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New collimator for RC telescopes

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16 replies to this topic

#1 Mert

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Posted 05 June 2019 - 01:11 PM

Hi all,

 

Just recently I came across this device: https://www.teleskop...eskoptypen.html

 

I'm not sure if this way to collimate the RC8 is valid, would someone chime in

please to see if this could be true???

As far as I have been trying with my laser collimator, first of all I try to have the

laser pointer hit the center mark, and after that I adjust the secondary.

But they state, to adjust the secondary first to get the centermark in the center and

after that adjust the primary¡!

Can all this be true??

Hope to see your experiences and opinions about this, I wouldn't like to

spend 100€ to get some gadget that sc..ws up my collimation!!

Thanks for any feedback!!

Mert


Edited by Mert, 05 June 2019 - 01:47 PM.

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#2 bobito

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Posted 05 June 2019 - 01:18 PM

Wow, that looks promising!



#3 Hawkdl2

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Posted 05 June 2019 - 01:38 PM

It looks very interesting.  Hopefully someone has tried it, but even if not, I think I'll get one and try it out. 



#4 Mert

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Posted 05 June 2019 - 01:44 PM

For those of you who can read German, they sent me

some sort of user guide more or less saying the same:

It is a PDF file and I don't know if I can share it here???

 

Sorry not having an English version but this is what TS

sent me today!

Attached Files


Edited by Mert, 05 June 2019 - 01:45 PM.


#5 Ishtim

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Posted 05 June 2019 - 02:02 PM

Google Translate "should" work on PDFs

https://translate.go...s&sl=auto&tl=en
 



#6 Mert

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Posted 05 June 2019 - 02:13 PM

Can this work???



#7 bobzeq25

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Posted 05 June 2019 - 02:18 PM

Can this work???

The question in my mind is does it measure optical collimation, or just mechanical, like a Cheshire eyepiece?  The two things are frequently different on the inexpensive RCs.


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#8 Benni123456

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Posted 05 June 2019 - 04:55 PM

I would suggest to get a Hotech advanced Laser collimator and then do an adapted procedure 11 of this manual

 

https://www.astrosir...anual-V9_3D.pdf

 

While the hotech is originally for sc's, i think this procedure 11 should set up everything (focuser, secondary) centered and parallel.



#9 John Miele

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Posted 05 June 2019 - 07:21 PM

The question in my mind is does it measure optical collimation, or just mechanical, like a Cheshire eyepiece?  The two things are frequently different on the inexpensive RCs.

When you say mechanical collimation do you mean that the physical center of the two mirrors are aligned with each other? And if the mirrors were not lined up and had some amount of lateral offset (or decentering) how could that even be fixed? AFAIK there is no way to adjust the mirrors other than tilt. Or am I wrong about that?

 

I would love for this device to work!

 

Thanks...John



#10 Benni123456

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Posted 06 June 2019 - 10:12 AM

It would be great if there were a 3 axis tilter that can adjust the focusser not only in the z axis, but also the x and y axis with respect to the primary.

 

This would be important for both the RCand aplanatic scts like edge hd's



#11 Mert

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Posted 06 June 2019 - 11:25 AM

Personally çI am not quit convinced since they start adjusting the secondary

mirror in order to get the center mark centered.

AFAIK one should adjust the laser-pointer to point to the center and then adjust

the secondary to get the beam back onto "itself".

I don't know if I explain myself with this? question.gif question.gif

In the mean time I am looking a software called CCDInspector and I don't

know if that would help collimating??



#12 cturek

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Posted 06 June 2019 - 11:41 AM

I'm a sucker for these kinds of gadgets. I just ordered one from Teleskop Service which, by the way, I've had great success in the past ordering from them and shipping to the US.

 

I'll compare it to the Takahashi Collimating Scope on my classical cassegrain, SCT's and my 8" Edge.

 

Google Translate did translate the pdf instructions to English but didn't pick up the pictures. Just have to print the German document and cut/paste the English text in between the pics.


Edited by cturek, 06 June 2019 - 11:46 AM.

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#13 Mert

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Posted 06 June 2019 - 12:41 PM

Sounds great, I also have had very good experience with them and over the

past years bought a lot of equipment from them!

Right now, I dismantled the RC8, got rid of the tiltplate and mounted my

lasercollimator with the 1,25" to 2" Howie Glatter Paralizer, quit stable.

The laser dot was way off the center mark going straight from the focusser

to the secondary.

So I adjusted the drawtube of the focusser such that the laserdot points

to the centermark ( more or less in the center )

Then adjusted the secondary mirror to reflect the laserdot back onto

the center of the screen of the collimator.

Let's see what I have, whenever the clouds go away for a while.

 

I also checked with CCDInspector, but that I have to learn.

 

Hope to read your experiences when you get the collimator, it looks

quit simple to me, hope it works as they stated!!

Mert



#14 Benni123456

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Posted 06 June 2019 - 02:56 PM

 

 

In the mean time I am looking a software called CCDInspector and I don't

know if that would help collimating??

CCD Inspector has an evaluation period.

 

In my case it turned out to be a waste of time working with it. For collimation, it really needs long exposure times in order to get enough stars, which is a problem if you have longer focal lengths.

 

And then CCD Inspector is susceptibe to seing problems and guiding errors.



#15 bobzeq25

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Posted 09 June 2019 - 09:33 AM

When you say mechanical collimation do you mean that the physical center of the two mirrors are aligned with each other? And if the mirrors were not lined up and had some amount of lateral offset (or decentering) how could that even be fixed? AFAIK there is no way to adjust the mirrors other than tilt. Or am I wrong about that?

 

I would love for this device to work!

 

Thanks...John

Imagine it, or draw it.

 

Offset the mirrors a tiny bit.  Then tilt them a tiny bit.  You can get them in mechanical alignment, even though they're now not exactly parallel to the tube.

 

On my 6RC the first step I used was to get mechanical alignment with a Cheshire.  Then I used, sequentially, artificial and natural stars to get optically aligned.

 

Worked fine.

 

https://www.astrobin...page=2&nc=&nce=

 

When I was done I checked the Cheshire again.  Unsurprisingly, it now said my mechanical alignment was off a bit.  I ignored that, of course.  If this system aligns mechanically....

 

The RC design is unusually sensitive to collimation (and so, to mechanical design and execution).  This is one reason why the inexpensive versions can be difficult.  A good RC is more expensive than most people will choose to spend, and it looks rather different.

 

http://www.knaeble-eng.com/telescope-2

 

The design is fine for professional observatories, suboptimal for amateurs on limited budgets.  The inexpensive RCs, (I'm referring particularly to the 6 and the 8) have great optics, but.... 

 

They're not magic.  They're inexpensive because of the mechanicals, and the RC is very sensitive to the mechanicals.  With one thing and another, I now have about $1200 in my "$400" telescope.


Edited by bobzeq25, 09 June 2019 - 09:42 AM.


#16 CeeKay

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Posted 11 June 2019 - 12:49 AM

Sounds like a good "tool" to have... will be looking forward to a review from anyone that uses it on a SCT.



#17 cturek

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Posted 22 July 2019 - 06:34 PM

I'll compare it to the Takahashi Collimating Scope on my classical cassegrain, SCT's and my 8" Edge.

Just an update. I received the REEGO collimator from Teleskop Service. I had to wait for it to get back in stock. After TS shipped, it only took four days to get to my door by UPS Express from Germany. First some pictures:

 

This is the top view with the battery and mode switches.

file1-14.jpeg

 

For Newtonians and Cassegrains, you use the red mode.

file2-9.jpeg

 

For Refractors you use the four white LEDs.

file-33.jpeg

 

I tested the REEGO on a 4" SW Evostar Pro 100. Looking into the peephole in this mode you see multiple reflections of the four white LED's If the scope is collimated, all the reflections will line up in a cross pattern with all the reflections in line. My Evostar was very close to well collimated. It's pretty easy to see when it's off. Testing my Celestron 102, which I know is slightly off, the REEGO picked up this showing some of the reflections a little out of align. Using it on my ST80 that I know is way off, the REEGO also showed this.

 

Moving to my 8 inch Edge, you switch to red mode and you see the how the primary is aligned by the concentricity (word?) of the outer rings you see looking into the peephole. You can't check the secondary because the mirror is not center marked. I pulled the fastar secondary and using my 3d printer, I made a cup matching the diameter of the secondary and put a 1mm hole in the center. Using the cup upside down, I placed a Sharpie dot at the center of the secondary. My Edge 8 I know was in good collimation and the REEGO confirmed this. If you're not comfortable marking your secondary, the collimator won't do you any good for an SCT.

 

The main reason I purchased the REEGO was for my new 6" GSO classical cassegrain. I have the Takahashi collimating scope, but I couldn't resist getting the REEGO to play with. When I received the CC6, collimation was very very close per the TAK scope. Checking with the REEGO, it looked like it was in collimation. I made a very fine tweak to the CC6 secondary bringing the black dot to the center of the doughnut. Checking again with the REEGO it still looked in collimation.

 

I must point out that the TAK scope has a great advantage here as it magnifies everything by a factor of 6 making the enlarged image of the secondary doughnut MUCH easier to see when when the black dot is centered in the doughnut. Other than this difference, I think the REEGO holds it's own with the TAK scope.

 

I haven't used it on any of my newts yet. Overall, I'm very happy with the REEGO. I think it is a good, all purpose collimator that works well. Would I buy it again? - yes.

 

I was able to track down and translate separate copies of directions for Newts, Refractors and Cassegrains. I didn't post them as I don't want to violate any TOS. If you get the REEGO you can PM me and I'll email them to you.

 

Carl




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