Can someone just confirm my math is correct based on the image shown below please?
This link is to an image which has been resized by exactly 50%
regards
Kev
Stage micrometer slide image
Moderators: rjlittlefield, ChrisR, Chris S., Pau
- Photosbykev
- Posts: 14
- Joined: Fri Mar 06, 2015 4:37 pm
- Location: Gloucester, UK
- Contact:
- rjlittlefield
- Site Admin
- Posts: 23621
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
- Photosbykev
- Posts: 14
- Joined: Fri Mar 06, 2015 4:37 pm
- Location: Gloucester, UK
- Contact:
- Photosbykev
- Posts: 14
- Joined: Fri Mar 06, 2015 4:37 pm
- Location: Gloucester, UK
- Contact:
- rjlittlefield
- Site Admin
- Posts: 23621
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
That's the correct approach to nominally minimize aberrations.Photosbykev wrote:I mounted the LSA on a M42 tube extension and a M42 > M52 helical focuser and then used the focuser to focus on a star last night so it's at a true infinity.
If having exactly 10.0X magnification ever becomes important, you can slightly increase the extension behind the LSA to achieve that. With the roughly 3% increase needed to go from 9.67X to 10.0X, you would never notice a change in aberrations. This is the method that I used to match magnification and field size in my tube lens tests at http://www.photomacrography.net/forum/v ... hp?t=23898 .
--Rik
- Photosbykev
- Posts: 14
- Joined: Fri Mar 06, 2015 4:37 pm
- Location: Gloucester, UK
- Contact:
I'm not overly worried by the exact magnification, 9.67x is just fine now I know what it is I need to flock line the extension tube to minimise any internal reflections and I'm good to gorjlittlefield wrote:That's the correct approach to nominally minimize aberrations.Photosbykev wrote:I mounted the LSA on a M42 tube extension and a M42 > M52 helical focuser and then used the focuser to focus on a star last night so it's at a true infinity.
If having exactly 10.0X magnification ever becomes important, you can slightly increase the extension behind the LSA to achieve that. With the roughly 3% increase needed to go from 9.67X to 10.0X, you would never notice a change in aberrations. This is the method that I used to match magnification and field size in my tube lens tests at http://www.photomacrography.net/forum/v ... hp?t=23898 .
--Rik
regards
Kev