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Re: [APML] Astrograph lenses??

At 22:17 12/17/02 -0600, you wrote:
>I was looking at astrographs on astromart and seen these suposed astrograph
>lenses: http://www.astromart.com/classifieds.asp?c=2
>Are these indeed useful to make an astrograph?
>If so, I have an american science and surplus store here that sells these
>things for like 5 bucks and Id say there are about 30 of them just sitting
>there in a pile.

         Which one - the Kodak or the Pacific telscope one?  In either 
case, they are and are not good.  These lenses are or were designed to be 
balanced for sharp focuss int eh red, not the blue.  Without a red or 
yellow fitler, blue light will bloom out liek crazy on you.  Fine with tech 
pan however.

         also, the kodak one (serial number should read EM, not EN) is 1943 
vintage,a nd I have a 178mm myself, so odds are this one used Throium slats 
in the reat two elements, so it is radioactive, but mildly so.  Not 
dangrourus, but if you leave on on a sheet of film overnight, you will see 
fogging / strikes.  Not sure if the Pacific one is hot or not, but I woudl 
bet the Kodak one is.  I know my 178mm Kodak (same year of manufature) is.

         BTW - bit of triv1a for all of you - you can date any kodak Ektar 
(or other lens) by the serial number.  Woks like this

  C  A  M  E  R  O  S  I  T  Y
  1  2   3   4  5   6  7  8  9  0

         therefore, the serial numbers on the astromart ad given as "EN727" 
- and should read as "EM727" - translates into E= 4 and M=3. there, 43 - or 
1943 - is the year of manufacture.
         However, they are superb lenses, overall amazingly sharp, 
considering the time they were made.

         On a side note, can you really get them cheap nearby?  if so, they 
make superb large format lenses (daytime, terrrestial shooting),a nd i 
woudl love to pay my hands on one.  Contact me off list if you would.

>How do you make an astrograph out of one of these things?


         Now that's a long story, but unless you are looking to shoot tech 
pan in medium or large format, they are nto worth the effort.
anytiem
joe




http://www.oneilphoto.on.ca
http://www.multiboard.com/~joneil
Una salus victis, nullam sperare salutem



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