Had to pull this one up from the dead
for an update.
Today I got in two products to go along with my C130 Mak (see above):
1. A C90 Mak - fantastically good range scope value - much more handy size for lugging to the range & back than the C130:
http://www.opticsplanet.net/celestron-c90-mak-spotting-scope.html
3. An Ex-Cel eyepiece, 18mm - this one:
http://www.opticsplanet.net/celestron-telescopes-eyepieces-xcel-series.html
which I can use with either/or Celestron Mak-Cass (or just about any other scope for that matter).
The focal length of the C130 mak is 2000mm and the focal length of the C90 Mak is 1200mm, and the effective magnification of the unit is the focal length of the scope divided by the focal length of the eyepiece, so:
1. With the stock 32mm eyepiece on the C130 Mak, I get
63 power.
2. With the 18mm eyepiece on the C130 Mak, I get
111 power.
3. With the stock 32mm eyepiece on the C90 mak, I get
38 power.
4. With the 18mm eyepiece on the C90 Mak, I get
67 power.
Lemme tell you, the view with the 18mm eyepiece and the C130 is unbelievable! I believe I could see an aphid on my neighbor's flowers across the street at 50 yards. Tremendous clarity.
So impressed that now I'm thinking of getting the 12.5mm or the 10mm eyepiece to go with/mix & match.
The 12.5mm would give me:
5.
160 power with the C130 and
6.
120 power with the C90
Or, the 10mm would give me:
5.
200 power with the C130 and
6.
150 power with the C90
Which would you get if you were me? Where is the upper limit of useful power with 130mm and 90mm objectives, for my main use of range spotting little holes at long distances, given the diminishing exit pupils here?
I'm thinking get the 12.5mm, and dedicating it to the C130, giving me
160x for stargazing (exit pupil 0.81mm), and dedicating the 18mm to the C90, giving me
67x for range use to 200 yards. (exit pupil 1.34mm). Ideas/input?
If I got the 10mm, then I could dedicate it to the C130, giving me
200x for stargazing (exit pupil 0.65mm), and still dedicate the 18mm to the C90 at
67x for range work. Is a 0.65 exit pupil too small to keep your eye centered over, realistically?
I'm thinking that the 12.5 is the way to go next. Hey, this is fun!
But where will it end?
Time to start shooting .17 rem at 300 yards at a black paper target to test these bad boys.
P.S. Like the C130, the C90 has two exit paths for the light, with a flip switch to flip the mirror. The top one allows you to have a 90 degree scope (good for using to look at the sky). The rear one can be used with the 45 degree elbow, for terrestrial tabletop or tripod viewing, and presumably, one could also get a straight 0 degrees piece if one wished (though maybe not).