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Comet C/2022 E3 (ZTF),
Mars Occultation

Posted: 31 January 2023

The sky was clear Sunday night, 29 January 2023, but I didn't open the observatory. Clouds were visible along the western horizon most of Monday, 30 January.

Open: Monday, 30 January 2023, 1818 MST
Temperature: 42°F
Session: 1827
Conditions: Mostly clear

12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
2" 9mm 100° eyepiece
Focal Reducer

iPhone 13 Pro Max

1824 MST: LX600 ON, StarLock OFF, High Precision OFF.

SYNCed observatory clock to WWV time signals.

Viewed Venus, Jupiter, and Mars, 102X. Then viewed the Moon, 102X.

Took this handheld iPhone 13 Pro Max afocal 102X photo of the waxing gibbous Moon using NightCap Camera (ISO 34, 1/1150sec, 1X lens).


1837 MST: Wi-Fi ON.

Did some tests of the iOS app ScopeBoss to confirm it still worked with the latest iOS version. It did.

1840 MST: Wi-Fi OFF.

Did some lunar observing, 271X. Viewed Mars, 271X. I planned to use the 2" 9mm 100° eyepiece (271X) for the Mars occultation later in this session.

1851 MST: Viewed Comet C/2022 E3 (ZTF), 12x50 binoculars. Then viewed Mars and the Moon, 12x50 binoculars.

1857 MST: Took this handheld D850 DSLR photo (f/5.6, 1/500sec, ISO 400, FL 300mm, cropped) of Mars and the Moon about 3 hours before the occultation would begin.


Next, I prepared the D850 DSLR for imaging of the comet. Mounted the D850 DSLR at prime focus + focal reducer, focused on the star Kochab, and locked the 12" primary mirror.

1911 MST: Wi-Fi ON.

Used SkySafari 7 Pro on the iPhone to GOTO Comet C/2022 E3 (ZTF).

1913 MST: StarLock ON.

1923 MST: Comet C/2022 E3 (ZTF), StarLock autoguided, 15 seconds, ISO 12800. The coma and dust tail are visible. The ion tail is faintly visible downward from the comet. The bright Moonlit sky was a major nuisance.


1925 MST: StarLock OFF.

1936 MST: Viewed the comet, 102X and 271X. The comet's rapid motion was very obvious in just a few seconds at 271X.

1938 MST: Wi-Fi OFF.

I then began waiting for the Mars occultation to begin (2145 MST). While waiting I viewed the Moon and Mars, 271X.

2132 MST: Mounted the iPhone 13 Pro Max on the 9mm eyepiece using the Levenhuk adapter. Did a video recording using NightCap Camera to test exposure settings. This is one frame from that video.


2145 MST: Video recording of the disappearance of Mars, iPhone, NightCap Camera (ISO 100, 1/801sec, 1X lens), afocal 271X. Click to view the video (59 seconds).

2249 MST: Video recording of the reappearance of Mars, iPhone, NightCap Camera (ISO 100, 1/801sec, 1X lens), afocal 271X. Click to view the video (61 seconds).

2255 MST: LX600 OFF.

Close: Monday, 30 January 2023, 2303 MST
Temperature: 36°F
Session Length: 4h 45m
Conditions: Mostly clear

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