The result of 30+ hours of "pushing the outside of the envelope" in PixInsight image processing. See the 3.5 hour time-lapse animation here: flic.kr/p/2ofokk7

C/2022 E3 (ZTF) is a long-period comet from the Oort cloud. It reached perihelion (1.11 AU from the Sun) on 01/12 for the first time in 50,000 years. Since its orbit has changed, the comet will either return in many millions of years or be ejected into interstellar space. On 01/24, the comet clearly displayed an ion tail, dust tail, and rare anti-tail as Earth passed through its orbital plane. The green glow in the coma is the emission of diatomic carbon. It passed 0.28 AU from Earth on 02/01.

On the morning of 01/20, I took a huge gamble and tried to shoot this comet with my new Tamron 70-200mm f/2.8 lens. It was a massive sacrifice to sleep 3 hours, wake up at 02:00 EST, set up/troubleshoot the previously untested rig, shoot until dawn, pack everything up, and leave for a long, exhausting work day. After stacking the images later that day, I was extremely disappointed with the result.

The otherwise fantastic lens suffers from internal reflections that are impossible to correct or remove. I spent days desperately trying to salvage the data with new calibration frames, different focus distances, etc., but I realized it was no use. From what I can tell it seems to be a pupil ghost (www.cloudynights.com/topic/536295-flat-not-correcting-cen...) caused by the glass elements and/or reflective rings inside, and there is no solution. I would have discovered the issue if I had tested it before. It was an excruciating lesson to learn.

Somehow, I was lucky enough to get another clear morning on 01/24. This time, I switched back to my trusted and proven deep-sky telescope. I woke up at 01:00 (4 hours of sleep), set everything up to start shooting around 03:00, packed up at dawn, and left for another long, painful day at work. Comet image processing was another mountain to climb, but I figured out a good workflow (influenced by Adam Block's technique: youtu.be/TaEwvC1lzKM) after 10 days of experimenting. The hard work has finally paid off and I'm super proud of this result!!

Apparent magnitude: 5.9 Distance from Earth: 0.40 AU Orbital period: 50,000 years (before) / unknown (after) Velocity (relative to Sun): 24.6 mile/s (39.7 km/s)

Total integration: 2 hours 8 minutes 128 x 60 seconds ISO1250 01/24/23 07:55 to 11:25 UTC

Camera: Canon 7D Mark II Telescope: Explore Scientific ED80 f/6.0 Apochromatic Refractor (with ES field flattener) Mount: Orion Sirius EQ-G Guide scope: Svbony 50mm f/4.0 Guide Scope Guide camera: ZWO ASI224MC Capture software: N.I.N.A., ASTAP, PHD2 Bortle Class 6 ~19.32 mag/arcsec^2 (Summerville, SC) Processed with PixInsight and Paint.NET