Laser Collimation

[malc-c]

OK before I start I just wanted to say that I've noticed lots of posts on the subject of collimation and don't want to stir up the debate over the use of non-laser and laser based collimators.

I've seen the video on Youtube of one of the top end laser collimator that has a self centering all singing all dancing facilities which cost around £100 - £120 which is out of my price range. So a look through various web sites and came to the conclusion of purchasing a Revelation Deluxe Laser Collimator

These retail for less than £40 which is around the budget I have. But in this price range there are several other offering such as the Skywatcher

or the Antares

I would welcome comments as to which of these would be the best of the bunch.

[steppenwolf]

I can see that the £40.00 one is collimatable but cannot be sure about the other two. If you do go for a laser collimator, make sure that it is user collimatable because the first task when using one of these to ensure that the collimator itself is accurately collimated and that if it isn't, you can do something about yourself!

[malc-c]

Steve,

It it easy to collimate a collimator ?

I take it you are referring to this one

[John]

I have one of the Revelation ones. It is collimatable and it was just as well as it needed collimating !.

I used the "V-block" method:

Laser Collimator Collimator

I used a piece of paper fastened to a wall about 25 feet away as the "target". After a fair amount of fiddling it is pretty accurate now.

[xboxdevil]

I have the Revelation collimator and it is easy to collimate once you understand the principle. This will give you an idea what you will need to do (if anything): Astromart Articles - Collimation of Laser Collimators

EDIT

John, just read your post and that's the ugliest V block I've ever seen! luckily mine looks more like this one: http://www.cloudynights.com/item.php?item_id=520. There again if it works then who cares :-)

[John]

...John, just read your post and that's the ugliest V block I've ever seen! luckily mine looks more like this one: How-to Collimate a Laser Collimator - How To. There again if it works then who cares :-)

Actually mine is a bit nicer than the one on the web page I linked to - I just thought the article was good and the collimator was a clone of the Revelation

As you say, if it works then what the heck

[JamesM]

One of the problems of the 'V' block method is that you are using two pivot points to reference the centering. In theory (..I believe I'm correct) you should only collimate using the part that has contact with the scope, therefore only one point of contact.

Lasers are great - once you collimate the damn things.

James

[malc-c]

Thanks guys for the comments,

So for a novice who has never collimated a scope before, would it be more advantageous to spend double the amount and get a HoTech SCA

which I gather is self centering ?

My concern is that without tuning one of the revalation one correctly I could put the scopes optics more out of line than before I started ?

[malc-c]

Oh and once one of the revalation ones have been collimated, do they stay collimated ?

[xboxdevil]

I take pretty good care of mine and keep it in a Maplin's flight case jobby, but so far after maybe a few months and about 20 uses it is still spot in, but I guess these kind of things could be quite variable.

[acey]

I have the Antares and use it for adjusting the secondary on my 12". When I get the spot shining on the centre ring of my primary, if I just put a bit of pressure on the collimator or turn it in the focusser, the spot moves. That doesn't matter because there's a good margin for error at this stage. But if I carried on and used the reflected laser spot in order to adjust the primary, I'd end up out of collimation. So I use a Cheshire for the primary.

I used to have one resembling your first pic. The screw switch was very primitive - it just pushed the button on a mini laser pointer inside the unit. There was nothing to stop you turnnig the screw too far and damaging the plastic button on the pointer, which I soon did. I replaced the pointer with a similar one off a key ring but could never get the thing properly collimated again and trashed it. The Antares at least has a decent switch (and a brightness setting).

[Geno]

I take pretty good care of mine and keep it in a Maplin's flight case jobby, but so far after maybe a few months and about 20 uses it is still spot in, but I guess these kind of things could be quite variable.

Have had mine a few months and use it quite a lot and has stayed collimated (I check it now and again). I too keep it in a flight case along with my EP's.

I made a wooden V block and used that to collimate it, I thought the wooden block with 4 nails was a great idea but opted for the deluxe wooden version.

[sixela]

Thanks guys for the comments,

So for a novice who has never collimated a scope before, would it be more advantageous to spend double the amount and get a HoTech SCA

If you're desperate to spend more money, get an Orion LaserMate Pro Kit (not Deluxe) or if you're stinking rich a Howie Glatter laser collimator from the 'States (my scope is expensive enough to warrant one, especially since the presence of a Paracorr means it matters more than on other scopes, and I'm the resident collimation doctor in two countries so I like to have tools that Just Work).

Of course, that's only my personal advice and opinion, but from someone who's had to collimate and troubleshoot laser collimators from other people ad nauseam.

If you have £40, you might as well just spend the money on a good sight tube/Cheshire combination tool.

which I gather is self centering ?

It is indeed, but centring is not the issue, avoiding tilt is, and for that the self centring adapter offers little help.

My concern is that without tuning one of the revalation one correctly I could put the scopes optics more out of line than before I started ?

Actually, for setting tilt of the secondary laser collimators are very sensitive, which also means that small movements of the dot on the primary aren't really that much of a problem (unless you're a collimation nit, have a Paracorr, or are doing photography).

Using the return beam of a laser collimator in preference to a Cheshire to set the tilt of the primary is a bit hazardous (at least used for fine tuning) but even for correctly collimated laser collimators. To do that well with a laser collimator requires other gizmos, self built or not (just google "barlowed laser Nils Olof" and "TuBLUG" for some examples).

Of course, a lot also depends on the collimation tolerances of your scope. I wouldn't obsess over smaller collimation errors in a 6" f/8 Dob, but an f/4 scope with a Paracorr used for photography is quite another matter.