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 >> ATM, Optics and DIY Forum

Pages: 1 | 2 | 3 | (show all)
derangedhermit
Pooh-Bah


Reged: 10/07/09

Loc: USA
Re: Secondary Size Revisited - A New Realization? new [Re: dvb]
      #6169811 - 11/01/13 08:47 AM

Quote:

I would not reduce the tube diameter to make decrease the secondary size - at least 1" is needed in addition to the radius of the primary to ensure proper air flow to deal with thermal currents in the tube.




Tube currents are probably the dominant factor in picking a tube size for tube OTAs, unless forced air cooling removes the need for the extra room. The need for additional UTA diameter for cooling or airflow considerations for truss telescopes is much less clear. I've seen no statement that a problem exists that needs to be addressed.

I was trying to inform on the purely optical tradeoffs. If people want a larger secondary and bigger OTA or taller focuser so the eyepiece height is lower, that's another tradeoff.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | (show all)


Extra information
14 registered and 20 anonymous users are browsing this forum.

Moderator:  ausastronomer, richard7, Starman81 

Print Thread

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


Thread views: 1886

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics