The image shows:
the (upside down) Horsehead Nebula, Barnard 33;
the red emission nebula IC434 (mag 7.3);
the emission nebula NGC 2024, Flame Nebula (mag 10);
the very bright star Alnitak (mag +1.7 and +3.7 double);
the smaller nebula NGC 2023 (mag 10); and
an Earth orbiting satellite trail.
The Horsehead is a challenging object for visual observers to detect but using live stacking photography it is a sheer joy to behold, as it it slowly reveals, on site, the red nebulosity and the dark outline of the Horsehead itself.
Visual magnitude: na
Apparent size: 6′ x 4′
Distance: 1,600 light years.
Altitude: 47° above NE horizon.
Exposure: 61 x 60 sec = 61 min. Live stacked.
Date: 2018-12-08 commencing approx 11.15 pm
Location: The Oaks, NSW.
Sky: semi-dark rural.
Image acquisition software: SharpCap.
Image post-processing: GIMP.
[ZWO ASI071MC Pro]
Output Format=PNG files (*.png)
Frame Rate Limit=Maximum
White Bal (B)=61(Auto)
White Bal (R)=59(Auto)
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Anti Dew Heater=On
Display Black Point=0
Display MidTone Point=0.5
Display White Point=1
Imaging telescope: Skywatcher Esprit 120ED Super APO triplet refractor.
Focal length: 840 mm, focal ratio: f/7.
Imaging camera: ZWO ASI 071 MC Pro
Guiding: off (guide camera malfunction).
Telescope mount: SkyWatcher EQ6-R.
Polar aligning method: QHYCCD PoleMaster.
Polar alignment error: 1′ 51″.
Field flattener: yes; filter: no.
This was another frustrating night because again the mount would not carry out a successful three star alignment. It will shortly be on it’s way back to the manufacturer for replacement under warranty.
I was determined not to let the problems beat me and I managed to image not only the Horsehead but also Comet 46P Wirtanen.
Despite my alignment woes, I was able to manually manoevre the telescope to find the Horsehead. Regardless of its dark nature, it was surprisingly easy to find, being very close to the bright star Alnitak in Orion’s Belt.
Since posting this I have learned that to avoid inclusion of satellite trails I need to select sigma-clipping alignment in the live stacking options. Too late now!
Image © R.Powell