Scanning Data:

22.64 day moon, 38.9% waning

Range: 388602 km; 241,517 nautical miles (1.602)

960807  0239 Local  08h39m CUT target acquisition time for colog

Tracking Camera: Panasonic WV450

Scanning Camera: GBC CCD-400

Scope: 16" f/4.5, 1830mm fl

T-C Adaptor: Orion variable universal camera adaptor, set at min

Ocular: Sirius Plossyl 26mm/Orion #11 yellow/green Wratten filter

Simulated cam range w/26 mm epp, 400x: 600 miles. FOV 400 miles 

Target Image

http://www.lunarscan.com/lunascan/images/session_18/18_tycho01_crop.jpg

BOS 7H 11m; 1:11 AM approx record start
LOS from TLI = 31 mins approx
Signal resumed at 7H 41M 00S CUT; 1:41 AM local

0:32:44 copernicus

0:44:05 rupes recta

0:45:31 rupes recta

0:51:15 tycho imaged at 2:32 AM, 7-mins prior to target cologitude

0:51:36 tycho

0:52:13 tycho

0:58:11 aristothenes

1:17:38 rupes recta

1:18:24 eratosthenes

1:18:33 eratosthenes & copernicus

1:18:35 copernicus X

1:18:54 kepler

1:19:49 copernicus X

SESSION #18 - THE TYCHO EVENT

Preparation: Wednesday, August 7, 6:00 PM.

Weather report: Clear skies for the evening and following morning, with possible scattered thundershowers by Wednesday afternoon. Contacted Jeff Lyons of WFIE TV14 who gave us the all clear, but said skies would be a little hazy.

We hauled out the massive 16" scope on the Scope Transport Unit and used the Laser Collimator to align the optics. The moon wouldn't be up until after midnight, then still behind the tall trees in the east.

We checked the Coordinated Universal Time and at 10:30 PM set all our digital clocks to CUT, including the pc's internal clock. A fresh tape was placed in the Panasonic VCR and the two betamax units were rewound and zeroed. This session utilized a Recoton dubbing enhancer to boost the image from the main CCD camera. After the signal passed through 50' of RG59/U to the Sanyo Betamax 6800, it was put through a Archer Amplified A/V switch panel and fed into the dubbing enhancer, then to the VCR.

Richard Motzer of Scottsdale, Arizona, advised us to eliminate the dubber and is sending us an Aperture Video Corrector Circuit for future sessions scheduled for late August or early September.

The only problem we had was in the RG59/U! The male "F" connectors on the ends of these 50-foot K-Mart coax cables (same as used for normal video home hook-ups) are very vulnerable, especially if they are unscrewed very often. We had considerable difficulty troubleshooting the LOS (loss of signal) from the main camera. We use four of these 50-foot cables, two black and two white. Each has an outgoing and a return line. That way the tracking camera (black line) and scanning camera (white line) have signals going into the facility and back to monitors at the scope site. By playing back a pre-recorded session on the recorders, the return lines checked out OK. There was picture of the small moon on one monitor and a close-up on the other. The problem HAD to be on the "live" incoming main line. It turned out that the "F" connector was loose and had actually pulled off. This happened two times before out of four cables! So, be advised, this cable is around $10 for 50-foot sections and is OK except for the ends. Replace these with heavy duty ones wedged on by a special tool. Then, since the male RCA connectors from the cameras have to be plugged into these, use female "F" connector-to-femaIe RCA adaptors to connect, rather than unscrew. By doing this you keep pressure on the connectors and help keep them from becoming loose.

We also eliminated the need for two monitors on the scope site by putting a video cable AB switch at the end of the two return lines, then running the single short video line to the monitor. By switching from "A" to "B" we had the live VLPS (Very Low Power Scan) images from the tracking camera or the HPS (High Power Scan) live images from the scanning camera. Keep in mind, this is for on-site observation and taping where we tape everything in the facility but enjoy the fresh air and cool clear nights outdoors. In-door observations only utilize the outside monitor for alignment and focus.

The Tycho event, if originally caused or enhanced by lighting conditions, should have repeated the 1992 event witnessed by ALPO's David 0. Darling. We were watching for illumination inside the crater shadow-filled area. The central peak had become nebulous in appearance and there were streamers reported in the 1992 event. We had to keep this information confidential until after the session so as not to "lead" other observers.

The colongitude calculations predicted very similar lighting conditions for this morning at 8H39M CUT, which was 2:39 AM here in SW Indiana. The Moon had appeared on the horizon right after midnight, but too low to observe because of the obstruction of some trees. Once noticed, however, the STU was moved to a better vantage point and alignment and focussing began. As stated earlier, there was trouble with the main signal. Sometimes it came in, other times not,  and very unstable. By the time the event was supposed to be nearing, the image was lost. Frantically we worked, and panic & loss of sleep was starting to have its effect. Then the bad "F" connector was discovered and corrected, at least most of the time. The problem then became in the keeping of the lunar highlands, and the Tycho area in particular, in the field of view. We we not prepared for thr "track" mode and had to use the "pan" mode and scan across the lunar surface as we usually did. For this event we should have been prepared to "track", but we didn't get our "dress-rehearsal" in time.

Francis Ridge
Coordinator,
The Lunascan Project