Focal Reducer

I've played around with our Opticstar CCD cameras enough now that I feel limited by their relatively small field of view (FOV). For the 14-inch telescopes the FOV w/ CCD is approximately 8 x 6 arcminutes. Saturn and the Ring Nebula (and other planetary nebulae) fit just fine, but I'd also like to image larger objects, like globular clusters.

The easy solution is a focal reducer. We recently purchased what seems to be the only focal reducer in the universe that will work with our CGE Pro EdgeHD telescopes. It's a beast of an accessory at 3.25 pounds, so today we balanced one of the scopes with the focal reducer and camera.

The reducer will reduce (go figure) the the focal length by 0.7. By my calculations, the new field of view (for the CCD camera) should be about 12 x 9 arcminutes. It's not a huge gain, but it will allow me to fit globulars like M10 and M12 (constellation Ophiuchus) in the field. The Hercules Cluster, M13, may be too big, but I'll likely try to image the core anyway.

Focal reducer at base of 14-inch w/ Opticstar CCD camera

BTW, I calculated the FOV in arcminutes using this:

FOV = (S x 3438) / f

where S is the size of the CCD chip in mm, and f is the focal length of the telescope in mm. Exciting, I know.

I don't plan on changing out the focal reducer anytime soon since balancing the scope is a pain in the keister. What will the FOV be with a regular eyepiece? A rough calculation gives me 32 arcminutes for our 26 mm eyepiece and 44 arcminutes for our 40 mm eyepiece. Big, but not quite big enough to fit the 60 arcminute Brocchi's Cluster. We may have an eyepiece (a Panoptic?) with a larger apparent FOV, though. I'll have to check.

Nice night, but no pictures

Last night was absolutely gorgeous. I made it to the observatory a little before 9pm. My mission was to re-align the east 14-inch scope. It was being fussy during the observatory beta test. The scope aligned just fine, and tracked well. I played around a bit, bopping here and there, but didn't do any photography. With a first quarter Moon and a tiny amount of haze, the sky was a bit glowy.

I spent some time looking for the possible nova in Delphinus. I think I found it, but since it looks like a regular magnitude 6 star, I can't be certain. On the bright side, I did find a faint planetary nebula (also in Delphinus), NGC 6905.

Observatory Beta Test

We had a clear night for the observatory open house beta test. We were able to see Saturn, M57 (the Ring Nebula), NGC 6826 (the blinking planetary),M13 (Hercules Cluster), and Albireo (double star system in Cygnus, well actually a triple star system, but we can only see two).

I had hoped we'd somehow get to take more pictures, but alas, we only snapped a few of the Albireo system.

Lots to think about before the next open house.