Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Mounts

Pages: 1 | 2 | (show all)
Raginar
Post Laureate
*****

Reged: 10/19/10

Loc: Rapid CIty, SD
Re: First equatorial mount questions new [Re: orlyandico]
      #5663254 - 02/05/13 10:17 AM

Quote:

One issue with OAG is that it places much more stress on your focuser.



+1. It can introduce issues through flexure as well.


Post Extras: Print Post   Remind Me!   Notify Moderator  
orlyandico
Post Laureate
*****

Reged: 08/10/09

Loc: Singapore
Re: First equatorial mount questions new [Re: Raginar]
      #5663306 - 02/05/13 10:36 AM

i mention the OAG focuser flexure issue because i used an OAG for a while.

the focuser sagged a tiny bit which caused the CCD sensor to become non-orthogonal to the image plane. net result - stars were oblong on one side of the image.

the only way to address focuser sag is a pricey Feathertouch focuser. that focuser alone is 400 bucks - as much as a used CG5 mount.

i went back to guide scope, because i wasn't willing to pony up for the Feathertouch.


Post Extras: Print Post   Remind Me!   Notify Moderator  
neptun2
scholastic sledgehammer


Reged: 03/04/07

Loc: Bulgaria
Re: First equatorial mount questions new [Re: orlyandico]
      #5663372 - 02/05/13 11:06 AM

Well i personally never had problems with focuser load and OAG and my scopes used pretty standard focusers. My load is nikon d90 dslr , flattener/coma corrector , TS 9mm off-axis guider and meade dsi 2 pro. The whole weight is around 1.2 kg. I used it on both my 8" newtonian and now on my 120 ed refractor without any problem. The newtonian was relatively old skywatcher model from 2008 and used pure rack and pinion focuser without fine focus adjustment. The refractor is with dual speed crayford with relatively long travel distance. Of course it is possible that some combinations of of focuser and accessories can cause such ortogonality problems but it is not so common and not always needed to go with feathertouch to avoid it.

Post Extras: Print Post   Remind Me!   Notify Moderator  
orlyandico
Post Laureate
*****

Reged: 08/10/09

Loc: Singapore
Re: First equatorial mount questions [Re: neptun2]
      #5663408 - 02/05/13 11:27 AM

i had a much bigger OAG than the TS9. this caused a longer moment arm.

the TS9 isn't exactly cheap, either..

but you won't know till you try. the problem with AP is that when you solve one problem (the biggest enemy of star roundness is the mount) some other factor comes in.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
18 registered and 37 anonymous users are browsing this forum.

Moderator:  Dave M, richard7, bilgebay, iceblaze 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1393

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics