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Greetings, I purchased the Hotech CT Collimator and have had a difficult time getting good results with it. I have watched the instruction videos multiple times over and I think I understand the concept well, but my collimation still suffers. My use case for the collimator was to help me achieve rough collimation when swapping between my Hyperstar and native focal-length imaging, I don't expect this tool to deliver perfect results. Based on the results that I'm seeing I'm concerned there's a bigger issue going on, but I'm not able to wrap my head around the output I'm getting and what would cause it. Would appreciate any help from members that have experience with this tool. 1. The co-alignment looks pretty good, and I should be able to progress to the next steps. (Slightly off in this pic, just needs a small tweak)  2. The diffused ring looks decent as well.  3. Here's where the problems start. Based on the collimation ring in the pic above, I would expect to see the "alignment dots" below be more aligned. What I see is the bottom dot in decent position, but the other two are way off the "Y-shaped" alignment lines. How do you get light to torque like that? It would make better sense if all 3 alignment dots were torqued in the same amount away from the alignment lines. My mind wants to think that if the tool is well-collimated, all three alignment dots should be equally spaced from each other on the grid.  4. Another interesting item is that on the reflector/target installed on the C11 baffle, I am not able to get the 3 laser beams to intersect. I can get them close, but never can I get them to overlap perfectly. I can get the "blob" that you see below to land on the center of the target, but then my collimation goes even further out of alignment.  Here's what I am theorizing based on what I'm seeing from the device output: 1. Hotech Collimator, Bad Collimation: If the C11 and the Hotech unit are co-aligned well, could the output seen in item #3 above be caused by collimation issues in the Hotech device itself? If so, how do I validate and then collimate the Hotech device? 2. Potential Issues with C11 Corrector Plate: This C11 is fresh from Celestron repair to replace a shattered corrector. Is it possible that the corrector plate needs to be better aligned? Celestron collimated the scope before it left repair and I would assume that they know what they are doing. If the corrector is to blame for this, would it also explain why I'm not able to get all 3 beams to overlap on the target reflector on the rear of the C11? 3. The Hotech Tool is Ineffective and Should Not Be Used: While I'd be disappointed in giving up on this, I'm not above it. Sometimes things just don't work as the seller suggests they will. Maybe it's time to just move on and stick to collimating with a Tri-Bhatinov mask only. Thanks for any comments or guidance, I do appreciate the help. Jeramie |
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I tried one of these with my 8" edgehd and my 8" RC. I think i got lucky with it the first time (or the scopes were already collimated). The second time I used it and several times after I just couldn't nail it down. I ended up selling later. I've used the Ocal PRO with an artificial star a few times now which was a lot more successful for daylight collimation Does anyone on AB use this Hotech device regularly with success? |
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| I've also tried emailing support and have had no response from them. It's hard for me to call it "snake oil" when some others have had success with the tool, but that's what its looking like. |
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I use one of those on my Edge HD 11. It works great getting the collimation close. You can try adjusting the focus to bring the outer dots closer to center and tighter. That's what I do anyway. I would suggest that you always finish by turning the focuser counter-clockwise a bit just like you should do focusing in the field. This "lifts" the primary mirror against gravity when you are out in the field. Since you are oriented horizontal with the laser collimater you are just trying to make sure the primary mirror is roughly tilted the same way it will be in the field. They definitely tilt a bit moving the focuser opposite directions. If you still have concerns on the corrector plate, they are match marked to the primary and secondary mirrors with a small black sharpie line. It should not be to hard to see those lines with a flashlight to see the one on the edge of the primary mirror. You can see the one on the secondary when you pull it out like you would changing to your hyperstar. The one on the corrector plate can only bee seen if you take the retaining ring off. There are also serial numbers etched into the corrector plate. They are usually at the 9 o'clock position but not always. You also have to remove the retaining ring to see the serial numbers. I personally would collimate the scope without the hyperstar first. When you collimate with the hyperstar don't mess with anything but the push pull screws on the hyperstar to get as close as you can. If you start trying to adjust the corrector plate centering with the hyperstar on it is very easy to get things really far out from the factory alignment. If that has happened just start over doing only the scope without the hyperstar first. CS, Jeff |
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Jeff Reitzel: Thanks Jeff. I'm trying to collimate at 2800mm currently and that's where I'm stuck. If I recall correctly, prior to the new corrector, the Hyperstar had a similar issue with collimation using the Hotech device. I'm beginning to think that the Hotech device is flawed in some way. I may attempt to build a collimation device for it to get it aligned. This all started when I was measuring some recent images and ASTAP showed that there was serious tilt in my subs and I wanted to get the alignment straight. I assumed that Celestron did a good job of collimating the scope after repairs, but now I'm questioning if the scope was even repaired correctly. Interesting you made the comment about matching serial numbers. After the scope dropped and shattered the corrector, I was under the impression that the primary/secondary/corrector would all be matched. Celestron stated that with their manufacturing tolerances today they are able to easily swap these parts out for new stock. |
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| I would bet the new corrector had alignment marks put on at the factory. Probably to match the ones that were already on the mirrors once they had it installed correctly. Maybe that's a difference in EdgeHD optics vs C11 too. I'm not sure on that. Just curious, have you tried to collimate with an actual star? The Hotech device will only get things close at it's best. Getting everything perfectly square using it is probably not possible. Just very close is a reasonable expectation. I always had to make final adjustments under the stars at it's native focal length. Usually the Hotech device was close enough for the Hyperstar. Or, at least I couldn't see much room for improvement on the stars. I don't think you are terribly far off from your pictures. Even with the Edge HD scope, the dots never perfectly fell on the "Y" lines you mentioned. But they were absolutely round and on the same distance ring. There were always 3 dots at the rear target like you show as well. But they were very close together and all within the center circle when everything was collimated. At least you have an idea what I saw using the Hotech. |
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| It's important to get the mirror device from Hotech at the proper backfocus distance. I suspect that the problem you are having is that the eyepiece mirror is not at the right distance. Hotech customer support is nonexistent and there are several contradictory user manuals in circulation. I sent my EdgeHD 11 back to Celestron for collimation. Hopefully FedEx didn't bounce too much. Good luck. |
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Jeff Reitzel: I have a really nice Tri-Bhatinov mask, and I attempted to use it this week with no success. I saw this video that shows how you can cover a portion of the mask to help pinpoint which knob needs to be adjusted, but that only made it worse. |
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Bill Becher: I actually just did this yesterday! The reflector/target is sitting at 146mm, but it didn't seem to help with the dots lining up any better. I really do think that I have dud with this unit and may attempt to collimate it. I seriously doubt Celestron would send this scope back to me with something this out of whack with the optics. |
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I just noticed something from my #3 picture above, all of the red collimation dots have the collimation "rings" around them. Almost the same as when you're using video to collimate, and you have the scope out of focus. Is it possible that the scope is out of focus and causing problems? Another question I have is how far should the collimator be from the corrector plate? During one of the Hotech training videos it is mentioned that the further the collimator is from the scope, the better. And then several minutes later (or in the second video maybe) it mentions that you only need the collimator 1 tube length away. So... which is it? And while I'm at it... what are all the different rings used for? What is the difference between rings 1 or 4 or 6? Is it aperture-dependent perhaps? Appreciate all the conversation on this. |
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Update: David from Hotech reached out and had a great conversation about my challenges. David provided detailed steps on how to test for collimation issues with the device and I’ll report back with details once I’ve had a chance to validate and document. Jeramie |
