The Great Pegasus Cluster (M15) - 2025-10-05 - RGB
This image was captured while I was taking advantage of a bright, moonlit urban sky to check out my imaging system. The capture occured while I was validating that NINA-automated meridian flips were occuring on time and executing correctly,
While there is a target object in this image, this is essentially a stars-only image, illustrating that great stars can be obtain in a what seemed to be an impossibly bright sky. Two points relative to stars-only images are worth mentioning.
90s exposures were way longer than needed, because the histogram sky fog peak was separated from the left edge by over 3,000 ADU, the camera (16-bit) provides enough dynamic range to prevent the brightest stars' centers from saturatinng. With test exposures, I could have significantly lowered the exposure duration and still have gotten the same quality image I got with 90s exposures.
A ton of Luminance frames were shot. I made a couple of attempts to add luminance with LRGBCombination, but found that it degrated my image. My sense is that I could have adjusted the stretch of my luminance image to get a combined image at least as good as the image appeared without luminance, but I don't think that adding luminance would ever improve the image. This illustrates that there is enough signal in RGB that the stars can stand on their own.
Equipment:
ZWO ASI6200MM-P/EFW 2" x 7 (RGB)
TeleVue NP101is (4" f/4.3)
Losmandy G11
Software:
Captured in NINA
Processed and finished in PixInsight
Integration:
24 frames x 90s for each RGB filter
Total integration: 1;48
The Great Pegasus Cluster (M15) - 2025-10-05 - RGB
This image was captured while I was taking advantage of a bright, moonlit urban sky to check out my imaging system. The capture occured while I was validating that NINA-automated meridian flips were occuring on time and executing correctly,
While there is a target object in this image, this is essentially a stars-only image, illustrating that great stars can be obtain in a what seemed to be an impossibly bright sky. Two points relative to stars-only images are worth mentioning.
90s exposures were way longer than needed, because the histogram sky fog peak was separated from the left edge by over 3,000 ADU, the camera (16-bit) provides enough dynamic range to prevent the brightest stars' centers from saturatinng. With test exposures, I could have significantly lowered the exposure duration and still have gotten the same quality image I got with 90s exposures.
A ton of Luminance frames were shot. I made a couple of attempts to add luminance with LRGBCombination, but found that it degrated my image. My sense is that I could have adjusted the stretch of my luminance image to get a combined image at least as good as the image appeared without luminance, but I don't think that adding luminance would ever improve the image. This illustrates that there is enough signal in RGB that the stars can stand on their own.
Equipment:
ZWO ASI6200MM-P/EFW 2" x 7 (RGB)
TeleVue NP101is (4" f/4.3)
Losmandy G11
Software:
Captured in NINA
Processed and finished in PixInsight
Integration:
24 frames x 90s for each RGB filter
Total integration: 1;48