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Information on the Takahashi Mewlon 210 and Mewlon 250

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#76 dr.who

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Posted 25 November 2016 - 10:25 PM

Did we actually get a side by side comparison review result? 210 owner here who I think will still be happy that I chose it over the 250 due to size and weight differences. The 210 is a really nice weight and size and still pulls in quite a bit. Still, if someone can post the their impressions between the 210 and 250?


Waiting on rings mate. Soon as they are in, I have a bit of time for myself, and clear skies I will ring it in for you. Sorry about that.
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#77 dr.who

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Posted 27 December 2016 - 11:43 AM

The rings came in. The Feathertouch focuser as well. And so have the clouds. Or the "life gets in the way" things. So I have had zero first light on the Mewlon. 

 

I like carry handles on my scopes. And I like being able to move accessories from one scope to another. I use the Celestron Vixen Universal Dovetail for this purpose. I use the ADM Accessories VA Vixen style dovetail plate adapters (LINK) on my accessories so I can quickly move things.

 

The D plate is a Losmandy Universal D Plate. It is positioned in what I hope is the balance point for the scope. Since I have yet to mount and try it I won't know for sure until then. If it isn't then it will be time to adjust the rings a bit since I can't go back any further on the screw holes or the back ring. Only option is to move the front ring closer to the back one.

 

Also some photos of the business end of things too. Yes. The black paint on the finder is the same toothpaste quality as the green paint. I scuffed it when putting the rings on. <grumble>

 

IMPORTANT NOTE: If you get the Parallax rings the gap you see on the rings are normal per Parallax and will slowly shrink (note need to check adjustment of tension on the clamps!

 

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#78 mich_al

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Posted 27 December 2016 - 12:32 PM

You could get a rough balance by resting it on a wooden dowel or a pencil or a broom handle etc.


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#79 dr.who

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Posted 28 December 2016 - 11:17 AM

Cheers. I didn't bother using a dowel because I have been slammed with work and life events. And it is now actually moot. I got first light last night.
 
I put the scope up on my Mach1 with the Losmandy pier extension on top of my Berlebach Planet tripod. A very stable combination but it put the scope so high up (I am just shy of 2 meters or 6'6" tall) that I had to lift the scope up above my head to put it on the mount. With the rings and everything it turned out to be heavier than I thought it would be. And promptly banished any thoughts of getting a Celestron EdgeHD 14" or Meade 16"! ;) I usually use my mount in that configuration because I have the AP 155 on it and don't want to lay down to view at zenith. It gives enough height that from 45* to 90* I can be comfortably seated and view through the scope.
 
I needed four (4) 9 lbs counterweights to balance it on the Mach1. The weights were at the end of the CW bar. The very surprising thing was the balance point. I was using a 17mm Ethos and a Tele Vue 2" diagonal. So some decent weight on the back end on top of the mirror. I figured the balance point would be somewhere about where the green paint started on the back end of the mount to even further back towards the EP. I was badly wrong. It was actually just in front of the ring that is touching the green painted part in the above photo! 
 
I liked the fans. I was mostly ambivalent with a touch of hatred towards the motorized focuser. So I am moving off from the I positively *HATE* the thing at this point. It focused acceptably though I had to go inside and outside of focus to tell if things were focused properly. Something I am not used to with my "regular" focusers.  It still frustrates me that the focuser is a major single point of failure that could render the scope useless. That is just bad engineering in my book.
 
What was especially frustrating last night was that I had the unit plugged into a 110-120v plug on my 12v battery pack  and the plug kept coming loose from the controller. Also with all the cables (power for the mount, the hand controller for the mount, and the controller for the scope) things got a bit tangled which was a frustration point. For sure I will be putting the 9v battery in there if I use the bloody thing. I found that if I had the plug come loose then plugged it back in the scope would unfocus itself by a decent bit. No idea why it does this. Anyone know?
 
Next step will be fitting the Feathertouch focuser to it and seeing if I can abandon the motorized focuser completely. That will be a joy. I hope. ;)
 
No binoviewers used this time. I am in a barely red mostly white LP zone which sucks for me but it is what it is. No dark sky first light. :( The only EP used was the 17mm Ethos which gave me 147x magnification on targets. Speaking of which the targets in order were:
 
SAO 113271 Betelgeuse
NGC 1976 Orion Nebula
NGC 224 Andromeda galaxy
Uranus
NGC 752 Open cluster in Andromeda
NGC 457 Dragonfly cluster
 
Betelgeuse - Bright, big, a bit soft, and a bit woolly. And diffraction spikes which don't bother me. It was shortly after the fans were on so the scope was no where near TE and that's fine. It was better than what I would get in my SCT's out of the box and even about 15-20 minutes in with TEMPest fans.
 
Orion Nebula - Also a bit soft but clear nebulosity and the A-C stars clearly visible. Again too close to startup to provide a good view. Sadly when I used my TEC 140 (also first light) later on in the evening I got the A-D stars with hints of E & F. I do love my refractors. And with it being open cluster season it is really a better time for them.
 
Andromeda galaxy - It was there. There was some hints of structure which was nice.
 
Uranus - Wow! A bright light blue ball! That was nice! And even through it was poorish seeing I believe I could have pushed up to 250x with a 10mm Ethos and caught a good bit of detail. I didn't but I fully expect this scope to shine on the Moon and other planets.
 
Open cluster in Andromeda - Good number of stars in the field but couldn't get the whole cluster in the FOV. Saw some faint stuff in there. Caught what looked like a mag 8 and 9 or so double star in the cluster. Likely not a true double but they were close enough together for me to call it as such.
 
Dragonfly cluster - One of my personal favorites. Nice to see it again.
 
Coming up: A Binoviewer test. A report on the installation of the FT focuser (there is a trick to it). A test of things without the motorized focuser. A BV test with the FT on the scope. A shootout between the 210 and the 250.
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#80 Daniel Mounsey

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Posted 29 December 2016 - 11:13 PM

Carson me lad. There's a long ways to go my friend and seeing, thermals etc will play a crucial role. My skies are extremely light polluted and yet, as you can see in this review with just a modest 4" refractor, 6 stars were quite visible in the bad light pollution. 

Attached Thumbnails

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Edited by Daniel Mounsey, 29 December 2016 - 11:14 PM.

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#81 dr.who

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Posted 29 December 2016 - 11:29 PM

Cheers Daniel! This was a very fast very sloppy first light. It was right in the middle of a busy work week with less than optimal skies. I wanted to squeeze it in and was planning a dark sky trip this weekend where I could let the scope fully acclimate and cool. Sadly, thanks to the rain forecasted for Fri/Sat/Sun, that is a Non Starter.

While you live in LP you also live under relatively stable skies which is a big plus. So I am not surprised a Tak 102 did as well as it did.
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#82 Lola Bruce

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Posted 17 January 2017 - 02:05 PM

On my 250 there is not enough back focus for the camera rotator, diagonal, eyepiece adapter, and eyepiece much less an external focuser. PM me when you might go out.

Bruce


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#83 dr.who

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Posted 18 January 2017 - 12:14 AM

Interesting Bruce. Per Wayne I am OK where I am at. Have yet to test it though. I will PM you. Though with the weather report I just heard it may be a while. Grrrr....
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#84 chonum

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Posted 20 January 2017 - 04:20 AM

On a general optical design point, always remember that the DK design is a cost compromise of the classical cassegrain with easier surfaces (Elliptical/spherical).

Its performances off axis are much lower than an equivalent Newton or Cassegrain telescope.

 

Corrected DK are much much better.

 

That being said I measured two µlon 250 and one 300. They were very good on axis for HR work except for some an astigmatism issue with one of the 250. The primary support kind of silicon support (behind the primary) tends to get hard with time and cause astigmastim.

 

The 250/300 have a premium mecanic (as with the CN212). The 180/210 are cheaper in construction. The absence of a frontal ring at the tube entry make the alignment not very durable as the spider is attached directly on the tube.

 

When looking for a µlon210, try to look for a CN212 that is much more interesting. But more rare as well.


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#85 Jeff Young

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Posted 25 January 2017 - 06:01 PM

I hate the motorized focuser too.  On the pre-CRS version (at least), there's enough back-focus for Tak's rotator/focuser, diagonal, and eyepiece as long as you use a short 2" adapter.

 

Visual-Train.jpg

 

The one pictured here is from Vixen:

 

Vixen-Eyepiece-Adapter.jpg

 

Cheers,

Jeff.


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#86 dr.who

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Posted 26 January 2017 - 01:08 PM

Cheers Jeff. Ideally I will have a spare hour or so tomorrow to work with Wayne at Starlight to attach it and can post it up. I will also post more detailed photos of attaching the stock Telescope Express right angle adapter for polar scopes on to the Mewlon's since I have had a couple questions about making it fit. May even shoot a video (God help me! Sigh.)



#87 Gucky

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Posted 26 January 2017 - 06:40 PM

:gotpopcorn:



#88 Seiko4169

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Posted 09 February 2017 - 02:36 PM

If possible could you post some side by side size comparison pictures between the 210 and 250?



#89 dr.who

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Posted 10 February 2017 - 04:13 PM

Sure. Will be working on it later today. Will get to it as soon as I can.
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#90 jrbarnett

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Posted 10 February 2017 - 05:15 PM

When I was doing my research on the Takahashi Mewlon family of scopes I wasn't able to find very much out there that was related to what I wanted to find out. These scopes tend to be pretty rare in the wild and thus there isn't all that much out there. The things I was looking for were:

What accessories worked with the scopes
What focusers would be compatible
What rings or mounting plates could be used
How the views were compared to other scopes I had used
What was the size of the scopes
How much did they weigh
How long does it take to cool them
How hard are they to collimate

And so on. Since I am now the owner of a Mewlon 210 and a Mewlon 250 I want to use this thread to document my own findings and experiences with the scopes as well as constructive information and experiences both good and bad ONLY ON THE TAKAHASHI MEWLON SERIES so that hopefully someone like me coming along behind me doesn't have to go through the learning curve I did.

Please note the information in bold underline capitals. That means I do not want this thread to drift off course or to start discussing other scopes unless it is in relation to the Mewlon series. For example I have done side by side comparisons between an 8" and 11" SCT and the Mewlon 210 so I will likely be mentioning what I found in that comparison. I will not be going off on a tangent on how the Meade f/8 10" ACF is far superior/inferior to the Celestron EdgeHD 11" SCT because that has no bearing on the topic.

Again the purpose here is to provide information to others thinking about either scope.

First up some quick data:

Mewlon Family Specifications
Mewlon 210 Owners Manual
Mewlon 250 Owners Manual

The reason why I went with the Mewlon series of scopes is because I wanted to very best Reflector scope I could find that was in a similar footprint of a SCT.

Don't get me wrong. I loved my SCT's they were fantastic performers and did everything advertised. I was fortunate to have very good mirror samples on mine. However I also observe from Southern California which means that temperatures can swing from day to night. Not as much as other locations but still enough that I was waiting on cool down for my scopes. And my observing sessions tend to be very short due to life happening. So I wanted something that would give me the refractor like views of the Edge series of SCT, the ability to go deep like the Edge, but that would cool much faster and stay that way with less intervention.

The Mewlon 210 was the ideal scope for this. It is light enough to go to the field easily, its mirror quality was top notch, its mechanical quality was acceptable (more in a moment), and it cooled to the point where I wasn't seeing wooly stars (I HATE wooly stars) in half the time of my SCT even with the Deep Space Products TEMPest fans (I highly recommend these for your Edge SCT).

I usually pair my 210 up with my TSA 120 when I am at dark sites and structure my 4-6 hour observing session around objects that each scope excels on. I have found the 210 punches way above its weight class delivering refractor like views to the edge of the field when cooled in a detail level similar to a 9-10" SCT. Especially on planets. I used to not be a big fan of Jupiter. It was my 5th favorite planet after Saturn, Mars, Uranus, and Neptune. Until I got a look at it with the 210 in good stable air. It was amazing the detail and the colors I could see. Ditto on the moon. I would usually spend only a few 10's of minutes at most on the moon. Until I started using the 210. Now I can find myself loosing track of time and spending hours on it without realizing it. Globular clusters are quite nice with individual stars easily resolvable. Same with small planetary nebulae and the appropriate filters. Really really nice to look at.

I found I liked the 210 so much that I decided that I was willing to spend the substantially extra amount of money to down size from the EdgeHD 11" with excellent mirrors I had to the 10" Mewlon 250. Fortunately my local shop, Woodland Hills Camera and Telescope, was very helpful giving me a very generous trade in value for the Edge so I could (barely) afford the 250.

If you can swing the 250, go 250.  The 250 has a center-etched secondary and collimates in seconds using a Takahahsi collimating scope.  The 210 has an unmarked secondary and collimation is like collimating and SCT x5 in difficulty.  I find the 210 to be "mush" (ha ha, bad but sadly true pun!) more sensitive to miscollimation than my C9.25.

 

In fact my last tangle with Mewlon 210 collimation has me fuming.  It's been in its box for 20 months.  I plan on boxing her up in her original container and sending her to Dr. D. for TLC.  Rarely do I ever become so disenchanted with a mechanical (and necessary) process like collimation, but the combination of super tight, hard to turn collimation bolts and poor performance with anything less than exacting collimation, has me miffed at this instrument.

 

The 250 is more costly, devilishly heavier, etc., but collimating it is a piece of cake by comparison, so your view quality will be easier to ensure.

 

Best,

 

Jim


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#91 bobhen

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Posted 10 February 2017 - 07:19 PM

My experience collimating my Mewlon 210 is different.

 

As a matter of fact, I just pulled the primary for a cleaning (which took all of 10 minutes). After reassembling the scope the collimation was just a little off. It took a couple of very small tweaks on the collimation screws and some back and forth checking on a star to get the scope collimated; maybe 15-20 (?) minutes. Exactly the same effort as collimating an SCT except you need to make very small turns with the Mewlon. The collimation screws are tight but the scope holds collimation very well. Also, NEVER use Bob’s Nobs with a Mewlon.

 

Besides the aperture increase, and if you can handle the weight, I think the best reason to get a 250 over the smaller Mewlons is because the 250 comes with fans.

Depending on your location, cooling any Cassegrain can be problematic and in that regard fans are a big help. I added fans to my Mewlon 210 for the same reason the larger Mewlons have them.

 

Bob

 

 

 

Bob


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#92 chuckscap

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Posted 10 February 2017 - 09:20 PM

I had a Mewlon 250.  I bought it used, had it collimated on an optical bench by S&S Optika in Denver and had them install the in baffle corrector.   It was a totally amazing scope.   I sold it due to the fact that I had a heart issue and couldn't carry it out, and also for two years we had bad forrest fires so I kept inside two whole summers.   When the skys were clear and steady it was just stunning.


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#93 jrbarnett

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Posted 10 February 2017 - 09:25 PM

My experience collimating my Mewlon 210 is different.

 

As a matter of fact, I just pulled the primary for a cleaning (which took all of 10 minutes). After reassembling the scope the collimation was just a little off. It took a couple of very small tweaks on the collimation screws and some back and forth checking on a star to get the scope collimated; maybe 15-20 (?) minutes. Exactly the same effort as collimating an SCT except you need to make very small turns with the Mewlon. The collimation screws are tight but the scope holds collimation very well. Also, NEVER use Bob’s Nobs with a Mewlon.

 

Besides the aperture increase, and if you can handle the weight, I think the best reason to get a 250 over the smaller Mewlons is because the 250 comes with fans.

Depending on your location, cooling any Cassegrain can be problematic and in that regard fans are a big help. I added fans to my Mewlon 210 for the same reason the larger Mewlons have them.

 

Bob

 

 

 

Bob

Yeah, my pain started when I switched to Bob's Knobs.  I wanted SCT-like ease of tweaking, but the BK's needed as much force as the stock bolts to turn and I ended up leaving finger-skin on the BKs, which caused me to move back to the bolts.  It was enough out of whack after the swap and swap back, that I am wondering whether I may have another issue like a tilted center baffle or mis-centered spider/secondary.

 

I should add that my Mewlon was purchased new and arrived from OPT completely FUBAR.  It required major adjustment to get it collimated, but once collimated, it held it pretty well.  But the experience of the super tight bolts (they squeak when you tweak them) sent me looking for an easier tool free method of adjustment.  Mistake.

 

At any rate a Mewlon 210 with large scale collimation deviations is no fun whatsoever to collimate, and it's not a matter of minor SCT-like tweaks.  I have never seen an SCT as far out of collimation as the Mewlon I received from OPT.

 

Regards,

 

Jim


Edited by jrbarnett, 10 February 2017 - 09:30 PM.

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#94 dr.who

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Posted 11 February 2017 - 01:51 PM

Jim

You should send it to either TNR or Dr. D. and have it sorted out. Once you get it to where it should be you will likely be quite happy with it.
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#95 Daniel Mounsey

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Posted 11 February 2017 - 04:37 PM

Carson me lad, I sent you my 30 minute Mewlon video I made. Happy to help Jim with the 210. Trust me, don't run to any conclusions until we talk more about your 250.


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#96 mich_al

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Posted 11 February 2017 - 08:37 PM

Carson me lad, I sent you my 30 minute Mewlon video I made. Happy to help Jim with the 210. Trust me, don't run to any conclusions until we talk more about your 250.

 

 

Is it available for purchase?  What does it cover?


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#97 Daniel Mounsey

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Posted 11 February 2017 - 10:12 PM

 

Carson me lad, I sent you my 30 minute Mewlon video I made. Happy to help Jim with the 210. Trust me, don't run to any conclusions until we talk more about your 250.

 

 

Is it available for purchase?  What does it cover?

 

 

 

Oh no it's not for sales purposes. It's a video review that goes into technical details. I'm doing another part that covers collimation details but it hasn't been made public yet. The editor is visiting tomorrow and I'll ask him to release it on YouTube tomorrow publicly. It covers details such as thermals and details about open vs closed tubes. The version Carson has will be slightly altered with improvements tomorrow but it's basically all done now and ready for release on YouTube. 


Edited by Daniel Mounsey, 12 February 2017 - 12:08 AM.

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#98 dr.who

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Posted 12 February 2017 - 12:13 AM

It's a great video. It covers the 250, the Temma 2 early version, and a passel of other things. I will post the link when Daniel sends it over.
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#99 dr.who

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Posted 12 February 2017 - 12:58 AM

Per Seiko's request here are the comparison photos. Please note the reason why you see red in the 250 is because I was wearing a red shirt when I took it. The last shot is a perspective shot. In order that is a FSQ-85, TSA-120, TEC 140, AP 155 EDFS, Mewlon 250, and Mewlon 210. So a 85mm, 120mm, 140mm, 155mm, 250mm, and 210mm scope. It gives you an idea how big the Mewlon's are.

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#100 Seiko4169

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Posted 12 February 2017 - 06:12 AM

Fantastic. Thanks so much. It's a much larger scope than the 210.
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