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Collimating the Laser - A Right Pain!

SnakeyJ

By SnakeyJ
in DIY Astronomer

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SnakeyJ

SnakeyJ

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As the outlook is not looking so good for the next few days, I decided it was time to get around to collimating the laser collimator.  How hard can it be, it's only three pesky little grub screws!

First I decided to improvise my own V block for the purpose, using some off cuts of unistrut to form a bed.

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I then mounted on this on my now redundant EQ5 tripod - aiming it at a piece of white painted MDF some 6-7m away.

med_gallery_26731_2373_1275902.jpg

Once I'd got the direction right I clamped the V Blocks to the head of the tripod.

So far so good this unistrut works really well and the collimator rotates freely, but can be removed and replaced finding the same position.

Next up I had to access the collimation screws on my collimator - these were sealed under some black silicon that proved surprisingly unwilling to come out.   Once cleared I found an appropriate Allan key (2mm I think) and then went on to the next stage.

Unfortunately this is where it all goes wrong.    First off I rotated the collimater so that each of the grub screws was up most and marked the position of the laser spot on the board, which gave me a rather odd triangle of points over about 40mm at 6m!    Adjustment required!

The laser must be held and pivot forward of the adjustment screws as the action of the screws is opposite to what you would expect, but this was quickly rationalised and I think I know what I am doing.    However I can only get the three spots down to a radius of 15mm or so at 6m then it seems to go a bit odd - now spent three hours chasing my rear on this and getting frustrated, so have decided to take a long break!

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Helite

Helite

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I have one of these and found the laser actually "flops" as I was rotating, I stripped it down and meddled with it to get it sorted, but for 23 quid new I didnt expect too much out of it, but it sounds like the issue I was having with mine where I couldn't get it centered. I would check for any movement with it as you rotate. Love the V block!

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wookie1965

wookie1965

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I have one of these and found the laser actually "flops" as I was rotating, I stripped it down and meddled with it to get it sorted, but for 23 quid new I didnt expect too much out of it, but it sounds like the issue I was having with mine where I couldn't get it centered. I would check for any movement with it as you rotate. Love the V block!

Can you show how to strip it down please.

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Helite

Helite

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Afraid not, I work offshore and wont be back for a couple of weeks, but I would be more than happy to break it down and take pictures when I get home if still needed. It was a little bit of a pest if I remember correctly, but nothing to serious, all pops out the back but I cant recall the specifics of what was holding it in i'm afraid.

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wookie1965

wookie1965

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Just making sure...

Your laser collimator has two set screws for adjustments (X and Y directions). The 3rd is a "lock" set screw. You can identify "which is which" by their location.

Jason

Now i have had mine apart is there anyway of finding out which one is the lock screw.

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SnakeyJ

SnakeyJ

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Mine has three adjustment grub screws at 120 degrees, but no lock screw.

No flop as it rotates just eccentric action.

The unistrut v block works a treat - but I do recall another recent thread where someone was using baked bean tins ;)

typed on my mobile with Tapatalk

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Jason D

Jason D

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Than you very much for that mine are 120 degrees opposite each other i will study this and see if it works.

In this case you do not have a locking set screw. I was referring to the laser collimator pictured in the first post of this thread.

Jason

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SnakeyJ

SnakeyJ

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Jason,

cheers for this link and excellent diagram - it would be an eminently more sensible design for the collimator, but sadly mine is the slightly different design with 3 x 120 deg grubscrews!

I've just dug the box out from the loft and mine was the Next Generation Laser Collimator, which I purchased last year from ebay - more fool I :)    Lifting the tray out of the box it does come with a nice colour printed useage guide showing how to use it to collimate a Newtonian - but no mention of need to check it's own alignment, or even a mention of the adjustment screws!   I'm pretty sure that this is a generic unit made in China by Synta as it seems to be sold under many badges.

Jake

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Jason D

Jason D

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I stand corrected. Mine is very similar and I assumed it is the same. See attached photo. I own all these laser collimators. I was referring to the one in the middle.

However, since I got my Glatter (left laser collimator) I do not use the others.

Jason

post-5330-0-10143600-1382129833_thumb.jp

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SnakeyJ

SnakeyJ

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Hurrah - I think I'm going to declare myself satisfied at this point, having got the grouping down to less than 10mm radius at 8m - not 100%, but probably good enough for my F5 given the size of the spot it produces.   

med_gallery_26731_2373_1194162.jpg

Spot(s) on :)

Really I only want this as a sanity check at night and I think I have more faith in the trusty long tube cheshire which works really well for me in daylight (and I will try and find a clip light.    Though I also want to use a laser to check the collimation of my BM AR152S refractor - I should underline the word check, as I've never collimated a refractor before and, if it needs adjustment, will probably wait and do this with a more experienced friend.

Much bigger response than I had expected on this thread again - so big thanks to all contributors.   Good luck with your own laser Wookie1965, not so bad once you get setup - though recommend taking a few steps back if it's getting frustrating!

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SnakeyJ

SnakeyJ

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I am going to try and do mine tomorrow just found a piece of trunking (electrical) which is just right for the laser collimator.

Darn it - I was just about to list my collimating rig in the classifieds ;)

I'm just off out to the obs to test my newly collimated laser and see how my 200P is doing!

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SnakeyJ

SnakeyJ

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Only joshing - good luck with collimating the collimator tomorrow!

BTW mine seems to work a treat now.   Where previously the best I could do was to prescribe an orbit around the centre spot as I rotated the laser, now I can keep is bang in the middle (or as near as my eyes can tell) as I rotate the laser in my self centring adaptor.   Guess I can hold off on that Hotech until I buy something faster/more sensitive!

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wookie1965

wookie1965

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Only joshing - good luck with collimating the collimator tomorrow!

BTW mine seems to work a treat now.   Where previously the best I could do was to prescribe an orbit around the centre spot as I rotated the laser, now I can keep is bang in the middle (or as near as my eyes can tell) as I rotate the laser in my self centring adaptor.   Guess I can hold off on that Hotech until I buy something faster/more sensitive!

I know lol

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Paulhenry85

Paulhenry85

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Success!! I've just collimated my collimator.

post-32516-0-28828100-1382643984_thumb.j

I had to make the V block from plastic fitting then using a small spirit level to adjust, as the collimator itself isn't straight. The adjustment of the laser was easy (no silicon or muck covering the screws) and smooth

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