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D850 DSLR: Moon; Owl & Stars;
Visual on the "Pup Star"

Posted: 27 February 2018

Open: Monday, 26 February 2018, 1829 MST
Temperature: 69°F
Session: 1206
Conditions: Clear, breezy

Equipment Used:
12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
2" 2X PowerMate
1.25" 5.5mm eyepiece
Focal reducer


1834 MST: LX600 ON, StarLock OFF, High Precision OFF.

Viewed the waxing gibbous Moon, 102X.

Then mounted the D850 DSLR at prime focus + focal reducer.

This is a 1/320sec, ISO 100, White Balance Auto, full-frame exposure of the Moon:

Click or tap on image for larger version

Removed the focal reducer and added the 2X PowerMate. This 1/320sec, ISO 800, White Balance Auto, full-frame exposure, shows the Crater Copernicus and the ray pattern from the crater:


1905 MST: ended imaging. Removed the camera.

1911 MST: slewed to the star Rigel and checked the separation of its companion star, 443X. The Rigel companion has nearly the same visual separation as Sirius B (the "Pup Star") from Sirius A. Then slewed to Sirius and began trying to observe the Pup Star. I placed the bright Sirius A along the edge of the 5.5mm eyepiece field-of-view. 1925 MST: after lots of slewing along the edge I finally managed to see and then confirm the sighting of the Pup Star, 443X. It was a difficult object.

1928 MST: LX600 OFF.

Close: Monday, 26 February 2018, 1938 MST
Temperature: 55°F
Session Length: 1h 09m
Conditions: Clear, breezy

As I left the observatory I saw a Great Horned Owl on the house roof. As the Nikon D850 DSLR does not have a built-in flash and I didn't have my external flash with me, I knew I would have to take advantage of the very high ISO capability of the D850 in order to get a photograph of the owl. The bright moonlight would help. I did several handheld photos using various shutter speeds and ISO settings. The owl cooperated and stayed on the roof the entire time I was taking his photo. Although this photo is somewhat noisy, it actually shows the owl and the stars the best. On the right half of the photo is the bowl of the "Big Dipper". The photo was taken at f/2.8, 1/10sec, ISO 102400, FL 70mm.


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