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| 2002 Takahashi Mewlon 250 I have sold this Telescope to a great guy from San Jose. He has been using it and really loves it! I will leave this page on my Website.
I have owned many Refractors over the years and every time I bought a telescope with more aperture for Deep Sky Objects I was usually disappointed. When I bought my 18" Obsession, I found a great light bucket. As I stated in the 18" Obsession review, I had the best view of Jupiter ever in the 18". But the seeing was a solid 9/10 and that is very rare. The thing I miss is portability. The 18" is easy to setup, but I use it very little, because I am too lazy to drag it out of the garage and set it up. I wanted to find a telescope that was a compromise between the 6" Refractor and the 18" Dobsonian. But I had to keep pin point star images and it had to be portable! The 10" AP Maksutov popped up. Everything sounded great, except my chances of getting one were between slim and none and slim has left town. So I kept looking. The Mak/Newt has been a hot topic lately, but I wanted a telescope that I could view through sitting in an observing chair and be able to view the whole sky from 30 degrees and above comfortably. While reading posts in the Takahashi Yahoo group, the Mewlon 250 (10") Dall-Kirkham kept coming up. Owners reported Refractor quality pinpoint stars and nice 10" DSO performance. Wait a minute, the Dall-Kirkham design is famous for bad coma? I read that all the time! But the guys that owned the Mewlon 250 say there is no coma? What was I missing? After further research I discovered that with quality optics and careful design a Dall-Kirkham could be designed to be coma free for about a one degree field of view. Takahashi has been able to produce a wonderful Dall-Kirkham! My dream telescope? Maybe! Having a Tak FS152 and a Starfire 178 already, I was a little nervous about spending more money on a telescope that was really in the range of the two refractors I already owned, except better performance in the DSO area, but that was what I was looking for. After weeks of gut wrenching back and forth indecision, I decided to order a Mewlon 250 and another EM-200 mount. Actually the price for the whole package including tube assembly and mount was about the same as the 10" AP Mak tube assembly alone. It looks like a wise decision! I have a Telescope with Refractor pinpoint star images and almost twice the light gathering power of a 7" and almost three times the light gathering power of the 6". The Mewlon 250 is also very portable and is very easy to use. Read On!
1/22/03 - I have had my Mewlon 250 for about two weeks now. The Takahashi Mewlon 250 is a Dall-Kirkham design. Basically it is a folded Reflector optical design. It is a 10" F12 and a 3,000mm focal length. The secondary has a 29% obstruction. Which is not too bad. The tube is metal and very sturdy. It is an open tube design just like a regular Reflector, so you do have to deal with dust! The finder is mounted permanently, but can be adjusted. The finder is also used for a handle. Focusing is done by an electric focuser that moves the secondary, so batteries are a must. If the batteries go dead, so does your observing session, so keep extra batteries available. The M250 sitting on top of the EM-200 mount is great for the eyes! It looks like a two tone green and white sports car going 80 mph, only it's standing still! It is the first telescope that my wife actually likes sitting in the living room. That is a good thing!
The triangle dovetail plate setup is very precise and secure and is very easy to use. The heavy rear end (all mirror) of the tube assembly makes it very easy to carry with the finder/handle. Although the tube weighs 27lbs, it does feel lighter. The EM-200 is a perfect mount for the M250. It is rock solid and very precise!
At first I was not happy with the electric focuser and the toggle switches. After using it for 6 nights I have changed my mind! You use the "High speed"-"Low speed" toggle switch to get the eyepiece in focus and then switch it to "Low speed". There is also a dial on the hand paddle that also controls focus speed further and I turn that to the slowest setting. Perfect focus is very easy and precise. The optics have a nice wide area of critical focus, which is wonderful. There is "0" focus shift, which I love! Collimation was off a little when it arrived. The collimation process is done at the secondary with three sets of push/pull screws and an allen wrench. It is very easy to collimate. The tube should hold collimation very well! Also the center tube that carries the light from the secondary to the eyepiece is heavily baffled. I counted ten baffles. It does help considerably in controlling light scatter.
I live in Southern California, so cool down is not as critical as it would be for people that live in other parts of the country that can get real cold. Removal of the tube back is easy and replacement in the dark is easy. I set up the M250 and remove the back an hour before observing and the optics have been perfectly stable every night. Temps usually start in the high 60's and end in the 40's.
I have had the M250 out 6 nights. The first 4 nights were poor. 4/10- 5/10 at best. The M250 does not like poor seeing! The last two nights the seeing improved greatly. It started at a 7/10 and improved to an 8/10 both nights. When the seeing gets good the M250 comes alive! Saturn, at 333x was beautiful! It was tack sharp and surface detail was strong. The ring system was well defined with nice sharp edges! Great fun to view! DSO performance was as I expected! M36, M37, M38, M42 and the Double Cluster were stunning! Pinpoint stars on a nice black background. Resolving power is what you would expect from a 10" Reflector. I hated to see the Moon rising above the horizon! Using the Tak LE 30 at 100x there is no coma! I did use the 31mm Nagler on the Double Cluster (they just fit) and I could detect a slight amount of coma at the very edge of the field. Could be the optics, could be the eyepiece. I will report on this further, but it really is a non-event! To all those people out there that have stated that the Dall-Kirkham design is poor, because of coma, take a look through a Takahashi Mewlon 250! You might be surprised! The Mewlon 250 does have a narrow field of view, one degree at the most, so big DSO's will not fit in the Field of View. M42 is perfect with the LE 30mm.
Takahashi does need to come out with a 9mm or 10mm LE eyepiece. With a 3000mm focal length telescope the 12.5mm is at 240x and the 7.5mm is at 400x. I used the 9mm Pentax Ortho for 333x. After the last two nights, I can say with confidence that the M250 should be a great all around telescope. I must add that I have had this telescope for a very short period of time. It will take a while to really get a good idea on just how good it is. I will be starting a side by side comparison between the M250 and my FS152 and SF178 Refractors. That will be the real test! For now the Mewlon 250 is off to a good start! 1/28/03 - I have had the Mewlon 250 out a couple more nights and it has been performing wonderfully! On Friday night after observing for about 15 minutes, I thought it was strange that there appeared to be tube currents. It seemed like the telescope had not cooled down! The telescope had been out for over an hour, the air temperature has been stable and about the same for the last two weeks. I then realized that I had forgotten to put the rear tube cover back on! In the manual it does state that you should put the cover back on before observing, as heat from your body could cause unstable Images. I was surprised at how obvious the currents were! I put the cover back on and in 5 minutes the Image was stable!!!! Your body heat will send currents up the tube! Seeing has been around a 7/10 all week, sometimes a little better, sometimes a little worse! I have been using 165x -235x for very stable, sharp Images. At times 333x is possible. Saturn is in a perfect position for observing and Orion is full of wonders to view. I printed out one of Eric Jamison's wonderful sketches of Saturn on heavy photo paper and have been using it at the eyepiece. It is a great aid in locating things in the ring system and the planet's surface! The 10" Light gathering power is a nice addition to Refractor quality pinpoint stars! The M250 is very easy to use and is very easy to setup! I believe it will become my most used telescope! I have also ordered a ScopeGuard case for the M250 from Don Holcombe! His cases are the best!
To Be Continued!
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