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Showing posts from May, 2016

Summer is Approaching

In the northern hemisphere, when you start seeing the Milky Way crawl over the eastern horizon in the middle of the night, you know summer is approaching.

Below are a couple images of the Milky Way rising over GMARS. The first is an 8-panel mosaic taken at GMARS around 12:30AM on May 28th. The far left end of the image is looking northeast, and the far right end is looking southeast. From left to right, the light pollution domes are Las Vegas, Joshua Tree & Twentynine Palms, and the Coachella Valley (Palm Springs, et al) on the far right. Also on the far right is Mars, nearing opposition.

The second image is similar, but taken the following night from a different part of GMARS and uses 15 individual frames to create the mosaic. Notice the difference in green airglow from the first night to the second night.

Images like these aren't terribly difficult to take. You just need a tripod, a decent DSLR and a good editing program like Photoshop. Rather than trying to describe the equ…

There's a Little Black Spot on the Sun Today

A man by the name of Gordon Sumner wrote those words some time in the early 1980s. They were especially applicable yesterday (May 9, 2016) because there was in fact a little black spot on the Sun, and not an ordinary one.

There are almost always areas of intense magnetic activity on the surface of the Sun that appear as small, black, irregularly-shaped spots. We refer to them sunspots. But the little black spot in question yesterday was an interloper, an intruder, a wanderer... and extremely circular in appearance. It was the planet Mercury.

Mercury, being the closest planet to the Sun, transits the face of the solar disk now and then, every few years or so. The only other planet to do this is Venus. Venus transiting the Sun is a much rarer occasion. It last occurred in 2012 and won't happen again until 2117.

Actually, all planets transit the Sun, just not from our perspective here on Earth. Many events in the solar system are a matter of perspective. We can only see Mercury or Ve…