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Re: (meteorobs) Photographic Meteor Rates (Reply)
In a message dated 97-03-20 15:38:58 EST, you write:
<<
Millman classifies cameras used in meteor programs as follows:
Type A: Conventional lenses - F-4.0 to F-8.0 - focal length 100-500mm
Type B: Conventional lenses - F-l.0 to F-3.5 - focal length 50-200mm
Type C: Baker Super Schmidt Meteor Cameras - F-0.65 focal length 200mm
These cameras have average efficiencies of: A:B:C: - 1:5:200. That is to
say, if camera "A" photographs one meteor, camera "B" should record five,
and camera "C" two hundred. With the camera "A" catagory, Millman reported
securing one photograph per 100 hours of exposure time. This is of course
increased if you photograph during peak shower periods. Professor John A
Russell reported,that the spectrograph that he was using would record a
detectable spectra of a zero magnitude meteor. He was using an F-2.5 - 7
inch fl Kodak Aero Ektar with a 30 degree objective prism on Kodak Royal X
Pan 1250 ASA film. One could expect to go two magnitudes or so fainter with
a direct camera. Spectrographs are less efficient as the light of the
meteor is spread out into a spectrum. Camera efficiency is also dependent
on the velocity of the meteor. You will reach fainter magnitude meteors, if
it's angular velocity is slow rather than swift.
>>
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Hi Ed!
The equipment you are referring to above doesn't sound like the typical
equipment for one to easily find on the market. I highly doubt the average
joe is going to come up with a Baker Super Schmidt Meteor Camera at
f/0.65....and if he did, I think you are going to hear some screeching brakes
when he see's the price tag. You also mentioned the use of a Kodak Aero Ektar
camera...not too many folks can get their hands upon an aircraft camera
lately either. I think the average person...particularly the novice is going
to start out with a 35mm....and probably stick with the 35mm....or perhaps go
to the medium format at best. I think camera info for beginners would be more
useful if given in terms of a 35mm camera.
You refer to lenses as being "Conventional" for Type A and Type B camera's.
What do you mean by "Conventional"? I haven't heard this term being used
before. Is this another way of saying a lens is "Normal"?
Another useful book for meteor photography...particularly for beginners is
the one by Juergen Rendtel for IMO entitled "Handbook for Photographic Meteor
Observations". I think it will be a little more easier to acquire than the
one's by Millman and others you have listed.
George Zay