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Hotech SCA Laser collimator for use on a SCT.

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#1 Julio

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Posted 25 February 2013 - 08:41 PM

Would love your opinions on this product. I know one has to critically align using a star to acquire perfect collimation first. However i would love nothing more than simply aligning a laser beam to a specific spot on the target vs fiddling with critical collimation on nights of less than perfect seeing in the dark if my scope de-collimates. The idea behind this collimator is that once one has acquired perfect collimation it is easy to once again align the optics with this collimator on a SCT. How precise is this unit has anyone used it? :question:

http://www.hotechusa...tegory-s/22.htm

#2 Mitchell Duke

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Posted 26 February 2013 - 09:59 AM

I tried it and its useless unless you are realigning the baffle, primary, and secondary. However the advanced unit supposedly works very well for indoor collimation.

#3 n1wvet

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Posted 27 February 2013 - 12:21 AM

I share your dream of a simple repeatable collimation method for an SCT. I picked up a used Hotech at a star party really cheap, tried it and it doesn't work at all. Save your time and money on this approach. The laser beam goes down the tube and reflects right back on the secondary back to the Hotech. Beam doesn't even hit the primary or corrector. No way to collimate since most of the optical surfaces are not involved.

Fail.

#4 gaz-in

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Posted 27 February 2013 - 06:46 AM

Now the CT Laser Collimator is a good bit more expensive and a much different beast.

http://www.hotechusa...tegory-s/23.htm

#5 Julio

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Posted 27 February 2013 - 11:57 AM

Yes I noticed that, a significant price difference. I don't mind collimating with a star, however critical collimation with a non tracking mount on star is quite a challenge.Unfortunately I can't see polaris from my POV. Would love to have a product that simply allows me to return to a critically collimated state without the use of a star and not spend an arm and a leg .lol. :jump:

#6 jrcrilly

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Posted 27 February 2013 - 02:12 PM

Would love to have a product that simply allows me to return to a critically collimated state without the use of a star and not spend an arm and a leg .lol. :jump:


For that, any single beam laser that can reliably be placed in the same position again would do the trick. The Hotech SCA that you mention is a good example.

#7 Julio

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Posted 27 February 2013 - 03:11 PM

Would love to have a product that simply allows me to return to a critically collimated state without the use of a star and not spend an arm and a leg .lol. :jump:


For that, any single beam laser that can reliably be placed in the same position again would do the trick. The Hotech SCA that you mention is a good example.


Interesting because some reviews on other websites swear it works well for such purposes while opinions here differ.

#8 jrcrilly

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Posted 27 February 2013 - 03:19 PM

some reviews on other websites swear it works well for such purposes while opinions here differ.


If the goal is simply to place the secondary back into a pre-determined position, as your original question described, how could it NOT work? I believe that the negative responses in this thread are answering a different (and unasked) question about using a single beam laser for initial collimation. That, of course, would not work.

#9 Cliff Hipsher

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Posted 28 February 2013 - 07:23 PM

A single beam laser is not going to work PERIOD, END OF STORY.

You have four choices:

1. Use a star.
2. Sell your first born child and buy the Hotec gadget.
3. Use an artificial star.
4. Use the sun glint off of the chrome on a Harley. (Works every time...)

#10 Julio

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Posted 28 February 2013 - 08:52 PM

A single beam laser is not going to work PERIOD, END OF STORY.

You have four choices:

1. Use a star.
2. Sell your first born child and buy the Hotec gadget.
3. Use an artificial star.
4. Use the sun glint off of the chrome on a Harley. (Works every time...)


Of course critical collimation is achieved this way initially, with a star. The question was, is it possible to return the secondary to this critical state with a laser without the use of a star. This product was supposed to do just that.

#11 n1wvet

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Posted 01 March 2013 - 12:49 AM

Let me answer once again the asked question...it doesn't work well. If you try to return the secondary to the pre-collimated postition you will find it frustrating. The laser is so bright on the grid and the dot so large it is difficult to see. The dot is not that small returning from the secondary and the laser tends to "shimmer" a little giving false positions.

#12 Julio

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Posted 01 March 2013 - 01:46 PM

Let me answer once again the asked question...it doesn't work well. If you try to return the secondary to the pre-collimated postition you will find it frustrating. The laser is so bright on the grid and the dot so large it is difficult to see. The dot is not that small returning from the secondary and the laser tends to "shimmer" a little giving false positions.


I appreciate the more precise answer thanks for the good information.

#13 Whichwayisnorth

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Posted 01 March 2013 - 03:26 PM

Just get one of those hubble artificial star flashlights, tape it to the top of a camera tripod at one end of your house, set up your ota at the other end and collimate away.

My house doesn't have a long enough direct path so I end up waiting until dark and setting up my telescope on the mount at one end of the yard shooting in through my patio doors, down the hall and into the living room. If you want to collimate with your telescope at 45degrees to account for mirror weight, you can always place the camera tripod up on the roof or inside an upstairs room. So many options and they all work.






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