Explore Scientific AR-102

102mm, f6.5, air-spaced doublet achromat


Explore Scientific manufactures these in their own factories in China.  As far as I can find out they are not sold under any other brand names.

 The scope arrives with the tubes wrapped in tissue paper.  The OTA is boxed in Styrofoam rings, the finder and diagonal are wrapped and packed in styro separate from the OTA.  A very secure and reliable packing system. 

Construction is quite good, there are no obvious flaws, scratches, etc. Optics are clean and appear to have even coatings.  Weight, with rings and handle, is around 11 pounds.  Handle has a 1/4" slot in the top and is advertised as a camera mount.  I have my PST riding on it.

Provided mounting plate is standard Vixen, so it will fit a wide variety of mounts; I am using my Celestron Advanced GT under it.  The plate is adjustable for orthogonality.

So far I have had a few brief moments of use between the clouds.  It is one of the nicest achromats that I've used.  View is nice and sharp, focus is easy to achieve.  Yes there is color fringing, but nowhere near the levels of the ST-80 I have.

label Label is actually a metal plate.  The data is somewhat questionable though.  ES states the scope is f6.5, the label says f6.5, but 6.5 x 102 = 663, not 633.  Which is the real typo?  Does it really matter in the long run?  Not enough to be a concern.
cell Front cell uses a standard push-pull adjustment.   Mostly metal, but the front retention ring appears to be plastic.  Out of the box the collimation seems to be right on.  Due to the oversizing of the cast ears a grossly oversized dew shield is required.
focus The scope is equipped with a 2" dual-speed Crayford focuser.  Feel is good and smooth.  Tension is controlled by two thumbscrews under the focuser, they work OK, but I have yet to get them tight enough to lock the focus.  Eyepiece or diagonal is held in by a clamp ring that is tightened with three thumbscrews. 

The 2" diagonal is rated at 96% and seems to be a fairly nice unit.  Both the 2" opening and the 1.25" adapter use clamp rings.
finder A decent 8x50 finder is provided.  The mount is an old style 6 screw type, I've always had good luck with them holding the adjustment real well, just a pain to adjust.  Two of the screws have spring plungers to make it a little easier to adjust, however you must tighten them down after adjusting the other screws for them to hold the finder in place tightly.

The finder mount cannot be removed/installed while the main scope is mounted in the rings, not enough room.  It appears to be the same quick release that Meade used on the LX-200 for years.
Solar I obtained the scope primarily for solar imaging with a Baader Herschel Wedge.  My TV-60is does not have enough front focus to bring the wedge to focus.  A search of the web turned up a few folks using this scope with the wedge with great results.  Since the wedge has a Continuum filter included for use on achromats there is little need to use an APO.

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