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Einstein Cross?, Gegenschein

Posted: 11 October 2021

Open: Sunday, 10 October 2021, 2115 MST
Temperature: 63°F
Session: 1675
Conditions: Clear

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


2119 MST: LX600 ON, StarLock OFF, High Precision OFF.

Viewed Saturn, then Jupiter, 102X.

2125 MST: dome OFF.

Prepared D850 DSLR for imaging. Mounted the D850 at prime focus, focused on Algenib, and locked the 12" primary mirror.

2135 MST: Wi-Fi ON.

Used SkySafari 6 Pro to GOTO the Einstein Cross (RA 22h 40m 30.3s, DEC +3° 21' 31").

2140 MST: StarLock ON.

Took a StarLock autoguided image, 5 minutes, ISO 12800, of the Einstein Cross. This is the full-frame image (mouseover or tap for a label).

Mouseover or tap on image
Mouseover or tap on image for label

This is a magnified image showing the Einstein Cross (I think).


2147 MST: StarLock OFF.

Mounted the D850 DSLR with a 14mm UWA lens on a camera tripod to photograph the Gegenscheinsunlight scattered by interplanetary dust, similar to the Zodiacal Light . When Tim Hunter, co-founder of the International Dark-Sky Association, visited Cassiopeia Observatory in September 2021, he noted that he saw the Gegenschein as he was leaving. I looked and saw what he was pointing at, but I could not quite convince myself that it really was the Gegenschein.

Using the Gegenschein Position Calculator, I determined that it would be located at RA 1h 2m, DEC +6° 39'. Using SkySafari I slewed the telescope to these coordinates to be a pointer at the Gegenschein location, near the Great Square of Pegasus.

2201 MST: Wi-Fi OFF.

2208 MST: took this photograph of the sky (f/2.8, 40 seconds, ISO 3200). It captured the Gegenschein, as well as some other objects (mouseover or tap on the image for labels).

Mouseover or tap on image
Mouseover or tap on image for labels

I then looked at the sky and easily saw the Gegenschein, confirming that I had seen what Tim had pointed out to me in September. Seeing the Gegenschein demonstrates how dark my sky is. I have now seen the Zodiacal Light and Gegenschein from Cassiopeia.

2215 MST: LX600 OFF.

2221 MST: dome ON.

2225 MST: took a Sky Quality reading.

Close: Sunday, 10 October 2021, 2228 MST
Temperature: 56°F
Session Length: 1h 13m
Conditions: Clear, SQM 21.05

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