----- Original Message -----
From: "Mike J. Shade" <mshade@No-Spam>
To: <sf-bay-tac@No-Spam>
Sent: Sunday, September 28, 2003 4:19 PM
Subject: [TAC] (OT) C14 secondary alignment
> what is the alignment for the secondary for a C-14? Don't the numbers
on
> the front of the secondary "point" about to the Celestron sticker on the
> side of the OTA, more or less?
The corrector plate has a serial number that aligns with the celestron
sticker on the side. You cannot see the serial number unless you remove the
retaining ring.
The FASTAR secondary has a slot where the alignment pin is inserted. That
slot aligns with the same celestron decal, which is the one on the right
side of the scope as you are looking at the visual back.
>
> Amount of variation allowable?
Just get it close.
>
> Also, what is the tension on the retaining ring for the secondary? It
> should be turnable with little hand pressure not really not tight,
correct?
If you make it too tight the entire FASTAR receiver will rotate in the
corrector plate. My C14 also has a bit of lateral play in the FASTAR
receiver. It is a really good idea to remove the fastar secondary, look down
the front of the scope and make sure that receiver is properly concentric
with the primary mirror. Mine needs to be shoved all the way to one side.
Out of two C14's I am intimately familar with, both have their optical axis
offset slightly from the mechanical axis. I believe the baffle tube is not
perfectly perpendicular to the rear casting and have learned that Celestron
had a QA problem with their subcontractor that did the machine work for
them.
Mine works great once I learned all this stuff and aligned it properly. I
also made and installed mirror locks to further improve it for imaging,
which is all I use mine for.
http://www.rdcrisp.darkhorizons.org/mirror_locks_to_solve_c14_page.htm
When I added the Dichroic Beam Splitter to permit the use of an AO7, it
really kicks butt:
http://www.rdcrisp.darkhorizons.org/dichroic_beam_splitter_page.htm
http://www.rdcrisp.darkhorizons.org/trapezium_sii_page.htm
Hope this helps, Mike.
Richard