Collimating a Laser Collimator

[Mr. Subatomic]

Ahoy hoy,

I've been trying to collimate my laser collimator using the three adjustment screws and a mount that I bodged together using a block of wood and some nails. I was wondering whether there is a trick to this adjustment because I'm having no success from my completely random approach.

Thanks!

[g__day (Matthew)]

So you have created a craddle - using the block of wood and 4 nails - two at each end overlapping as a cross and you rest the collimator in the craddle and rotate it to check the beam doesn't move when you project it onto a dot on the wall?

More details = easier to give you help!

[Merlin66 (Ken)]

If the beam appears to trace out a circle when rotated and projected onto a wall say 3 metres away; the trick is to know which screw to adjust.

A bit of paper blu tac'd to the wall mark the circle; guess where the centre should be and mark it with a dot, rotate the collimator until one of the adjusting screws is at the top, and adjust it to bring the image about half way to the centre; rotate the collimator to bring the next screw to the top and repeat, same again for the third screw. This should allow you to get the image pretty central and fixed within a couple of iterations.
( If your collimator is like mine and has two sets of three screws, alternate the adjustments between the back and front set of screws to bring the body of the laser onto the axis.)

[Mr. Subatomic]

Thanks, that sounds much easier.

Originally Posted by g__day

So you have created a craddle - using the block of wood and 4 nails - two at each end overlapping as a cross and you rest the collimator in the craddle and rotate it to check the beam doesn't move when you project it onto a dot on the wall?

More details = easier to give you help!

That's exactly what I made, but I'm hoping to build something a bit more sophisticated if I find that it doesn't do the job.

[tempestwizz (Brian)]

After dropping onto a concrete floor, mine lost collimation. Fortunatley, I have a metalwork lathe. If you can access one re-alignment is relatively simple.
Place the collimator into the lathe chuck so that the light beam shoots through the chuck, back through the gear end of the lathe, not out toward the tailstock end. (This allows you access to the adjustment screws and holds the collimator as it would be held in the telescope.)
I placed a piece of cardboard as far away as my lathe as the workshop would allow, and traced the circle the beam made as I rotated the head by hand. The central point is then fairly easy to locate. Make a dot in the centre. Adjust the colimator screws to bring the trace onto the centre dot.
Re-check by rotating the head again and repeating any fine adjustment if neccessary, until you are happy with it.

HTH,

BC

[erick (Eric)]

Good approach. I've come to realise that it's best to rotate it as it is mounted in the focusser, rather than rely on the body of the collimator mount to be "square". Now if only I had a lathe.

[astro_nutt]

Here's another one!
Mine came with it's own collimator which is basically 2 wooden V-groves on a platform with a rubber band to hold the collimator on place..After outlining the beam on the wall about 4 metres away..rotate the collimator 180 degrees and outline the beam again..measure the distance beteewn the two and mark the middle..after each adjustment rotate the collimator 180 degrees to check the adjustment until it's centred.
Cheers!