These are my attempts at the Helix and Rosette using a SXVR-M25C single shot colour camera. It has highlighted the fact that I need to move to a mono camera to get the detail I want.
In relation to your guiding question ,the following is the Astro Imaging setup I used for both objects.
1. 960 mm ED127 Refractor
2. Skywatcher AZ-EQ6 Mount
3. Celestron OAG
4. PHD2 - Locally modified.
5. Guide Camera - QHY5L-II
6. Guide duration - 3 seconds
Given the fact that I had a good polar alignment and my gear was well balanced , I believe I was able to achieve the 20 minute guides as a result of the modifications I made to PHD2. Prior to the mods I was only able to get passable 10 minute guides. Nobody ever questions the guiding software but blames everything else for bad guides. To me PHD2 seems to overcorrect forcing one to play with a multitude of interacting parameters to correct the over correction.
I made two modifications to PHD2
1. I binned the guide image from 1280*960 to 640*480 . The effect of this is to sharpen the guide stars which tends to help PHD2 as it appears to like nice round definite guide stars.
2. I modified the guide exposure time , so the round trip time of guide exposures matched the setting in the PHD2 dialog. It is interesting to note that a guide exposure of 1 sec with the QHY5L-II takes approximately 1.25 seconds. This additional time represents one quarter of the exposure time.
Good to see some images from you, Rob! If you get a chance to drop a copy of your calibrated masters somewhere I'd be happy to have a quick crack at them to see if I can bring out more detail.
Leaving guiding accuracy aside, I am astounded about how dark the sky must be to allow you to achieve 20 minute subs without the skyglow overtaking the detail.
Your not that far away from Brissy and other built up areas. I am amazed!
Bottom line though - a great shot of a fairly dim surface area object. Well done!
Bruce.
You should have told me I need to improve my image enhancement skills. Hopefully with a bit of Rick's tutelage I will improve this aspect of my Astro Imaging endeavors.
Rod - I think I have told you before that the Celestron OAG is a very good bit of kit. Thanks for recommending that I buy it. I think Dunk is considering buying one also
Bruce - The helix was imagined in my backyard at Caboolture with a fair bit of sky glow. It is hardly discernible in the raw image. The Rosette was imaged at a dark site location at Blackbutt about 100k's inland. I am trying to get a handle on how my camera performs and what length of exposure times to use for the different sky conditions. I tried a series of 10 minute subs on both objects but these failed dismally. When I went to 20 minutes the detail pooped out.
beautiful images.
