Difference between Hotech collminator and a DIY version ?

[AstroNerd]

I'm looking to get a laser Collimator (so not a thread about lasers or not!) and have been looking at the Hotech one as there's been some great reviews on SGL and other sites.

But seeing as the price tag is a little too high and out of my reach atm I was wondering if the Orion Precision Eyepiece Centering Adaptor with the Revelation Deluxe Laser Collimator would be just as good and indeed if thats what people already use and do !! ??

Thanks

[russ]

I had the same idea and bought those two last year. The Orion Adapter does indeed do its job well and i use it all the time now. But the Revelation laser had to be collimated itself before i could get an okay(ish) collimation. Wasn't entirely satisfied the laser was collimated, even after i spent two hours turning it in a jig making adjustments. If the Hotech is collimated out of the box it would be worth it i think.

[AstroNerd]

Glad I asked now .. Great minds think alike !

I would go for the Hotech but it my budget atm is really tight for astro gear. I'm having a obsy delivered tomorrow (shed that's being converted) and I've just bought a 200D PS !

Hence the Collimator hehe..

I guess all the cheap collimators are the same ?

[beamish]

TBF, that's exactly the difference. The HoTech is not user collimatable(?), it's bang on from the factory and the whole collimator is a single product not a device which contains a bog stnd laser within it.

If you can be bothered to collimate a cheaper laser such as the rev and use it in conjuction with the Orion SC adapter ( I use one now for EP's & it's fab !!BTW) then there's no reason why you ought not to get perfectly adequate results

HTH

[albedo0.39]

The Orion SC adaptor is a cracking piece of kit and you will find it a good choice. Ref the Laser... if you have a Barlow lens (mid quality) then you can easily turn your "cooking" collimator into a barlowed version and then experience near perfect collimation irrespective of the mounting of the collimator in the eyepiece.

Nils Olof Carlin has a lot of information about them here

Worth mentioning, that even when the laser is dramatically improved (with a barlow) NOC mentions that it approaches the accuracy of the humble cheshire ! - have you tried using one of these ?

[AstroNerd]

I've heard of the Barlow collimation with a laser, I think I just presumed that it would still suffer from the same problem as being 1.25" in a 2" hole issue and 'move'.

I like the sound of how precise it will be as I'll be using it for photography, maybe I'll get the Orion adapter along with the Rev collimater and use the Barlow addon too!

Thanks for your replies.

[TopHouse]

The orion adapter with cheaper collimater is fine, I used the Antares collimater (the black one not the grey one) BUT the collimater wasn't collimated out of the box.

You don't actually need a jig to collimate the collimater if you have an orion centerer and it's not a hard thing to do, just frustrating and time consuming.

Put the orion centerer in, then put your collimater in and tighten the orion JUST enough to allow you to rotate the collimater with no play, look down the telescope tube at where the red dot of the laser is hitting and rotate the collimater, if the dot stays still when you rotate, then it's OK, if it 'draws' a circle then it needs collmating, you use the 3 collimating grub screws on the antares to adjust it's collimation.

It's all well and good using a non collimated laser for barlowed laser technique but you still need either a 'dot' laser or a sight tube to align the secondary, barlowed laser only does primaries.

And of course, lasers AND sight tubes can lie! In a week or two I'm going to be posting what I think is some really interesting stuff on collimation which proves that lasers lie. There also will be a prototype device launched more on this when I'm ready.

[ribuck]

Having used both solutions, the orion adapter is ok but you have to make sure that your laser is collimated itself as it's just a cheap laser pen in a tube to disguise it. The problem with this is that every time the batteries run out you have to re-collimate the laser let alone even looking at your scope.

The Hotech on the other hand is exceptionally well engineered and gives absolutely perfect collimation every time.

Just seems odd in my mind to buy nice telescopes and then skimp on the tools to keep them in perfect working order to give you proper views.

It's like cheap toilet paper, looks a great bargain but, you end up suing twice as much.....some thing's you just dont skimp on.......lol.

Remember this hobby is a long term investment, that's what i keep telling myself.

Rich.

[TopHouse]

The Hotech on the other hand is exceptionally well engineered and gives absolutely perfect collimation every time.

No laser gives perfect collimation, agreed, a barlowed laser does a damn fine job on primary but no laser except possibly one of the new holographic Glatter versions does the secondary perfectly. A laser cant identify rotational/skew errors unless holographic.

[TopHouse]

I've been studying this quite deeply recently, with a LOT of reading and experimentation with various 'prototypes'.

Your secondary mirror can be adjusted in MANY 'axes' lets just look at two, the first i'll call 'rotational' this is where you loosten the center screw and 'rotate' the secondary. Now, if you discount any 'waggle', by waggle i mean tilt in any direction. if everything else is kept square and you 'rotate' the secondary with a laser collimater fitted and the scope with focuser at top, rotating slightly clockwise or anti clockwise will make the laser dot on your primary move in a straight line left and right.

By rotating, i don't mean huge amounts, I mean even millimeters in either direction will move the dot quite a bit. In fact an amount that isn't recognisable by using a sight tube.

Now, if you lock up the center screw on secondary with the laser dot 'off' the center of your primary (off to one side) you can actually move it back over again using the adjustment screws on secondary using the movement known as 'skew' so, to a laser, both before and after rotating the secondary, the scope will appear collimated, even to a hotech, even to a barlowed laser, yet technically it isn't.

[ribuck]

Hi tophouse,

I guess it's how you define collimation in your own mind. For me, the laser simulates the path of light, and if that path of light is perfectly centred in my primary and then reflects off the secondary dead centre into my eyepiece / camera and gives a massive visual / photographic improvement, then it's good enought for me...:)

[TopHouse]

Except the laser can't perfectly center the path of light, and Nils Olof, Jim Fly and Vic Menard all agree on that.

[haitch]

I've just figured out barlowed laser collimation. It only works for the primary (but that is the most sensitive to slight miscollimation). It works whether the laser is slightly miscentred and even miscollimated. It's something that's difficult to explain you have to see it for yourself. What you rely on is the reflection of the doughnut in the diffuse beam the barlow gives. You can wiggle the laser and focuser as much as you like and the doughnut will stay rock steady still. the only thing that moves it's position is adjustment of the primary.

PS Mine is a Revelation laser.

[TopHouse]

Yup, it throws you a bit when you wiggle the laser and the shadow doesn't move doesn't it lol

[ribuck]

Sounds good, I guess everyone has their own personal preference. I'm personally very happy with my Hotech i got from FLO and would recommend them highly as i find them easy to use and gives good results.

[TopHouse]

I have my second prototype collimater in production now with an engineering friend, my first prototype was a bit rough & ready but it showed an accuracy of collimation, specifically to secondary that was better than either laser, collimated laser or cheshire. The final items will be focally tuned to the focal length of the scope, since mine is a 200P, that's what the prototype will be, I have two people lined up already but ideally I'd like 5. The idea being that the five give it a try and mail it on to the next person, then give me feedback on various aspects. So, anyone with an F5 newt, ie 200P, watch this space.

[ribuck]

Hi Tophouse,

If you need a hand, I have a 200P as well so If you need any help testing i'd be more than happy to test it and give you feedack on the features that i like / dislike etc.

Rich.

[TopHouse]

OK, I'll add you to my list, went to the engineers today though and he hadn't even started it.