From: "Kreig McBride" 
To: 
Reply-To: "Kreig McBride" 


My personal choice is f/6 (I always prefer the larger number).  Using a
small ladder can actually be an advantage. I find the ladder a usefull tool
for observing, allowing me rest against the ladder and observe longer. 
When chaseing down Pluto in my 8"  i like to be able to to position my
head so i can concentrate on the view, counting stars and looking at star
patterns. Much easier sometimes than standing without a balance support.

The BEST views I have ever seen of Saturn were through a homemade 14" f/7 Newt.

Kreig


----- Original Message -----
From: "Bob May" 
To: "atmlist" 
Sent: Sunday, July 13, 2003 11:12 PM Subject: Re: ATM 14 inch f/6 or f/5


>
> Ah, the choices!
> Do you go for a nice instrument that you can easily use without the need
for
> a stepladder or do you go and get the nicer long focal length but need to
> have a stepstool step or two to see near the top of the viewing range!
> My preference is to see where your eyes are when you get on a single step
> (the homemade eyepiece case that you can step on to see things high in the
> sky) and consider that to be the focal length that you wish to strive for.
> Anything less and the times that the need for magnification will be more
> difficult to achieve while anything more will tend to keep the scope from
> looking at the stuff that is near overhead at the moment.
> At 14", the choices are rather large and I'd suggest the longest that you
> can feel comfortable with will be the best choice.
> Also look at what any particular EP will give for a FOV if you are more
> desirable of the larger views.
> I'll also note that there is nothing wrong with a partial figuring with
the
> mirror and you should probably do so.  Since you are making up a stressing
> harness, why not do it in reverse (push on the center of the glass while
> doing your final polishing) and see how close you can get to a paraboloid
> while doing that.  My bet is that you will very nicely do a paraboloid the
> first time if you can do a good sphere while the mirror is stressed!
> Bob May
> http://nav.to/bobmay
> bobmay{at}nethere.com
> NEW! http://bobmay.astronomy.net
>
>
>

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