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mtb54703
sage

Reged: 11/12/08

Loc: Eau Claire, WI

HOTECH SCA 2" Collimator Owners... new

new

#5234058 - 05/22/12 01:26 PM

How accurate is your collimator?

I have a HOTECH SCA 2" laser collimator, Last night after tightening the collimator in the focuser (Feather Touch) and adjusting the secondary to center the laser on the primary (center spotted using the CatsEye template), I then loosened the collimator, rotated 180 degrees, re-tightened and the laser dot on the primary moved about 1/2" Going back to the original position and the dot was centered again.

Primary mirror is accurately center spotted (and verified).
Everything in the optical path is tight (focuser, spider, secondary holder, etc...)
The collimator hasn't been dropped or roughly handled.

Anything else I could be missing?

Is there an adjustment on the collimator?

Thanks!

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SKYGZR
sage

Reged: 08/14/09

Loc: Planet Earth, Milky Way Galaxy...

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5234140 - 05/22/12 02:21 PM

Remember, the Laser is just for roughing things in. When using mine, I always leave it with the 45^ window pointed towards the Primary (cause that's how it's supposed to be positioned.)

I haven't tried rotating it, as that would seem counter intuitive as to how it's supposed to function. I suppose I could try and see what happens.

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GeneT
Ely Kid

Reged: 11/07/08

Loc: South Texas

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5234178 - 05/22/12 02:45 PM

A Hotech 2 inch used to be my primary collimator. A few years ago, I bought a Howie Glatter 2 inch laser and TuBlug. I found it be be a much better, more accurate collimation system. I now keep my Hotech as a spare backup in case my Glatter collimator goes down.

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GShaffer
Carpal Tunnel

Reged: 02/28/09

Loc: Bogart, Ga USA

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: GeneT]
#5234373 - 05/22/12 04:28 PM

No such thing as an inaccurate laser....regardless of who makes it. There are however plenty of mis-collimated ones out there. Find a machinist who has a good V-Block and test it. If it needs collimating then you should be able to fix the issue.....

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GeneT
Ely Kid

Reged: 11/07/08

Loc: South Texas

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: GShaffer]
#5234880 - 05/22/12 09:21 PM

Quote:

No such thing as an inaccurate laser....regardless of who makes it. There are however plenty of mis-collimated ones out there. Find a machinist who has a good V-Block and test it. If it needs collimating then you should be able to fix the issue.....

OK--I'll restate it: I achieved more accurate collimation using a Glatter system than a Hotech. The Glatter + TuBlug is a barlowed system, which gives better results. True, I could have hooked up a barlow to the Hotech, but Hotech does not offer a barlowed system. Glatter offers such a system. The screen on the Glatter system is larger than the Hotech, making the return beam easier to adjust, again giving me more accurate collimation.

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vorkus
professor emeritus

Reged: 08/18/10

Loc: Pgh, PA USA

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: GeneT]
#5234888 - 05/22/12 09:42 PM

I posted a similar question. It is basically useless. I was so disappointed. I've gone back to my cheap Orion,which I collimated. I tried the barlowed laser and didn't like the fuzzy disc it provides. I'm back to using the cheshire for the primary.

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Scott in NC
Mad Hatter

Reged: 03/05/05

Loc: NC

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: vorkus]
#5235439 - 05/23/12 10:25 AM

Quote:

It is basically useless. I was so disappointed. I've gone back to my cheap Orion,which I collimated.

Really? Wow. I suspect there was something wrong with yours--miscollimated, maybe? I have had the opposite experience. I found my Hotech so much easier to use, and more accurate (in the sense of eliminating "focuser slop") than my prior Orion one that I sold off the Orion one. And there wasn't really anything wrong with the Orion collimator, just that it didn't fit quite as precisely as the Hotech in all of my focusers.

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Magellan
Pooh-Bah

Reged: 01/26/06

Loc: Enfield, NS Canada

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: Scott in NC]
#5235490 - 05/23/12 10:44 AM

I love mine, never had an issue with it!

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mtb54703
sage

Reged: 11/12/08

Loc: Eau Claire, WI

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: Magellan]
#5236550 - 05/23/12 11:27 PM

Follow up - I contacted HOTECH and if I think the SCA is out of collimation, they will check it and re-adjust if necessary free of charge!

I need to investigate further on a bench setup to confirm, but need to get a piece of tubing machined with a 2" ID.

Thanks for everyone's input.

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beatlejuice
scholastic sledgehammer

Reged: 04/05/11

Loc: Hamilton, ON,Canada

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5236602 - 05/24/12 12:09 AM

Can you not take off the 2" collar to test it as a 1 1/4" collimator.

Eric

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GShaffer
Carpal Tunnel

Reged: 02/28/09

Loc: Bogart, Ga USA

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5236641 - 05/24/12 01:17 AM

Whats the machined tubing for? If this is something you think you need to do to check it I have a better suggestion.

Any good machinist shop should have several sizes of V-Blocks around and would likely be happy to let you test it yourself....wont take but a couple minutes.... If it is good you are out nothing and if it isnt then you might offer to pay them for the use of the block while you collimate it.....its usually VERY sensitive to adjust regardless of who made it.....might take you a little bit to get it right.....

Quote:

Follow up - I contacted HOTECH and if I think the SCA is out of collimation, they will check it and re-adjust if necessary free of charge!

I need to investigate further on a bench setup to confirm, but need to get a piece of tubing machined with a 2" ID.

Thanks for everyone's input.

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Scott in NC
Mad Hatter

Reged: 03/05/05

Loc: NC

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: GShaffer]
#5237075 - 05/24/12 11:17 AM

Do you have a kid with Legos? If so, you can make your own Lego V-block collimator stand.

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mtb54703
sage

Reged: 11/12/08

Loc: Eau Claire, WI

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: GShaffer]
#5237118 - 05/24/12 11:41 AM

When you test a collimator in a v-block you really only want the part of the collimator that goes into the focuser to reset on the v-block. There a page on the HOTECH website that explains this in more detail.

I have 2" Kendrick collimator (# 2062 I believe) and that one sits nicely on a v-block, and it's collimation can be accurately tested and adjusted.

On the HOTECH, if you set just the portion that fits into a focuser onto a v-block it will tip off. I suppose one could figure some way to hold it in place.

To collimate the HOTECH in a v-block, ideally you will need a holder for it - machined on both the ID and OD to minimize any variable in the OD. I had a piece of 2.25" aluminium tubing sitting around I thought I could use, but when I checked it with a micrometer the ID was too small (< 2") and the OD was pretty close to 2.25", but varied by several thousandths. If the OD is not consistent then the holder is rotated in the v-block, the beam will move due to that error.

Quote:

Whats the machined tubing for? If this is something you think you need to do to check it I have a better suggestion.

Any good machinist shop should have several sizes of V-Blocks around and would likely be happy to let you test it yourself....wont take but a couple minutes.... If it is good you are out nothing and if it isnt then you might offer to pay them for the use of the block while you collimate it.....its usually VERY sensitive to adjust regardless of who made it.....might take you a little bit to get it right.....

Quote:

Follow up - I contacted HOTECH and if I think the SCA is out of collimation, they will check it and re-adjust if necessary free of charge!

I need to investigate further on a bench setup to confirm, but need to get a piece of tubing machined with a 2" ID.

Thanks for everyone's input.

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GShaffer
Carpal Tunnel

Reged: 02/28/09

Loc: Bogart, Ga USA

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5237222 - 05/24/12 12:47 PM

They make attachments for V-Block testing that will eliminate the balance issue.....If they have V-Blocks then they are likely to have the needed attachments also. You might ask....no need to re-invent the wheel if you dont have to

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beatlejuice
scholastic sledgehammer

Reged: 04/05/11

Loc: Hamilton, ON,Canada

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5237622 - 05/24/12 04:06 PM

I also replaced my 2" Hotech with glatter laser and tublug after trying to collimate the Hotech and making a mess of it. I will probably send it to Hotech for collimation and then sell it.
This is Hotech's view of using a V-block and after trying it myself I have to agree with them. Using V-block to collimate Hotech

Eric

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GShaffer
Carpal Tunnel

Reged: 02/28/09

Loc: Bogart, Ga USA

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: beatlejuice]
#5237673 - 05/24/12 04:45 PM

They are referencing a totally improper way to V-Block it.....It should be obvious that trying to use 2 blocks isnt going to cut it....

You would have to use a single block with only the portion that inserts in the focuser being touched....which because of the design of the HOTECH would require a clamping mechinism (of which there are many specifically designed to do this) that would still allow the body to be rotated....

If you go to just about any machinist supply and look at V-Blocks you will likely find a variety of mechinisms....and most machinists who use V-Blocks are likely to have something that will do it.....

I went with the Glatter and tublug to start with myself.....

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vorkus
professor emeritus

Reged: 08/18/10

Loc: Pgh, PA USA

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: GShaffer]
#5238230 - 05/24/12 11:37 PM

For those of you who are happy with your Hotech, have you tried the 180 degree test? I had used the cheap Orion laser on my big 12" dob and was happy with it too. It was just by chance that I was fighting with collimation issues in my images that I reversed it only to find the dot was in a completely different place. I then purchased the Hotech thinking it would be better and it was actually worse. I've since collimated the Orion using a 2" to 1.25" adapter and a handy vise I have in my woodshop.

Try the 180 degree test. I think you will be surprised at the results.

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spaceoddity
Pooh-Bah

Reged: 07/28/09

Loc: Cloudsylvania

Re: HOTECH SCA 2" Collimator Owners... [Re: vorkus]
#5238372 - 05/25/12 02:53 AM

The biggest problem I've had with my "2 inch" hotech is that once removed from the adapter. It was very difficult to get it tight again and it has just gotten worse over time to the point that the thing is useless unless I put it in my antares twist-lock centering adapter instead. The laser itself is just a cheap one like the zhumell or orion with the exception of the self centering adapters which I found to be mostly a PITA. Get a Glatter, Farpoint or Kendrick instead. It may cost more initially but you'll save money in the end. JMO The farpoint 2" set which includes a very good quality 2/1.25" laser, 2" cheshire, mirror template and 4 center spots is a good deal for $130-$145 depending on vendor. This laser is well built and the dot does not move at all when rotated in the focuser and the fit is snug.

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HOTECH
Vendor - Hotech

Reged: 10/23/08

Re: HOTECH SCA 2" Collimator Owners... new

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[Re: spaceoddity]
#5239407 - 05/25/12 05:42 PM

Hello Rod,

“laser itself is just a cheap one like the zhumell or orion with the exception of the self centering adapters..”

We don’t built ‘cheap’ quality laser collimators by enclosing a laser pen in a tube. It is not fair to compare between a Lamborgini and a Ferrari since both drivers don’t mix but they all share great features in their own ways like all other collimator brands. The exception of the SCA makes the laser more adaptable and stable in the focuser from our field experience, thus it is incorporated as our patented signature.

It is odd that your sales history in CN were highly recommended for “good communication”. If you have an issue with any product(s), I would assume the first contact would be the vendor as the reflection of a “good communication” skill unless with some other intention. We do have free service on both recalibration and o-ring replacement as other members had already stated. So far we don’t have a ‘Rod’ contacting us regarding the specific issue you stated in our record. All you have to do is ask by emailing us and we will be happy to resolve your specific issues.

Sincerely,
David

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GeneT
Ely Kid

Reged: 11/07/08

Loc: South Texas

Re: HOTECH SCA 2" Collimator Owners... new

new

[Re: mtb54703]
#5239589 - 05/25/12 07:34 PM

Quote:

Follow up - I contacted HOTECH and if I think the SCA is out of collimation, they will check it and re-adjust if necessary free of charge!

This is all you can ask for.

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