O R A C L E    O B S E R V A T O R Y Report 11-12 May 2007

The weather forecasts were good so off I went to Oracle Observatory. I left home at 0445 PDT Friday morning and arrived at Oracle at 1300 MST. The temperature was 93°F under partly cloudy skies with a slight breeze blowing. Here's my setup and you can see some of the clouds:

After setting up everything I walked around, taking some photographs of the flowers on some of the cactus plants:

Then an Antelope Squirrel decided to come out for a snack:

As sunset approached the cloud cover was not getting any better, although the temperature had dropped to 76°F by 1915 MST and the sky looked like this:

Unfortunately the situation did not improve as the night progressed and so I did not do any astronomical observing nor astrophotography.

Saturday morning dawned mostly clear with some high cirrus clouds. By 0700 MST it was clear and 67°F. Maybe tonight would live up to the forecasts.

By 0810 MST it was up to 84°F with some high clouds again. I did some solar observing using my PST; no sunspots were visible but there were several nice prominences at several locations on the Sun's limb.

Later in the morning I noticed this little guy on my chair:

I did some more walking around and took these photographs. The bird is a House Finch.

By 1045 MST it was 94°F and the sky was clear but there was a wind blowing. Here is a photograph of a Eastern Fence Lizard:

At 1230 MST it was 102°F. Here is how I stayed cool:

By 1400 MST it was 98°F and the sky was becoming mostly cloudy:

At 1450 MST I called home to check on the forecast; it was supposed to clear so I decided to stay. However, at 1700 MST it started sprinkling! I scrambled and brought some items inside the tent. An hour later the sky to the East looked like this:

At 1830 MST it did some sprinkling again. About 1900 MST there were a couple of nice "sun dogs" visible (vertical rainbow colored bands of light on either side of the Sun, near the left and right edges in the photo):

Here's a telephoto shot of the one on the right:

And here is a view of some of the clouds to the North:

Sunset was very pretty:

But by 1920 MST with the temperature down to 80°F it was obvious that things were not going to be good tonight. So I packed up all the telescope equipment, returned to the tent, and listened to Old Time Radio programs (like "X Minus One") on my iPod mini. I did come out a couple of times during the night and it remained lousy until about 0030 MST by which time it had cleared up. Oh well, so much for the weather forecasts...

I have frequently commented that atmospheric mechanics is not as accurate as celestial mechanics. The various online weather forecasting services typically have different forecasts, sometimes dramatically different. I have seen forecasts 3-5 days out that have "clear" on one service and "rain" on another service. It is distressing when the forecast for just a few hours in the future is wrong. Here is a nice study of forecast accuracy from various online weather services:

www.omninerd.com/2007/02/08/articles/69

As a result of the poor weather both nights my focusing tests of my new Nikon DG-2 Magnifying Eyepiece for my D70 DSLR plus Off-Axis Guider will have to wait until my next trip to Oracle Observatory.

Until next time.