From: shoppa@almach.caltech.edu (TIM SHOPPA)
Newsgroups: rec.models.rockets
Subject: Re: Astrocam 110 Film
Keywords: 400 speed 110 film still being produced?
Date: 11 Sep 92 18:28:00 GMT
 <9SEP199214030585@almach.caltech.edu> <BuE9zI.HGJ@usenet.ucs.indiana.edu>
Organization: California Institute of Technology
News-Software: VAX/VMS VNEWS 1.41
News-Software: VAX/VMS VNEWS 1.41

In article <BuE9zI.HGJ@usenet.ucs.indiana.edu>, ntaib@silver.ucs.indiana.edu (Iskandar Taib) writes...
>In article <9SEP199214030585@almach.caltech.edu> shoppa@almach.caltech.edu (TIM SHOPPA) writes:
> 
>>My Mission: to launch my Crown Graphic 4" x 5" sheet film camera to 2000 ft.
>>Actually, with all this talk, I'm seriously thinking about launching a
>>small 35mm camera on a rocket.  With a nice lens, decent exposure, and
>>a short enough shutter speed to eliminate blurring, I'm sure I could make some
>>remarkable shots!  I wonder if I was clever enough, if I could use
>>some mercury switches to ensure the camera was pointed at the right angle
>      ^^^^^^^^^^^^^^^^
>uh oh not again  9-) Remember this?
> 
Yes! As you and many others have pointed out, it is hopeless to use
mercury switches in an accelerating/deaccelerating/rolling rocket to
sense direction.  I'm a physicist (or at least a proto-physicist) so
I should have known better!  Doing nuclear physics all the time tends to
make you forget about, say, gravity...


>>to take the picture, thus eliminating the "blue sky" shots I ended up
>>when I used my astrocam (launched 3 times many, many years ago before
>>being smashed to pieces when the engine blew out of the back of the rocket
>>instead of deploying the recovery system!)
> 
As has been suggested here before, perhaps the way to go is an auto-advance/
continuous firing camera.  Cheap ones can do a shot every 1.5 seconds or so,
while some special cameras with high-speed motor drives can do 8 or more
frames a second!
> 
> 
Iskandar points out (in a comment which I unfortunately accidentally deleted)
that disposable cameras are light and cheap, too very good points for mounting
them in a rocket.

I have several disassembled disposable cameras sitting here in my desk
drawer (I take them apart and develop the film myself.)  They are really
very easily reloadable (in a darkroom).  They actually wind the film into
a metal cartridge as the film is advanced (instead of out of a metal cartridge)
so even in the event of a crash the exposed film might survive unharmed!
Perhaps I'll see if I can fit one of these with a homemade spring-wound
autowinder.  With 36 frames per roll, two frames per second might be a
reasonable rate to capture most of the flight.  Most of the frames might
be pretty dull, but you don't have to print those!

Playing with one of the disposables in my desk drawer, I have just found that
by holding down the fire button while advancing the film that these
cameras do have a "continuous firing" mode!  (The ones I happen to have here
with me are all Kodak Panoramics.)  They have a built in counter which limits
them to 12 frames, but by removing the counter/cam disk on which the numbers are
displayed, I can get as many exposures as there are in the roll of film.  All
I have to do is hold down the shutter button and advance the film to get as
many exposures as I want!  And it looks like the wind rate can easily be
above 2 frames a second!  This is great!  Now all I need is to find the
mechanism to wind the film, maybe a disassembled windup toy car will do.

Sorry for thinking on the net like I just did in my previous post, but
sometimes I think most creatively in front of a keyboard!  This weekend
I'll try to get something thrown together, and report on it next week!
This looks promising!
					Tim (Shoppa@erin.caltech.edu)
Newsgroups: rec.models.rockets