With the summer arm of the Milky Way now starting to dominate the late evening sky I’m slowly returning to imaging DSO objects, this time literally in a new light using the ZWO1600MM-Cool camera. Because of the inclined orientation of the Milky Way it is the lower altitude objects that first become accessible, which is unfortunate as seeing conditions will generally always be poor at these levels.
However, the problem is compounded here at Fairvale Observatory by high hedges and numerous large trees that obscure much of the southern horizon below about 28o and in this case also severely restricting imaging time. It’s a real pity as the constellation Sagittarius that is located in this region of the sky abounds with some wonderful objects.
On this occasion my primary target was M20, the Trifid Nebula (NGC 6514). At some 28” size and an apparent magnitude of +6.3 it is just feasible with my equipment, so long as I could overcome the obstructions along the southern horizon! Located 5,000 light-years from Earth in the Scutum spiral arm of the Milky Way, at about 300,000 years old M20 is one of the youngest star forming regions in the sky. The feature is a combination of open star clusters, emission nebula and reflection nebula separated by dark dust lanes, that together form three lobes i.e. Trifid. As a stellar nursery, close to the centre the most massive star is twenty times the size of the Sun surrounded by a cluster of 3,100 young stars.
Despite the limited imaging time available and other difficulties, I’m pleased with the resulting images, which have been processed in SHO and Ha-OIII bicolour. Furthermore, just evident along the left side of the main image is the western edge of the much larger Lagoon Nebula or M8; unfortunately being even lower in the sky I don’t think I’ll ever be able to image M8 from this location.
Together with the recent success of the Eagle Nebula and Eastern Veil, things are shaping up well for astrophotography once again as the Milky Way and other features pass across the night sky over the coming increasingly dark weeks. I’m certain to return to M20 again as it’s a wonderful object, hopefully from a better vantage point next time that will allow imaging of some of its neighbours. I have long been aware of M20 and in my ignorance was going to call this blog Gardener’s World but now realise that it is the Trifid not Triffid nebula!