02/05/2024 – Planetary Nebula PK 136+05 and PN G136.1+04.9

Clear and cold night with no Moon! Great night to collect some light from Hechathorn-Fesen-Gull 1 (aka HFG1 or PK 136+05) a planetary nebula located in the constellation of Cassiopeia. HFG1 is the SkyWatcherUSA Target of the Month (TOTM) for February 2024. In the same field of view is another planetary nebula PN G136.1+04.9 which I hope will resolve in the processing as well.

Uncovered the scope and cabled everything up in the early afternoon. I decided to try 5 minute exposures so I cooled the camera to -10 C and captured 2 hours of 5 minute darks (24 x 300 seconds) at 121 gain, 30 offset, and bin 2×2. I also captured 100 x 0.000032 second bias frames to calibrate flats.

Once the Sun set I checked focus and the polar alignment. The Ekos Auto Focus set the focus steps at 10364. I ran the polar alignment routine 3 times: to West, then to the East, and then back to the West. I got the polar alignment dialed in almost dead on. Plate solving is calculating the focal length at 570 mm, F/5.6.

Primary (Imaging) Secondary (Guiding)
Scope: SVBONY SV503 102ED
Reducer/Flattener: SVBONY SV193 0.8 FR/FF
Filter: ZWO 2″ Duo-Band Filter
Camera: ZWO ASI294 MC Pro, Cooled to -10 C
Focuser: ZWO EAF
Mount: Sky Watcher EQ6-R Pro
Scope: SVBONY SV106 60mm Guide Scope
Camera: Orion Star Shooter Autoguider (OSSAG)
Telescope Control, Image Acquisition, and Image Processing Software
Equipment Control and Imaging Software: KStars/Ekos connecting to INDI Server on a Raspberry Pi
Stacking and Processing Software: Siril astronomical image processing tool

I was able to grab 3 hours and 5 minutes of light from Hechathorn-Fesen-Gull 1 (aka HFG1 or PK 136+05) and PN G136.1+04.9. That is 37 x 300 second exposures at 121 gain, 30 offset, and bin 2×2. Stacked and calibrated using Sirilic, then cropped and processed in Siril.
Planetary Nebula PK 136+05 and PN G136.1+04.9 - 37 x 300 seconds captured on 02/05/2024. Processed with Siril
HFG1 is the lower left planetary nebula and PN G136.1+04.9 is the planetary nebula up and to the right of in the FOV. Starting to see a bit of details in HFG1, but I need to gather some more light. I used the pixel math R=Ha, B=OIII, and G=OIII for the image above.

I did some tinkering with the pixel math. In the image below is the same stack, but I am only applying 80% of the Ha data. My pixel math is R=Ha*0.8, B=OIII, and G=OIII.
Planetary Nebula PK 136+05 and PN G136.1+04.9 - 37 x 300 seconds captured on 02/05/2024.  Processed with Siril
I also think I did a bit better job on the stars in this second one… what do you think?

I am going to try to collect a bit more light from HFG1 before I submit to the TOTM. My other SkywatcherUSA TOTM 2024 Submissions are here.

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