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If I had to go back and collimate a e-130D, I’d use the Tak tools as a I did before and I suspect I would not find it particularly intimidating. I have now participated in several discussions on Newtonian collimation. Using proper tools like the Tublug and Catseye tools, it is methodical and repeatable. My observation is that people want to take short cuts and double down on bad methods. The discussions degenerate into unfounded opinions and mythologies. If the opinions were weighted by the quality of the writers’ images, I think it would yield a much better signal to noise ratio.
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The screw is pushing or pulling on a tilt plate or a mirror for collimation. It takes practice. I was pretty lost my recent first try. My RASA perhaps has internal problems. I wanted less frustration and more imaging without corner stars elongated and shredded. In my case all 4 corners and it wasn’t back focus. I realize that fast comes with a big trade off. Many comments on how little people thought of the epsilon collimation process and instructions. The only good part of the collimation seems to be you can do it in the daytime when you’ve just had your coffee. That beats out in the dark. |
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Arun H: This applies to so much! Off topic, but so many people talk about how great a mount performs when loaded to over capacity, but not a single round star in sight! This is actually one thing I really like about Abin forums. You can easily view people's galleries to see if their advice matches up with personal expectations. |
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https://www.youtube.com/watch?v=OPmyPxsdeQM So this guy linked here. He's a well known YouTube astro video guy, and he previously owned a Newt. Guys like me who have never used a Newt see someone like this and go, "wow, if he can't do it..." What was he doing wrong? He said he was returning the Epsilon! When I came upon this vid, I was looking to find a vid that went like, "Ok guys, now just LOOK how easy this is!" |
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14.24
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First of all - he is using a Catseye autocollimator rather than the Tak tools which are more appropriate for the Epsilon. and assuming he was actually collimating a regular Newtonian rather than an Epsilon, he appears to be adjusting the primary with the autocollimator. With a regular Newtonian, one uses a Cheshire or Tublug to collimate the primary, then an autocollimator to do the secondary and iterates until both show collimation. The reasons behind this have been gone over some 10 years ago by Vic Menard and Jason Khadder. |
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19.90
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Paul Wilson: As mentioned, he is using the wrong tools in the wrong way. Additionally he was trying to collimate the secondary using an artificial star and centering the central obstruction shadow... which is incorrect with the epsilon! The CO shadow will always be offset with epsilon when properly collimated. Videos like this are why people think its a nightmare without every having tried. Wrong tools, wrong process, wrong everything... I.e.- User didnt take the time to try and understand what they were doing and after fiddling a little bit gave up. I can see why he had a "nightmare" experience. |
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Paul Wilson: I replied to that video about a year or so ago in the comments and explained what went wrong. It's not uncommon for Newt users to make that mistake. |
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Ok, I can appreciate that he was using wrong tools in wrong way. Ha, been there, done that! Where can I see and hear the right way to give me more confidence in this (beautiful and no doubt well made) scope? |
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Paul Wilson: https://www.astrobin.com/forum/c/equipment-forums/takahashi-epsilon-160ed/collimation-of-the-e160ed/ The process is the same for all of them. The adjusters are not all designed the same, but what you are doing to collimate is consistent. |
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Well a guy accustomed to being around Newtonian scopes couldn’t do it. So it was different, or un-intuitive, or both.
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Paul Wilson: Its different because the optical system is different. |
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Paul Wilson: My experience previous to epsilon was TS UNC, ONTC and I cut my teeth on TPO. I've used lasers and catseye collimation. When I started with epsilon the first thing I did was not assume it was just another newt. I RTFM and asked a couple of questions before I started making adjustments. It was a tiny leap to execute with the tak tools once I learned about them. The guy in your video (and his buddy) might have previous experience with newts but he did nothing to educate himself before denouncing the product and process. Irresponsible for a you tuber, but I guess that's not a criteria these days. In any event, my horse has left this race. I hope that people don't fear these wonderful telescopes because they read or watched some "expert" go on about how terrible their experience was. As always, you can buy a quality refractor if you don't want to get your hands dirty. But the rewards are great with a scope like epsilon if you are willing to take the time to get there. |
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Lol, when all else fails, RTFM. I will buy that. But people said they had trouble with the translation. Has it been improved? |
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Paul Wilson: I dont have all the manual copies on hand to make that determination, nor the time to do it. It is good enough to get the job done, also others have written up guides that help. |
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Bill Long, thanks I went and read your response to the guy that couldn't collimate the 180. I noted you suggested the just slightly slower 160 instead. Do you own the 160 and would you still recommend it? Especially to someone like me, coming from the difficult F2 RASA? |
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Paul Wilson: Bill does indeed have the 160ed. Here is his latest image: https://www.astrobin.com/cnny9n/B/ |
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Paul Wilson: There is more than just a speed difference between the E160ED and E180ED. The corrector in the E160ED is a new corrector that is not present in the other two models, and it has better correction for modern small pixel CMOS cameras, like the IMX455. Similarly, it also has nicer collimation adjusters on it that make it much easier to collimate in that regard. |
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Paul Wilson: ***cool. That’s what I was wondering. Thanks for comment. I have the small pixel ASI 2600s. I just don’t want to create new problems for myself.! thank youfor your reply here *** |
0.00
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Hello Shinpah, Hello Shinpah, I haven't noticed the light leaks your are talking about. It could be at the base of the saddle and that could be solved with some gasket past. |
1.51
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Hello Shinpah, I've resolved it, but mine was here (and also a trivial amount from the flange to the OTA)  |
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Hi, Strange 8-O. I have just check mine with a light in front, I have no leak. Maybe I have a new version focuser. I bought it a month ago. We almost have the same setup, I also have a RisingCam. |
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I wanted to do an update to my efforts to pick some more brains. I ended up getting an octopi and started really digging into hocus focus and the aberration inspector and have mostly (down to about 12 microns +-) corrected the tilt (it's still mostly apparent in the bottom left). My current issue is this persistent astigmatism that doesn't respond to collimation.  You can see that the right side of the image has bird stars. I've tried nailing the collimation down as precisely as I can, and it doesn't make any difference. I've also tried looking at various states of miscollimation to see if slightly offsetting the primary/secondary alignment in different combinations would shift around the bird stars to a different section of the frame/change their shape. It doesn't. I'm willing to accept that this is still in fact a collimation problem. But if that were the case, wouldn't my efforts to miscollimate have an effect? I am at a stage where I think this could be a bad mirror. |
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I wanted to do an update to my efforts to pick some more brains. I very much don't think so. Your issue is still with the combination of tilt and coaxiality between all the various elements (primary, secondary and corrector) but you are nearly there from what I can see from the image. |
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I've did a little test, rotated the primary and recollimated. No change to the right hand stars. (other than some slight tilt getting reintroduced).
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Currently still (slowly) playing around with tilt. I recentered the octopi once or twice over the last month. On of the curious things that I ignored from HF runs was a backfocus error of "35-40 microns" - I slapped on a whopping 1mm spacer and it said it improved it and then tried another .5 mm and it got better yet. I'm not sure how this is possible but seeing as the Risingcam 571 sensor I'm using has like .1mm+- of tilt across the sensor it's possible that it just isn't precisely manufactured to have a proper focal flange distance. I've been having this other interesting issue where I have this uneven vignetting that's appeared both pre and post-octopi:  It shows up as compressed vignetting on one side that doesn't quite flat calibrate out. Touching collimation doesn't seem to alter it so I assume it's some misalignment of the filter wheel path and the sensor. |
