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Ho-tech SCT Collimator?

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#26 rmollise

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Posted 18 January 2015 - 10:50 AM

The Hotech collimator? It easily produces a collimation good enough for most observing. And, in the winter, I dare say it produces a better collimation than what many people could do on a star. :FarmerRon:


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#27 Bob Becker

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Posted 28 June 2015 - 10:48 AM

I  just purchased the Hotech collimator for use with my 8" Meade LX200GPS.  I have attached a couple of pictures of the results.  I have the Meade microfocuser and a Televue 2" everbright start diagonal installed.  I went through this 2 times now and feel that I am pretty close.   I have the returned dots as close to symmetrical on the collimator as possible. Then when I check the reflector, I see the converged lasers are not centered.  I have tried rotating the diagonal, and inserting the reflector right into the microfocuser, no changes.   I messed with some shims on the secondary and was able to move the lasers on the reflector to the center, but this of course moved the returned dots on the collimator.  When I  adjusted the secondary to re-set the dots on the collimator the converged lasers on the reflector again were not centered.  This is where I am now.

Any Ideas guys??

Attached Files



#28 Lola Bruce

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Posted 28 June 2015 - 02:05 PM

Looks good but I do mine without the diagonal. I have found my Zeiss/Baader diagonal is off center within it's self. As a result I leave any diagonal out of the primary optical train, even my Everbrite.

Bruce


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#29 BLACKDRAGON

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Posted 28 June 2015 - 02:55 PM

Looks good but I do mine without the diagonal. I have found my Zeiss/Baader diagonal is off center within it's self. As a result I leave any diagonal out of the primary optical train, even my Everbrite.

Bruce

 

If you collimate without using a diagonal, and get it spot on, then introduce a diagonal isn't there a chance of the star diagonal being slight out and changing the calibration from being spot on to slightly spot on or worse?   I'm only a beginner with using an SCT since April this year although I've been using Newtonians for a fair while now and realise how finicky Newtonians can be by seemly to come out of collimation by just breathing on them, so I don't like doing a collimation and then putting another optical piece inbetween :confused:



#30 GShaffer

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Posted 28 June 2015 - 04:40 PM

My experience with the Hotech can be described as been there, done that and had enough.......

 

I bought one, used it maybe 5 times and decided that while it was great for getting a badly misaligned SCT back close to collimated it was no substitute for tweaking a fairly closely aligned SCT up on a star. It followed the route of quite few gadgets over the years and it someone else's high tech toy now. 

 

I am interested however in trying the metaguide method as it sounds like it is not dependent on seeing at all and will allow you to get it well past any seeing limitations......Not to mention it requires no great investments......



#31 rgsalinger

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Posted 05 July 2015 - 02:33 PM

If you do some research I think you'll find that this means that the secondary is not centered with regards to the primary by some tiny amount. In the Edge HD scopes I think further that this is adjustable and one of my club members took his Edge apart and adjusted it. I would email hotech with the picture. They don't seem to answer the phone but when I was testing mine, I always got a response within a day or so.

Rgrds-Ross



#32 Whichwayisnorth

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Posted 08 July 2015 - 07:46 PM

The HoTech advanced laser SCT collimator doesn't just help you collimate your secondary.  What I've seen David do is also align your entire optic system.  This helps with centering your corrector plate.  Centering your secondary.  Collimating your focuser and camera.  Everything you need to do to get it all perfect. Also the way it is set up you don't have to do it parallel with the ground.  You can set it up on a tripod and angle it down and your OTA up so that the weight on the primary mirror represents what it would be like under the stars.    Check out this video if you have some time.  This shows you how powerful this tool can be.  https://youtu.be/4BDwa0RVZw0?t=28s

 

Also while collimating on a star is easy, it is easy only to a point. You can get good results even if you don't know what you are doing.  To get excellent results takes some knowledge and practice and to get perfect results takes even more skill and knowledge.  I find that I am in the "good but not good enough" category most of the time.  

 

I've tried Metaguide and had success with that.  Really isn't that difficult and I've been meaning to make a video showing how to use it.  What I did is took some screenshots as I went along and emailed Frank asking for help.  He offered a few suggestions and some advice and eventually I had it going good.  Unfortunately my seeing is so bad where I live that it was not just the limiting factor but it made my efforts futile.  Some night when I accidentally have good seeing I will try again.



#33 Gary Z

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Posted 08 July 2015 - 08:32 PM

Here in Eastern New Mexico, we always have wind.  Having a Nexstar SE Mount and an 8" SCT, it doesn't take much wind to move the scope around.  For me, the artificial stars at 35 feet in the house was the ticket.  No worrying about thermal currents swirling about,  and considering the collimation was a first for me, it made a big difference.  I first use my cannon dslr with the live view.  While this was helpful, I have also learned from a few folks that depending on what you are doing, visual or using a camera, it is best to collimate to that end.  Also for me, getting a set of Bob's Knobs also helped with the effort.  Never felt comfortable introducing a screw driver to the glass.....Now that I've done it using the artificial star, I really do need to be able to do it with real stars...lol.

 

Clear skies or clearer skies....lots of weather this summer!

 

Gary




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