Hotech collimation laser

[metz]

seems these are the best or if not one of the very best for collimation ..Hotech laser , i might be wrong .

[Rossco72]

Mainly regarded for the self centering adapter I believe...

[pvaz]

So they say. Maybe I was unlucky, but mine is off enough to give me worst star tests then a simple collimation cap or a cheshire.

They charge me 45$ in postage to align it. I'm not willing to spend more money on it so I got a nice 120£ paper weight now.

[Rossco72]

Can't you collimate it yourself? I thought there were 3 hex screws in all lasers to allow them to be aligned if needed. Then a simple V support to allow you to rotate it and a wall to shine the dot onto with a piece of paper to mark out the circle and you are sorted....

[pvaz]

I probably can. I don't have much free time on my hands at the moment to experiment with it.

But my point is: for the price, I shouldn't have to.

[Rossco72]

I agree with you wholeheartedly that it should be factory set and robust, but I hate to think of it sitting going to waste...

[calibos]

You're definately wrong

The Howie Glatter range of Laser collimators are Numero Uno.

AFAIK while the self-centering adapter will prevent gross collimation errors caused by an ill fitting collimator barrel tilting in the drawtube, the whole idea of self centering is moot unless you have a self centering adapter for use with eyepieces. Whats the point of the self centering adapter ensuring the lightcone is collimnated to the exact centerpoint of the drawtube and then putting in an eyepiece without a selfcentering adapter and the thumbscrews or compresion ring pushing the EP over to the side.

[sixela]

Yup. Centring is not the issue anyway (unless the laser collimator's barrel is hopelessly underdimensioned), tilt is. And for that, precise machining, a good shoulder to register against the focuser draw tube's shoulder and a long barrel help more than some rubber. I happen to think the Howie Glatter laser collimators are pretty good, and other people have said good things about the Farpoint laser collimators that are also sold as the "Orion Lasermate Pro" (not the Lasermate Deluxe, which is anything but what I'd call "Deluxe"). Yet others seem to have had good luck with Kendrick and Astrosystems laser collimators but I'm not sure they work in all focusers equally well (I'm not stating they don't, I'm simply saying I'm unsure), and then comes the Hotech (which is certainly a lot better than a host of Chinese built cheapies and the Baader Laser Collimator, which suffers from a short and underdimensioned barrel if you have a Synta scope).

The HoTech is, in Europe, frequently the best of the laser collimators on offer i many shops, but sometimes that's not too hard, unfortunately. I've had quite a few good laser collimators (and still have two, one of which I keep to help other people collimate scopes with 1.25" focusers), but I'm afraid I had to buy them all in the 'States. This one:

http://www.scsastro.co.uk/catalogue/orion-lasermate-pro-collimation-kit.htm

is the one I'd buy if I had to buy one in Europe, but unfortunately it's still not a 2" laser collimator. If I had to buy collimation tools from First Light Optics, I'd pick their CatsEye passive tools (which I also have -- I even have two sets until I send my old set to someone else) over any of the laser collimators on offer.

[metz]

gordan Bennet just when i think ive sussed it , i find collimanators need collimating themselves , looked on youtube and collimation dont look a problem at all , but it would if i was using a instrument to do the collimation that was out lord above , im using the celestron slt 102 and tricked myself into thinking of getting a dob , mind you i been thinking bout one for the last 8 months however cooling on it now folks lol theres hardly any dob 200p left right now 4 weeks before any more get in been ringing round

[sixela]

gordan Bennet just when i think ive sussed it , i find collimanators need collimating themselves ,

Not if they're any good. The problem with laser collimators is that there are a lot of bad ones around. And of those that aren't bad, there aren't a lot of them that can stay collimated if you drop them on concrete.

The second problem is that they don't solve some aspects of the collimation puzzle as well as a simple sight tube/Cheshire combination tool and that some vendors use smoke and mirrors to cover up that fact (some more than others -- the vendors who also sell barlow attachments for the "barlowed laser protocol" aren't going to tell you to use the return beam of the unbarlowed laser, and those that sell holographic attachments will also point out that the secondary has to be placed under the focuser ).

But collimation is not a really hard problem, and certainly not something that should prevent you from buying a Newtonian. I always recommend a sight tube/Cheshire combination tool to someone who doesn't know what to pick. It's cheap, it's a complete solution and it's robust. If you need anything else, you'll know it .

[pvaz]

gordan Bennet just when i think ive sussed it , i find collimanators need collimating themselves , looked on youtube and collimation dont look a problem at all , but it would if i was using a instrument to do the collimation that was out lord above , im using the celestron slt 102 and tricked myself into thinking of getting a dob , mind you i been thinking bout one for the last 8 months however cooling on it now folks lol theres hardly any dob 200p left right now 4 weeks before any more get in been ringing round

Collimation usually takes me 2 or 3 min with a simple collimation cap. Many scopes come with one or you can make one from a old camera film can.

Besides if it's a bit off you probably won't notice with magnifications up to 150x, so there's no point being scared about it.

PS-> The only frustrating part about it, is getting a fancy gadget and finding out it does a worst job then the free plastic cap. :)

Yeah... I know I'm just sounding bitter now...

[metz]

good little post there me old mucka lol you have restored my faith

[sixela]

PS-> The only frustrating part about it, is getting a fancy gadget and finding out it does a worse job then the free plastic cap.

Well, the free plastic cap usually won't help you set the tilt of the secondary at all, so I doubt it's better than the HoTech for that.

Don't get me started on the marketing fluff from some laser collimator vendors. I think many people wouldn't be so miffed if the vendors explained exactly what their tool was good for instead of insisting it's the universal panacea because it's more expensive than a collimation eyepiece and has "LASER" written on it and has useless ghee-whizz feature XYZ as well.

Useless ghee-whizz features in my book: side window or pattern to read the return beam on, self centring adapter, cross hair pattern.

Useful features: barrel just narrow enough to fit in all focusers but not more, long barrel, aperture stop to make the dot round and surround it with a diffraction pattern, all the gadgets to use the barlowed laser protocol for setting the tilt of the primary, holographic attachment that projects a grid.

I dis bad laser collimators like the best of 'em, but we do need some perspective too: they do work well in the dark and for setting the tilt of the secondary they're sensitive tools, and errors that look "humongous" on the primary are actually not that harmful on their own (that's the flip side of having a sensitive tool), at least unless you also plan to use the return beam (the fix is not to trust that, and if you don't have something to implement the barlowed laser routine, to indeed trust another tool like that collimation cap).

But yes, the collimation cap is more reliable than the return beam of a laser collimator, which is why Nils Olof Carlin invented the barlowed laser routine.

That's a fact, and you won't see e.g. Howie Glatter dispute it (that's why he designed an aperture stop that emits a diffraction pattern with a screen in which you can read the silhouette of the centre spot in the return diffraction pattern, a barlow attachment, the BLUG and the TuBLUG).

Even Farpoint/Orion ship the LaserMate Pro kit with a laser collimator *and* a Cheshire (the fancy version of your simple collimation cap) plus a matching centre spot , a sign that they Get It.

[JamesM]

The Hotech is adjustable using the three screws hidden underneath the front bevel that itself unscrews.

Don't collimate the laser using a 'V' block as that introduces two axes when in fact you only use one when it its in the focuser. I mount mine on a vertically held bit of board with a precisely cut hole in it that matches the external diameter of the 1.25" focuser ring that fits into the end of the focuser or diagonal. This allows the Hotech that is fitted inside this to freely rotate. Choose a blank surface 25' feet away and keep turning the Hotech/adjust the alignment screws until the laser point stops circulating and stays put. It takes a little bit of time in preparing this but once done you can adjust (rarely need it) as and when.

The real advantage of one of these laser collimators is if you have a particularly long scope as you can adjust the mirror from that end whilst viewing the effects. On a refractor it a useful tool to check the alignment and rotational movement of the focuser to ensure it is aligned with the objective glass and again if your refractor is particularly long.

James

[pvaz]

Thanks JMB.

As soon as I get some free time I'll give it a go. It's no use having it just gathering dust.

[metz]

The Hotech is adjustable using the three screws hidden underneath the front bevel that itself unscrews.

Don't collimate the laser using a 'V' block as that introduces two axes when in fact you only use one when it its in the focuser. I mount mine on a vertically held bit of board with a precisely cut hole in it that matches the external diameter of the 1.25" focuser ring that fits into the end of the focuser or diagonal. This allows the Hotech that is fitted inside this to freely rotate. Choose a blank surface 25' feet away and keep turning the Hotech/adjust the alignment screws until the laser point stops circulating and stays put. It takes a little bit of time in preparing this but once done you can adjust (rarely need it) as and when.

The real advantage of one of these laser collimators is if you have a particularly long scope as you can adjust the mirror from that end whilst viewing the effects. On a refractor it a useful tool to check the alignment and rotational movement of the focuser to ensure it is aligned with the objective glass and again if your refractor is particularly long.

James

:icon_eek: im lost again

[pvaz]

The 1st paragraph was about aligning my laser colli to make it usable. Its a boring, potentially long, task.

The 2nd was about: With a colli cap you have to constantly adjust the primary bolts and then go to the front and take a peak, then go back adjust a bit more, go back front and peak again and repeat that as many times as needed.

The main advantage of a laser colli is that as you adjust the bolts in the back, you can see the laser moving so you don't need all this "traveling" to get it done. It is indeed much more practical... if only it worked as well.

I need to try and align my laser colli when I get a free afternoon (they are rare this days).

[Astro_Baby]

Harking back a bit here to my post about astronomers and their quirks lasers do seem ripe for some comedy.

Let me get this straight, you need to undo a screw so you could just use a cheap screwdriver from Halfords, its simple, reliable and most people use them however some astronomers prefer to buy a the more advanced socket set. It only handles metric bolts but with they make up some plastic card to turn it inso a screwdriver adapter. Course the bit on the end breaks frequently and it also turns out that you can only fit the botched up screwdriver by having a specially made rig to set the driver bit correctly

Buy a laser and collimate it yourself by making a V block or a specaiily made accurate block of wood with a precision hole drilled into it and then spend 3 hours aligning the laser.........or, and perhaps I am a poor benighted soul who is too simple to understand the reasoning of whay you need to do this.....you buy a Cheshire which comes out the box and oh dear it works. Clearly too simple to be reliable and as everyone knows anything which doesnt take batteries and doesnt have flashing lights on it is low tech, old hat and cant possibly be considered. After all if you bought a Cheshire you'd not get the chance to buy some jewellers screwdrivers to adjust the laser with, you'd never have the 'fun' of making a collimation test bench, and just as readily you'd never have the deep satisfaction of owning a laser powererd paperweight when you realise that you still need a collicap to set up the secondary.

Lasers do have their place of course .....i just cant think where right now

[sixela]

The 1st paragraph was about aligning my laser colli to make it usable. Its a boring, potentially long, task.

The 2nd was about: With a colli cap you have to constantly adjust the primary bolts and then go to the front and take a peak, then go back adjust a bit more, go back front and peak again and repeat that as many times as needed.

Quite. But then you know the scope is collimated, or at least have a direct reading making the focuser axis cross the optical axis at the focal plane.

If you use the return beam and that side window, you're never quite sure. The only thing you're sure of when that return beam hits the right spot is that the focuser axis and optical axis cross at the centre of curvature, but not at the focal plane unless they're completely overlapping (i.e. that the forward beam points the right way with sub-millimeter precision and hasn't moved even a wee bit when you moved the scope in Alt to reach the collimation bolts).

Mind you, I think it's fine for rough alignment, but I'd certainly still finish with a Cheshire (heck, I use a TuBLUG which is actually as precise as a Cheshire, then a dual-pupil autocollimator, and I *still* finish with a Cheshire to ease my mind).

The TuBLUG is actually a work of art, if you really like the convenience of a laser collimator. It lets you use the laser collimator, is more convenient even than the laser collimator's return beam, and is just as precise as a Cheshire.

Doesn't mean that I don't walk back up to the TubLUG just to check it more precisely and then walk back to the collimation bolts. I can see ridiculously small errors better when the TuBLUG is close to me, and old habits die hard .

I'm really mostly agreeing with Astrobaby: either you have the money for a laser collimator that you can trust (they do exist) or you're better off investing in another tool.

[metz]

Im gonna wait on buying a reflector until someone designs one where the mirrors are welded, superglued , nailed down , riverted , and sealed in concrete ,then and only then will i consider one

[sixela]

Im gonna wait on buying a reflector until someone designs one where the mirrors are welded, superglued , nailed down , riverted , and sealed in concrete ,then and only then will i consider one

Or buy a Cheshire/sight tube combination tool for next to nothing and leave all that laser talk to others .

Collimation fear is not a rational reason for not considering a reflector.

[pvaz]

Lasers do have their place of course .....i just cant think where right now

The trash can will probably do!

I just checked and I do need very tiny Allen keys... Now it sounds even more fun! I just need to get specific Allen keys, which I probably wont use again, then spend a perfectly good Saturday afternoon locked up, making my own collimation workbench! I'm chuffed to the nickers!

[Astro_Baby]

Thats astro...baby

[lee allen]

happy days! not

[Jason D]

I have nothing against laser collimators or cheshire eyepieces but these days I use neither. I mainly use an autocollimator

Jason