Xsubmariner

Hi 

I forgot to mention in my report a big thank you yo José @carballada for your patience and advice with the Mesu 200 Mk2. Without your reports/videos I might have stalled with my decision. Your observatory is amazing and I want your skies.

Hi Kinch,

Thanks, this is my first SiTech controller and I have a lot to learn.

Hi tooth-dr

My pier is near centre, 20mm off to East.

Hi Skipper

Thanks for your advice I plan to apply some extra protection to the weights. Perhaps in the future I can consider stainless steel.

Last night offered the first chance to commission my Mesu 200 MKII mount and the forecast indicated a 2 hour window.

The Initial Polar alignment was conducted using the Polemaster. I was surprised at the ease with which this process was completed using the 3 x 12mm bolts and was finished in 5 minutes. At this point I noted how rigid the whole mount setup was, devoid of the fine adjustment couplings associated with my other mounts.

The excellent Mesu 200 guide covers operating the mount with various planetarium software, Cartes du Ciel, Stellarium  etc. I use Sequence Generator Pro for control of my observatory so will only comment on this arrangement.  The only application tweaks needed were to select “SiTechDII Telescope” as the Telescope in the SgP and PHD2 applications. Note the Ascom Mount driver was loaded during the SiTech software install.

Once the Telescope is connected in SGP, the mount driver automatically opened and the connection is made.  The SiTech driver panel provides comprehensive control of the mount and a plethora of technical data figures for the user. The mount connection in PHD was just as seamless.

At this point, the mount driver panel indicates the mount is “not initialised”.  This is the  normal starting position where it’s either; a new install, or mount was switched off without parking, signifying the mount doesn’t know where it is.

I leave my scope pointing at NCP, so it was just a matter of conducting a blind plate solve. After 2 minutes the image was solved and a sync sent to the mount, this opened the SiTech “IntPoint” panel, where you are given various options; to accept, cancel, change direction the GEM scope is pointing W/E, and others. The sync will automatically be accepted after a time delay if no option is chosen. I was surprised to hear a voice talk to me giving the Mount status, my Mesu has a voice.

I conducted several successful slew to targets and was rewarded with the target next to centre of the camera image every time, all after 1 plate-solve. Using PHD2 default settings I completed a PHD2 calibration and commenced guiding. Given the seeing was poor with twinkling stars and image halos, I was somewhat surprised to see PHD report mount tracking sub 0.3 arcsec in both RA and Dec.  Following a few minutes of guiding I initiated Guiding Assistant and tracked the mount for 15 minutes unguided. The guiding report estimated my PA was 0.3 arc-min.  Both the tracking and PA results were impressive for a first attempt at operating and guiding this mount using default PHD2 settings. As all to often, suddenly the sky was gone and I had to stop. While disappointed, I was also excited at the thought of exploring this mounts capability further.

To summarise;  The installation of the Mount, Operating Software and Configuration Setting were all relatively straight forward and well within the capability of any astronomer looking to acquire a mount of this pedigree. 

The initial tracking performance I have experienced coupled with the Mesu proven track record more than validate my decision in choosing this mount. Roll on clear skies.

Update

Last night provided the opportunity to try out the mount further and I was not disappointed. Unfortunately the seeing was again poor, better than nothing. I was able to prove the Park/Unpark capabilities and the mount slewed to the first target and took only 2 attempts to platesolve and centre on target (I use 5 pixels in SGP).

The window was short but I managed to capture some imagery and experience further the mounts raw capabilities.

I attempted an automatic meridian flip on a target but it failed when the mount stopped at Mid-2 mins. I have no doubt this is a configuration setting problem either with SGP of SiTech application. Now to put my head back in the SiTech controller documentation.

Please note this is with a bare bones install as I haven’t had time to refine and hone the mount settings. I am looking forward to some good clear nights.

Some images of the mount performance last night.

After receiving my Geoptik weights I excitedly set about installing my new mount, a Mesu 200 Mk2. Here are my initial thoughts, I hope you find some part beneficial.

I have always wanted a Mesu but shied away because of cable snag concern with unattended dome operation. This new mount removed my prime concern and I think demonstrates Lucas has been listening to his Mount users. 

Installation: 

Minor alterations to my pier top plate (drill & tap 3 holes) and the mount wedge is easily fitted. My wedge is specified for Lat 52.  The assembled mount is then fitted to the wedge by 3x12mm SS bolts. These 3 bolts are also used for polar alignment adjustment. With the counterweight bar fitted there was only 10cm gap with the ring of my 2.2M dome.

I use a Polemaster or Sharpcap/camera for PA. So for this mount I utilised an Ioptron adapter plate to fit the polemaster camera, 6xSS washers and job done, kind of looks neat as well.

While I have never operated an original Mesu 200, I was aware of the importance of good mount balance. Whereas the original Mesu has permanently coupled motors the new unit has motors that can be de-clutched. Simply rotating the motor by a little black knob, it is either coupled or decoupled from the friction drive. Mount locks are also fitted to both axis plates and 180 degree rotation locks/unlocks the drive plate. I made a note to check locks are disengaged before the operating mount. I will fix some labels indicating the lock and unlock positions.

Threading service cables through the mount was a pleasure. None of the angst of my other mounts, this was simplicity itself. Given the available space, I shouldn’t need to fit DC distribution, USB hubs and PCs piggyback style.

I balanced my WO Gtf81 setup, its lightweight and short focal length were ideal for initial testing. During the balancing with motors disengaged I noticed some very light resistance (probably the friction drive) so don’t expect the finesse of a CEM.  Overall the task was quick, easy and don’t foresee any problem balancing heavier loads. 

Software:The Mesu 200 MKII uses the Sitech Controller I for mount control. While new to this controller and software the download and installation was straightforward.  Thanks to Steve Richards excellent “Mesu 200 Quick Guide to Installation” the task of configuring the SiTech software for the mount was simply a case of following the guide. 

Of note, Lucas Mesu pre-configures the Servo configuration file for the mount and these setting must not be changed, the only minor alterations are to the owner’s local settings. I completed the installation by backing up the configuration files. 

Next Commissioning.

Jonk,

That is a nice SS billet you have there to work the weights. May I PM a request for your source? I have just taken receipt of 3 Geoptik 10kg CW for my mk 2, but plan to replace with SS weights at some point.

I opted for a wedge to fit to my existing observatory pier and will consider a bent knee pier replacement, once I can be assured the package will fit and operate within my 2.2M dome.

The engineering design and manufacture of your adapters is excellent, you must be a professional engineer.

looking forward to your next update.

Hi,

I thought some of you might like to see the revised Saddle Plate for the new Mk11 Mesu 200.

Having received it this morning direct from Lucas, the fit and finish is excellent and it compliments the mount nicely. Once I receive the modified weights from Geoptik, I hope to install and commission the mount. 

New to the Mesu and Sitech controllers, it is likely I will need some advice and hope this forum will be kind enough to assist. 

Saddle pictures, regards Martin

Thanks Vlaiv Hi Vlaiv & Bryan,

Thanks for your feedback.  Bryan: no the edge is several years old although I have only had it for 6 months, installed in ROR observatory in January.

Vlaiv: there are no overhead obstructions and I image with a heated dewshield where cable is away from scope plate. I will check earlier Sbig images to see if they were present.

thanks again for your continued support, it is much appreciated.

Martin

Vlaiv, a friend was with me that night and was introducing me to Pixinsight. Will it help if I post a Lu file. What file format could I forward that will meet the 2Mb limit. Thanks 

Martin

Hi Vlaiv & Ian,

Thanks for your feedback. The OAG is clear of the sensor and to double check I removed the prism and guide camera completely, yet the spikes were still present.

I have fits files available, unfortunately they are 32Mb.

Martin

Hi,

Please can anyone help with suggestions on the likely source of some diffraction spikes I am experiencing when imaging with my C11 edge/0.7 reducer/S.L. maxi wheel with OAG/Baader2” filters/SX-36 setup.

The spikes can clearly be seen in the uncalibrated picture below. They were present only fainter in some Atik 383 images I took earlier in the month.

I removed and examined the reducer and it looked fine. 

Any advice would be greatly appreciated before I attempt a strip down of the scope.

thanks Martin