Collimation laser movement.

[Lordspace]

Sorry for a asking so many questions.

I know how to collimate my reflector scope but am I just going to have to make do with an ok'ish collimation rather than very good collimation as the laser shifts when using the thumb screws to hold it in the focusing tube.

The Lazer collimator is aligned as I check this when it arrived in the post.

How can I know that the mirrors are actually aligned properly??

[Adam1234]

8 minutes ago, Lordspace said:

 the laser shifts when using the thumb screws to hold it in the focusing tube.

I'm glad you posted this, I'm having this exact same issue with the laser shifting with the thumb screws, I'm getting it with my cheshire eyepiece too. Makes you wonder how to tell if the collimating device itself is in the centre of the focus tube.

[Lordspace]

Its driving me mad, I've tried to collimate using the thumb screws and without but if I move the collimator while it's in the focuser the Lazer moves around the center of the mirror. Maybe my scope is just too budget to even bother trying to get it better.

My stars all look like smudges rather than sharp.

[Adam1234]

I know the feeling, it was driving me up the wall when I was trying to collimate yesterday, thought I was going to end up turning into the hulk.  

I've been trying to unscrew both thumbscrews by the same amount, then screw them back in at the same time to see if that helps, I've not reached a conclusion as to if this helps at all though.

 

[Lordspace]

I'm going out later so hopefully I will find out if the collimation is better this time around.

[Adam1234]

Good luck!

[Lordspace]

No good, no matter how much I try and get it spot on the stars still look oblong...

Maybe this is the best I can expect from my scope 😕

[Louis D]

I have a 1.25" or 2" laser, and can only get it to work in 2" mode because there's too much play in the 2" to 1.25" adapter, and it's a really nice one.  If your laser is 1.25" only, I don't know what to tell you.  If it can be used in 2" mode, use it in that mode to help minimize play.  Make sure the focuser is retracted all the way as well.

If you can get your secondary aimed at the center of the primary using the laser, put it away and switch to using an Aline collimation cap to align the primary back to the secondary.

[Alan64]

Trouble with the 1.26" visual-backs?  When the thumbscrews are battened down against the barrel of an eyepiece, that leaves a 0.010"(0.25mm) gap on one side.  Simulate that with a partial shim of that thickness, something slippery, and with the thumbscrew(s) fully loosened.

 

 

[Lordspace]

I was thinking of putting some tape around the barrel of the Lazer so it fits in snug without the need to use the thumb screws. I will give it a try and see what happens.

When the Lazer is fully aligned I look down the focuser and can see that the mirrors aren't actually centered. 

[Merlin66]

If the laser is pushed to one side of the focuser by the screws.........don’t you think the same thing will happen to your eyepiece?

use a Cheshire eyepiece or similar to find / get best collimation.

 

[Alan64]

52 minutes ago, Lordspace said:

I was thinking of putting some tape around the barrel of the Lazer so it fits in snug without the need to use the thumb screws. I will give it a try and see what happens.

When the Lazer is fully aligned I look down the focuser and can see that the mirrors aren't actually centered. 

You don't want to go all the way round with a shim, for when the thumbscrews are battened down the eyepiece will be secured slightly off-centre.

[Neil H]

Mine moves a little to but I still collimate and image is spot on stars are sharp , must because the eyepieces sit the same as the collimator

[Lordspace]

I'm not sure but as I moved the primary mirror up to reach focus with the DSLR that could maybe mess with the collimation but I have no idea if moving he mirror can cause collimation issues. 

[ScouseSpaceCadet]

I was having the same issue with my 200p. Until reading this thread and tried again this morning...

Do not use the 2"-1.25" adapter that came with the telescope. Use the adapter supplied with the collimator. The adapter that came with the collimator only has one thumb screw rather than the two on the telescope's.

Wind in the focuser and tighten the focuser locking screw.

The result; no collimator slop and 15 mins later perfect collimation.

 

Edited February 12, 2020 by ScouseSpaceCadet

[Lordspace]

My scope only has 1.25" inch. I've tired to line it up buy eye as if I use the laser then look down the empty focuser then everything looks very wonky. 

Every video I've seen says you should be able to see both mirrors as a perfect circle. 

[Jiggy 67]

Regarding movement of a laser collimator. You might not want to hear this but the only laser collimator I would use is this one which is quite expensive but excellent 

https://www.firstlightoptics.com/hotech-collimation-tools/hotech-sca-laser-collimator-with-cross-hair.html

It uses compression rings to secure it so it doesn’t suffer the thumb screw movement. It is also factory collimated....I find it very easy to use 

[Lordspace]

53 minutes ago, Jiggy 67 said:

Regarding movement of a laser collimator. You might not want to hear this but the only laser collimator I would use is this one which is quite expensive but excellent 

https://www.firstlightoptics.com/hotech-collimation-tools/hotech-sca-laser-collimator-with-cross-hair.html

It uses compression rings to secure it so it doesn’t suffer the thumb screw movement. It is also factory collimated....I find it very easy to use 

I've gone the method of lining everything up by eye and my eyepiece with a hole in, seems to work better than the Lazer but I can't say for sure until I see some stars tonight.

[wookie1965]

Get yourselves a self centering adapter does not use thumb screws and centres any eyepiece or collimator.

 https://www.harrisontelescopes.co.uk/acatalog/twistlock-adaptor-1.25--2.00.html?gclid=EAIaIQobChMI_6Wx3pjM5wIVDUTTCh0oCQjsEAkYASABEgKhyPD_BwE

Cheaper version, https://www.ebay.co.uk/i/382821201785

Edited February 12, 2020 by wookie1965

[Neil H]

I just redid mine and by slowly doing up both screws in focuser got no play

Edited February 12, 2020 by Neil H

[CraigT82]

13 hours ago, Lordspace said:

No good, no matter how much I try and get it spot on the stars still look oblong...

Maybe this is the best I can expect from my scope 😕

This is weird.... an out of collimation newt doesn't produce oblong stars.  What scope is it?

 

 

 

 

[Lordspace]

1 hour ago, Jiggy 67 said:

 

 

49 minutes ago, CraigT82 said:

This is weird.... an out of collimation newt doesn't produce oblong stars.  What scope is it?

 

 

 

 

Its a skywatcher 114p I did move the mirror up the tube but have now put it back to stock and I will just have to use a Barlow when using the DSLR.

No idea of putting the morrow up the tube affect the image.

Someone said it looked like my scope was suffering from bad coma.