Monday, August 24, 2015

H-alpha imaging with a 110 mm APO

On 8/22/15 Alann and I made our way to Sierra Vista to visit family and hopefully do some astronomy. It seems like every weekend has been cloudy since the monsoon season started. Dean Ketelsen ( ) let me borrow his 110 mm APO refractor and I have been itching to try it out with the "new" CCD camera. Getting the equipment ready after a long hiatus was interesting. I found a big black widow right by the DEC motor where I put my hand to disengage the drive. Fortunately I noticed it before I put my hand there! Because it had just rained the day before, the air and ground were thick with moisture, which made it a wonderful environment for mosquitos. After struggling to get everything bolted together and fired up, I finally had everything working. Only problem was that it was still cloudy : (

From 8pm to 11:30pm the clouds were relatively heavy, with only a few patches of semi-clear sky. Just enough to get the telescope focused and ready in case the skies cleared up.

Around midnight the skies magically opened up, just as the moon was setting. It was time to get down to business and get some shots!

Dean's 110 mm attached to my equatorial mount. This is a beautiful scope!

First object of the night, the moon in H-alpha. This image was shot through hazy clouds

Above is a periodic error plot showing the tracking performance of the mount, using a starshoot auto guider. I'm not convinced its this good, I suspect that the angular resolution of the auto guider system is not sufficient to detect sub-arcsecond perturbations. Although, the mount can track unguided for 10-15 minute exposures with very round stars.

M27, Most of the exposure time was in H-alpha (approximately 20 minutes)

The Pacman nebula, again mostly in H-alpha (approximately 20 minutes). I don't think the focus was quite right for this shot. But overall it turned out well

As I was packing up this giant spider decided to pay me a farewell visit. He was a good 2-3 inches in diameter. I was also visited by kangaroo rats, a jack rabbit and the sound of coyotes howling in the distance.

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