Corona Australis with QHY268M

[Wilsil]

We had almost three clear nights last weekend so I jumped to the opportunity and set up again.
This time I tried a faint object, the Corona Australis.

"The Corona Australis Nebula is a bright reflection nebula formed by bright stars surrounded by a dark cloud of dust. It is an area where new stars are being formed. The Coronet Cluster is an open star cluster surrounded by gas and dust. It is one of the closest known regions of star formation. NGC 6541 is a globular star cluster that is estimated to be around 12.9 billion years old."

As it was already high up in the sky when it was dark and my house is getting in the way in the west, I couldn't use the full time.
Luckily I had 2 night from 7.30pm till 1am and 1 night from 7.30pm till 10pm when the clouds rolled in.

Taken from my suburban backyard bortle 6. Surely a dark site will give better results, but I am pretty happy with this considering that the moon was still up.

51x 300s R
55x 300s G
48x 300s B
18x 300s L
Total of 172 subs used, 14 hours and 20 minutes integration.

Equipment used:
Skywatcher HEQ5 Pro Goto mount
Skywatcher ED80 telescope 600mm focal length, f/7.5
QHYOAG with ZWO ASI120mm mini guide camera
QHYCFW-L filter wheel with 2" Optolong LRGB filters
QHY268M camera at 56 gain, 20 offset and -10 degrees C
Pegasus Powerbox for power and data distribution

Software used:
Sharpcap for PA
NINA nightly for acquisition
PHD2 for guiding
DSS for stacking
Photoshop 2020 for processing

[Andy01]

Nice result , especially considering your conditions! :)

[Wilsil]

Thanks Andy, will definitely try again at a dark site with no moon.

[gregbradley]

A wonderful part of the night sky and quite a fine rendition.

One bit of advice. Mode 1 Gain 56 Offset 50 is for narrowband where
you go for lower read noise and are not worried about blowing out bright areas that much. I use 600 seconds either 1x1 or 2x2. You don't lose much resolution with 2x2 with these cameras so I often use that as well to get the more manageable file sizes.

In broadband images (LRGB) this setting can lead to blown out stars with no colour which is what you have.

So for broadband try Mode 0 Gain 26 Offset 40. You get maximum dynamic range and more tolerance on your star colours at 300 second exposures.

If you were imaging a bright core glob then I would use Mode 2 and Gain 26 offset 40.

This is for a QHY600m but it would be the same for the QHY268M as they have same pixel structure.

Think ISO where you see gain in these CMOS sensors and you can apply your knowledge from digital cameras and ISO settings.
Same thing. If you imaged with a DSLR and used 300 or 600 seconds at ISO 3200-6400 you're going to end up with all white stars that are not
correctable.

Greg.

[Wilsil]

Thanks Greg, appreciated. That's why I am still a beginner. :-)
Mode 0 is the first selection I guess? Mode 1 is high gain?