AAAA News and Activities

A Starlike Glow on the Gibbous Moon

January 25, 1999

Ron Zincone
Richmond, RI
rzincone@uri.edu

March 12, 1999

Dear AAAA:

My name is Ron Zincone and I am a beginning amateur astronomer and a new AAAA member who's primary interest is astrophotography. I wanted to write this article about an observing experience I had not to long ago which was really exciting and so I wanted to share with the amateur astronomy community.

As a kid, I remember having spent countless evenings in my parent's backyard in the city gazing at the heavens with one of those department store telescopes that my parents bought me one year for Christmas. Even though it was a small scope, at the age of 12, 1 was thrilled and enjoyed many nights under the celestial skies. Recently, I decided to go back into gazing at the heavens especially since I now own a home and very lucky to be located under some rural dark skies away from major light pollution.

The day after Christmas of last year, I purchased a Meade 4500 (4.5 inch Newtonian Reflector). Certainly, quite a step forward from the toy telescope I had as a kid. In January, I purchased a neutral density moon filter for my lunar observations. At this time, I only had in my arsenal a 36X MA eyepiece which came with the telescope. At this low power, the moon is quite bright and a moon filter is very useful to bring out lunar detail and to keep your eyes dark adapted.

On the night of January 25, 1 decided to venture out onto my front porch to observe a Gibbous moon and try out my moon filter for the first time. Several hours earlier, we had some light snow but the skies had cleared and the temperatures remained in the 20's. I was up later than usual that night and so set up my Meade 4500 and started my moon observation at 11:30 p.m. EST. The Gibbous moon was high in the West-Northwest sky. I could see the terminator line clear and sharp with 36X. The wind was very light and so the moon was steady. Because it was so cold I moved away from the telescope for a minute or two several times to warm up but the telescope remained outside. Sometime between 11:30 and 11:50 p.m. an event occurred which caused me to observe at 11:50 p.m. a steady, starlike glow, yellow-white in color along the outer limb of the moon. It was well away from the terminator within the dark side but close to or along the limb. The glow seemed to pulsate or twinkle in intensity but always remained fixed in the same position. I moved around the eyepiece and readjusted my eye to it, but the starlike glow never changed. I noted in my observing log that the glow lasted for about 5 to 1 0 minutes and then disappeared.

I was able to estimate, since the Newtonian reversed the image, that the glow was located in the southwestern region of the moon to the west of the large crater Clavius. Unfortunately, I didn't have time to remove the moon filter to see if the observation would change and I had no other higher magnification eyepieces to switch to. My main goal at that moment was to keep the glow in my eyepiece for as long as possible. It had entered my mind that I may have been observing a Lunar Transient Phenomena event since I had done some reading on the subject.

It was certainly an exciting observing session and one that was very eerie. The event caught me completely off guard since it was a last minute observation decision to view the Gibbous moon and to try out my new moon filter. I even wondered if the moon filter played any role in bringing out the glow. Since I am also new to astrophotography and doing mostly camera on tripod unguided shots, I was not able to take any photographs through the telescope.

I don't know for sure it this was a LTP but after I logged the event in my observation log, I decided the observation was important enough to contact David Darling who is the contact person regarding lunar transient phenomena reports. We have been in contact with each other since the event and so far it is being handled as an LTP report with the possibility that the observation I made on the night of January 25, 1999 could have been from an impact crater.

As for myself, I find that observing such a rare event, even if the cause remains unknown, and to be one of thousands of other lunar observers who have reported LTP's is exciting. It is also exciting to be able to contribute data from an observation which may be of scientific importance to the astronomical community and the hobby. This is one of the high points of amateur astronomy and astrophotography as a hobby, in my opinion, in that you never know what you will observe or capture on film during a night under the stars.

Clear skies,

Ron Zincone
rzincone@uri.edu
Member of AAAA and ASSNE

Lunar Graze of 5 Tauri

Ron:

I have done a bit of research on your observation of January 25. Using a planetarium program called SkyMap, I have determined that at about midnight EST at your location, the gibbous moon was very near to a star in Taurus designated with Flamsteed number 5 Tauri. It can be found on a good star chart, such as the Tirion Sky Atlas 2000.

I am almost sure that, as you can see from the chart above, the event you saw was 5 Tauri right next to the dark edge of the moon. If you had watched a bit longer, you might have observed the star "blink out," which would have been an occultation, or you might have seen a lunar graze. It seems that you were in the right place at the right time!

Sincerely,

Ed Flaspoehler
Vice-President, AAAA

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