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 >> Eyepieces

Pages: 1
AlbertaSun
member


Reged: 02/15/13

Loc: Alberta
5x Barlow?
      #5683496 - 02/16/13 01:05 PM

I am new at this and could really use some words of wisdom. My scope is a 500mm F6 - 80mm tube. For some planet and moon shots I would like to crank up the magnification so I can still use a primary lens arrangement. If I put a 5x Barlow in line with my camera, I believe I will achieve a magnification of around 80x (plus).

Although, this isn't a huge number compared to using some of the larger scopes, I think I could be quite happy with images that I would attain. It does cause me to have a lot of questions in my mind -

- Does this make sense??
- How long of an extension tube will I need to achieve focus? Will it be larger than the one I use for my 2x Barlow?
- Because I am starting on bright images, with an F6 tube and a guided mount, will there be any problem with "enough" exposure?
- Should I just bight the bullet and look at and afocal setup? This would come with a whole new string of questions for me.

I know, I know - too many questions (and I probably missed the important ones). Any thoughts, input,experience, would be appreciated. Oh, and one more, if this does make sense, any suggestions on an affordable, reasonable quality product.

Thank you
Larry


Post Extras: Print Post   Remind Me!   Notify Moderator  
johnnyha
Postmaster
*****

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: 5x Barlow? new [Re: AlbertaSun]
      #5683721 - 02/16/13 03:19 PM

Sure, F30 is good for planetary imaging. I'd go with the 1.25" 5X Powermate to avoid vignetting and focus issues. Also, if you are using a DSLR you can unscrew the top of the 5X Powermate and add a T-ring adapter to attach the camera directly.

Post Extras: Print Post   Remind Me!   Notify Moderator  
AlbertaSun
member


Reged: 02/15/13

Loc: Alberta
Re: 5x Barlow? new [Re: johnnyha]
      #5683975 - 02/16/13 06:00 PM

Johnny - thanks for the confirmation on F30 being suitable. I will alos follow-up on your suggestion. This does lead to another question/curiosity in my newby head.

I presently am using a 2" diagonal and my other Barlow is 2" at 2x. When should I be pursuing 2" pieces and when not? Comments??

Thanks
Larry


Post Extras: Print Post   Remind Me!   Notify Moderator  
howard929
Member
*****

Reged: 01/02/11

Loc: Low End of High Ground
Re: 5x Barlow? new [Re: AlbertaSun]
      #5684023 - 02/16/13 06:29 PM

There's a limit to the size of the field stop in a 1.25" eyepiece that forces a jump to 2" eyepieces for large AFOV combined with long focal length. For instance, at 82 degree AFOV, that limit is smaller then 18mm in focal length. Longer focal lengths with the same AFOV requires the larger field stop of a 2" eyepiece. So basically, a 2" eyepiece isn't better, it usually has a wide AFOV and is long in focal length.

Edited by howard929 (02/16/13 06:32 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
AlbertaSun
member


Reged: 02/15/13

Loc: Alberta
Re: 5x Barlow? new [Re: howard929]
      #5686248 - 02/18/13 12:07 AM

Good info Howard - I am going to have to read up a little more on the Powermates(a bit different from a standard barlow). I also need to bone up on some on the technical jargon (ie field stops, etc.)

I would be interested in any additional experience or recommendations out there on using 5x barlows.


Post Extras: Print Post   Remind Me!   Notify Moderator  
AlbertaSun
member


Reged: 02/15/13

Loc: Alberta
Re: 5x Barlow? new [Re: AlbertaSun]
      #5687034 - 02/18/13 02:36 PM

As a less expensive option has anyone tried the Antares "1.25" 5x Barlow with twist lock eyepiece and t-thread"

Larry


Post Extras: Print Post   Remind Me!   Notify Moderator  
rodnocjolly
member


Reged: 10/13/12

Re: 5x Barlow? new [Re: AlbertaSun]
      #5697832 - 02/24/13 06:30 AM

TV 5x Barlow is a great piece of glass.

I use it with success with TV 24 Panoptics and a Baader Hyperion Zoom 8-24.


Post Extras: Print Post   Remind Me!   Notify Moderator  
csrlice12
Postmaster
*****

Reged: 05/22/12

Loc: Denver, CO
Re: 5x Barlow? new [Re: rodnocjolly]
      #5698078 - 02/24/13 11:09 AM

If you're using it for AP, go for the Televue Powermates, with a regular barlow, you could see some field curvature with some eyepieces (especially wide-fields, and it could be from the scope OR the eyepieces). Powermates are telecentric and are better for AP then nontelecentric barlows.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1


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

Moderator:  ausastronomer, droid, cbwerner, kkokkolis 

Print Thread

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


Thread views: 703

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics