Re: ATM Still seeing double after remounting secondary...!

["samorawski" <samorawski@3web.net>]

Hi Chris
To eliminate the diagonal mirror...
Try setting your mirror on a sturdy test stand that adjusts up and down and
holding an eyepiece in a adjustable home-made eyepiece holder at the
focus.The eyepiece will be off axis,  so as your head does not block
incoming rays.With patience you can catch the moon, Venus or a bright star
just above the horizon, or easier yet a neighbours security lamp.
The eyepiece holder can be made from scrap 3/4"pine, boring a 11/4 in. hole
for the eyepiece, a slot, for adjustment with a bolt and nut and a base.
During daylight a distant tree, bushes or hydro lines can be focused and
observed, hopefully with crisp images!
Regards
Sam Orawski
samorawski@3web.net


----- Original Message -----
From: "ChrisR" <chrisr@es.co.nz>
To: <atm@shore.net>
Sent: Saturday, August 11, 2001 5:39 AM
Subject: ATM Still seeing double after remounting secondary...!


>
> Was "Troubleshooting double image from 10 " f6 Dob."
>
> Those of you who replied to my previous questions, thankyou.  I
> remounted the secondary mirror using 3 small spots of a silicone
> adhesive that remains flexible when set.  Still I see exactly the same
> double image!  The doubles are perhaps a little clearer due to the lack
> of strain in the secondary...  The eyepieces are not in question and the
> alignment is fine.  I can only think that the main mirror is at fault or
> the secondary mirror was permanently deformed from its hard glue
> experience.  If anyone has any tests up their sleeve to isolate the
> problem I would love to hear them.  Personally I was really set on the
> secondary mirror being the problem....maybe its still warped?  It had
> previously been used in a 12.5" telescope with no problem apparently.
>
> To remove the secondary from the aluminium slab  (it was hard glued with
> one of those two part glues as it turns out) a special solvent was
> used.  The outer areas of the glue disolved and the stress between the
> remaining glued portion of the secondary and the aluminium was such that
> the back of the secondary fractured!  The secondary came free leaving a
> few mm sliver of glass on the aluminium.  The secondary back was then
> reground flat and came out a few mm thinner but still 10 mm thick in
> total.
>
> Regards,
> Chris.
>
>
>
>
>