TSMKOLLI Collimation Generic equipment discussions · Reg Pratt · ... · 12 · 662 · 7

I recently received the new TSMKOLLI collimating tool for use with my Newtonian and RC telescopes. I’m fortunate to have had good results collimating both telescopes with just a laser and Cheshire. However, with the Newt getting into awkward positions to look through the focuser isn’t fun, especially when you’re over 6 feet tall like I am. My first attempt to solve this was to order the CATSEYE WiFi Cheshire.  The camera works well if your mirror has a reflective center spot. To my knowledge most (if not all) consumer reflector telescopes come with a non-reflective primary spots though. These spots do not show up in the Cheshire camera even with extremely bright light shining on it. I emailed Jim of CATSEYE COLLIMATION and he informed me that the device works best with a reflective center spot. Fair enough, but re-spotting the mirror is a task I really didn’t want to get into and I suspect many others wont either. 

A few days ago a buddy of mine made me aware of the new TSMKOLLI. This device utilizes a guide camera, or any camera with a 1.25” nosepiece. The device has a lens at the front along with 4 LEDs inside the tube. This LEDs project a set of patterns onto the camera sensor. I found the instructions and demonstration video on Teleskop Service website to be kind of vague so after taking some time to get it figured out I thought I’d do a little write up for anyone else looking into this device or looking for a way to make collimation easier. In all fairness though, it only took me about 10 minutes of messing around with it to get a handle on what I’m looking at and what needs to be done. The device itself can accommodate both 2” and 1.25” focuser draw tubes. Besides removing the need to look down a focuser for collimation, the biggest advantage of this tool is that it doesn’t rely at all on center spots on the mirror. It uses only the reflections made by the mirrors and lens. That means if you have a center spot that isn’t set properly on the mirror (or don't have one at all) it doesn’t matter. There is also a 1.25” filter thread at the front of the device and according to TS using one will provide additional reflections which increase collimation accuracy. I don’t have any 1.25” filters on hand but I have ordered some and would be happy to update this thread with new images using them if anyone wants.







For the demonstration I’m using an 8” GSO RC, 2” Esatto focuser w/ 2” compression ring adapter , ASI174mm mini guide camera, and Sharpcap on my laptop. Let me be clear that I understand the result shown below is not the absolute best possible collimation I could achieve. The purpose of this write up is more to demonstrate how the tool works. But as you’ll see after only 10 minutes learning the device and another couple minutes playing with the mirrors, I was able to achieve a reasonable level of collimation and would only require a small tweak to really nail.


TL;DR 
1. Focus camera so faint pattern is visible. 

2. Set exposure so faint pattern is defined. 

3. Adjust primary and secondary mirror until pattern is symmetrical. 

4. A star test to verify collimation wouldn’t be a bad idea. 



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Focus:
This is the biggest thing I had to figure out on my own. The instructions state the focus the camera and when done in the video it was easy to see the pattern change as the mirrors were adjusted. This was not my experience. When I focused as sharp as I could the pattern barely changed at all when adjusting the primary mirror. Eventually I found that if I moved the camera slightly intra-focus a fainter pattern shows up in the very middle and that was the key. On a well collimated telescope that pattern will appear symmetrical. As I purposefully took the telescope out of collimation, the pattern shifts and becomes uneven. Moving the primary and secondary will move the pattern in different ways as demonstrated by the video below. You need to work with both mirrors to make the inner pattern symmetrical. When the pattern is symmetrical, your mirrors are properly aligned. It could be possible that my pattern was different because it isn't the same telescope, but I suspect where one should focus may vary a bit based on the telescope they're trying to collimate.




Exposure:
The exposure needs to be at a point where the pattern inside the 4 LED spots are visible. You will see 2 different patterns here… 4 smaller bright dots just inside the 4 large LED spots, and a fainter pattern inside that. If you underexposure the camera you will not be able to see the fainter pattern and you need to because that is mostly where collimation is judged. If you over expose the camera you won't be able to see the faint pattern either. I think guide cameras or planetary cameras will be best to use because they can run at high FPS making it easier to get proper exposure. I took this footage in the early evening in my bright kitchen and dialing in the proper exposure was quite easy by setting the exposure time to 4.65 ms and gain to 0.




Software:
The image of the pattern is quite small so it would be a good idea to zoom in with your capture software. Again, I am using Sharpcap for this and zoomed in to 600% to make the inner patterns easier to see.

This is what the pattern looks like after collimating the telescope. As you see, with proper exposure and zoom the middle patterns are clearly defined and visible. Even a small change to mirror alignment is quite obvious on screen. 








In this video you can see me demonstrate what happens to the pattern when I move the primary and secondary mirrors. 

Demonstration Video

David Nozadze:
Thank you very much for sharing this! 

D

Sure thing! It's a very interesting device. So far a little less straight forward on the Newtonian but once I get that worked out I'd be happy to report back with my findings.

thanks Reg for sharing. I'd seen this device previously and was interested. Does it by chance have a screw-on thread or is it only for insertion?... i do wish that collimation tools were all screw based as I've never had much luck with consistent seating for something and sensitive as collimation even with quality rotatable clamping systems.

It only has a nosepiece that is half 1.25" and 2". I suppose since it has a 1.25" filter thread at the end of it one could technically thread on an adapter since since filter threads tend to be sallow I don't know that I'd trust such a connection.

Thanks for sharing your experience. I received mine last week but didn't work out that it is the smaller pattern in the center that is the core. Look forward to the next installment. CS

Earle Waghorne:
Thanks for sharing your experience. I received mine last week but didn't work out that it is the smaller pattern in the center that is the core. Look forward to the next installment. CS

It took me a minute to figure it out because that's not how it appears in their short demo video on the product page. I would imagine different shape mirrors will give different patterns at different points of focus. I believe it where exactly you need to focus and what the actual pattern looks like depends on the telescope.

After I figured all this out I went back and watched their video again. Then I put the camera into prime focus and purposefully threw the mirrors out of collimation again. The pattern did move in an understandable way for the secondary but not the primary so I really do believe my method is best at least for my telescope. 


Also for anyone interested I threw this on my 10" GSO newt and this is the best result I was able to get. You can see that the inner pattern looks different but the goal of making the pattern symmetrical remains the same. It's close here but not perfect. I had a hard time getting that last bit at the bottom left fixed but I didn't try for too long either. I will investigate more and report back. 

Does this allow you to achieve relatively flat and balanced field in the RC8?

Earle Waghorne:
Thanks Reg, that’s really helpful. We have clouds for the weekend, so I’ll try it out again. I have some 1,25 in filters so can see what they do. CS

I ordered a 1.25" filter myself which should be here in a few days. I'll definitely throw it on and see how much of a difference it makes and report back.