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Orion SkyQuest XT10 Collimation

Collimation Orion
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#1 RonAikins

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Posted 28 September 2021 - 01:16 PM

New to everything. Trying to collimate my XT10 (no specific forum for Orion?) and having trouble with the 1st adjustment: centering the secondary mirror in the focus tube. It needs to be moved to the right. Turning the adjustment screw of the base of the mirror counterclockwise makes it move to the left, moving it right begins moving it to the right but then it starts moving to the left???

 

Any experience or help here?

 

Thanks,

Ron



#2 kopite

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Posted 28 September 2021 - 01:40 PM

New to everything. Trying to collimate my XT10 (no specific forum for Orion?) and having trouble with the 1st adjustment: centering the secondary mirror in the focus tube. It needs to be moved to the right. Turning the adjustment screw of the base of the mirror counterclockwise makes it move to the left, moving it right begins moving it to the right but then it starts moving to the left???

 

Any experience or help here?

 

Thanks,

Ron

I have a Orion XT8 so it’s the same procedure. The key is NOT to loosen the center screw of the secondary mirror, just the three collimating screws. Start by loosening the three screws, then adjust each screw a little bit at a time. Assuming you are using a laser collimator, you will get the feel of how each screw affects the movement of the red dot in relationship to the circle on the primary mirror. Start tightening each screw individually. For instance, tighten the first screw until the red dot is as close to the circle as possible, then go to the next screw and do the same, then the last one. The key is to adjust them a little at a time until the red dot is centred. Then you need to adjust the primary mirror. If all else fails, there are lots of videos on YouTube that will show you how it is done. Hope this helps.


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#3 Vic Menard

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Posted 28 September 2021 - 02:16 PM

New to everything. Trying to collimate my XT10 (no specific forum for Orion?) and having trouble with the 1st adjustment: centering the secondary mirror in the focus tube. It needs to be moved to the right. Turning the adjustment screw of the base of the mirror counterclockwise makes it move to the left, moving it right begins moving it to the right but then it starts moving to the left???

 

Any experience or help here?

First, "It needs to be moved to the right" is a little difficult to understand. The secondary mirror has three adjustments--tilt, rotation, and position closer to or farther from the primary mirror. When you're trying to "center the secondary mirror in the focus tube", you should be looking for three circles:

the bottom edge of the focus tube, (light blue circle)

the actual edge of the secondary mirror, (green circle) and

the reflected edge of the primary mirror. (red circle)

You want to make these three circles concentric.

I've attached an annotated image to help. Note that, when you get your scope collimated, all of the circles (and the primary mirror center marker/donut) will be concentric, except the silhouette reflection of the secondary mirror (violet circle) which will appear offset toward the primary mirror end of the tube assembly. And don't worry about offset--if you make the three circles concentric, the silhouette reflection will automatically be offset.

 

It will also help if you use a tool to keep your eye centered. If you don't have a collimation cap, you can get one like this:  https://agenaastro.c...t-eyepiece.html

 

And it will also help you see the actual edge of the secondary mirror if you place a piece of white copier paper behind the secondary mirror against the inside of the tube wall (opposite the focuser). Do NOT cover the primary mirror!

Attached Thumbnails

  • offset2.jpg

Edited by Vic Menard, 28 September 2021 - 02:28 PM.

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#4 Vic Menard

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Posted 28 September 2021 - 02:17 PM

And welcome to Cloudy Nights!



#5 RonAikins

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Posted 28 September 2021 - 07:49 PM

All right! Thanks for the quick responses and clear instructions. You guys should have written the Orion manual for this telescope. The first thing the manual suggested was adjusting the center screw of the secondary mirror.  It was not clear to me what that was doing, hence my "move to the right" guess. I  am trying this "by eye" first, mostly to get what's going on, then will use the.laser. Hopefully its manual is clearer.

 

Thanks for the help and the welcome! 

 

Ron 



#6 Vic Menard

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Posted 28 September 2021 - 08:13 PM

With a (good) simple thin beam laser, you can get the secondary mirror tilt corrected to good precision, and the primary mirror tilt coarsely corrected. If you add a simple collimation cap, you can get a better primary mirror tilt alignment, and when combined with your laser, good secondary mirror placement too. See here:  https://www.cloudyni...ment/?p=5260727

 

I wouldn't count on your Orion manual or your laser manual to make collimation any clearer than the help you'll get in this forum.


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#7 SteveG

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Posted 28 September 2021 - 09:38 PM

I have a Orion XT8 so it’s the same procedure. The key is NOT to loosen the center screw of the secondary mirror, just the three collimating screws. Start by loosening the three screws, then adjust each screw a little bit at a time. Assuming you are using a laser collimator, you will get the feel of how each screw affects the movement of the red dot in relationship to the circle on the primary mirror. Start tightening each screw individually. For instance, tighten the first screw until the red dot is as close to the circle as possible, then go to the next screw and do the same, then the last one. The key is to adjust them a little at a time until the red dot is centred. Then you need to adjust the primary mirror. If all else fails, there are lots of videos on YouTube that will show you how it is done. Hope this helps.

Adjusting the secondary tilt is not what he’s trying to do. To center the secondary under the focuser, he will have to loosen the center screw and then tighten the 3 tilt screws.



#8 SteveG

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Posted 28 September 2021 - 09:49 PM

New to everything. Trying to collimate my XT10 (no specific forum for Orion?) and having trouble with the 1st adjustment: centering the secondary mirror in the focus tube. It needs to be moved to the right. Turning the adjustment screw of the base of the mirror counterclockwise makes it move to the left, moving it right begins moving it to the right but then it starts moving to the left???

 

Any experience or help here?

 

Thanks,

Ron

First confirm that the secondary hub is centered within your tube. Measure the spider vanes from the tube edge to the center, making sure they are equidistant. The vanes should be very tight, and aligned with the optical tube length.

 

What you are describing above sounds like the centering of the secondary while looking down into the focuser. For this you need a tool, either a site tube (best) or a combo tool (often referred as a collimating eyepiece or Cheshire). If when looking through this, the secondary mirror appears too far to the left, then you would loosen the center screw and tighten the 3 tilt screws in order to move it to the right. It’s important to understand that the secondary adjustments are push/pull, and need to be tightened against each other in order to hold collimation.

 

Next adjustment is secondary tilt and rotation, then you go to the primary tilt.

 

Do you have any additional tools aside from the Orion laser?



#9 MJB87

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Posted 29 September 2021 - 05:22 AM

Moving to Reflectors forum for a better fit.



#10 DSO Viewer AZ

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Posted 29 September 2021 - 07:20 AM

Hey Ron,

Welcome to CN! 
I would add something genius, but Vic got here first. lol.gif 
So I will just say, congratulations on the XT10! I LOVE mine. There are a ton of threads on the Orion line here. The Zhumell line is very similar and you can use most of those threads for your scope as well. Might search the Zhumell mega mod for some great ideas for your fancy scope in the future. waytogo.gif 
Also, look into replacing the three culmination screws with “bobs knobs” screws. This did help quite a bit on mine. They are a cheap upgrade, and the bigger heads are easier to get a hold of.
Clear Skies!!


Edited by DSO Viewer AZ, 29 September 2021 - 07:38 AM.

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#11 cuzimthedad

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Posted 29 September 2021 - 11:38 AM

Welcome to Cloudy Nights and to the Reflector forum Ron!



#12 RonAikins

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Posted 29 September 2021 - 03:51 PM

Adjusting the secondary tilt is not what he’s trying to do. To center the secondary under the focuser, he will have to loosen the center screw and then tighten the 3 tilt screws.

Actually I was trying to make all adjustments for collimation by the book (manual). The manual says to loosen the tilt screws first to make adjustments with the center screw. Then the tilt screws are used to adjust the secondary mirror tilt, followed by primary adjustment. Not saying that is necessarily correct, just that it's what the manual says.

 

Also, look into replacing the three culmination screws with “bobs knobs” screws.

I assume you're talking about the secondary mirror screws, not the primary? I will google them, thanks. The manual also says the secondary tilt screws are phillips head. On mine they are (~2mm) Allen head. Yes, replacements would be nice. 

 

I also have a bent tightening screw on my 1.25" collar on the focusing tube. Good place to find replacements?



#13 Vic Menard

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Posted 29 September 2021 - 05:23 PM

Actually I was trying to make all adjustments for collimation by the book (manual). The manual says to loosen the tilt screws first to make adjustments with the center screw. Then the tilt screws are used to adjust the secondary mirror tilt, followed by primary adjustment. Not saying that is necessarily correct, just that it's what the manual says.

To get a better idea of how the secondary mirror placement is assessed and corrected, read the first six posts here:  https://www.cloudyni...rror-alignment/

 

The images in posts #3, 4 and 5 are animated. You may have to click on the image to start the animation.



#14 DSO Viewer AZ

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Posted 29 September 2021 - 06:06 PM

I assume you're talking about the secondary mirror screws, not the primary? I will google them, thanks. The manual also says the secondary tilt screws are phillips head. On mine they are (~2mm) Allen head. Yes, replacements would be nice. 

 

I also have a bent tightening screw on my 1.25" collar on the focusing tube. Good place to find replacements?

Yes, on the secondary. Your primary should be just fine. I purchased ones on scopestuff.com, good site for those odds and ends that may need to be replaced. Look under “collimation stuff” They may have something for the collar as well. Good resource to have. I purchased my flocking from there as well, never had a problem and stuff came fast. 




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