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EQM-35 and Explore Scientific AR102(doublet) - first contact

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#1 Sp0nG3Bo8


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Posted 19 June 2019 - 06:57 PM

So i got myself a bunch of stuff here is a list:


-EQM-35 Goto mount

-Explore Scientific AR102(doublet) 102mm APO 

-Celestron 8-24mm Zoom Eyepiece (1.25")

-Vello T-Mount Lens to Micro Four Thirds Camera Lens Adapter

-Farpoint Prime Focus T-Ring Adapter (1.25")

-Sky-Watcher Star Adventurer Ball Head Adapter



here is a little review or first contact thoughts :


-EQM-35  well first i must say they should change their grease because the thing is way too stiff to be accurately balanced. the second thing is that initially the RA (?) axis did not move as the driving motor for the goto did not make contact with the gear of the axis therefore motor was spinning int the wind... quick fix : unscrew tree bolts of the plastic cap of the motor , slack the 2 hex bolts holding the motor mount just enough to move it a little then just make sure gears are in contact and tighten it all up , put cover back on. also i don't know how to adjust the rings for the polar scope  so i "guessed it"  ( it was loose). other than that everything else looks ok for the mount.


-Explore Scientific AR102(doublet) 102mm APO here i was a bit disappointed...  first it was missing the screws to attach the finder-scope to the main scope.

mine also had what looks like Styrofoam particle on the front lens ( inside)  the "rack and pinion" isn't a rack at all , there is no teeth looks to be just friction wheels so i would be careful if there is lots of weight at the back as it will slip. There are 1 screws to lock it in place however that seem to do the job once the thing is adjusted. the 2 things i did not like : a) the scope was not properly seated in the plastic "cradles" (they were out and about and loose) the scope shows no damage but it could still have unseen damage. b)  total absence of instruction on how things work... (not even a card with a link to a website. )  [how does the screws under the focuser work ?? ]


-Celestron eyepiece ... over-packaged tongue2.gif but seems to be doing good have not looked trough it much only inside . the thing is solid.

-T-mount and T-Ring they are solid ( metalic) and fit perfectly my olympus EM5mkII.  there is a inside tread on the Tring adapter on the "front" side if you are looking to add filters. i am not too sure for now but i think the 1.25" might be small for the Micro4/3 sensor :-/  well see .


-Star Adventurer Ball Head Adapter disappointed here ... does not fit the EQM-35 ( its not really made for it anyway ...)    the mount only has the dovetails at the corners of the "mount grip" and thus not working ... oh well ...




A 2" T-ring adapter   and a bahtinov mask...  are on their way as well.


i decided on the doublet instead of a triplet a) because budget tongue2.gif b) iam already planning for a filter wheel so ...

the mount is not tested with the load but my camera will be about 2lb ( 1kg)  and the APO is advertised at 10lb  and weight 10.6 with finderscop and dovetail rings/handle attached.) so i will be only a smidgen over the half limit of the 22lb capacity.



once i can take it outside ill try to update as to what is what...

comments welcome


**admins feel free to move this to proper forum section.

Edited by Sp0nG3Bo8, 19 June 2019 - 06:59 PM.

#2 Pauls72



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Posted 19 June 2019 - 09:22 PM

Sorry to inform you that the AR102 Doublet Refractor is not an APO. You will have CA (Chromatic Aberration) with it.



The Styrofoam particle is easy to fix. Get a can of compressed air from a computer store, office supply or even Walmart has them in the computer department. Hold the scope straight up and down vertically with the lens at the top. Attach the thin tube to the can of compressed air and shoot some air up the scope through the eyepiece opening. The Styrofoam particle will fall down and hopefully out. If nothing else it will be off the lens. You shouldn't have to shoot a lot of air.


The AR102 comes with a "2-inch Two-Speed Crayford Focuser". This is not a Rack and Pinion focuser. Crayford focusers use friction of the shaft against the focuser draw tube to move it in and out. Some crayford focusers have 2 thumb screws and others only have one. The single thumb screw adjust the friction and will lock down the focuser.


You can get a 2" nose piece to connect the T-Ring to the focuser, which will have a larger light path. One like this:



A 2" threaded filter will screw into the front of a 2" nose piece. Sames thing a 1.25" threaded filter will screw into the front of a 1.25" nose piece.


The vast majority of Telescope mounts accept either the smaller Vixen/CG5 style dovetail or larger Losmandy style dovetail bars.Their are some that accept both styles.




You can find ES manuals here:



There are also some Youtube videos on the scope.


When considering weight, you need to add up everything:



Adapter Rings


Guide scope or Off Axis Guider

Guide camera

Finder scope

Dew heaters,

Even the weight of all the cables hanging down


Since it appears you want to do AP, you will also need a remote shutter release or intervalometer to control the camera. Ideally you would want to use computer software to control the camera and live view for focusing. But I don't know of any AP software that supports Olympus camera's.

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#3 Sp0nG3Bo8


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Posted 22 June 2019 - 12:18 AM

i have the remote shutter ;-) ( i can also control this with the app tongue2.gif


yeah i am aware that the AR series isn't apo frown.gif i meant ota(?)  But i plan on shooting separate LRGB images with a motorized filter wheel (next paycheck lol )  hopefully this will mitigate comma and lack of focus on the blue ( since this is a doublet green and red should be corrected and blue out of focus .Or did i not understand that properly ?)


considering this is my first telescope i thought was was not such a bad deal ...  it was either that or a mak of comparable price.



as for weight i weighted the camera 1.8lb +adapters  i give it 2.2lb  the ota is 10.6 with finder-scope and rings mounted.  Mount has a 22lb capacity...  i think the stiff grease will be more of a hindrance than the weight lol.gif


i am pretty well equipped for the oly ...  i can even use it as a 4k camera trough a elgato cam-link.


accessories i will probably add will be a filter wheel and a auto-guiding cam and a different finder-scope auto-focuser ... possibly upgrade with a carbon Triplet i may upgrade the mount at that point lol.gif  

Edited by Sp0nG3Bo8, 22 June 2019 - 12:25 AM.

#4 nicoyenny


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Posted 22 June 2019 - 12:47 AM

You are jumping in faster than an Olympian swimmer trying to beat the world record! :lol:

Take it easy, there is a learning curve, be patient with yourself and your gear...try resisting the temptation to “mod/upgrade” everything at once... learn your stuff, learn your workflow/technique, and then you can start thinking about  that $$$$ loan to get more “i need” gear...

before jumping into AP i made sure i would have a lasting relationship with astronomy... is worth it...

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