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Re: (meteorobs) camera clusters configuration for Leonids
>> I guess changing film in the middle of storm is bad - does that
means I need to stretch the (36-1) shots to cover the 1 -1/2 to 2 hours
duration with dead time in between shots? A 3 minutes on and 1 minute
dead time means 35x4= 140 min or 2 hrs 20 min or variation of these.<<
Not knowing what your end purpose for meteor photos are, but here goes....why don't you wait until you start seeing signs of high activity? Then start your 2 or 3 minute exposures during any storm like activity. Also have a reserve of backup cameras making 10 minute exposures during this time, to salvage any losses while tending the cameras making the shorter exposures.
What I use to do was mount two cameras with 28mm lens onto a star tracking device. It covered a large part of the sky if aimed right. I knew that my normal quick alignment would give me pinpoint stars while making at least 25 minute exposures. Quite often I would have pinpoint stars while making 30 minute exposures. A few times I got real lucky and was able to make 1 hr exposures and still had pinpoint stars....but not too often though. Using a 50mm lens I would have to make shorter exposures than with the 28mm....usually 20 minutes when using that set up. Some of the drawbacks with a 28mm lens was that for Leonid meteors to show up on the film, the meteor magnitudes had to be of at least -1 magnitudes. They wouldn't show up too bright though. For the 50mm, I needed meteors of around +1 or 0 magnitude. The lower in the sky the meteors appeared, the less likely it seemed that they would expose the film. Probably a distance thing. With the 50mm lens, the stars would look more pleasing(and less like beach balls) if you step down your aperature about 2 stops from wide open. So...if you had a 50mm f/1.8 lens, you might want to set the aperature to f/2.8. With the wide angle lens (28mm), stepping down isn't a real problem. The stars will not appear as large as they would with the 50mm. With the 28mm I was looking for fireballs and not the low life dimmer ones.
Now if you don't have a star tracking device, you might want to piggy-back onto an aligned telescope. Be sure not to be sloppy with the alignment of your scope, or in the end your pictures will tend to look a little on the crappy side. As with unguided cameras, you need to know your exposure start/stop times down to the second. When a significant meteor appears in the camera's field, you need to record the appearance time to within about 3 seconds. With a guided camera you can get away with about 30 seconds for appearance times. While operating cameras and recording times it can get mighty hectic. I used a tape recorder to talk my times into. I also painted with "white out" a number on the back of each camera....such as C-1, C-2 etc. Then when I referred to any particular camera I would give it's C number. This would make sorting out what recorded event matches film exposure a little easier later on. If you piggy backed onto a telescope, make some try out exposures before the big day. This would give you a "feel" for what you got to do and how long exposures you can make. Exposure times are dependent upon end purpose of your pictures. If you are trying to record lots of meteors on one frame....make longer exposures. If you are trying to determine meteor rates photographically....make short exposures.
GeoZay