Dean W. Armstrong

The Sun is a convenient source of radio waves. You can see this yourself by watching weather radar around sunrise or sunset. Radar works b...

Colin is spending the summer and next year in Santiago, Chile. I pulled up a recent TERRA image of Chile & surrounding areas: http://ra...

Mercury, Saturn, and Venus bunch up low in the evening sky. http://skyandtelescope.com/observing/article_1534_1.asp

For some reason I trust newspapers' web sites to provide me with news that is important to me--like important local news that may affect...

Sam bought a surplus fresnel lens for me. It's June, mostly clear, and it's time to melt some bricks.

I always had thought that the bright white appearance of foliage in the near infrared was due to chlorophyll fluorescence--indeed, in a coll...

This is a split screen image of Yerkes Observatory in the visual and near-infrared. I moved the camera in between images and wasn't plan...

I have placed most of the near infrared images I've taken at http://www.lib.uchicago.edu/~dean/infrared/ . All of the images were norma...

This Saturday members of the Ryerson Astronomical Society visited Yerkes Observatory to use the 41-inch reflector. Luckily the clouds clea...

Plus, a graph of the transmission of fully exposed and developed color negative film, from recorded by here : This helps explain how dust r...

Steven conveniently graphed the data from my geiger counter, covering a week in the Ryerson Astronomical Society office. http://gateway.spc...

This was a trip to Las Vegas. Maximum altitude was at 39,000ft, and the flightpath was a relatively northern one across Nebraska and Colora...

I added a third layer of color negative to the filter, and this makes the sandwich completely opaque to the naked eye. The sun is barely vi...

http://www.lib.uchicago.edu/~dean/blog/ir1.jpg http://www.lib.uchicago.edu/~dean/blog/ir2.jpg http://www.lib.uchicago.edu/~dean/blog/ir-norm...

A nice image of exaggerated maria colors on the Moon: http://www.rc-astro.com/img/moon_colors_2005-04-18_web.jpg. Visually, you can see this...