how to adjust seben laser collimator

[houston]

Anyone know if these lasers can be adjusted, some indents in barrel but no screws to adjust, tried taking stickers off but no screws under there either.

[Twiggles]

I have one, not tried adjusting it though. They don't get great ratings on here and I ended up using a cheshire which seems to have worked ok.

There are two rubber circles on the barrel, which is just an anti tamper rubber bung. Remove it using a small knife to expose some hex head screws (2mm allen key I think). I would assume that there may be a third screw under the laser warning label. Keep meaning to try collimating mine anyway, as it disagrees wildly with my cheshire, yet the viewing has definitely improved since I collimated with the cheshire.

[houston]

It seems aligned ok so far, shouldn't have went for the cheap option i guess. Cheers, ill have another look for the screws.

[moogoomonkey]

Ah man! I was gonna buy one of these. Are they really that bad?

[Twiggles]

Ah man! I was gonna buy one of these. Are they really that bad?

Can't really say too much as not well experienced, but I found it to be a really bad fit in the eyepiece, to the point where you could get it aligned just by moving it around and adjusting the tension screws. Could possibly fix that I suppose by adding some thin O-rings or wrapping with electrical tape. Because of the loose fit though I decided not to trust what it was saying and instead bought a cheshire eyepiece and collimation cap which I then used to sort the primary and secondary. Rechecked with the laser and it again suggested it was out, until I played with the position to once again find I could get alignment in or out just by playing around with the tension screws. Even tried the barlow collimation method and had same results.

I must admit, I did not try checking the alignment of the laser itself, however to help out the OP, I removed the seals and played around with the screws. Holding the laser on a table showed that the screws do indeed adjust the laser. I've now knocked up a wooden block and nail collimation rig for the laser. May need some work though as its still quite rattly on the block! Had a go at adjusting the laser and I've got it centred as well as I can until doing some modifications to the block. Rechecking the telescope however once again shows that its all to easy to get a positive or negative result depending on how it is held in the eyepiece.

At the end of the day I have to say I haven't spent a great deal on it, so can't complain too much about the quality (solid metal construction, and the light emitted is certainly bright), on the other hand it would be nice if it had been easier to collimate the thing by not covering the screws in the sealant, and providing some instructions on both using it and collimating it. I've not used any other laser collimater nor seen one being used, so not sure if is normal for the light emitted to appear as a line rather than a dot? But I found that being a small line made it a little inconvenient at times, may also be a disadvantage for those trying to hit a very small centre point on the primary.

I'd say either invest in a cheshire or save your pennies and get a better reccomended model. Works fine as a laser pointer though

[101nut]

Mine's the same type but differently branded (and cheaper at the time). They are collimatable but have an elliptical beam - in that respect they're better than some and no worse than others. If you want one, you pays your money ... I use other collimating tools, the laser is just for a quick primary check ...

AndyG

[houston]

It was cheap. Around £20 on amazon a while back. Came with no instuctions. I just use it with barlow for primary in the dark.

[FireLighter]

i collimated my 200pds with this laser and it looked good.  popped a cheshire in and it was miles and miles out    collimated with the cheshire and views are spot on   given up on the laser as it cant be trusted

[Daniel-K]

the only lasers to trust are the baader hotech and the howie glatters.

[PHIL53]

I may have been just lucky, but my Baader Laser Collimator Mark III has proved trustworthy for the past 3 years (always carry a spare set of batteries along as they do not last very long)...http://www.teleskop-express.de/shop/product_info.php/info/p754_Baader-Newtonian-Laser-Collimator---precise-fast-adjustment.html

 

[Dave In Vermont]

I've found most lasers with access to the 3 screws can easily be collimated. As such, there is no need to pay high-prices for a usable laser. The ones available with adjustable brightness controls work great! You need to peel back a label and dig out a little putty to get at the screws, but big deal. The only shop here that carrys these personally collimates them prior to shipping. They are available across the pond and have been for awhile. They save on eye-strain and spot-blindness if you've got a long collimation to do.

Happy collimation -

Dave

[baggywrinkle]

I had one of these clones and made a V block, dug out the sealing rubber and adjusted it. I set up a target on one side of my living room made of paper and rotated the collimator to see what the error 'throw' was. It was way out, but after much tinkering I managed to get it to stay within a circle that replicated the collimating circle on the primary.

The V block needs to be set up on a straight edge, if it is slightly angled that will result in poor collimation of the laser.

[Dave In Vermont]

If you have a good, tight-fitting focuser, you can also just insert the laser into it and tighten down your retaining-screw just enough to hold it while still allowing the laser to turn in the focuser. If it draws a circle as it rotates - adjust the collimating-screws accordingly.

This may not be as accurate as a good v-block, but at the distance you're working with, it will get you close enough to star-test for the final tweaks.

Hope this helps,

Dave