The Moon occulted Mars in January, and I got to try out a new piece of Affordable Astrophotography equipment! (Click here for all my Affordable Astrophotography posts.)
Yes, I have a new cheap smart phone! Many of my Affordable Astrophotography posts have featured a $10 phone I got at a grocery store more than a decade ago. But recently I needed a temporary phone for a trip. So I got a pay-as-you-go one — for $20. The phone plan I bought for the trip has expired, but the phone’s camera still works.
When the Moon passed in front of Mars on January 13, I tried to use both cheap phones for some photos. The battery in the $10 phone is very weak, however. In the cold it promptly collapsed. That left me to use the $20 phone to shoot through the eyepiece of my cheap “assembled from cast-off equipment” telescope. Here are some of the results:
I did nothing fancy to get these pictures. I “just” aligned the camera over the eyepiece, messed around to try to get the right amount of Moon in the image to not overwhelm the camera with brightness, and took photos showing the Moon and Mars growing closer together. The quotation marks are because this aligning process can be tedious.
Let’s try to do a little science with these photos. If I zoom in on the Moon and Mars, I can tell a couple of things. For one, it is obvious that Mars is redder in color than the Moon. The other is that the surface brightness of Mars is not radically different from that of the Moon. Mars seems to be brighter than a dark lunar mare, but not distinctly brighter than the brighter parts of the Moon.
(The “photo” on the far right is a simulation from Stellarium, for comparison. I had to flip it around to match the mirror-reversed image of my telescope — hence the backwards lettering.)
But, Mars is much farther away from the Sun than the Moon is. So, the sunlight that illuminates Mars must be weaker than the sunlight that illuminates the Moon. All things being equal, Mars should appear darker than the Moon on account of that weaker light. The fact that it does not appear darker suggests that Mars is better at reflecting the Sun’s light than the Moon is. In astronomical terms, these photos seem to suggest that Mars has a higher albedo than the Moon.
Albedo is not quite that simple. It can be measured in various ways at various wavelengths of light. But if you look up information on the Moon and Mars, you will find that yes, Mars has a higher albedo than the Moon, pretty much any way you look at it. So, my crude little measurement is in line with accepted results.
The new cheap-o phone also got some nice pictures of the Moon with Mars behind it!
And it got some decent pictures of Mars on the other side of the Moon.
I did not take photos of Mars as it was partially occulted, because I wanted to be watching that with my eyes (no messing with a camera). Actually, when the Moon was covering Mars over, I let my godchildren look (they had come over to see) and when the Moon was uncovering Mars, I watched the whole thing myself. The covering/uncovering was very cool, taking only about 30 seconds each.
One interesting thing is how the photos reveal how much worse the turbulence in the air (the “seeing”) was when Mars had emerged. Look how oval Mars appears in the image at right.
Why is this? Probably because the Moon was starting to pass over my neighbor’s house by the time the right-hand photo was taken. Heated air rising off the house distorted things. All the photos I took after Mars had emerged from behind the Moon show a highly distorted Mars.
Occultations, albedo, turbulence, and some pretty pictures, too! Not bad for a cheap phone and a beat-up telescope! Astrophotography, and astronomy, can be affordable, fun, and cool.
