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Starmaster 14.5 telescopes   Message List  
Reply | Forward Message #17683 of 17869 |
RE: [starmaster_scopes] Starmaster 14.5 telescopes

Thanks so much.Joseph.
-------------- Original message from "Joe Castor" <Joe_Castor@...>:
--------------




Dear Joseph,
A paracorr is a "required" option. At 4.3f, coma is a given effect, but is
easily corrected with a TeleVue paracorr.
Also, the weight balance of your Starmaster is set to assume the use of a
paracorr.
I've had my 14.5 for nearly 4 years now and just love it. it is the second
most perfect Dob on the market. It was the best until the 16.5 FX was
introduced last year.
Joe C
SM 14.5 w/SkyTracker

-----Original Message-----
From: starmaster_scopes@yahoogroups.com
[mailto:starmaster_scopes@yahoogroups.com]On Behalf Of rozasj@...
Sent: Monday, July 06, 2009 2:19 PM
To: starmaster_scopes@yahoogroups.com
Subject: [starmaster_scopes] Starmaster 14.5 telescopes

Hi,I just bought a 14.5 Starmasters hybrid telescope and experiencing quite
a bit of coma.I used mainly a televue 11mm nagler and 25mm plossl eye
pieces.Should I buy a parracorr? Maybe it has to do with poor
collimation.Thanks for your help.Joseph. rozasj@...

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]
Tue Jul 7, 2009 3:02 pm

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rozasj@...
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Forward 		Message #17683 of 17869 |
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Hi,I just bought a 14.5 Starmasters hybrid telescope and experiencing quite a bit of coma.I used mainly a televue 11mm nagler and 25mm plossl eye pieces.Should... 		rozasj@...
rozasj...
Offline Send Email 		Jul 6, 2009
8:32 pm

rozasj, Yes, you need a parracor for the kind of scope f/ratio you are dealing with. Jim ... From: <rozasj@...> To: <starmaster_scopes@yahoogroups.com> ...
Jim DellaPenna
tomentco
Offline Send Email 		Jul 6, 2009
9:36 pm

Thanks.Joseph. ... rozasj, Yes, you need a parracor for the kind of scope f/ratio you are dealing with. Jim ... From: <rozasj@...> To:...
rozasj@...
Send Email 		Jul 7, 2009
3:50 pm

Dear Joseph, A paracorr is a "required" option. At 4.3f, coma is a given effect, but is easily corrected with a TeleVue paracorr. Also, the weight balance of...
Joe Castor
joe_castor
Offline Send Email 		Jul 7, 2009
2:11 am

I've owned an 18" f/4.5 Starmaster for a little over a year, and it's my first big dob. Should I be using a paracorr? I have noticed that especially at higher...
Michael Hrivnak
musician247
Offline Send Email 		Jul 7, 2009
2:21 am

All parabolic mirrors have coma as one of the optical abberations of the design. It is not a side effect of a poorly manufactured mirror. A perfectly made...
Charlie Miller
millercharlie86
Offline Send Email 		Jul 7, 2009
3:44 am

... But at higher power you magnify the coma. I used to think that coma increased "faster than linear" as you move away from the center of the FOV, so indeed...
John Mahony
jmmahony
Offline Send Email 		Jul 7, 2009
12:52 pm

Charlie Miller CTO, PBXcentral, Inc. 512-744-1510 You are correct. At higher power you are seeing the center of the FOV where coma is smaller but since you...
Charlie Miller
millercharlie86
Offline Send Email 		Jul 7, 2009
1:14 pm

... If it increases at a declining rate as you move further from the center, that implies that it would be less noticeable at low power. -John...
John Mahony
jmmahony
Offline Send Email 		Jul 7, 2009
1:51 pm

... center, that implies that it ... While the "rate of increase" is slower as you move away from the center, the amount of coma is still increasing. So, the...
Charlie Miller
millercharlie86
Offline Send Email 		Jul 7, 2009
2:30 pm

Thanks.Joseph. ... If it increases at a declining rate as you move further from the center, that implies that it would be less noticeable at low power. -John ...
rozasj@...
Send Email 		Jul 7, 2009
3:50 pm

Thanks so much.Joseph ... All parabolic mirrors have coma as one of the optical abberations of the design. It is not a side effect of a poorly manufactured...
rozasj@...
Send Email 		Jul 7, 2009
3:51 pm

Thanks so much.Joseph. ... Dear Joseph, A paracorr is a "required" option. At 4.3f, coma is a given effect, but is easily corrected with a TeleVue paracorr. ...
rozasj@...
Send Email 		Jul 7, 2009
3:50 pm

Hello Charlie, I haven't been online lately, however, I was at TSP with Rick's 22 and my 16.5FX 3.6 and the 28" F3.7, and I completely agree with your details....
John VeDepo
starmaster_2...
Offline Send Email 		Jul 8, 2009
1:38 am
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