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anyone have experience collimating a triplet?

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4 replies to this topic

#1 nateman_doo

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Posted 19 September 2019 - 09:46 PM

I recently bought an ED 102 triplet APO for a star party in a few days (second hand), and it requires collimation.  

 

I am on the fence.  Do I meddle with it (i have PLENTY of experience collimating an R/C scope which has much more complexity) or have it collimated under warranty?  I would hate to waste the chance to use a widefield refractor at a dark site (BFSP)  Looks simple enough with the adjustment screws on the front of the scope.  

 

GskRg5n.png

wg5w8u2.png

 

First light:  https://i.imgur.com/pbrshp9.jpg

(see bottom left especially)

 

I also bought the field flattener for this scope and all the proper adapters.

 

The Sharpcap screen captures are with the focal reducer/field flattener made my explore scientific, and the M13 image is with an astrotech field flattener.

 

 



#2 ngc7319_20

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Posted 19 September 2019 - 10:20 PM

Triplets often have smalls screws on the sides of the glass elements to center them.  This is in addition to the usual tip/tilt screws which move the entire cell on the OTA.  There may also be adjustments for tilting the focuser on the OTA.  Probably between a laser, cheshire tool, and star test you should be able to figure it out.



#3 nateman_doo

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Posted 21 September 2019 - 06:19 AM

laser?  what is the beam reflecting off of?  Cheshire?  What is the ring reflecting off of?  I dont really see any way to collimate other than a star test.  lasers and cheshires require some form of reflecting off a mirror.  



#4 Der_Pit

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Posted 21 September 2019 - 12:49 PM

You should get (weak) reflections from each air-spaced surface of a triplet.



#5 nateman_doo

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Posted 21 September 2019 - 01:00 PM

I put my cheshire in there and I saw nothing.  Didnt put the laser in there, so I guess I will look more into it. I called the manufacturer and they said me fiddling with the collimation wont do any harm in terms of the warranty.  So thats good. 




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