I have 20 exp each of 2 and 3 min shots (jpg/raw) with canon 4ti thru 10”lx200, first night after getting ag zwo 1290mc to work, used these with darks, flats and bias in dss but get a terrible result, can see no nebulosity. So have to figure out how to use dss, was so focused on getting ag to work didn’t do a drift alignment, so polar alignment was not spot on and didn’t rotate camera to catch wings of nebula, the focal reducer doesn’t allow a good wide shot. I was surprised by the detail in the single shots so excited about what will look like when properly stacked. And the shots posted here just pump me up that much more. Photo attached is only 36kb so may be poor rep of actual single shots.
Hey thanks for sharing. I would love to help if I can but keep in mind I just started in the last 9 months or so.. I really want to make some short vids for youtube talking about some of these common issues I had to figure out! Soo couple questions that jump out is...
Are you using different calibration frames Dark/Flats for the different exposures? Also note while you can have a library of calibration frames the ambient temp will determine if they will be of value to your subs! Anything more then about 5 degrees difference +/- will not looks so good after stacking. Either too much or too little correction! It is totally good to combine different sets of data from different nights but if they are wildly different such as a 2min sub at 200 iso and 5min subs at 800 iso DSS will probably mess it up.
Might be a silly question but are you attempting to stack the jpegs with the raw files as well? They will not be compatible. The camera will tinker with a few things before saving the JPEG images RAW files is all you want!
Also note the default settings in DSS work generally. For a DSLR don't reset the black point to 0. Use average method for stacks of lights less then 10. Kappa Sigma at 2.5 if you have 11 or more. This feature does wonders for removing airplanes shooting stars and other anomalies that like to ruin subs. Better than deleting them!
Most important step in the end is after the stacked file is displayed in DSS be sure to save it without the auto stretching DSS will apply. When you first open the stacked file it will be linear and not cool! That's when the magic happens! You will only be able to stretch the data so far so if your exposures are lets say closer to 25% your stacked file will still be very dim after stretching max without introducing image destroying noise. My solution was to expose at least 50% sometimes maybe 65%. This makes it much easier to tease out the nebulosity! The longest part of imaging for me is framing and then finding the balance of exposure time that will be a happy median for imaging throughout the night (factoring for the lower/higher exposure times depending on the moon cycle).. Maybe 3min subs are great for the first few hours but once the moon is set I could be capable of 5mins... Soo my happy median maybe being 4min subs. Be careful of overexposing but underexposing can also turn the whole batch of data into a dim waste of time and make you think there's a flaw in your ways!
What program do you use for autoguiding?
The subs should almost look terrible if exposed properly. I'm at work now but give me like an hour and I'll link what my subs looked like from M42!
I think you got it man just need more exposure time!
Edited by SuperJustin, 19 January 2018 - 01:56 PM.