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SkyTracker Pro M31 & M33;
Extragalactic Supernova Project M31 & M33

Posted: 9 October 2018

Clouds from an approaching low pressure system began arriving mid-morning on Saturday, 6 October 2018, with the sky becoming mostly cloudy by late afternoon. Rain arrived on Sunday, 7 October. Received 0.32". Cloudy skies continued on Monday, 8 October, but the sky was mostly clear by sunset.

Open: Monday, 8 October 2018, 1812 MST
Temperature: 68°F
Session: 1288
Conditions: Mostly clear

Equipment Used:
12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
Focal Reducer
SkyTracker Pro


Upon arriving at the observatory I set up a live trap in order to try to capture a packrat. I then set up the SkyTracker Pro with the D850 DSLR and 24-70mm lens on the observatory patio.


1836 MST: LX600 ON, StarLock OFF, High Precision OFF.

By this time the planet Venus was not visible. Viewed Jupiter and 4 moons, 102X. The moon Io was about to begin a transit of the planet's disk. Then viewed Saturn and Mars, 102X.

1845 MST: High Precision ON.

Viewed M31 (Andromeda Galaxy), 102X. The nucleus and its companion galaxy M32 were visible against the bright twilight sky.

1915 MST: viewed M33 (Triangulum Galaxy), 102X.

1918 MST: polar aligned the SkyTracker Pro. In order to get both M31 and M33 galaxies in the D850 DSLR field-of-view at a focal length of 70mm I had to place the camera in this position:


This is a tracked photo of M31 (left) and M33 (right), f/2.8, 30 seconds, ISO 12800, FL 70mm, cropped from the full-frame image:

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

1939 MST: ended SkyTracker Pro sky imaging.

2000 MST: began preparing to image M31 and M33 with the 12" telescope for my Extragalactic Supernova Project. Mounted the D850 DSLR at prime focus + focal reducer, focused on the star Mirach, and locked the primary mirror. 2009 MST: StarLock ON.

Due to the apparent size of M31 and M33 and their brightness, I did not use my normal galaxy exposure time (5 minutes) for the images. For M31 I also did three images, one centered on the nucleus and the others with the nucleus off-center. These are the StarLock autoguided images, 1 minute, ISO 6400, White Balance 5000K for M31, and 2 minutes, ISO 6400, White Balance 5000K for M33.

M31 (Andromeda Galaxy)

M33 (Triangulum Galaxy)

2033 MST: StarLock OFF.

Removed the DSLR and focal reducer. Viewed M33, 102X.

2043 MST: viewed NGC157 (galaxy), 102X. I plan to image this galaxy on the next session.

2047 MST: LX600 OFF.

Close: Monday, 8 October 2018, 2058 MST
Temperature: 52°F
Session Length: 2h 46m
Conditions: Clear

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