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Short Session with Venus & Mercury

Posted: 13 February 2020

The sky was cloudy on Sunday, 9 February 2020, as a storm system approached. Had 0.43" rain on Monday, 10 February, and another 0.55" rain on Tuesday, 11 February. Tuesday's rain started out as graupel. It pretty well covered the ground and was still around 2 hours later.


There was still some ice on the ground Wednesday morning, 12 February. The sky began clearing mid-afternoon on Wednesday.

Open: Wednesday, 12 February 2020, 1809 MST
Temperature: 60°F
Session: 1436
Conditions: Partly cloudy

12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
1.25" 15mm eyepiece
Atmospheric Dispersion Corrector

iPhone 11 Pro Max

1815 MST: LX600 ON, StarLock OFF, High Precision OFF.

I had a long list of things I had planned to do in the observatory this session, but the sky coverage by unforecasted clouds made it unlikely I would get much done.

I first viewed the planet Mercury, low in the western sky, 102X. A slightly less than half-phase was visible as Mercury had passed its greatest eastern elongation on 9 February. Seeing was not good.

I switched to the 1.25" 15mm eyepiece (163X) and viewed Mercury. I added the ZWO Atmospheric Dispersion Corrector (ADC) to see if that would help improve the view but it didn't. Seeing was so bad that I could not even get a good focus.

1830 MST: viewed the planet Venus, much higher in the sky and currently clear of the clouds, 163X + ADC. Seeing was not very good there either but the view of the slightly gibbous phase was good during very brief moments. At least I could get a good focus on Venus.

I locked the 12" primary mirror using the ScopeStuff mirror lock and slewed back to Mercury. Still could not get a good view of Mercury at 163X with the ADC.

1848 MST: I stepped outside of the observatory and took this handheld photo of the western sky using the iPhone 11 Pro Max (1X lens). I used the "Night Mode" of the iOS Camera app. The exposure was 2 seconds.

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1850 MST: the only portion of the sky that was mostly free of clouds was a small area near Venus and Mercury. The rest of the sky was mostly cloudy.

1900 MST: decided to close up due to the clouds.

1902 MST: LX600 OFF.

Close: Wednesday, 12 February 2020, 1909 MST
Temperature: 48°F
Session Length: 1h 00m
Conditions: Mostly cloudy

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