With a square sensor and this focal length, many targets fit really well. This one does not 🙂 , also with Alnitak right in place.
From Wikipedia:NGC 2023 is an emission and reflection nebula in the equatorial constellation of Orion. It was discovered by the German-born astronomer William Herschel on 6 January 1785. This reflection nebula is one of the largest in the sky, with a size of 10 × 10 arcminutes. It is located at a distance of 1,300 ly (400 pc) from the Sun, and is positioned ~15′ to the northeast of the Horsehead Nebula.
Additional info:This is only about 1,5h of exposures, as the mount constantly starts to fail on RA. Tightening or loosening the gears did not solve it, as sometimes RA suddenly is off about 400". So happy to have had three clear but cold nights in a row, this hobby also brings with it a lot of frustration... With all the fiddling around, that's all that was left. 🙂
A good tip to get the reflections of bright stars under control is to cover the struts of the secondary mirror spider with some velour. The spikes really don't reach through the whole image, even with Alnitak, as nice as that can be.
Velour "on-off":
Guiding in RA suddenly failing, slowly recentering:
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