From: "Russell Jocoy" 
To: arsenault{at}upei.ca, atm{at}shore.net
Reply-To: "Russell Jocoy" 


>From: Garth Arsenault 
>Reply-To: Garth Arsenault 
>To: atm{at}shore.net
>Subject: ATM secondary mirror
>Date: Thu, 17 Jul 2003 00:08:37 -0300
>
>
>Hi list,
>
>I have just finished figuring my 10" BVC mirror (what an ordeal!) I
>ended up doing my figuring with a full sized lap and it only took
>about 25 figuring sessions (groan) to get my figure. I am anxious to
>star test to verify if the 1/25 wave error is accurate from my
>foucault test. I have the rest of my truss style dob almost complete.
>What is the best material to fasten the secondary mirror to the
>diagonal wooden dowel. Should I use silicone, epoxy or another
>adhesive?
>
>Also, To date I have only a 25mm eyepiece, will this be sufficient to
>do my star test or do I need to have more power than this will give
>me? My mirror has a focal length of 57.5 inches which will give me
>about 60X mag.
>
>Thanks
>
>Garth
>



("atm{at}shore.net")

  Garth my friend,
  Buy yourself some nice eyepieces smaller than 25mm. You have made a mirror
that has the potential
to resolve 350x to possibly 450x , you need to check it out.. A star test
is usually done with the max
that your mirror can take without distortion.  This will tell you more than
a lower power eyepiece which
will tell you what you "want to see". Test that baby out, and see
if your interpitations on the tester are
correct.    You can look through an incomplete mirror at low power and think
the image is fine,  I
know my image of the moon looks fine but the ronchi screen tells me I have
a turned edge and
an incomplete parob..
                   You can find inexpensive eyepieces from many places, but
the cheapest cost and best
quality can be found at surplus shed.,, which can be found on the net.,,
                If you have the cash go ahead and invest into some real nice
plossels or if you are independently wealthy just buy the whole teleview
line of eyepieces & then buy two or three Naglers preferably the wide
angle hand grenades. Sorry I am getting carried away into my own  dreams of
grandure.....
                Your secondary mirror can be attached to your own  choice.
If you have a fixed dowel, I would
modify it to have some type of adjustment. Your primary mirror can not
adjust all to your secondary.
  Typically in days of old you would glue a piece of felt to the dowel's
diagonal and use mini clips to
hold the secondary. Nowdays most people use silicon caulk to connect the
secondary to primative
supports. There are numerous site on the web for various modifications of
this attachment.
                                        Russ Jocoy
("atm{at}shore.net")

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