Tracing the Leonids backward and they converge to a radiant inside the Leo's Sickle
Orion vs Leonid
Canon T-70 6 - Camera Array -
Automatic simultaneous 6 minutes exposure sequence from x1 command back
In 1999 inspired by Robert Mc Naught's 5-camera arrays that I saw in Jordan 1999 I started to look for similar constructions in the web. The T-70 multiple camera system was pioneered by Robert Haas from DMS. The DMS group had been using this type of set-up extensively in their meteors expedition including this year leonids.
I was attracted by the automatic nature of the set up - so you can spend more time enjoying the meteors than manning the cameras. No cable releases were required and the 'command-back' of a single camera will control other cameras to have similar exposure duration and interval settings. This model auto rewind too.
The camera was designed to use little power for keeping the shutter open - a crucial factor for avoiding battery-drain problem in long exposure. I have decided by 2001 I will have similar setup ( minus the rotating shutter ) and special thanks to Robert Haas info on the circuit diagram I finally understand how to link all the cameras together with a 'slightly' different implementation. Two years had gone by and it took me more than a year to obtained T-70 cameras - grabbing them as they surfaced on local 2nd hand camera shops. The special T3 Remote Adapter is harder to find. My first trial order ended one was the wrong type ( T3 cable release adapter). They looked almost identical. I kept it anyway. Just a few weeks before this Leonid I finally found a source right in Singapore! By then I had only four T-70 cameras with standard 50mm f/1.8 lens (body+lens cost US$150). I needed more T-70 cameras. Finally I ordered two US and they came just days before my departure. Assembly is easy - I got a plank of laminated pine from D I Y shops, drilled 1 1/4" holes ( 6 camera so 360/6= 60 degree apart). Secured a ball head($US 10.00-15.00) to the board with 1-1/4 2" screw.
Cameras were linked in RING via T3-adapter - mini mic jack - RCA cable ( custom- made US$1.00 each). The six cables were plugged into a multiple RCA connectors with grounds all shorted, and the + shorted. I sat the whole set up on C5+ field tripod. I also weigh the whole system and it was close to 13 Kg! The cameras, tripod and the 6 ball heads took up most of the weight.
Result of the six Canon T-70 Array
Method: Six cameras with 50 mm f/1.4-1.8 lens were mounted in a 'ring' configuration. Exposure and film transportation time is assumed same over the six cameras. Program sequence is 6 minutes exposure ( ASA800 color film) and 3 seconds delay. The sequence is repeated until end of film. Upon development of the films, visible leonids are counted vs film number. Each camera had 3 1/2 hours of exposure. Camera was operated from 17:23 - 21:00 UT
Result of Leonid Count:
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