Overview
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.
Background
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.
Imaging details
| Date | January – April 2023 |
| Location | 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 |
| Image credit | Lee Pullen |
Processing
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!
Source data
Previous version
I first imaged NGC 7822 back in October 2021, using my wide-field Askar FRA400 telescope.
* 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
Seestar S50
Seestar S50 image to be added later…
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