Sunday, July 12, 2009

Clear weather and cloudy computers

Our high school science teacher professional development workshop continues here at McDonald Observatory. We've got 19 teachers who have been learning about the lives of stars and white dwarfs. Right now, they are all sitting around styrofoam cups full of hot water, measuring how fast it cools. We'll then relate this to white dwarf, which emerge from planetary nebulae with surface temperatures of a hundred thousand degrees, and cool down to a few thousand degrees over several billion years.

Below are some pictures of the night sky at McDonald taken by one of our participants, Leslie Howell, a science teacher from the Ft. Worth area. If you look at the large versions of the images (click on an image to enlarge it), you can see both the colors of the stars and their trails, created as the Earth rotates about its axis. You can also see the Milky Way, the band of starlight caused by the billions of stars in our own galaxy. The picture with a telescope dome is of the Harlan J. Smith 2.7-meter telescope; the yellow glow on the lower parts of the dome is a reflection of the rising gibbous moon. In this picture, you'll notice that the star trails are wider on the right of the image than on the left. That's because the North Pole is behind the dome, and stars further from the pole have to make larger arcs to circle the pole.

These images were taken with a Nikon D70s digital camera; the image of the Milky Way was a 45-second exposure, and the image including the telescope dome was a 105-sec exposure. The Milky Way seen from McDonald Observatory

The Milky Way behind the Harlan J. Smith Telescope

Alas, although the weather has been great, we've had no end of problems with computers. We are trying to perform an activity where the teachers measure the brightnesses and colors of stars in star clusters; we've done this activity for many years and thought we finally had all the wrinkles ironed out. Unfortunately, we are having buggy problems with the computer program we use to analyze the data, bugs we've never seen before. And, worse, the bugs are intermittant, and don't affect everyone. So, the teachers are getting pretty frustrated with the activity. Tonight I need to try and smooth things over, and I'm still debating how to do that.


  1. Were these pictures taken just w/a naked camera, or was there a telescope or binoculars used as well?

    i am trying to get some solid tips on reliably photographing with a digital rangefinder through binoculars (i figure it's easier, since you can sight through the other viewer)


  2. I believe these were taken with a digital SLR with a standard lens on an unguided tripod.

    I honestly don't have any tips on photography through binoculars. I've managed to get a handful of images through a telescope just by holding a point-and-click camera up to the eyepiece, but it's tricky. The problem is not just aiming the telescope, but making sure that the optical path of the camera is aligned with the optical path of the telescope. I assume the same problem exists with binoculars.

    Your best bet is probably to find a local astronomy club or an online astrophotography forum to get some hints. We professionals have the luxury of engineers doing all the hard alignment and machining for us, so we can stay blissfully ignorant of all the troubles involved.