Cassiopeia Observatory - Report - Jupiter Galilean Moons, NGC2336 Galaxy

Jupiter Galilean Moons, NGC2336 Galaxy

Posted: 18 February 2014

I first set up my LXD55 GEM and tripod outside the observatory for a planned imaging attempt later in the night. At 1829 MST, viewed Jupiter, 83X, and then 222X. Four moons were visible. At 1838 MST, took this handheld iPhone 5s afocal image, 222X, showing the four Galilean Moons (Jupiter is overexposed):

1859 MST: viewed M82 galaxy, 83X. Supernova SN2014j was still visible, although obviously getting fainter now.

1900 MST: began setting up for DSO imaging. Mounted the D7000 DSLR at prime focus of the 8" using the off-axis guider (although I didn't plan on doing any manual guiding).

While waiting for astronomical twilight to end, did a rough polar alignment of the LXD55 by just centering Polaris in the polar alignment scope. Hoped it would be good enough for short exposures later.

1925 MST: using 12x70 binoculars viewed M82 and M81 galaxies. Using averted vision I seemed to be able to see the supernova in M82.

1931 MST: stepped outside the observatory to do some Dark Sky Meter (iOS app) testing with the iPhone 5s. The Zodiacal Light was very easily seen. DSM Pro worked and successfully recorded a magnitude limit of 6.74:

Returned to the observatory and did a focus test image with the 8" and Bahtinov Mask on the star Pollux. Just as I completed the test, the neighbor to the northeast turned on his bright, horizontally aimed, "dog" floodlight. I slewed the telescope to NGC2336 (galaxy) in the northern sky (it is a circumpolar object). Rotated the dome to block the neighbor's nuisance light from hitting the telescope. Did a 2.5 minute framing test image (unguided), ISO 6400, of NGC2336. Framing and tracking were OK so did 11 more 2.5 minute, ISO 6400, exposures. This is a stack of the 12 exposures, yielding an effective exposure of 30 minutes:

Ended imaging of NGC2336, removed the D7000 DSLR from the telescope, attached the 70-300mm lens, and mounted the camera on the LXD55. Then the difficulties began. Focusing was difficult since I didn't want to slew too far from M82; in fact, I never got a crisp focus. Getting the camera pointed at M82 using the GEM was a challenge; never did get it. But none of that mattered since tracking was not good and 2 minute exposures all trailed. Guess the polar alignment was not good enough for a 300mm focal length. I have successfully tracked with the LXD55 using 18mm and 8mm lenses, but 300mm is apparently too long without a much better alignment. Had to end the attempts at 2058 MST as the eastern sky was brightening due to the rising waning gibbous moon. I will have to work on a better piggyback solution.

2102 MST: northeast neighbor turned off his floodlight. Clouds were coming in and a breeze was beginning to blow.

2111 MST: took a quick look at M42 (Great Nebula in Orion), 83X. Then began closing up.

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