TYCHO

L.T.P. EVENT

2 SEPTEMBER 1991

07:34 TO 08:40 UT

BY

DAVID O. DARLING

After witnessing the unusual appearance of the central peak of Tycho 10 December 1990.  I decided to view the crater the next time the sunset took place on the crater Tycho. Wanting to make sure that the lighting conditions were similar. It took about 8 months of getting up early to monitor the crater as the sunset terminator passed over it. On Sept 2, 1991 I was successful by detecting inside the shadow filled area of the crater two arc's of light.

I used my 12.5 f5 Cave Newtonian for the observing session at a magnification of 10mm/159X. Also I attempt to conduct a Moon Blink when a Wratten 25 Red and 38a Blue filter to check the craters response when viewed through each.

The following is a summary of my log entries on the morning of the observation.

07:34 UT:  Using the 12.5 f5 Newtonian reflector to examine the crater Tycho. I want to continue to monitor the central peak and floor of this formation in attempt to determine what caused the glowing patch over the central peak and arc's of light inside the crater. This is a follow up on the 10 December 1990 Tycho lunar transient phenomena report.

07:38 UT: Using the 10mm/159X eyepiece to examine the central peak of Tycho. The central peak appears star like in appearance with only brief signs of nebulous patch similar to that seen on 10 Dec 1990 event.

07:46 UT: The central peak is still visible and remains star like in appearance and at certain times while I watch it takes on the appearance of a nebulous patch. But no where near the intensity of the 10 Dec 1990 observation. The vast majority of the time the central peak appears like a faint star. I also can detect some soft scattering of light inside the shadowed region of the crater.

07:49 UT: Increasing magnification to 6.4mm/248X eyepiece. I still can see a very slight indication of the central peak. It is still star like by very faint. I am finding the seeing not steady enough to stay at this magnification, dropping back down to 10mm eyepiece.

07:54 UT: The central peak now appears to have a washed out fuzzy appearance. The star like appearance that was present earlier has subsided. While I was watching I would occasionally see the arch of light inside the crater. It may be caused by reflection of sunlight off the eastern rim down into the crater bowl.  While I was watching I saw the central peak flare up and look star like again.

08:02 UT: I am still able to detect the central peak in Tycho. I can just make out the smallest point of light down inside the crater. The star like appearance becomes fuzzy in appearance for just a few moments. I took an albedo reading of the inner wall of the east rim and found it to be 9.0. As I continued to watch the central peak flared up and became a very bright for just a brief moment.

08:09 UT: Decided to try a Moon Blink using Wratten # 25 Red and Wratten # 38a Blue on the crater Tycho. The luminescence that taking place inside the Tycho appears brighter in the red filter and I can not make out anything in the blue. The central  peak region shows up better in the red filter as well.  I can make out several crossing luminous strands. Note see drawing depicted below that shows the luminous arcs of light.

Drawing © 2004 by David O. Darling, Director L.T.P. Research

08:11 UT: Conducted the Moon Blink again. Using the W# 25 Red and W# 38a Blue filter and found the halo and arcs of light appear to be enhanced in the red filter and are not visible in the blue. At this time the central peak remains visible with out using any filters.

08:15 UT: Did and examination of the crater Reiner, Aristarchus, Herodotus, and Copernicus and can detect nothing abnormal. The detail in Copernicus and Aristarchus is excellent allowing me to see the many terraces inside them

08:19 UT: I have returned to the crater Tycho and can still see something shining inside the crater Tycho. While I was watching the central peak flared up again, popping out at me.

SOLAR TERRESTRIAL ACTIVITY REPORT

When examining the solar data for Sept 2, the solar data for Solar Flux, Sunspots Numbers, and Planetary A index were very active.