Celestron Regal 100 (7 Viewers)

[IvanCavallazzi]

Assuming the collumination is correct and the problem is a poor eyepiece will the C90 or the C135 outperform the Regal 100 because of the longer focal length of the C scopes? No sense to buy another scope if I can get the performance I need with a simple change of eyepieces.

No. The focal length just means you will acquire different magnification with one specific eyepiece.
(For example a 17mm eye piece will show a far bigger magnification in the C90 if compared to the regal)

C90, C5 and so... are cheaper because the design(catadiotric) is cheaper to make.

It uses mirror to condense the light instead of lenses.

The design do not show the same contrast you will be able to find in refractors.

If you want the best image possible, refractors are the way.
The only way to see even better images than spotting scopes is to remove the porro prism and using a star diagonal(reversed images left to right).

 

[henry link]

A "better" eyepiece is not going to help. Cheap simple eyepieces will show all the detail available in the field center of your scope's image if you're using enough magnification. Even edge sharpness should be OK with a cheap eyepiece since your scopes present an easy f/10 light cone.

 

[Gary R]

Henry..... would you then suppose the problem with non sharp immages is in the collumination?

 

[RJM]

Gary, there are many variables that conspire to prevent you from achieving your goal. Even if your optics were perfect the dust/turbulence in the atmosphere will tend to blur your images at the high magnifications needed to resolve the target at distance. Even if the atmosphere was perfectly clear/stable the high magnification you will need yields small exit pupils that also affect your ability to resolve fine detail.

You can determine the minimum magnification needed by measuring the furthest distance that you can see bullet holes clearly naked eye and then dividing this distance into your expected target range. So say you can see holes clearly with your targeting eye at 6m and you expect to shoot at 600m, 600/6=100x minimum magnification. Practically 100x is only doable on the C135 as you really don't want an exit pupil less than 1mm as your eye's ability to resolve detail will suffer. To get 100x on a C135 requires and eyepiece with a focal length of ~12mm. As Henry said, virtually any eyepiece design will be "good enough" in these CAT scopes. The main feature you need to look for is comfortable eyerelief.

 

[normjackson]

A bit OT

Yesterday evening watched a bit of "Surviving the Cut" about training snipers for military :
http://dsc.discovery.com/videos/surviving-the-cut-unknown-distance-test.html
Would have thought some kit which allowed only near infrared onto a CMOS or CCD device of reasonable resolution could work well. Presumably wouldn't need a highly colour corrected scope either In the stuff I watched, the snipers "helpers" used small Leupold Golden Ring scopes and the adjudicator a Kowa Highlander bin by the look of it $$$$

Wonder if Gary checked his scopes...