BossDog Creations
M27 Dumbell Nebula
FUN night results: TLDR 15 second exposures, lots of them and no guiding! Long post lots of info. Capture info in comments.
I was experimenting again last night with very short exposures, no guiding, no stress. Granted M27 is a very bright object but I wanted to see if I could stack many subs without having to guide and not get walking noise like I did last time I tried.
RGB was taken with Sharpcap and no dithering. I got slight amount of banding noise that the ASI 183 is known for. But seemed to be fine for the RGB channels. I took 120 frames of each color or 30 minutes each.
LUM I took with APT and dithered every frame through APT without the need for PHD2 to be involved. No walking noise at all, but I had a little issue a couple times where the mount dithered right across the frame lol. May have been a sticky DEC. Thin clouds came and went during LUM capture and it was getting late so I only got like 100 frames or less than 30 minutes. I would normally hope to get a couple hours of LUM.
Darks were really a big key difference in noise. Since exposures were only 15 seconds each I was able to take 30 darks in just a couple minutes so the temps were very very close to exposure temps 75F!! for RGB and 65F for LUM. Amp glow was a non issue after calibration.
My scope is little and slow. 65mm aperture and 420mm focal length for a ratio of 6.4. My camera is an un-cooled mono which is also has tiny pixels and does not capture a ton of light, and when it does, stars quickly saturate due to small full well capacity. I took so many frames that I was able to toss any that came out poor which I normally do not have the luxury of doing. My stars were nice tiny little round things, so satisfying!
Next time I will try some narrowband though I am not holding my breath for too much success. If the night is good and the target is in a good spot, I can get 60 second unguided exposures though.
Overall, I am extremely happy with the results and have the 8" RASA on my wish list :)
M27 Dumbell Nebula
FUN night results: TLDR 15 second exposures, lots of them and no guiding! Long post lots of info. Capture info in comments.
I was experimenting again last night with very short exposures, no guiding, no stress. Granted M27 is a very bright object but I wanted to see if I could stack many subs without having to guide and not get walking noise like I did last time I tried.
RGB was taken with Sharpcap and no dithering. I got slight amount of banding noise that the ASI 183 is known for. But seemed to be fine for the RGB channels. I took 120 frames of each color or 30 minutes each.
LUM I took with APT and dithered every frame through APT without the need for PHD2 to be involved. No walking noise at all, but I had a little issue a couple times where the mount dithered right across the frame lol. May have been a sticky DEC. Thin clouds came and went during LUM capture and it was getting late so I only got like 100 frames or less than 30 minutes. I would normally hope to get a couple hours of LUM.
Darks were really a big key difference in noise. Since exposures were only 15 seconds each I was able to take 30 darks in just a couple minutes so the temps were very very close to exposure temps 75F!! for RGB and 65F for LUM. Amp glow was a non issue after calibration.
My scope is little and slow. 65mm aperture and 420mm focal length for a ratio of 6.4. My camera is an un-cooled mono which is also has tiny pixels and does not capture a ton of light, and when it does, stars quickly saturate due to small full well capacity. I took so many frames that I was able to toss any that came out poor which I normally do not have the luxury of doing. My stars were nice tiny little round things, so satisfying!
Next time I will try some narrowband though I am not holding my breath for too much success. If the night is good and the target is in a good spot, I can get 60 second unguided exposures though.
Overall, I am extremely happy with the results and have the 8" RASA on my wish list :)