12" Meade LX-850 f/8 OTA & Moonlite CSL 2.5" Review
By: Vlad Fedosov
The Meade LX-850 line of SCT’s is their newest design from Meade that uses the newest f/8 Advanced Coma-Free optics with UHTC coatings as well as a much-improved 2-speed Crayford focuser. I have had a few Meade SCT’s in the past in the 12” size but this was my first go with this new top of the line design. I bought this scope brand new to use in my new roll-off roof(ROR) observatory for electronically assisted astronomy(EAA). The 12” LX-850 has a focal length of 2438mm and weights in at about 40lb. Let's take a look at how this beast of an OTA performs in the real world.
I have always wanted an observatory in my backyard but have been holding out to move to a better location in regards to having more room and darker skies. Well as the years go on, I’m beginning to realize that this dream of a better location might not happen in the near future. Once I got into EAA I also realized that one of the downsides to my current home is not as big of an issue as even in my mag 4 light polluted backyard I can see more with EAA than I can from a dark sky site with my 18” dob! I decided to just do it! The ROR observatory that I built to house this scope was on the smaller side at 6’x6’ because of the limited space available.
Once the observatory was built I was anxious to try out the new scope in there! The mount that I have dedicated to the observatory is a Losmandy g11. Once mounted the 12” LX-850 looked magnificent! The first night out with the scope in the ROR was great. Definitely, a dream come true! Since I’m in the city all of my neighbors feel like they need to have prison style floodlights on ALL THE TIME… Well, the observatory does do a very nice job in blocking almost all of the local light pollution. Wind is also not really an issue anymore being behind the walls. Did I mention the carpet inside? So nice to be able to put a knee down on the ground and not having to be worried about getting dirty or a jagged rock cutting your skin. The thing that became clear fairly quickly was that while the scope has plenty of room in the building, I did not. Moving around the scope is possible but definitely a bit of a practice in acrobatics especially when it is pointed at certain parts of the sky.
On to the actual performance of the scope itself. The first time I used the OTA I taught that there was something wrong with the focuser. It was very difficult to get going using the rough focus knob. After running it up and down the entire focus range it did become better. The rough focus knob does still feel rough… lol. I did do some reading online about this and it seems that other owners complain of the same thing. The fine focus knob is very precise and easy to turn. Overall the focuser is definitely a step up from the standard LX-200 or Celestron SCT focuser. I did add a Moonlite focuser to my scope not because I thought that the stock unit was insufficient but rather to get autofocusing. My particular sample of the scope also had almost zero image shift. Very nice! I do wish that it still had a mirror lock, but for my use for EAA, this was not too much on an issue.
Optically I found that my scope produces a consistently nice image. Seeing definitely does start to affect the larger aperture of the scope and on most nights here in the Northwest I felt that I had too much scope for the seeing conditions both visually and with EAA. Speaking of visual and EAA work, I had the scope rigged up with a Meade 2” flip mirror. What I normally do is take a look visually at the object I'm studying and then switch over to EAA. Sometimes if I’m looking at a really interesting object I can't help but to hop online and find an even better image. Since the scope is an f/8 it does have a larger central obstruction. In actual use, I did not notice any ill effect on contrast or sharpness of the scope.
Since the OTA is a relatively fast f/8 I did initially do most of my work on the Herschel 400 at the native focal. Since Meade does not make a dedicated focal reducer for this scope I decided to give my f/6.3 reducer and see how that worked. This turns the scope into an f/5 system. Well, the good news is that for EAA this works quite nicely! Visually there is quite a bit of coma developing at about 50% of the FOV of the 20mm and 24mm 68° eyepieces that I tried. this setup also does have a significant vignetting. There are aftermarket reducers on the market that are made for these scopes but I have not tried them so I cannot comment on them. Displayed are images of NGC 1502 at f/8 and f/5.
One very nice feature of the OTA is that it comes with a Vixen style saddle that can be used to mount a guide scope without any other add-ons. I really like that. The new blue textured finish that Meade uses is also very nice. I know that some people don’t really care for it, but it is ultra durable and to me looks awesome. Overall I think that this is a beautiful OTA.
In summary, I think that these new LX-850 OTA’s from Meade are a home run. Besides the fact that they are on the heavy side and the rather rough course focus mechanism I really can't say anything bad about the scope. The optics are very nice. Do keep in mind that a 12” scope of any type will require good seeing(this seems to be particularly true for SCT’s). You will also need a g11/CGE class mount that is rated for 60lb as a minimum to carry this OTA.