The Iris is a reflection nebula, a cloud of gas and dust illuminated by a central star. It’s six light-years across, and lies 1400 light-years from Earth. Its official name is LBN 487, while the stars clustered nearby are called NGC 7023.
Askar 130PHQ: August 2024
The Iris Nebula is one of the first targets I tackled seriously, back in 2021 using my Askar FRA400 telescope (scroll down to see the pics). It showed me that astrophotography from a city is perfectly achievable with the right approach. Since upgrading to an Askar 130PHQ I’ve been keen to have another crack at the target, using the bigger telescope, Optolong L-Quad Enhance filter, and new processing tools that are available in PixInsight.
Imaging this during the summer, I was prepared for it to be a long-haul — the short nights here in the UK limit the number of the hours you can get in on any given night. In the end I spent six weeks on it, which netted me 30 hours of good quality data.
WBPP in PixInsight is nice and speedy since I upgraded my PC and switched to 5-minute subframes instead of 2-minute (resulting in fewer files that go into the integration pot).
The resulting integrated image showed promise, and some careful editing brought out more detail in the Iris itself, as well as the surrounding dust clouds, than I’d managed before. I’m taking that as a win!
Imaging details
* 10 July – 21 August 2024 (six 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-Quad Enhance (RGB): 360 x 5 minutes (30 hours)
Total exposure time: 30 hours
By Lee Pullen
Processing walkthrough
Example source data
Askar FRA400
Version 2, reprocessed December 2022
From the Reprocessing Bonanza 2022. This version uses exactly the same data as version 1, but with better processing tools and skills. I spent a lot of time processing this image the first time around! I remember being happy at getting so much detail despite my city centre location. This new version has much tighter stars that emphasises the faint nebulosity.
Version 1, April 2021
This target was a challenge I set myself. Conventional wisdom is that light pollution wipes out The Iris Nebula, so it’s pointless trying to image it from a city. Maybe a modern camera coupled with a long integration time could manage it?
I’m happy with the result, especially considering how much I needed to crop in given my telescope’s short focal length. See the sample data images at the bottom to see just how small The Iris appears in my frame. It’s nothing short of remarkable that the dust clouds surrounding the nebula are visible, blocking the light from background stars.
It did take 20.5 hours of integration time to get to this stage, however. Darker skies would definitely make this an easier target! Just the fact that it’s achievable from a city is kinda mind-blowing though.
* April 2021
* Bristol, UK (Bortle 8)
* Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Mount: Orion Sirius EQ-G
* Guide: William Optics 32mm; ZWO ASI 120MM Mini
* Software: PixInsight, Photoshop, Lightroom
* Control: ASIAIR PRO
* 615 x 120 seconds
Total integration time: 20.5 hours
By Lee Pullen
Example source data
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