Cassiopeia Observatory

Moon, Earthshine, Asteroid 2012 DA14, Owl

Posted: 15 February 2013

The observatory was opened Friday, 15 February 2013, at 1808 MST, 64°F. The sky was partly cloudy. Friday had been an exciting day, starting with the Russian meteor and then the close approach of Asteroid 2012 DA14. I wanted to do more imaging of Earthshine on the moon and make an attempt at imaging the asteroid. Shortly after opening the SkyShed POD, I took this photo of sunset:

At 1820 MST, I briefly viewed Mercury at 77X through the clouds. Then slewed the Meade 8" LX200-ACF to the moon, high in the sky. Thin clouds interferred with the viewing but at 1826 MST, I was able to get this image with the Nikon D7000 DSLR at prime focus of the telescope using an exposure of 1/320sec, ISO 800:

I then began trying to image Earthshine. The bright moon and the thin clouds made imaging difficult. Finally, at 1902 MST, I managed to get an image which showed the Earthshine using the "Hat Trick" Method, ISO 500:

By 1916 NST, the thickest clouds were at the moon and the constellation of Ursa Minor. Unfortunately, Asteroid 2012 DA14 was in Ursa Minor at this time. I gave up on further moon imaging and began preparations for my attempts at imaging the asteroid. I connected my Apple iPhone 4 to the telescope using the SkyWire serial adapter. Using the Southern Stars app "SkySafari Pro 3.7.3" I controlled the telescope and had SkySafari slew to the current position of the asteroid. I began a visual search for the asteroid at 77X, but as the Magnitude (from SkySafari) was +12.6, I did not expect to see it. And the clouds did not help. I gave up my visual search at 1938 MST. I attached a focal reducer and the D7000 DSLR to the telescope. At 1954 MST, did a focus test on the star Kocab using the Bahtinov Mask and then locked the telescope focus.

Using SkySafari on the iPhone 4, I did a GOTO to the asteroid and did a 1 minute, ISO 6400, unguided exposure of the asteroid's position. When the exposure was completed, I could see the asteroid trail on the camera's viewscreen even though the image was taken through some thin clouds. After quickly congratulating myself and thanking Southern Stars for the SkySafari update that allowed it to track this rapidly moving asteroid, I did four more 1 minute, ISO 6400, exposures.

Clouds were a problem for each of the images but they all showed the asteroid movement during the 1 minute exposure. This is the last image, taken at 2005 MST, cropped from the full-frame image, showing the asteroid's motion:

This animation shows Asteroid 2012 DA14 as it moved rapidly across the sky for each of the 1 minute exposures (taken at 195649 MST, 195847 MST, 200042 MST, 200347 MST, and 200510 MST):

I ended imaging at 2006 MST, and due to the clouds, I began closing the observatory. As I was putting items away, I saw a great horned owl just outside of the observatory.

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