Concenter EP Alternatives?

[v4cascade]

Not so much an eyepiece but didn't know where else to post this so mods please move if needed. 

Why does all the good stuff seems to be on the other side of the pond? I cannot find one retailer in the U.S. that sells this and I don't want to sell off one of my kidneys to pay for the shipping and a long ETA. What are some alternatives to a Concenter EP? I already have a standard collimator, laser collimator and cheshire piece. None of this seems to satisfy my OCD to perfectly align the secondary mirror.  

[johninderby]

APM also sell concenters so maybe there is a US APM seller that could get one? 🤔

[Second Time Around]

First Light Optics here in the UK stock Concenters.  Many US buyers on Cloudy Nights praise their very fast and inexpensive service to the States.

I'm a very satisfied customer of theirs too.  They also sponser this site.

 

[Mr Spock]

I bought a TS Concentre from FLO. It enabled me to get my secondary spot on.

[Don Pensack]

Here are some things I noticed about the Concenter.  This is the version I had:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p5506_TS-Optics-Concenter-2--Collimation-Eyepiece-for-Newtonian-Telescopes.html

1) It does agree with other tools once you have collimated with the other tools. Read on as to why the "AFTER" other collimation tools is necessary.
2) However, it suffers from multiple problems:
a. it's too short. I couldn't focus on the rings even with reading glasses because they're only ~3" away from the eye.
b. I could not adjust the focuser to get even one ring to correspond to the outer edge of the primary mirror OR secondary mirror, even running my focuser from one end to the other. They're spaced wrong for my f/5 setup.
c. the rings are very broad and not particularly sharp in execution
d. the center hole in the reticle is larger than the hole in the center marker, but smaller than the Hotspot, so it isn't visible at all. It would collimate a mirror with a Sharpie center dot kind of like a collimation cap can, but wasn't useful in my scope for primary adjustment at all.
e. but the biggest problem and one that makes the tool completely worthless, is the terrible problem with parallax. The center hole isn't large, but with such a short distance to the rings, they wandered all over the place. I tried to stabilize my head by sitting and putting fingers on tool and cheekbone, but that didn't help at all. The wandering rings problem makes the tool worthless unless following after some normal collimation tools are used. I had no such problem with the Astrosystems LightPipe, even though it has a larger center hole than the Concenter.
f. The eye relief of the tool is perhaps 8mm to see all the rings and the outer inside edge of the tool. At that distance, I couldn't focus on the rings at all--they were just a blur. When I put my bifocal reading glasses on and looked through the bifocal section to focus on the rings, I couldn't even see my entire primary mirror.
g. When my focuser was nearly all the way in, I was at the apex for my mirror because the pupil of the Concenter sits almost 1.5" above the shoulder of the tool. I couldn't even get the pupil TO the focal plane of my scope, which is 0.75" above the racked in focuser.

Just a horrible execution of a decent idea.
It needs to be a longer tool--a LOT longer.
It needs to move the pupil in to about the top of the focuser so the entire field can be seen.
I have no idea how to solve the problem of the invisible center hole in the reticle. Maybe make it a lot smaller or larger?  Or make multiple f/ratio versions?

[johninderby]

Hence the Concenter Visius which is the new much longer upgraded version with a number of improvements which addresses the shortcomings of the old Concenter. Sold by APM.

Unfortunatey the improvements  push the price up a fair bit.

Edited May 11, 2022 by johninderby

[FLO]

10 hours ago, johninderby said:

Concenter Visius ... Sold by APM.

I wondered why Don had cut/pasted his negative review of the original Concenter into this discussion ... 

@v4cascade If you want to buy locally then look for a US stockist of TS Optics or TS Photoline telescopes then email them. They might be willing to add a TS Concenter to their next stock order. 

HTH, 

Steve 

[v4cascade]

5 hours ago, FLO said:

I wondered why Don had cut/pasted his negative review of the original Concenter into this discussion ... 

@v4cascade If you want to buy locally then look for a US stockist of TS Optics or TS Photoline telescopes then email them. They might be willing to add a TS Concenter to their next stock order. 

HTH, 

Steve 

Steve, thanks for replying to both my message and email as that cleared up a few of the questions I had. One more thing, do you stock the newest version of the concenter (visus)? I don't see it on your website? 

[johninderby]

I had the Concentre Visus and really appreciated the improvements particularily the longer length which made it easier to use.More expensive than the TS version though.

https://www.apm-telescopes.net/en/concenter-visus-precise-adjustment-despite-glasses

Edited May 11, 2022 by johninderby

[FLO]

6 hours ago, v4cascade said:

... do you stock the newest version of the concenter (visus)? I don't see it on your website? 

Not yet but I don't see any reason we cannot. I will look into it then let you know 🙂 

I confess I only became aware of the other version yesterday when I saw Don bashing the original (Don is an APM dealer).

Our customer feedback for the original is excellent and - so far - not a single customer return so I was not expecting to read such a full-on attack. 

Steve

[johninderby]

Think the Concentre Visus would be a nice option to stock although it will be more expensive of course.

I have used the TS version, and while not perfect, it is still an excellent product that does the job. 

[johninderby]

Couple of photos of the Visus.

[apaulo]

i bought the ts concenter, up to now i thought it was me and an ageing pair of eyes. i find it very difficult to use and see the circles, alignment etc. it has helped me set up my secondary mirror, but by no means did it make it a lot easier. i ended up using it in conjunction with a cheshire and a laser until they all agreed. its a bit like a lot of astronomy gear, getting upgraded updated simply because it was inferior in the first place, also making it over priced. 

[Jiggy 67]

I have to admit that I have both versions and I struggle to get good focus on the rings with both versions in my f5, though I’m not done yet and will keep trying 😀

[markse68]

I have the original and can't focus on the rings either, but I never tried the longer version. the designers must have young eyes. Mind you I can't focus on the cross hair in my cheshire either. I just got an Ocal and it's a really good tool. More expensive than a concentre and you need a computer to use it, but does pretty much the same thing and more, and easier I think. So I guess it's an alternative?

Mark

[Don Pensack]

8 hours ago, FLO said:

Not yet but I don't see any reason we cannot. I will look into it then let you know 🙂 

I confess I only became aware of the other version yesterday when I saw Don bashing the original (Don is an APM dealer).

Our customer feedback for the original is excellent and - so far - not a single customer return so I was not expecting to read such a full-on attack. 

Steve

I don't sell to the UK. Nor do I sell this tool.

I merely reported my experience with the tool. something, I believe, an amateur astronomer can report, based on experience and not hearsay?

I have used nearly every collimation tool there is over the years, and most have their ups and downs.  FLO, BTW, sells an incredibly nice combination Sight tube/Cheshire:

https://www.firstlightoptics.com/other-collimation-tools/stellalyra-premium-cheshire-collimating-eyepiece.html

Here in the US, there ae several very poorly-designed collimation tools that are sold, but sales don't necessarily equal good design.

I try new tools all the time to stay up on collimation trends.

 

As for the Concenter, I've stated my experiences with the tool, which I obtained at retail from the EU.

The new one doesn't solve problem G--you won't be able to get the pupil of the tool down to the focal plane of the scope.  In the case of the new one, perhaps not down to the apex, even.

The new design would seem to solve several of the other issues I saw with the tool, however.

[Dan_Paris]

In my opinion a Catseye Teletube or Telecat  is a  much better tool than a Concenter (and on your side of the pond). The former is a tunable sight tube while the latter is a combo tool that is both a sight tube and a cheshire.

More precise and easier to use than a Concenter. I have both and since I received my Catseye tools (Telecat + autocollimator) my Concenter and laser stay in the closet.

Edited May 13, 2022 by Dan_Paris

[v4cascade]

Thanks for all the replies everyone. I went down the collimator rabbit hole and purchase the Ocal collimation tool from FLO. It was one of their customer return items so I couldn't turn down that opportunity. 

[markse68]

2 hours ago, v4cascade said:

Thanks for all the replies everyone. I went down the collimator rabbit hole and purchase the Ocal collimation tool from FLO. It was one of their customer return items so I couldn't turn down that opportunity. 

Hope it works for you- I'm finding it a very useful tool. Looking at Flo's clearance page they have had a lot of returns! I wonder if that has to do with image shift from mounting it? Ocal advise to use threaded mounting but I use mine with a Glatter Parallizer 2"-1.25" adapter and a 1.25" nosepiece from an Asi120 camera- I had both of these anyway so no additional cost but this registers the camera pretty accurately so I get repeatable results after re-inserting the camera. I also tweaked my calibration offsets (you have to look these up in an excel spreadsheet based on your serial number) by turning the camera 180deg back and forth and adjusting till the offset to eg the secondary outline was balanced in both positions, for x and y. Otherwise I would get different results depending on the camera orientation.

Mark