Hotech laser - inconsistent results

[Corpze]

Hi, I am trying to collimate my astrpgraph, a TS N-AG10 with a Hotech 2" self centering laser and I am having some questions of the clamping procedure.
Each time i am trying to tighten the collar so that the laser would tighten up in the focuser, the laser dot is quite far off the earlier spot the laser hit.

I have sience bought a Howie Glatter 2" laser, when i adjust the secondary so that the laser dot hit exactly in the center of the primary dot and change laser to the hotech, the laser dot is about 4-5mm off, if I release the Hotech laser and re-tighten it, the dot will hit somewhere else.

I can not just trust the hotech laser - has anyone else experienced the same thing?

*Both of the lasers is collimated itself at 5 meters distance with the dots not moving at all.

/Daniel

[johninderby]

Had rwo Hotech lasers and both were absolutely perfect with no variation at all. Very strange that you would find it varies. 

 

 

[Corpze]

Hmm, ok, well that means either that i am doing something wrong or that something in the laser/focuser is affecting the tightening procedure.

My procedure is like this - i am first using it in a starlight feathertouch focuser with the clamping thumb screws backed off quite a bit, I put in the Hotech laser fully released in the locking collar, pushing down the laser very firmly towards the focuser and start locking the ring.
How ever, i have been thinking of very carefully appy som oil on the rubber rings so that they have the ability to "move" in to right position, could it be that they are to "grippy" on the inside of the draw tube?

[johninderby]

Sounds like it could be the rubber rings. Found I did have to check the rings were properly in the grooves before tightening. Perhaps removing the rings and applying some silicone grease and wiping off the excess might help. 

Edited March 27, 2020 by johninderby

[Corpze]

Yea, that might solve the issue.
Just to clarify - when you are mentioning the "grooves" - are you talking about the grooves on the laser that the rubber rings are sitting in or the grooves in the focuser for the brass ring that tightens the eyepiece? 

[johninderby]

The grooves in the Hotech.

Another thought the rings could be too loose when inserting in the focuser. I adjust them so it will just fit in the focuser so that the rings don’t slip out of position.

[Corpze]

Ok, so you don't insert the laser with the lock collar fully backed off, but tightened just so you can insert it in the focuser?

[johninderby]

11 minutes ago, Corpze said:

Ok, so you don't insert the laser with the lock collar fully backed off, but tightened just so you can insert it in the focuser?

Yes that’s what I do. 

[Ricochet]

3 hours ago, Corpze said:

I can not just trust the hotech laser - has anyone else experienced the same thing?

Yes, exactly the same. I returned mine for a refund. I think the fault was the self centring being inconsistent. I also thought the quality of the beam was pretty poor given the cost. 

[johninderby]

For what it’s worth.see the  Agenaastro reviews of the Hotech.

https://agenaastro.com/hotech-2-1-25-sca-crosshair-laser-collimator.html

Edited March 27, 2020 by johninderby

[Skyline]

I gave up using laser collimator's long time ago regardless how fancy the name is. Now I am using a 2" collimation eyepiece for the secondary and a chesire for the primary, not since have I had bad collimation.

N.