Re: ATM 6in. F/10

[das@po.cwru.edu (Dave Sopchak)]

> Could anyone give advice on how difficult it would be to grind a 6in, F/10
>or F/12 mirror?

Not bad at all- my first one was a 6" f/9.4

> Assuming no previous experience, how long should it take to
>complete it?

A weekend or two at most to grind out, maybe a week to polish (spare time
wise),and maybe six weeks (at most!)to get a killer figure. That's how long
it took me, and believe me, I took the long way home.

>would a mirror such as this give better planetary and lunar
>images than a 10in. F/6/ Any help appreciated!  JIM

Having just completed a 10" f/5.7, I'd have to say no, but it is certainly
in the ballpark. The main thing that the 10" does for me is to pull in
three times more light, which ups the contrast on planetary images and
allows me to go up higher in magnification before contrast suffers.

        I would strongly reccommend the 6" f/9ish as a first mirror. I
learned a lot making it, it wasn't a daunting task, and I did it with no
other info than Texereau's "how to make a telescope" book. You have the
advantage of being on this listserver and having access to all these folks
who can help you out every stage of the way.
        My 10" wasn't too tough, but I'm glad I had the experience of a 6"
f/9 and a 6" f/6 under my belt. This winter I start on my 18.5"er. You can
always give your 6" to a friend after you go up in size, that's what I did,
and I'm giving my other 6" to my brother.

My inspiration while figuring my first 6" was a great article in S&T, one
of the spring issues of 1992, where they compared 4 6" mirrors of varying
surface accuracy. The best one gave images almost as good as a 7" refractor
on Jupiter. If that doesn't get you fired up, nothing will. READ IT.

Good luck and clear skies,

Dave

___________________________________________________________
...and, for best supporting electrolyte, the nominees are...