#1  
Old 30-11-2009, 07:51 AM
tlgerdes's Avatar
tlgerdes (Trevor)
Love the moonless nights!

tlgerdes is offline
 
Join Date: Mar 2009
Location: Sydney
Posts: 2,284
Monochrome imaging with Achromat

Hi Guys and Girls,

If I am imaging with a mono CCD, apart from quality of lens, does APO matter?

Saving my pennies for a QHY9 mono, and already have a 120mm achromat sitting in the cupboard.
Reply With Quote
  #2  
Old 30-11-2009, 08:25 AM
avandonk's Avatar
avandonk
avandonk

avandonk is offline
 
Join Date: Aug 2005
Location: Melbourne
Posts: 4,786
If you use narrow band filters an achro is fine. You will need to refocus if you change filters.

If you intend to use RGB filters I am sure you will find that blue will give you the most grief as the deep violet will not focus at the same position as visible blue. Visible red and HA will also not be in focus at the same position but it is not as bad as the blue end.
I use a 150mm F5 Skywatcher achro for narrow band data. It has a Hutech FR/FF (7887) so has a focal length of 640mm and f/4.25.

Here is 16x2 min frames of HA at 1600 ISO before the cloud arrived. This is just a test. 2.5MB

http://d1355990.i49.quadrahosting.co...2070_32m_g.jpg

Bert
Attached Thumbnails
Click for full-size image (IMG_8977sm.JPG)
79.1 KB42 views
Click for full-size image (RZ_2MRZ_ALL_LGREY_10_10sm.jpg)
175.5 KB57 views
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 08:56 PM.

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