Comet 46P/Wirtanen is a short-period comet with an orbital period of five and half years. It is one of the approximately 400 Jupiter-family comets. These comets have an orbital period of fewer than 20 years, and they don’t go farther out than Jupiter before returning toward the earth and sun. 1 & 2
My Observations
| Date | December 6, 2018 |
| Time | 9:56 p.m. |
| Location | Seattle, WA |
| Camera | Canon 70d |
| Seeing | Above Average |
| Transparency | Above Average |
I remember the night of December 6, 2018, quite vividly. I was just getting back into astronomy and only had a Canon DSLR on a stock tripod to capture faint objects—I didn’t have a tracking motor so I spent a good deal of time on ISO and exposure adjustments to capture these faint objects from my light-polluted backyard.
Comet Wirtanen was the first comet I paid attention to since Hale-Bopp in 1997. I didn’t believe I would even capture it from the suburbs, but reports of its increasing brightness gave me hope.
Then, on the humid chilly night of the 6th, I started taking photos, jumping from star to star near the reported area of the comet. After 15 minutes, I noticed a small smudge after using ISO 8000 on the camera. I tried a few more photos and the smudge stayed in one place. I knew I didn’t have a high cloud; I found Comet Wirtanen.
As I recall, it was a nice moment as I sat in the dark shadow near the north side of the house looking at the DSLR camera monitor. It was a peaceful night.
Discovered photographically on January 17, 1948, by Carl Wirtanen
July 2013 perihelion only reached a magnitude of 14.7
Sources and Notes
The banner photo of the comet is licensed under the Creative Commons Attribution-Share Alike 4.0 International license. Attribution: Stub Mandrel at English Wikipedia
Animation from Phoenix7777. The file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
1 Jupiter-Family Comets: Cosmos. Jupiter-family Comets | COSMOS. (n.d.). Retrieved May 29, 2022, from https://astronomy.swin.edu.au/cosmos/J/Jupiter-family+comets
2 Wikimedia Foundation. (2010, March 25). Wirtanen. Wikipedia. Retrieved May 29, 2022, from https://en.wikipedia.org/wiki/46P/Wirtanen
The Garden Astronomer 
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