A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Amateur Astronomy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

would you say this is a good deal? 12.5 dob truss



 
 
Thread Tools Display Modes
  #1  
Old January 19th 05, 08:41 PM
Impact9
external usenet poster
 
Posts: n/a
Default would you say this is a good deal? 12.5 dob truss

http://www.astromart.com/classifieds...fied_id=325218

I'm considering purchasing this home made truss. Sellers ratings are
good and from other post i've read astromart is a good place to buy.

I don't really know what to ask the seller. Help!

I'm limited to some catadioptric and truss designs do to the fact I can
only get items shipped via USPS. (Overseas U.S.A.F.)

Thanks all

DH

  #2  
Old January 20th 05, 03:22 AM
Uncle Bob
external usenet poster
 
Posts: n/a
Default

Impact9 wrote:
http://www.astromart.com/classifieds...fied_id=325218

I'm considering purchasing this home made truss. Sellers ratings are
good and from other post i've read astromart is a good place to buy.

I don't really know what to ask the seller. Help!

I'm limited to some catadioptric and truss designs do to the fact I can
only get items shipped via USPS. (Overseas U.S.A.F.)

Thanks all

DH



Ask him more about the mirror figure. Ask him to fax you an
interferometry report. Everything else on the scope is low-ball, imho.
It's cheap, but we don't have any idea how good the optics are, or if it
moves well. I don't like the truss tubes. An f/4 scope is going to be
very sensitive to collimation, so either you're going to have to
re-collimate on every assembly, or do something with the truss tubes to
ensure repeatable re-assembly. Are those conduit clamps he's using at
the mirror box? Ugh!
The back of the mirror box is closed. It will take this scope a long
while to cool.

So imho, the value of the telescope structure is slightly more than
zero. The value of the optics are variable, depending on how good they
are. If the optics are good (and you can determine this with a foucalt
tester, ronchi or interferometry test), it might be worthwhile.

It appears to be a very unremarkable home-made scope on the surface.
I'd pass unless I could look through it before writing the check.
That's my *opinion*.
Good Luck!
Uncle Bob
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Good news and bad about Mars rover... Steven James Forsberg Policy 2 January 26th 04 12:12 PM
Truss tube design? starman Amateur Astronomy 18 January 3rd 04 10:14 PM
Requirements / process to become a shuttle astronaut? Dan Huizenga Space Shuttle 11 November 14th 03 08:33 AM


All times are GMT +1. The time now is 12:22 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.