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Comet C/2020 R4 (ATLAS)

Posted: 1 May 2021

Friday, 30 April 2021, was clear and once again very windy during the daytime, but the wind calmed down late afternoon.

Open: Friday, 30 April 2021, 1811 MST
Temperature: 86°F
Session: 1629
Conditions: Clear

12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
Focal Reducer


1821 MST: after opening the observatory I relaxed on the observatory patio bench.

1908 MST: sunset.

1921 MST: back inside the observatory. Prepared the D850 DSLR for imaging.

1925 MST: LX600 ON, StarLock OFF, High Precision OFF.

Slewed to Comet C/2020 R4 (ATLAS). It was not yet visible in the bright twilight sky.

1930-2000 MST: relaxed on the bench while waiting the stars come out.

2002 MST: back at the 12" telescope. Comet C/2020 R4 (ATLAS) was now visible, 102X. The coma was very visible.

Mounted the D850 DSLR at prime focus + focal reducer, focused on the star Arcturus, locked the 12" mirror, and slewed back to the comet.

2021 MST: StarLock ON.

This is Comet C/2020 R4 (ATLAS), StarLock autoguided, 1 minute, ISO 12800, White Balance 4550K. A short tail is visible pointing down in the photograph.


2037 MST: StarLock OFF.

2044 MST: viewed M83 (Southern Pinwheel Galaxy), 102X. It was too low in the southeastern sky for imaging. As the next day would be a busy one, I skipped imaging it this session.

2046 MST: LX600 OFF.

2055 MST: took a Sky Quality reading.

Close: Friday, 30 April 2021, 2058 MST
Temperature: 69°F
Session Length: 2h 47m
Conditions: Clear, SQM 21.19

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