Sh2-157 "Lobster Claw Nebula" (Cassiopeia), Sept 2023
Askar 151phq; AP Mach2 GTO
ASI6200MM, - Baader RGB & 6.5nm NB CMOS opt. filters
H,O,S: (68,78,73 x 330s, Bin 1, Gain 200)
R,G,B: (37,37,34 x 90s Bin 1, Gain 200)
Total integration time = 22.8 hrs
Just about everyone knows the Lobster Claw Nebula as the bright emissions that are close to the Bubble Nebula. I have always been drawn to this nebula as it has strong narrowband emissions in S+ and O+2 as well as Ha – resulting in a very colourful photographic subject. The shape of the nebula is a result of stellar winds from some local you giant stars. The blue and red “claw” is formed from an elliptical feature, one half of which is dominated by the brighter yellow colour resulting from more dominant Ha on the image right hand side.
Other interesting items include a very bright emission at the root of the lower pincer, likely powered by an newborn star, a dim planetary nebula marking the death of another star, and catalogued open star clusters, including NGC7510.
This was my first successful attempt at using the new Narrowband Colour Mapper (NBColourMapper) script by Mike Cranfield and Adam Block. This, right after my successful learning of another NB Colour process script by the same Mike and Bill Blanshan. Both are available here. I can see the advantages of both – Bill Blanshan’s is more controlled and “easier” to use, while the Adam Block (see his videos) method is a little more freeform. Which one will I use going forward? In any event, I highly recommend giving both a go and see what works for you.
P.S. If you don’t like the colours in the images, don’t blame the scripts – any shortcoming are completely my own.