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Colimate a Orion 130st with push pull screws on primary

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#1 night observer

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Posted 09 July 2020 - 08:39 AM

Hi I have a Orion 130st that I am colimating  and have found 2 issues with the process first getting the rotation of the secondary to stay in place when lazor colimating  the secondary and for the primary it has six adjustment screws instead of 3 and 3 locking screws. I can get the primary lazor culminated but it seems to go out easily I saw a old video on this type of system and they said you have to snug up all six screws to keep the culmination has anyone else had an issue with these scopes 



#2 SteveG

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Posted 09 July 2020 - 01:00 PM

Hi I have a Orion 130st that I am colimating  and have found 2 issues with the process first getting the rotation of the secondary to stay in place when lazor colimating  the secondary and for the primary it has six adjustment screws instead of 3 and 3 locking screws. I can get the primary lazor culminated but it seems to go out easily I saw a old video on this type of system and they said you have to snug up all six screws to keep the culmination has anyone else had an issue with these scopes 

Your scope has a nice 4 vane spider in it. The secondary is also a push-pull configuration, where the large phillips-head center screw pulls the mirror, while the 3 smaller tilt screws push the mirror. If it's not tight enough, you need to tighten that large center screw, provided you have the secondary centered under the focuser. 

 

Regarding the primary, you can get 3 small springs and place them one at a time between the mirror cell and back plate. This can eliminate the need for the push screws, but more importantly it will make primary mirror adjustments much easier.

 

I have a 5" f5 reflector, an the current batch of these are very good with great optics. Because they are so small, once you get good collimation you won't have to tweak it very often.


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#3 SteveG

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Posted 09 July 2020 - 01:17 PM

Here's a picture of the springs:

 

Primary Springs.jpg



#4 NDLaw

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Posted 09 July 2020 - 03:28 PM

Are those springs epoxied to the cell or is it just the pressure holding them in place?  Do you have any recommendations for how long the springs should be?  



#5 sixela

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Posted 10 July 2020 - 07:06 AM

The pressure and of course the bolts that go through them ;-).
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#6 night observer

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Posted 10 July 2020 - 01:19 PM

It looks like the springs go on the pull screws is that how they go? Also can you suggest what type of springs I can get. I will have to take my primary off to do this because all I can see are the screw heads.Thanks for the info on the springs.



#7 SteveG

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Posted 10 July 2020 - 09:42 PM

It looks like the springs go on the pull screws is that how they go? Also can you suggest what type of springs I can get. I will have to take my primary off to do this because all I can see are the screw heads.Thanks for the info on the springs.

Those springs are probably about 1/2" to 3/4" long, and very light duty. Heavier springs will work too, but you don't want them to be too long.

 

Yes, they go through the pull screws. To remove you mirror remove the 3 screws around the perimeter of the tube, and pull the mirror & cell out as one piece. Be sure to mark it and put it in the exact same way you removed it. When you get it out, install the springs one at a time, between the mirror cell and backing plate.You will have to collimate your primary, but that's easy with a simple collimating cap. I do not recommend using the return laser beam for this.



#8 jwpkrfan

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Posted 22 July 2020 - 04:16 PM

night observer,

 

I have the same scope you do and also have had issues with collimation. Part of it is my inexperience but I discovered that the focuser is also faulty. I'm curious about yours. I sent you a PM earlier. 




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