealing, showing new details when compared with previous DSLR images.  But it is with the bi-colour image that the exciting opportunities provided by using narrowband imaging become apparent – I can see I’m going to enjoy this!  I’ve also taken the opportunity to further explore and understand the nature of these types of images and their constituent parts by manipulating the colour channels, with some startling results.

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Rosette Nebula in HOS: William Optics GT 81 & ZWO 1600MM-Cool + x0.80 Field Flattener | 15 x 180 sec Gain 300 Offset 10 Ha, OIII & SII @ -20C + calibration | 24th March 2017

Not far from M42 is another of my favourites which I’d already used to achieve First Light with this camera using Ha – the Rosette Nebula (NGC 2237, 2238, 2239, 2244 & 2246).  This time I decided to use all the narrowband filters – Ha 656nm, OIII 672nm, SII 500nm all 7nm bandpass – and subsequently experimented with processing using the Hubble Palette with stunning results.  As the name indicates, this technique was originally developed for processing images taken with the Hubble Space Telescope which put simply, uses different mixes of each narrowband filter in different processing channels e.g. Ha in the red channel, OII in green and SII in blue, for short known as HSO.

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Rosette Nebula in  SHO

The outcome of my new adventure into narrowband imaging has been nothing less than a revelation.  Like so much of my preceding astroimaging, I knew about much of it before but doing it yourself and seeing the results is both exciting and very satisfying; like Peter Higgs I feel I have entered a new world!

First Light

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If nothing else, I have learned from life – walk before you run.  I have spent the past three years trying to learn about astronomy and astrophotography using a DSLR but late last year decided it was time to raise my game.  I was reluctant to go to a CCD mono camera as it involves greater complexity and, perhaps more significantly, during the aforesaid period clear skies have been in very short supply – making long, guided exposures over protracted periods something close to impossible where I live.  However, with the recent advent of the new CMOS cameras and their rave reviews, against my better judgement I took the plunge and bought a ZWO ASI 1600MM-Cool with a matching ZWO x8 EFW and 31mm LRGB, Ha, OIII and SII filter set.

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Wow! As expected, it’s a whole new world compared to DSLR and, as well as continuing week-after-week cloud cover, I have been battling with numerous set-up and processing issues. Still, rule number one with this hobby is patience and perseverance and I’m pleased to say I have just achieved First Light with the camera.

At first I set up the camera indoors on a tripod to test the equipment and quickly found that the camera and EFW would not work together; in addition to a USB 3.0 data socket, the camera also has two useful USB 2.0 sockets which can be used to power and control other equipment.  After more than 3-weeks, much help online and a mixed response from the manufacturer, ZWO suggested I try another USB driver which they sent me and it worked – so why not supply that in the first place or ensure users are aware of the issue and provide a solution from the outset?  Whilst the actual equipment is well specced, well made and well priced compared to CCD camera – though far from cheap, I found ZWO’s web-based technical guidance and general support poor and would expect better with such expensive equipment.  In retrospect, perhaps it is not a surprise as I had a USB problem when I purchased their ZWO ASI 120MC camera, with a similar response and outcome i.e. there is a theme here, which is a pity as their equipment itself is innovative and very well made.

During brief periods between the clouds I subsequently managed to try-out the camera in order to understand focus, capture and processing. Despite prior experience with the DSLR and software, this turned out to be new territory which I am still exploring. Briefly:

Focus – With the new camera I was faced with two fundamental focusing issues:

  • Establishing the correct optical train – I want to continue using the William Optics x0.80 focal reducer with the ZWO camera, thereby increasing the speed of the scope from f5.9 to f4.72. I therefore purchased a Canon EOS adapter to use with the existing EOS convertor which has previously worked successfully with the DSLR.  Despite the apparent complexity, the resulting set-up is within 0.50mm of the optimum distance and seems to work OK – with one exception. Whilst the locking pin on the EOS adapter works i.e. it locks, there is some unacceptable lateral play, which for now I have solved with the addition of a piece of electrical tape! I’m advised this is normal for such adapters but it seems like a poor product to me if this is the case.    ZWO cam_EFW_FF_annotated (Large)
  • Operating focus – after months of battling with focus when I started out DSLR imaging, I eventually discovered the Bahtinov mask and assumed this wonderfully simple method would work just as well with the new ZWO camera; of course, after my initial trials it was apparent this wasn’t going to be the case.  Not that the mask doesn’t work but in order to achieve good focus with the smaller pixels of the ZWO ASI 1600 requires much greater accuracy, which I’m pleased to say has now been achieved by using APT’s Bahtinov Aid (based on Neils Noordhoek’s Bahtinov Grabber), so that I am now getting much better results.  However, as the focus point can change with seeing conditions and when using different filters, it is apparent that I’ll need to return to this matter again to finesse the operation, probably by using an electronic focuser.

Capture – At the heart of my philosophy is the KISS principal – Keep It Simple Stupid! When working with the DSLR I therefore only ever used the Canon EOS Utilities software for image capture – it is simple, did what I needed and worked.  Moving to a mono camera with filters, the increase in complexity is exponential and inevitably requires more sophisticated image capture software.  Judging by the experience of others Sequence Generator Pro seems to be one of the best low cost programmes that will do this job and I have purchased a copy for US$99 and the accompanying Framing and Mosaic Wizard for an additional US$39.  However, in applying the KISS principal during the early stages of getting to know and understand the new equipment and processes, for now I’m using Astro Photography Tool (APT) – something I’ve had for a while but not used before.  It is a very capable programme that manages sequencing, cooling, filter management etc. well, with excellent support from its author Ivo but importantly seems easier to use than SGP, albeit inevitably with its own idiosyncrasies.  It’s early days but so far so good.

Processing – Mono images differ in a number of fundamental ways to DSLR other than just colour, which requires a quite different approach to processing and post-processing, in particular:

  • the images are FITS not RAW;
  • mono images are taken with a variety of filters which subsequently need to be compiled.

Despite successfully working with Deep Sky Stacker (DSS) for some time, I was not aware of any changes required when processing FITS files, which are the product of the ZWO 1600 camera; useful pre-assessment of the files can be carried out using the ESA/NASA free Fits Liberator software.  As a result my first try of the Beehive Nebula based on just Luminance subs was covered in bizarre ‘green spider-like’ artefacts after stacking in DSS.  These disappeared when transferred into Photoshop but then became covered in Bayer matrix-like coloured squares!

Thanks to help from the SGL Forum it was apparent that I had failed to turn-off the FITS colour option in Settings before stacking – unchecking this and restacking immediately resulted in a half-decent image of the open star cluster.  Meanwhile, since purchasing the ZWO camera I have read and watched numerous videos on post-processing and using LRGB files available online for practice, I have been able to start experimenting with this technique prior to obtaining my own data from the new camera.  It is much more complex and I’ve got a long way to go but the experience gained from DSLR processing has nevertheless helped immensely; walk before you run pays off in the end!

And so last week I managed my first reasonable image of the Rosette Nebula (NGC 2244) using only Ha-subs, which this object has in abundance.  I consider this marks the camera’s First Light and am pleased with the result but realise there’s still much more to learn, weather permitting!

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Rosette Nebula in Ha | William Optics GT81 + ZWO ASI 1600MM-Cool & x0.80 focal reducer + guided | 15 x 180 secs + darks & bias calibration Gain 300, Offset 10 | 21st March 2017

  • This guided image is 15 x 180sec Ha-subs + darks and bias, gain 300, offset 10 + minor stretching in Photoshop. The corners – particularly the bottom right – look like there may be some vignetting in the stacked image?  I haven’t managed to achieve any decent flats yet (another story) but I assume these would help eliminate this effect? However, I am surprised as I’m using the ZWO x8 EFW with larger 31mm filters, which with the focal length of 382mm (f4.72) should not result in vignetting.
  • Clearly my experimentation is ongoing with this new technology and I particularly need to understand better what is the ‘best’ gain and offset setting for different types of objects.
  • Whilst the CMOS chip is bigger than standard CCD sensors it is still smaller than a standard DSLR and with smaller pixels too (3.80nm v 4.30nm), the result when used with the focal reducer is a 29% reduction of the field-of view from 3.34o x 2.23o to 2.65o x 2.0o, which on-screen translates to increased magnification and allows me to get at some of the galaxies which hitherto have been too small; the benefit is minor but is worth having nonetheless.

 

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From Cloudy Nights Forum – compiled by Jon Rista

All-in-all the ZWO ASI 1600mm-Cool is an excellent piece of kit that has the potential to open up new vistas for my astroimaging.  At a fundamental level it does all the basic stuff very well and the addition of cooling is a major improvement which  reduces noise still further.  I’m particularly looking forwards to experimenting with narrowband and bi-colour imaging – not least in order to keep working when the Moon’s about, unlike broadband imaging.  However, the cameras intrinsically low read noise and ability to capture fine detail using only short exposures is surely set to mark the next revolution in astrophotography and furthermore reduces the need for very precise guiding; it’s clear the other manufacturers are scrambling to catch-up with this leading edge technology.  Timing is everything in life and I’m pleased to be part of this hobby at such an exciting moment.

Arctic Antics

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The globe pictured above on the island of Vikingen marks the location of the Arctic Circle off the western Norwegian coast.  However, surprisingly the position of the Arctic Circle is not fixed – as of 28 February 2017 it was 66°33′46.6″ north of the Equator but changes depending on the Earth’s axial tilt, which itself varies within 2° over a 40,000-year period due to differing tidal forces that occur as the Moon’s  orbit changes around Earth.  The region north of the Arctic Circle is famous for the midnight sun in the summer and its corresponding 24-hour darkness during the winter months, with major implications for life itself, as well as contrasting scenery and photographic conditions unique to this hostile region.

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During the last two weeks of February, when the return of limited daylight has just begun to mark the end of winter, I travelled by ship along the entire western and northern coast of Norway close to the Russian border, spending much of the time within the Arctic Circle.  The area is famous for its beautiful scenery, in particular the fjords which typify the coastline and for time immemorial have posed a significant challenge to all seafarers passing this way.

Our ship, the Richard With, was named after the Norwegian captain who in 1893 pioneered this difficult sea passage which we took from Bergen to Kirkenes and back.  Today a fleet of 12 ships are operated by the original Norwegian company Hurtigruten on a daily basis providing ferry transport for goods, vehicles and personnel, as well as a base for tourists seeking a view of the Northern Lights – in all the ship stops at over 30 ports in each direction.

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Apart from the scenery, during the winter months the area north of the Arctic Circle is probably best known for the occurrence of the Aurora Borealis or Northern Lights (Norwegian – Nord Lys).  A view of this feature is treasured by all who see them but for astrophotographers it will be one of their ‘must do’ images to acquire.  The Aurora is caused by a solar wind originating from the Sun that consists of charged particles, which when drawn downwards at the Earth’s poles by the planet’s magnetosphere ‘excites’ atmospheric atoms which produce different coloured lights depending on the type of gas which is excited by the charged particles; a similar feature occurs around the South Pole called the Aurora Australis and is also now known to occur on Saturn and Jupiter.  The lights are mostly green in colour (ʎ 557.7 nm), sometimes red (ʎ 630 nm) or blue (428 ʎ nm) and less commonly pink, ultraviolet or yellow, depending on the altitude and type of excited gas – which is mostly either oxygen or nitrogen.  The resulting aurora takes the form of rapidly moving clouds or often curtains of light that dart across the night sky, constantly changing shape under the influence of the Earth’s magnetic field and does not disappoint when seen.

The Northern Lights are best imaged with a standard DSLR camera on a sturdy tripod, using a wide angle lens at full aperture, set at between ISO 800 to 1,600 and exposures of about 8 secs to 25 secs, depending on the brightness and quality of the light and the speed of movement of the aurora; focus and all other control needs to be operated manually for best results.  On land a tracking mount, such as a Vixen Polarie, could be used to improve sharpness but on a moving ship set-up and technique is a more difficult.

In this case exposure needs to be carefully balanced in order to account for the ships movement – forwards + up-and-down on the water – and the quality of the aurora light.  As exposures will always need to be greater than a few seconds, star trails are unavoidable and have to be dealt with in post processing as best as possible. I found imaging directly forwards or to the rear of the ship helped minimise this effect but still trails were still inevitable. Experimenting with various settings I found about 12 to 15 seconds exposure and ISO 1,600 generally worked quite well but varied depending on the sea conditions and nature of the aurora at any time.

At such high latitudes it is still very cold in February and warm head-to-feet-to-hands clothing is absolutely essential.  On this occasion, together with wind chill the temperature at the ships bow ranged from between -20oC to -30oC (that’s a minus sign!), making camera control very difficult and uncomfortable!  I tried using an intervalometer for remote shooting but as settings have to be changed frequently by hand it was not very practical; I’m sure on land it would prove much more helpful.  Furthermore, much of the time I had to hold the tripod down with some force as the wind was very severe.

Notwithstanding, I’m very pleased with the results shown below and would love to return again one day, perhaps in the summer – it is a truly different and very special part of the world – hat’s off to Richard With and all those who still sail these waters.

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Photons & Photography

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I’ve been interested in photography from a young age.  As I child I played with my parent’s Kodak box camera and, as far as I can remember, my first camera was a Kodak Brownie at the age of about nine. It’s a wonderful medium that I have now experienced for over 50-years, on land, underwater and now for astrophotography.

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My cameras

I’d like to think I know a thing or two about photography by now; underwater photography and digital astrophotography have been particularly challenging in different ways but the latter is a real eye opener that has expanded my knowledge of digital imaging significantly.  Capturing images of distant objects that can only be seen with the use of sophisticated equipment and complex processing also requires an in-depth understanding of light itself.

Having spent the first half of this year reading Einstein’s biography, I have recently started an online course at Stanford University on his ground-breaking Special Theory of Relativity.  Einstein’s many insights into the physical world are profound, which more than 100-years on still challenge most of us to understand.  Light was at the core of his famous 1905 paper, in particular it’s duality as a waveform and light quanta, or photons – defined as a quantum of electromagnetic radiation.  His concept of the photoelectric effect has enabled the development of today’s digital camera sensors and CCDs.  The core principal is the production of electrons as light shines onto a material, whereby the light (photon) knocks out an electron which can then be collected electronically – the basis of digital photography.

In September I visited Lacock Abbey in Wiltshire, initially a 13th century nunnery which is now run by the National Trust.  Today it is better known as the home of William Henry Fox Talbot (1800 – 1877) – mathematician, astronomer and archaeologist but most famously the inventor and pioneer of photography, notably developing, fixing and printing.  The window photograph below (left) was taken at Lacock Abbey in August 1835 and is recognised as being from the oldest ever camera negative produced by Fox Talbot, on the right is the same window in 2016.

In the early 19th century Thomas Wedgwood had made photograms – silhouettes of leaves and other objects – but these faded quickly. In 1827, Joseph Nicéphore de Niepce produced pictures on bitumen, and in January 1839, Louis Daguerre displayed his ‘Daguerreotypes’ – pictures on silver plates – to the French Academy of Sciences. Three weeks later, Fox Talbot reported his ‘art of photogenic drawing’ to the Royal Society, which subsequently became the de facto basis of modern film photography.

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Fox Talbot’s desk in his study at Lacock Abbey

Fox Talbot lived and worked at the Abbey for most of his life.  As well as an excellent museum, which details the history of photography and photographic processes, the house contains his rooms where he developed (no pun intended) the aforementioned inventions and is surely a ‘must do’ visit for any keen photographer.  Like many at that time he was a polymath, with notable friends and accomplices who worked in similar and other scientific fields:

Sir John Herschel – astronomer, mathematician, botanist & chemist, Gold Medal winner and founder of the Royal Astronomical Society, son of William Herschel who discovered Uranus.

Charles Babbage – mathematician, philosopher, mechanical engineer, considered “the father of the computer”;

William Whewell – leading 19th century scientist, recognised in the fields of architecture, mechanics, mineralogy, moral philosophy, astronomy, political economy, and the philosophy of science;

Sir Charles Wheatstone – physicist, inventor of stereoscopic photography, the telegraph & accordion;

Sir David Brewster – physicist specialising in optics, mathematician, astronomer & inventor of optical mineralogy and the kaleidoscope;

Peter Roget – physician, theologian, lexicographer and publisher of Roget’s Thesarus.

This particular group are now remembered by a table setting in the Abbey’s dining room, where they gathered for dinner; the mind boggles at the conversation!

Fox Talbot’s pioneering photography work preceded the early 20th century understanding of light that arose from Einstein and its more recent application in semi-conductors as camera sensors, of which I am sure he would have approved.  At that time the Universe outside of our galaxy was also unknown and he would have marvelled further at the thought of imaging other such distant galaxies such as M33 below; like photons, photography has come a long way since his death in 1877.

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M33 Triangulum Galaxy – consisting of some 40-billion stars, the photons in this image have travelled 3-million light years to reach my camera’s sensor! | WO GT81 + modded Canon EOS 550D & FF guided | 18 x 300 secs @ ISO 800 & full calibration | 22nd October 2016

It’s All Relative

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I spent the first half of this year reading Walter Isaacson’s biography of Albert Einstein, which apart from providing a fascinating insight into the man and his work, whetted my appetite to understand better the science.  Following previous success studying astronomy courses online, I set out to find a suitable programme to achieve this goal.  As a result I enrolled for Understanding Einstein: the Special Theory of Relativity run by Professor Larry Lagerstrom of Stanford University, USA, which after two months I have just completed.spacetime

The course is a good mix of qualitative and quantitative information, which at times has been quite challenging but nonetheless proved very worthwhile. The lecturer is very clear and thorough, an essential quality when dealing with this difficult and often bewildering subject.  Einstein’s paper On the Electrodynamics of Moving Bodies outlines the Special Theory and was just one of four published at about the same time in 1905 (“The Miracle Year”) which included: Brownian motion, Mass-energy equivalence (E=Mc2) and The Photoelectric Effect, the latter of which won him the Noble Prize.  At the end I now feel I understand the basics of Einstein’s ground breaking science properly, which apart from being interesting provides valuable insight and understanding of the Universe and related issues of space and time.

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During this period I have also been thinking about how to improve my astrophotography and the way forwards.  I’ll be on the learning curve for years to come and accept that there’s much I can still improve on using current equipment and processes but after more than 2-years astroimaging, mostly with a DSLR camera, I feel I have reached something of a crossroads and need to change tack in order to achieve more meaningful advances once again.  Inevitably this is likely to mean new equipment and most likely a move to LRGB / Narrowband format.  In the interim, whilst I consider the options, I have also been researching suitable capture / sequencing software, post-processing techniques and programmes.  I am concerned that this will result in another level of complexity but I think it has to be done in order to progress – watch this space.

Continuing a trend that’s been apparent for the past year, clear nights have been something of a rarity since mid-September; this is a concern if I am to pursue astrophotography to the next level.  However, high pressure was unusually dominant over Fairvale Observatory during the last days of November and cold, clear skies have provided good conditions for astronomy at last.

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Getting better – PHD2 screen 30th November 2016: DEC is good but room for improvement with the RA settings. The impact on tracking and image quality is noticeable.

Whilst I have certainly not fully mastered guiding I am now routinely using PHD2.  This in itself has probably been the major breakthrough this year, which with the aforementioned clear skies I wanted to take full advantage of.  Hidden within PHD2 I have also discovered and am now starting to experiment with the on-screen drift align routine, with reasonable results; using the gamepad for mount control and a new wireless link with my tablet computer, I can also make focus and alignment adjustments at the mount without returning to the computer each time.

As a result I have dispersed with the SynScan handset for alignment and can now completely set-up and control imaging with the computer and tablet; this is nothing short of a revolution which I am hopeful will greatly increase set-up time as well as improving control and tracking accuracy – yipee!  Even with average guiding results I am now achieving good exposures of 5-minutes or more and therefore decided to put this success to work and re-image some winter wonders over three, yes three, consecutive nights at the end of November.

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Imaging targets between 28th & 30th of November 2016 – for descriptions & previous images taken of these objects click on the following list of names: (1) M45 Pleiades (2) Barnard 33 The Horsehead Nebula & NGC 2024 Flame Nebula (3) M42 Orion Nebula (4) NGC 2244 Rosette Nebula (5) NGC 1499 California Nebula (6) IC 405 Flaming Star Nebula

The night sky at this time of the year contains many of my favourite objects, but surprisingly I had not imaged some of the chosen targets for more than a year or two and it was both enjoyable and pleasing to reacquaint myself again.  With a new perspective gained from this exercise, the progress I have made with equipment and techniques is more apparent.  Notwithstanding, it’s time to move on – everything’s relative.

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M45 Pleiades, Taurus constellation: 12 x 300 sec @ ISO 800 | 28th November 2016

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NGC 2014 Flame Nebula & Barnard 33 Horsehead Nebula, Orion constellation: 15 x 300 sec @ ISO 800 | 28th November 2016

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M42 Orion Nebula & M43 De Mairan’s Nebula, Orion constellation: 2 x 300 sec @ ISO 800 | 28th November 2016

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NGC 2244 Rosette Nebula, Perseus arm of Milky Way, Monoceros region: 21 x 300 sec @ ISO 800 | 29th November 2016

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California Nebula, Perseus constellation: 12 x 300 sec @ ISO 800 | 30th November 2016

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IC 405 & 410 nebulae: 15 x 300 @ ISO 800 | 30th November 2016

Notes: all images taken using a William Optics GT81 refractor telescope + PHD2 guiding + modded Canon 550D DSLR & x0.80 field flattner @ ISO 800 with full darks + bias + flats calibration and processed in Deep Sky Stacker & Photoshop CS2