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Hi Star People

I'm not sure if my cheap line cheshire is off. When I measure the crosshairs they appear to be centered.  But when I look through the peep hole with the 45* cutaway covered they're off to one side. The larger quadrant being to side of the cutaway. 

Could the siting tube out of line?

 

 

20191130_130524.jpg

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Let me put this another way.

OK so I'm seeing the eye hole is centred and the cross hairs are centered, what's not straight is the bored tube....

When I check columation the doughnut is spot on, the crosshairs are right I think..... does the fact that the drilled tube is off make any difference?

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Could you take and post an image of the cross-hairs of the Cheshire, like this...

1506644708_Tectronsight-tube.jpg.4c442592f40a0dcd4d059d0e3a0b1f6d.jpg

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Rotate the Cheshire in the draw tube and see if the crosshairs are centred on the doughnut at all angles. 

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On 03/12/2019 at 04:11, Alan64 said:

Could you take and post an image of the cross-hairs of the Cheshire, like this...

1506644708_Tectronsight-tube.jpg.4c442592f40a0dcd4d059d0e3a0b1f6d.jpg

Ho Alan sorry about the slow response but here goes:::  one of the crosshairs and what I'm seeing thru the eyehole.

 

20191206_170835.jpg

20191206_171254.jpg

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On 03/12/2019 at 20:12, Ricochet said:

Rotate the Cheshire in the draw tube and see if the crosshairs are centred on the doughnut at all angles. 

Hi Ric. Good idea... I tried that and found my cross hairs are way off the doughnut but stay on the same spot when the eyepiece is rotated. Does this mean I need to reset the secondary first?

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It appears that a component of the tool has slipped out of alignment.  Are you able to repair the tool?  I probably could if I had it before me.

Orion(of California) Newtonians come with a collimation-cap.  I have the Orion "StarBlast 6" kit, and this is the one that came with it...

1354983854_collimationcap.jpg.cda9b18dc317730afa9658833d4bd4b6.jpg

Did you get one with yours?  If not, are you the original purchaser of the kit?

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The more I look at your first image, it appears that the reflective disk has come loose, and is now askew.  The cross-hairs, on the other hand, appear to be correct.

Edited by Alan64

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55 minutes ago, Alan64 said:

It appears that a component of the tool has slipped out of alignment.  Are you able to repair the tool?  I probably could if I had it before me.

Orion(of California) Newtonians come with a collimation-cap.  I have the Orion "StarBlast 6" kit, and this is the one that came with it...

1354983854_collimationcap.jpg.cda9b18dc317730afa9658833d4bd4b6.jpg

Did you get one with yours?  If not, are you the original purchaser of the kit?

I made one from a 35mm film canister.  My collimation is spot on with it. Everything "appears" centered but with the cheshire the crosshairs are way off centre. 

20191206_180902.jpg

Edited by strayring
After thought
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How does a star test look ?

That is the most important thing :smiley:

 

startest.png

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11 hours ago, strayring said:

I made one from a 35mm film canister.  My collimation is spot on with it. Everything "appears" centered but with the cheshire the crosshairs are way off centre. 

You can line the underside with a circle of aluminum-foil, the dull side, and for improved illumination of the collimation scene.

As John had mentioned, a star-test is the final test of how well the telescope was collimated.  A basic star-testing tutorial...

https://www.skyatnightmagazine.com/advice/how-to-star-test-a-telescope/

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I completely agree with the above, once I got my secondary mirror set perfectly with my Cheshire and locked it into place, I now only use a star test to finalise my collimation each time I set up as I know the secondary is right. It almost always needs a slight tweak of the primary screws each time to get that set perfectly, but it is a one or two minute job at most and away I go with everything looking sharp.  I check the secondary with the Cheshire maybe a couple of times a year but it rarely needs adjusting again. :) 

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