[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: [ATM] Off-axis Newt

To: <atm@atmlist.net>
Subject: Re: [ATM] Off-axis Newt
From: "John Sherman" <atm@mail.johnspics.com>
Date: Tue, 31 Jan 2006 15:22:41 -0500
List-Archive: <http://www.atmlist.net/pipermail/atm>
List-Help: <mailto:atm-request@atmlist.net?subject=help>
List-Id: The Amateur Telescope Makers List <atm.atmlist.net>
List-Post: <mailto:atm@atmlist.net>
List-Subscribe: <http://www.atmlist.net/mailman/listinfo.cgi/atm>,<mailto:atm-request@atmlist.net?subject=subscribe>
List-Unsubscribe: <http://www.atmlist.net/mailman/listinfo.cgi/atm>,<mailto:atm-request@atmlist.net?subject=unsubscribe>
Reply-To: atm@mail.johnspics.com
Sender: atm-bounces@atmlist.net


Hi Bob,

>So, I'm now contemplating
>converting my 16" f/5.4 Dob into an unobstructed scope.

Hmmm. You will still have 84" focal length, so, assuming a 3" secondary, your 16" will become a section of a 35" f/2.4 parabola. Can you live with the coma of a 35" f/2.4 mirror? Can you make a custom, "off-axis" coma corrector? I think a toroidial secondary only corrects astigmatism from tilting the 16" parabola. 

I expect you will always get the best image leaving it as a Newt. 

Be happy!

John



_______________________________________________
ATM mailing list http://www.atmlist.net/

Follow-Ups:
- Re: [ATM] Off-axis Newt
  - From: Mark Holm <mdholm@telerama.com>

Prev by Author: Re: [ATM] modern Herschelian telescope
Next by Author: Re: [ATM] Dense
Prev by thread: Re: [ATM] Off-axis Newt
Next by thread: Re: [ATM] Off-axis Newt
Index(es):
- Author
- Thread