ATM First Newtonian

[Greg Granville <greg@laser.arl.psu.edu>]

>I used the
>graphic collimation images on Mels page as a guide to rough colimation. 
>Any newbies out their, I was able to get a crisp image in about 15
>minutes using these graphic representations.
>
>But how much can my image suffer if I have not used a laser and end up
>being out by a beam diameter or two?  I suppose that would also depend
>on my focal ratio (f7.3).

If your mirror is F7.3, the scope should work just fine even if the
collimation is off just slightly. The center of the "sweet-spot" may not be
prefectly centered in your FOV, but it will probably be close. The so called
"sweet-spot" is fairly large for a scope this slow anyway. 

>Although I feel a laser would be the most precise method, is it really
>required. I don't know about any of you out their, but I find my
>personal budget has shrunk (but my quality of life has improved!) due to
>this hobby and I don't really want to rush out and buy a laser now
>unless required.

I'm firmly convinced that you don't NEED a laser collimator get good, or
excellent collimation. You should not feel that your scope won't perform to
its potential if you don't drop a wad of cash on a laser collimator - it's
simply not true.
I'm very frugal when it comes to buying "gadgets". Heck, I don't even own a
real Cheshire. The old 35mm film can (clear plastic) works just dandy for
me. I paint a very small black dot around the peep-hole. (to enhance the
edge of the peep-hole aperture)
It works great in the daytime, and at night I use a small penlight to
illuminate the plastic cap from the side.
If you want super critical collimation, tweak it while looking at a star at
high power. 
For me, this is what ATM'ing is all about - don't buy something if it's at
all possible to build it yourself :-)

~~~
Greg Granville  Applied Research Lab - PSU 
greg@laser.arl.psu.edu      greg@penn.com  
      http://users.penn.com/~greg