After a Hot Summer Night with Andromeda M31

[bdlbug]

So a few short weeks ago in south(ish) England we were experiencing night time temperatures in the 20's and I posted an image of M31 based on data acquired while fine tuning my new OAG based guiding setup on my AZ EQ6.  https://stargazerslounge.com/topic/319030-hot-summer-nights-with-andromeda/ The images were IMHO not particularly well captured, focus not accurate and sky quality not great, plus a very rapid process that didn't do the subject justice.

I had the good fortune that we had a couple of decent clear nights 10th and 16th Aug  so as its a relatively 'easy target I headed over to M31 again. I also had adjusted the worst of the  backlash out of my mount after last guiding session and was hoping to achieve good guiding to ensure I kept under the pixel scale of my imaging setup that is 1.5"/px and I achieved a RMS of 0.42" on RA and 0.32" on DEC so I am very happy with that. I also paid significantly more attention to the main camera focus using a bahtinov mask and the focus tools in APT.  The  image posted below that is my  best effort after many many hours of processing through APP and Photoshop CC with numerous plugins  - I don't follow a defined flow other than within APP stacking and calibration subs etc.  What I'm not satisfied with is the images I create always end up 'soft' probably due to the amount of processing I do to remove gradients (back garden edge of town etc..) and then I get noise and that then noise reduction makes the image soft. I also haven't got on top of star control, they end up big and fuzzy - perhaps learning about star masks is the next evolution in my processing skill set.  There are about 5 hrs of subs in the image LRGB all 60s captures and Ha  90s. Equipment as per signature using AT106EDT plus 0.75x reducer/flattener with ASI1600MM Cool . I would also be interested in opinions regards the colour I have ended up with - I did take quite a bit more care adding Ha into Red channel using about 30% overlay and a lighten merge - but still end up with stars with a reddish colour cast.

Happy to move conversation in one of the processing threads if someone can impart a little bit of learning my way so I can continue chipping away to improve my work.

The image is pretty much the full capture frame minus slight cropping to remove stacking and alignment artifacts.

Please let me have your feedback as I feel have reached a plateau right now and clearly when comparing to more experienced imagers I still have some way to climb.

thanks, Bryan

[JimothyC]

Well I'm no expert, but that looks fantastic to me. There's a lot of detail going on in there. I'm presuming the red areas of nebulosity along the spiral arms are from the HA channel? 

Your current setup is pretty much what I aspire to, so it's great to see the results in can produce. Can I ask what filters you're using with the 1600MM?

[tomato]

That’s a really fine image, nicely framed and focused, great detail in the Ha regions.

I imaged M31 recently in LRGB, total integration time of 100 mins and found the colour balance very challenging in the processing. Equal weighting gave a distinctly yellow hue to the result, which I couldn’t correct in Startools, but I tried the create colour image option in the APP tools menu and had more success with this. It took quite a bit of playing around mind you, to get what I regarded as a reasonable result.

[bdlbug]

@JimothyC - Yes , the red splodges of colour are the result of the Ha image and are areas where young stars are irradiating hydrogen gas in the galaxy - I am using Baader CCD LRGB filters and Baader Ha(7nm) filter - all 1.25" in a ZWO mini EFW - I am not using any light pollution filter with any of these fliters - I am considering changing the L filter for one of the new IDAS D2 Light Pollution Suppression Filters but currently FLO only have 2" or 52mm option

@tomato - agree I had a lot of isues with a 'warm' yellow hue across the image - interestingly when I imaged M31 about a year ago with 135mm Samyang lens , same camera and filters I did not have a yellow cast issue

 

thanks for your comments  and feedback