2022-08. SH2-113 & SH2-114 in H-alpha mono

[pipnina]

having completed my capture for a yet unprocessed mosaic, I turned my head to something less well known.

I basically looked for something random but (by stellarium's reckoning) nicely sized for my field of view. Hence I ended up looking at this region of sky, centered around RA:21:20:50 and DEC:38:22:00.

Sadly only one night of images calibrated with flats properly... Even though the setup hadn't been touched from the night before. This is driving my crazy since it seems there's no reliable way to get these flats to work. They just magically work for one night's images and then not work on the next. So this image is made from half images that are flat calibrated (from night 2) and half images that are not (night 1). I did my best to correct the vignetting and gradients afterwards but it still doesn't seem perfect.

It seems like it could probably need yet another 2 nights, because my goodness this object is faint! I want to combine it with some other filters to make a colour image, but I'm not sure if I should go the Ha-RGB route or something like Ha-Lum or HOO or SHO. I dont know if this object has other narrowband elements or if it would be best paired with broadband colour...

I'm also noticing weird changes from my RisingCam 571. It used to be that on high gain mode I could take a dark frame or bias frame and get a noise floor around 600-800ADU. But the darks I am getting now (10 minutes) are only around 0-20ADU (yes a lot of the pixels are plain black!) and my narrowband HA images have a median and mean value close to only 300ADU on a moonlit night! Something seems off here but I don't know much about these astrocams to diagnose what's changed.

Total: 58x600s H-alpha (3nm)

All in all it's a very interesting object. A lot of hard borders and detail in the wisps which I very much enjoy aesthetically. I'm not sure how it's supposed to be two objects though (supposedly one object should be upper center frame, the other lower center frame). But then I have found just plugging in stellarium's coordinates isn't always toally accurate to what I get from the camera and platesolver!

 

I think these sharpless objects might be a running theme for me going forward... If the weather permits!

Edited August 13, 2022 by pipnina