Orion Season Targets + Comet

I've been looking forward to the appearance of comet C2022E3 ZTF's appearance in the northern sky near Ursa Minor. The late January Maryland weather has been iffy at best with mostly cloudy weather forecasts. Fortunately, on 1/27 the skies cleared despite a partly cloudy forecast and around 10:30 PM EST the comet was just high enough and clear of a neighbor's north blocking tree to catch the image below. Some light pollution from a nearby, poorly shielded street lamp managed to invade an otherwise dark sky background. Several to be revisited Orion Season DSOs also follow. 

Comet C/2022E3ZTF (1/27/2023)

NGC1579 Northern Trifid Nebula

NGC2264

M1-Crab Nebula

IC 410 

IC 405 Flaming Star Nebula

Comet C2017T2, IC405, IC410, M33, NGC281, M42, NGC7635

Here are a few recent images acquired this 2019 winter. All were acquired at F/4 using the recently with Celestron 8+Starizona Night Owl FR+Orion SkyGlow Astrophotography filter. Camera: ZWO ASI294MC Pro, Mount: Celestron Advanced VX, Guider: Orion Magnificent Mini Autoguider. 

Look closely at Comet C2017T2 and you might notice the glow slanting down to its left. That's residual glow not zeroed out by the flat frame. Vignetting from the Night Owl is very aggressive and tough to zero out.  

Using SharpCap 3.2 I have found collecting flat frames at a narrow range of different exposures that give a histogram just above and below the "above 20%" criterion should provide a flat frame that does a good job zeroing out vignetting and artifacts. *

* More recently I have found a 20% to 80% histogram range, as recommended by SharpCap documentation works best. 

Update:03/13/2025 M33 reprocessed 

Comet C2017T2 PANSTARRS -- 15x60s @bin2

IC410 -- 6x300s @bin1

M33 (180s exposures)

IC405 -- 6x300s @ bin1

NGC281 -- 10x180s @bin1

M42 -- 25x8s @bin1

NGC7635 -- 6x300s @ Bin1