Go Back   IceInSpace > Equipment > Astrophotography and Imaging Equipment and Discussions

Reply
 
Thread Tools Rate Thread
  #1  
Old 08-02-2019, 03:32 PM
Stonius's Avatar
Stonius (Markus)
Registered User

Stonius is offline
 
Join Date: Mar 2015
Location: Melbourne
Posts: 1,495
Dumb question re field flatteners and barlow/powermates

So far I've used my powermates just for planetary where I don't bother with a field flattener because the curvature over the width of a planet is likely to be negligible.

But say I want to try for a smaller DSO - planetary for example, or a galaxy, whatever...

Do you then need to put the field flattener back in there, or does the magnification flatten things enough since you're just seeing the centre of the field on your sensor?

And if you *do need your flattener, does the imaging train go Flattener - Powermate - OAG or Powermate - Flattener - OAG?

I feel like I *should know the answer, but I don't. Guess I could spend a couple of hours faffing and find out, but I'd rather not waste precious imaging time if someone here knows the answer straight up. Otherwise, a-faffing I will go.

Thanks

Markus
Reply With Quote
  #2  
Old 08-02-2019, 07:24 PM
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,381
Can I add a dumber question please, do you need a field flattener for visual for any reason

thanks Stonius
Reply With Quote
  #3  
Old 08-02-2019, 09:16 PM
Camelopardalis's Avatar
Camelopardalis (Dunk)
Drifting from the pole

Camelopardalis is offline
 
Join Date: Feb 2013
Location: Brisbane
Posts: 5,425
If you’re putting a powermate in-line, then you’re effectively increasing the focal length of the scope, and thus increasing the radius of curvature of the scope, resulting in less severe field curvature than before.

Just remember that any field curvature is going to be at maximum on the field edge, not near the centre.

Field flatteners are important for imaging where the camera sensor is flat, whereas the focal plane (especially so in small refractors) is curved. Without correction, the stars would be out of focus towards the edges/corners.

The eye generally accommodates field curvature, but eyepiece design can influence how it appears, and some eyepieces are more suitable to some types of scope than others.
Reply With Quote
  #4  
Old 08-02-2019, 09:41 PM
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,381
Reply With Quote
  #5  
Old 08-02-2019, 10:23 PM
Stonius's Avatar
Stonius (Markus)
Registered User

Stonius is offline
 
Join Date: Mar 2015
Location: Melbourne
Posts: 1,495
Thanks Dunk.

And Jeremy, +1 to what Dunk said about visual. :-)
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 08:26 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement