(meteorobs) Re: Off-Topic X-ray film etc.

Ed Majden epmajden at shaw.ca
Sat Sep 3 19:57:47 EDT 2005

on 9/3/05 15:17, Richardson, Terry R. at RichardsonT at cofc.edu wrote:

> Ed,
> I am afraid I have some unfortunate news about your lens. The lens you have is
> called an "x-ray" lens because it was used to photograph the phosphor screen
> in an x-ray imaging sequence.

    Thanks for the info on the Rayxar lens.  I didn't consider it being used
to photograph a green phosphor screen but your probably right.  I wonder why
the high speed in this case?  Do you know what the spectral characteristics
of X-ray film are?  What range do they cover.  Millman/Halliday used Kodak
spectroscopic 103-0 emulsion on glass plates.  Probably rather expensive if
still available.  Many of these emulsions are either not available or are
special order these days.  Back in the 1950's Peter Millman had a special
lens made for near UV spectra, quartz I think.  At least the 300 g/mm
transmission grating was ruled on a quartz blank.  I have a B&L precision
replica, blazed for 4000A that I use on normal lenses.  I bought it second
hand otherwise I would have got one blazed for 5000A. I can get down to
around 3600A/3700A with it.  Ian Halliday said he didn't know the exact
specs on their lens but used it for meteor spectroscopy.  It covered a range
down to 3000A but that was probably the limit set by atmospheric absorption.
Ian Halliday wrote a paper on his UV spectra, Publications of the Dominion
Observatory Ottawa Volume XXV - Number 12, A Study of Ultraviolet Meteor
Spectra. (1969).  A very interesting paper on this topic.  Unfortunately, as
an amateur I don't have the big dollars to spend, so I try and find surplus
stuff and hope for the best! ;-)


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