Cassiopeia Observatory

Venus over Kitt Peak, Crescent Venus, Horsehead Nebula

Posted: 26 December 2013

Just prior to opening the observatory door and while standing outside my observatory, I took this photo of Venus (top) over Kitt Peak National Observatory (bottom left), D7000 DSLR, 18mm focal length:

Rollover or tap the image to see an inset showing Kitt Peak cropped from a 105mm telephoto lens photo taken from the same location.

After a delay to take a phone call on my iPhone 5s, I viewed Venus through the 8" LX200-ACF, 83X, at 1756 MST. The crescent phase is noticeably shrinking now from night to night. I switched to a 1.25" 9mm (222X) eyepiece and added a #21 orange filter as well as a moon filter to reduce the brightness of Venus and reduce the effects of its low altitude. The view of the planet was really enhanced.

I did some iPhone 5s slo-mo video recordings of Venus through both filters using my homemade iPhone afocal adapter at 222X and 444X (added the 2" 2X PowerMate). During post-processing I stacked 600 frames at 444X using Keith's Image Stacker, with this result (color saturation reduced):

I removed the iPhone and 1.25" eyepiece, switched to the 2" 24mm UWA eyepiece on the 2" 2X PowerMate (166X), and viewed Venus. The view was pretty good even though there was some atmospheric distortion. I also viewed Venus using the Celestron Cometron 12x70 binoculars. After dealing with some collimation problems (as discussed in my review), I could see the crescent shape of Venus.

I ended Venus observing at 1829 MST, and slewed to M57 (Ring Nebula), now getting low in the northwestern sky. It was faintly visible at 166X against a somewhat twilight sky. I continued to use the 2" 24mm UWA eyepiece + 2" 2X PowerMate (166X) for the rest of my observing this session. Viewed M56 (globular cluster), the double star Albireo, NGC253 (Sculptor Galaxy; some structure visible), M45 (Pleiades; some bluish nebulosity seen), and M1 (Crab Nebula; some structure seen).

At 1855 MST, I stepped away from the eyepiece for a few minutes to enjoy my dark sky. The Milky Way was high overhead. Two polar orbiting satellites were seen. At 1900 MST, Jupiter had just risen above the hill to the east. This is a 360 panorama made in November 2009 to show what the terrain around the observatory looks like:

I returned to the eyepiece at 1908 MST. Viewed Jupiter, 166X. It was still too low in the sky for good viewing, but the four Galilean Moons were visible. I also did some more sky watching. It was just too nice to not do that. I continued to monitor Jupiter at 166X as it rose higher.

At 1941 MST, slewed the telescope to M42 (Great Nebula in Orion). Nice view at 166X. Orion was not yet quite high enough in the sky to start imaging the Horsehead Nebula (IC434) but I began some preparations. I took a break at 1950 MST. As I exited the observatory I noticed that the Zodiacal Light was visible in the west. It made a "V" with the Milky Way and was visible to near the meridian. Nice.

I returned to the observatory at 2017 MST and continued preparations for imaging. Slewed to Rigel, Mounted the D7000 DSLR at prime focus using an off-axis guider, did a focus test with the Bahtinov Mask, and then slewed to the Horsehead Nebula. I did two framing test exposures and found a good guide star. The breezes were a little stronger now. My plan was to do 12 5-minute, ISO 6400, guided exposures of the Horsehead Nebula. The exposures would be stacked for an effective 1 hour exposure time. I began the first 5 minute exposure at 2044 MST. Shortly after starting the exposure, the breezes got really strong. One gust even moved the guide star around quite a bit in the 12mm illuminated reticle eyepiece. I completed the 5 minute exposure but decided to end imaging this night due to the wind. This is the single 5 minute, ISO 6400, exposure, cropped to show the Horsehead Nebula:

I will try to do the imaging sequence on another session. Due to the wind, I began closing up for the night.