Greetings, dear Meade users!
I want to achieve maximum magnification on my Meade Polaris 90, but without using Barlow lens.
As far as I understood theory for this model:
- Clear Aperture (") 3,5
- Focal Length f/10 (mm) 900
- Focal Ratio 10
- Eyepiece(s) Three (3) 1.25" MA (26 mm, 9 mm & 6.3 mm)
- Minimal Useful Magnification (CA/6) 15
- Maximal Useful Magnification (CA*2) 180
Therefore maximal useful magnification 180× is achieved with ocular 5 mm, which is just a not much smaller then that supplied 6.3 mm.
However market offers oculars 4 mm that theoretically deliver magnification 225×, but it exceeds maximal useful magnification 180×.
Do you suggest me to purchase a 4-mm ocular for this model of telescope?
What optical artifacts can I experience with a 4-mm ocular?
Thank you for a detailed reply.