Saturday Evening: Venus in the West

After a cloudy day with intermittent, light precipitation I was greeted by a mostly clear sky after sunset. The tiny point of light near the bottom center of the image is Venus. Clicking on the image will reveal a somewhat enlarged view.

Our Spotless Star

The above photo of the sun was taken today, 12 August 2008. A DSLR camera was used at the prime focus of a 102mm (700mm focal length) Schmidt-Cassegrain telescope. A full-aperture, white-light solar filter covered the front of the telescope.

I knew the sun was without spots today - as it has been for quite some time now. Nevertheless, even a spotless sun can be of interest. Notice that the limb (edge) of the sun is darker than the center of the sun. This is called "limb darkening" and is due to much of the solar radiation originating deep within the interior (rather than the 'surface') of the sun.

The sun goes through a roughly 11-year sunspot cycle. Approximately 11 years pass between sunspot maximums. Sunspot minimums occur roughly midway between the maximums.

Shooting the Moon

Shown above is a 'snapshot' of this evening's gibbous moon. It was taken under poor seeing conditions with a DSLR camera attached to a 102mm Schmidt-Cassegrain telescope (about 700mm focal length). This was one of two experimental images I took of the moon. The telescope's tripod was set up on my south porch - not the most stable of platforms, but sufficient for experimental purposes.

The Perseid Meteor Shower should be near its peak after the moon sets later tonight. If you read this early enough (Monday night - very early Sunday morning), have adequate sky conditions, and can affort to lose the sleep (a lot of 'ifs') you might want to spend some time lying back, staring at the sky, and counting meteors.

My First Star Field Photo

This is my first (and so far only) photograph of the night sky taken with my new camera. I attached the camera to a homemade equatorial wedge (built for a 102mm SCT) and set the assembly on my north porch. The "Little Dipper" asterism can be seen offset toward right center. Some nearby tree tops are silhouetted against the brighter night sky at the bottom of the photo.

Digital photography is certainly far more user friendly than film photography! One gets to see the results right away, and PCs make it easy to tweak the images as necessary. The above photo is a 30 second exposure at ISO 800 with an 18mm lens at f/3.5. It was taken at 11:59 pm local time on July 31, 2008.