An emission nebula around 3000 light-years from Earth, NGC 7822 is the birthplace of new stars. Their strong stellar winds and radiation shape the surrounding gas and cause it to glow.
Askar 130PHQ: April 2023
I won’t lie, this project was horribly difficult! I started it at the same time as imaging The Orion Nebula, gathering data each clear night when that nebula was no longer visible from my garden. That all worked fine, and I collected 20 hours of good quality L-Ultimate data (Ha and OIII). But then the weather turned, and blanket cloud coverage rather scuppered my plans. By the time the skies cleared enough for me to obtain Askar D2 data (SII and OIII), NGC 7822 was pretty low in the sky. This meant that, despite collecting 16 hours of D2 data, the quality was rather poor.
The result of this was that the combined data was a real challenge to process. In the end I took nine (nine!) processing attempts to get something I was moderately happy with. It was a frustrating experience. I actually started writing a PixInsight processing guide for Aksar D2 data based on this image, but was forced to give up because I had to squeeze the data harder than I’d like. With hindsight, I’d also choose different framing. Maybe I’ll return to this target another year, and hopefully better weather will mean it won’t take 12 weeks to collect the data!
Imaging details
* January – April 2023 (12 weeks)
* Bristol, UK (Bortle 8)
* Telescope: Askar 130PHQ Flatfield Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Mount: Sky-Watcher EQ6-R PRO
* Guide: William Optics 50mm Guidescope with 1.25″ RotoLock; ZWO ASI 120MM Mini
* Control: ASIAIR Plus
* Software: PixInsight, Lightroom
* Filters:
– Optolong L-Ultimate (Ha / OIII): 600 x 120 seconds (20 hours)
– Askar D2 (SII / OIII): 480 x 120 seconds (16 hours)
– No filter (for RGB stars): 45 x 120 seconds (1 hour 30 mins)
Total exposure time: 37.5 hours
By Lee Pullen
Example source data
Askar FRA400: October 2021
NGC 7822 is a faint nebula and so not often photographed, but I figured it’d be a good test of my kit and processing skills. The final integration is 20 hours, and to be honest I did struggle with the noise levels when editing so maybe I should have stuck with it for another 10. An early pass with Topaz DeNoise AI helped a lot though.
When editing I more-or-less followed my usual workflow, and as part of that split the image into R G B components fairly early on. There was good signal in the R channel (Hydrogen-alpha), but G and B were pretty poor. OSC definitely isn’t optimal for this target — a Mono camera would be better for sure, in particular for vacuuming up all that Hydrogen-alpha. But I got what I consider to be a decent result in the end.
I continue to be surprised by what’s possible with a small refractor and ZWO ASI2600MC plus Optolong L-eXtreme through the haze of my city centre sky. I think that the central region is passable even when cropped in tightly:
* NGC 7822 /NGC7822
* October 2021
* Bristol, UK (Bortle 8)
* Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Filter: Optolong L-eXtreme
* Mount: Orion Sirius EQ-G
* Guide: William Optics 32mm; ZWO ASI 120MM Mini
* Control: ASIAIR Plus, ZWO EAF
* Software: PixInsight, Lightroom, Topaz DeNoise AI
* 600 x 120 seconds
Total integration time: 20 hours
By Lee Pullen
Example source data
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