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Started by drachal, 04/08/2008 07:57AM
Posted 04/08/2008 07:57AM Opening Post
Has anyone seen anything while observing that they'd consider a LTP?

Twenty years ago, or so, I was looking at a waning gibbous moon and not too far from the terminator, on the unlit section, there was a slightly illuminated small area, which I can only describe as chocolate colored. I can only assume it had this color due to some odd illumination factor resulting from a reflection from the sunlit portion of the moon. As least that is the simpliest explanation I can come up with.

Has anyone else seen anything similar to what I am referring to? It didn't catch my attention enough at the time to make notes about it's position, date, time, etc.. It was only later that it puzzled me. I do recall first noting it under relatively low magnification and then upping the power to see what it was.

Darian R.
Posted 04/19/2008 07:51PM #1
What's an LTP, Darian? Lunar Transient Phenomena maybe? Just a guess, I'm kinda new at studying the moon.

Having a big time on a small scale grin
Posted 04/21/2008 08:37AM | Edited 04/23/2008 10:14AM #2
I never have seen any, though I've not spent that much time observing the moon compared to others. After doing a lot of reading about the subject, though, I've come to the conclusion that most TLPs are subjective observer effects, though there might be some dust-caused phenomena that some people are seeing.

Recent work on earth's magnetosphere and it's interaction with the moon, as well as Apollo crew, ALSEP & Surveyor observations of what might be dust "storms" caused by sunrise on the moon have gotten some attention lately;

The Moon and the Magnetotail

Moon Storms

Here's what the 1999 Sky & Telescope articles said (I think) in the August and September issues 2 TLP articles that seem to discredit them as either observer misperceptions or atmospheric effects:


It's All In The Seeing

The TLP Myth. There is a long history of Transient Lunar Phenomena (TLPs). Almost as soon as the telescope was invented, observers began seeing flashes of light, color changes, and other luminous phenomena on the moon. Reddish glows around the rims of the craters Aristarchus and Alphonsus have long been accepted as objective scientific observations. The most popular explanation of these color phenomena involves the eruption of gases around the craters.

In 1964, in an attempt to better understand TLPs, NASA organized a network of amateur lunar observers with communication links to the Corralitos Observatory in New Mexico. Corralitos possessed a 5-inch reflector equipped with color filters which could checkout network sightings. In almost 3,000 hours of surveillance, no color phenomena were recorded using the Corralitos instruments -- even when the network reported a colored TLP in progress. Are all TLPs therefore illusory?

The NASA program certainly suggested that TLPs might be subjective phenomena, perhaps something like the colored coronas observed during solar eclipses. TLPs are still reported nevertheless. And there are also recognized phenomena that might account for TLPs. One such phenomenon is prismatic dispersion in the earth's atmosphere. On the moon's surface, thermoluminescence is a possibility, as is the fluorescence of lunar soils being bombarded by solar wind.

"It is far easier to believe that misinterpretations of mundane atmospheric and instrumental effects are responsible."

(Sheehan, William, and Dobbins, Thomas; "The TLP Myth: A Brief for the Prosecution," Sky & Telescope. 98:118, September 1999.)


The text of another S&T article written by the leading TLP researcher who considers TLPs as a real phenomena can be found online at

Reprinted from Sky & Telescope Magazine, March, 1991.

by Winifred Sawtell Cameron

But beware that the webmaster / editor of this website refers to Richard Hoagland - that goofy Mars Face guy - and has inserted some remarks to that effect into the article.
Posted 05/03/2008 09:39AM #3
I thought I saw something on the terminator once in a 10" reflector. It looked like a red in color spark rolling across the surface of the dark face. I assume that micrometeors strike the Moon with the same frequency that they burn up in the Earth's atmosphere. I thought perhaps it was a small meteor grazing the surface of the Moon.