Open: Tuesday, 15 October 2024, 1806 MST Temperature: 74°F

Session: 2019 Conditions: Clear

Equipment:
12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
Focal reducer
12x50 binoculars
2" 30mm eyepiece

Camera:
iPhone 15 Pro Max
D850 DSLR

1811 MST: LX600 ON, StarLock OFF, High Precision OFF.

Viewed Venus, 102X.

Viewed Comet Tsuchinshan-ATLAS (C/2023 A3), 102X. The coma was visible in the bright twilight sky.

I then prepared the D850 DSLR for imaging the comet.

1819 MST: I took this handheld afocal 102X image of the comet using the iPhone 15 Pro Max. I used the NightCap Camera app (ISO 2000, 1/15sec, 1X lens) as the Apple Camera app would not focus using its autofocus (which I have complained about to Apple many times).

I mounted the D850 DSLR at prime focus + focal reducer, focused on the star Altair, locked the 12" primary mirror, and slewed back to the comet. I took several images of Comet Tsuchinshan-ATLAS (C/2023 A3) over the next 30 minutes as the twilight sky darkened.

1831 MST: Spotted the comet in the sky using 12x50 binoculars. The tail was visible in the twilight sky.

1833 MST: The comet was now naked eye visible in the twilight sky. The tail was faintly seen.

1850 MST: Comet Tsuchinshan-ATLAS (C/2023 A3), prime focus + focal reducer, 15 seconds, ISO 2000. The comet's anti-tail is faintly visible extending to the right of the coma. Compare this photo to telescopic images of the comet earlier this year in my Comet Astrophotography Album.

I removed the DSLR from the telescope and viewed the comet, 102X. The anti-tail was faintly visible.

1859 MST: I left the observatory and moved to a higher location where I had a good view of the western horizon.

1903 MST: Took this iPhone photo of the western sky using the Camera app (Night Mode, 10 seconds, 2X lens). The comet anti-tail is faintly visible. The planet Venus is the bright object at the lower left.

1907 MST: To the naked eye, the comet's tail was 15° long. It was unfortunate that the nearly Full Moon was making the sky so bright.

1915 MST: D850 DSLR photo (f/1.8, 2 seconds, ISO 800, FL 50mm) of the comet in the bright moonlit sky. The anti-tail is faintly visible.

1919 MST: I took this unique iPhone photo (Night Mode, 10 seconds, 1X lens) of Comet Tsuchinshan-ATLAS (C/2023 A3) at the left and the nearly Full Moon projected onto the Cassiopeia Observatory dome.

Click or tap on image for larger version

1925 MST: The comet was becoming difficult to see with the naked eye due to the bright moonlit sky as the comet moved lower in the western sky.

1930 MST: Took my final image of Comet Tsuchinshan-ATLAS (C/2023 A3) this night using the D850 DSLR (f/1.8, 5 seconds, ISO 2000, FL 50mm). The comet's anti-tail is visible. As easily seen in the larger photo, it was photobombed by 9 satellites in Low Earth Orbit and demonstrates that our night sky is being ruined by way too many satellites.

Click or tap on image for larger version

1934 MST: I returned to the observatory.

I viewed the waxing gibbous Moon, 102X and 81X.

1944 MST: Took this handheld afocal 81X image of the Moon using the iPhone and the Camera app (1X lens).

Lastly, I viewed the planet Saturn, 102X.

1951 MST: LX600 OFF.

Close: Tuesday, 15 October 2024, 2000 MST Temperature: 70°F

Session Length: 1h 54m Conditions: Clear

This may have been my last opportunity to view Comet Tsuchinshan-ATLAS (C/2023 A3) for a few nights. Clouds and possible rain are in the forecasts beginning on Wednesday, 16 October.

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