[APML]: N2 on film during exposure

[Alfredo Zanazzo <alferd@mbox.lol.it>]

Mike Regish wrote:
> 
> 
> 
> >>I knew I was going to catch you in my trap asking easy TP questions.;-)
> >but now, why dont' you reply to another pertinent question about TP:
> >you have mentioned that you keep TP in N2 WHILE EXPOSING at the
> >telescope.
> >Did I get it wrong or is it a secret?:-) (I have saved that message)
> >
>         I've heard of this, too. With the Pentax K1000 you can drill
> (carefully) a small hole in the tripod mount and get or make a fitting for a
> tank of N2 and just keep running a little gas through the camera. I don't
> know all the details, but that's the basic idea.
>         Don't know how you would do it with other cameras. Probably just
> variations on a theme.

It is interesting! As I use modified cartridges for 4X5 format with an
attachment for the vacuum pump, I could make a sort of double channel
(stereo :-)so while you operate from the back(oth film), you introduce 
...the N2 in the front (of the film surface).
Doubts remain in how to make the floating gas spread over all the film
area (for the 4X5 format) and what kind of vulva , sorry, valve, I could
use to avoid
empting a cylinder for evry single exposure.
Maybe some byble writer will show up....
Ciao
-- 

 Alfredo Zanazzo ( alferd@mbox.lol.it )

Astronomy home page: http://www.lol.it/~alferd/astropag.htm