MESU MK11 Install Part 2

[Xsubmariner]

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.

[Kinch]

Thanks for the report. I am not actually getting a MESU but my next mount will have SiTech control.....hence my interest. Best of luck as you continue to explore and use the new mount. Clear skies too   🙂

[Xsubmariner]

Hi Kinch,

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

[Jonk]

1 hour ago, Xsubmariner said:

I was surprised at the ease with which this process was completed using the 3 x 12mm bolts and was finished in 5 minutes.

That's reassuring, I've heard that from the 1 other Mk2 owner I know of too.

1 hour ago, Xsubmariner said:

I was surprised to hear a voice talk to me giving the Mount status, my Mesu has a voice.

It made me jump the first time she spoke to me too!

1 hour ago, Xsubmariner said:

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

Also reassuring, looks like I have this to look forwards to too!

[Xsubmariner]

Hi Jonk,

When I first heard the voice I thought someone was behind me in the observatory. Having seen your accessories and bent knee pier, yours will be a piece of art.  I look forward to reading more on your progress.

I would like to be MF free but having seen the space in my dome I don’t think I could accommodate a BKpier.

[WanderingEye]

I understand how you adjust for PA declination using the three bolts, but how is Azimuth adjusted..?.

[Xsubmariner]

Hi WanderingEye,

Here was the process I used:

1. Built a wooden 6mm ply triangular former which attached to the mount wedge by the 3 PA bolts a second circular ply disk was attached to the triangular former at the centre with a bolt and washers. The Polemaster base was screwed to the circular disk and the polemaster camera fitted. This enabled me to rotate the polemaster same as if it was on a mount.

2. Levelled the pier top plate.

3. The wedge was aligned to an existing NCP azimuth line (Rough) on my top plate and clamped.

4. I then effectively conducted a Polemaster PA of the wedge first. Then by making minor rotation adjustments to the wedge I achieved an accurate alignment of the wedge to line of NCP. 

5. The 3  wedge to plate mount holes were marked, drilled and Taped and wedge securely mounted.

6. When it came to Polemaster alignment of the Mesu, I found The two lower bolts effected an accurate Az alignment and the single top bolt was used for El alignment.

I know this was overkill, but it worked well and I found adjusting the PA with the Polemaster and only 3 x 12mm bolts a breeze. Early indications suggest my mount PA is in the order of 0.3 arc-min.

I now believe the wedge alignment to the rough NCP line would have been sufficient, but you will only mount the wedge once.   

[WanderingEye]

21 minutes ago, Xsubmariner said:

Hi WanderingEye,

Here was the process I used:

1. Built a wooden 6mm ply triangular former which attached to the mount wedge by the 3 PA bolts a second circular ply disk was attached to the triangular former at the centre with a bolt and washers. The Polemaster base was screwed to the circular disk and the polemaster camera fitted. This enabled me to rotate the polemaster same as if it was on a mount.

2. Levelled the pier top plate.

3. The wedge was aligned to an existing NCP azimuth line (Rough) on my top plate and clamped.

4. I then effectively conducted a Polemaster PA of the wedge first. Then by making minor rotation adjustments to the wedge I achieved an accurate alignment of the wedge to line of NCP. 

5. The 3  wedge to plate mount holes were marked, drilled and Taped and wedge securely mounted.

6. When it came to Polemaster alignment of the Mesu, I found The two lower bolts effected an accurate Az alignment and the single top bolt was used for El alignment.

I know this was overkill, but it worked well and I found adjusting the PA with the Polemaster and only 3 x 12mm bolts a breeze. Early indications suggest my mount PA is in the order of 0.3 arc-min.

I now believe the wedge alignment to the rough NCP line would have been sufficient, but you will only mount the wedge once.   

Thanks for that, but am confused as to how two of the altitude adjustment bolts, as there are three of those to alter the mount declination, could alter the azimuth of the mount...maybe I am missing something here... 🤔🤔

[tooth_dr]

51 minutes ago, WanderingEye said:

Thanks for that, but am confused as to how two of the altitude adjustment bolts, as there are three of those to alter the mount declination, could alter the azimuth of the mount...maybe I am missing something here... 🤔🤔

The three bolts are at an angle on the top plate of the wedge so moving the bottom two can rotate the mount slightly as they are pushing and pulling it . That’s how I see it, but which may also alter declination at the same time.

 

[WanderingEye]

1 minute ago, tooth_dr said:

The three bolts are at an angle on the top plate of the wedge so moving the bottom two can rotate the mount slightly as they are pushing and pulling it . That’s how I see it, but which may also alter declination at the same time.

 

But by using those it won’t just move in AZ but in ALT at the same time...because of the angle at which the bolts are on....that must be very awkward...surely there is a bolt in the base of the wedge to loosen so the whole wedge can be rotated in AZ, on the same level....?.

[tooth_dr]

13 minutes ago, WanderingEye said:

But by using those it won’t just move in AZ but in ALT at the same time...because of the angle at which the bolts are on....that must be very awkward...surely there is a bolt in the base of the wedge to loosen so the whole wedge can be rotated in AZ, on the same level....?.

There is.i think that’s what he says in his post. 

Edited January 21, 2020 by tooth_dr

[Xsubmariner]

Hi WanderingEye,

I understand you confusion and I was thinking similarly. But I can say from my experience that the system just works and I had absolutely no problem with achieving a good PA using the Polemaster. I haven’t tried Sharpcap yet it’s on my list of things to do. Unless you are a PA perfectionist, you should Have no problem with this arrangement. 

I believe a major benefit is the removing of the fine adjustment couplings in the mount structure which makes for a much more rigid mount, time will tell.

[MarcusH]

I too as @WanderingEye had a hard time wrapping my head around the idea that the two lower bolts would adjust the azimuth. But I think the crucial point here is that the wedge already was very well polar aligned (with the Polemaster) in the first place, probably < 1 arc min off.

It's easy to see that the top bolt would adjust altitude as the mount will pivot on a imaginary axis that goes through the two lower bolts. But adjusting either one of the lower bolts is going to effectively tilt the mount ever so slightly. This tilt could possibly manifest itself as a bigger movement in the azimuth than the altitude making minute adjustments in azimuth possible (with a negligible movement in the altitude at the same time) . This would however require a good polar alignment from the start as the adjustment probably is only few 10ths of an arc minute.

Or this could also be a totally nonsensical rambling about something I just don't understand....🤔

[AKB]

6 hours ago, Xsubmariner said:

I was somewhat surprised to see PHD report mount tracking sub 0.3 arcsec in both RA and Dec. 

That's most gratifying!  Great piece of kit.

I must confess that I'm deeply interested in how you achieve such enormous SNRs for your guide star.  In yourGuiding Assistant  image I see 161, and on the PHD screen 289?

Typically, I see 30 - 40, and this with a dedicated guide scope with ED glass, and Bortle 4 skies.

Can you explain this?  I can't help but think that if I achieve a better SNR, then guiding will be better too (I have a very good mount, although not  Mesu!)

Thanks

Tony

[WanderingEye]

1 hour ago, MarcusH said:

I too as @WanderingEye had a hard time wrapping my head around the idea that the two lower bolts would adjust the azimuth. But I think the crucial point here is that the wedge already was very well polar aligned (with the Polemaster) in the first place, probably < 1 arc min off.

It's easy to see that the top bolt would adjust altitude as the mount will pivot on a imaginary axis that goes through the two lower bolts. But adjusting either one of the lower bolts is going to effectively tilt the mount ever so slightly. This tilt could possibly manifest itself as a bigger movement in the azimuth than the altitude making minute adjustments in azimuth possible (with a negligible movement in the altitude at the same time) . This would however require a good polar alignment from the start as the adjustment probably is only few 10ths of an arc minute.

Or this could also be a totally nonsensical rambling about something I just don't understand....🤔

I agree...

I guess if it’s possible to polar align the wedge accurately enough the what does the mount have to be aligned again when fitted, why not just bolt the mount and wedge directly together with the two plates against each other, and just do the adjustment and PA on the wedge fittings to the pier...

But who am I to judge as it obviously works.... 👍😀

[MarcusH]

I think you get a much finer adjustment with the bolts between the wedge and the mount. Looking at the whole setup in Part 1 of the Mesu thread, it occured to me that those three bolts enable you to adjust the mounts RA-axis in relation to NCP (or SCP)pretty much the same way as the collimation screws lets you adjust the secondary mirror in relation to the primary on a SCT. In both cases you are already close to spot on but a minor tweak might be necessary.

The bolts between the pier and the wedge on the other hand is at an angle to the RA-axis and at a certain distance from it. This would translate to a much coarser adjustment only good enought to get you roughly close to spot on.

Sorry @Xsubmariner for hijacking your thread with these speculations, but I'm genuinely happy when someone wants to know why something works the way it does rather than bluntly accepting that it just works. 

[WanderingEye]

2 hours ago, MarcusH said:

I think you get a much finer adjustment with the bolts between the wedge and the mount. Looking at the whole setup in Part 1 of the Mesu thread, it occured to me that those three bolts enable you to adjust the mounts RA-axis in relation to NCP (or SCP)pretty much the same way as the collimation screws lets you adjust the secondary mirror in relation to the primary on a SCT. In both cases you are already close to spot on but a minor tweak might be necessary.

The bolts between the pier and the wedge on the other hand is at an angle to the RA-axis and at a certain distance from it. This would translate to a much coarser adjustment only good enought to get you roughly close to spot on.

Sorry @Xsubmariner for hijacking your thread with these speculations, but I'm genuinely happy when someone wants to know why something works the way it does rather than bluntly accepting that it just works. 

Yes it does intrigue me that such a high end mount with superb engineering, uses such a simple and “old fashioned” for want of a better expression, way of adjusting PA... but if it works....... 😀

[tooth_dr]

8 minutes ago, WanderingEye said:

Yes it does intrigue me that such a high end mount with superb engineering, uses such a simple and “old fashioned” for want of a better expression, way of adjusting PA... but if it works....... 😀

I know that you asked the same questions on this thread, and got the same answers.  It might be better dropping Lucas Mesu an email directly if you need more info?

 

 

[Xsubmariner]

Update with the build- having completed initial testing of the mount, I have now just completed the dual imaging setup and hope to start grooming the system when the sky allows 🥺. Last night afforded a minor window to plate-solve and slew the system to a couple of targets. All communication between devices check and working correct.

My plan is to run 2 instances of SGP for dual imaging; one Atik 383 mono/TS130 Apo, One Atik 383+colour (Thanks Carlos - you are a Star)/AA130 edt Apo.

When not used for guiding above , a third TAK60/Atik 383 will be used to collect simultaneous wide field frames on a second PC.

Next Steps:

Recheck PA.

Align the 2 master telescopes, one fitted on heavy duty ADM plate for adjustment.

Align the Tak 60 wide field scope.

Refine auto focuser settings for all 3 camera setups  

Adjust PHD guiding configuration for sub arc/sec guiding for both Tak 60/Atik 383 and OAG /ZWO guider options.

Wait a frustrating long time for the next quality clear sky, preferably without moon, I am allowed to dream a little.😴

Clear skies everyone, the mount guided well during trials here is a single 20 min uncalibrated Ha of Rosette Nebula, stretched and saved as JPEG in Nebulosity 4 to limit size.

 

 

 

 

 

 

[Jonk]

Could I make a suggestion? I would cover those mains sockets with something as they may, or probably will get wet with dew / frost.

Better still, maybe fit a couple of IP67 outdoor sockets?

I also hope your mains supply is protected by an rcd?!

[Xsubmariner]

Thanks for the warning, you are correct in your observations. Each power circuit is protected by RCBO’s even lighting. A bit overkill but you can not be complacent. 

 

[Xsubmariner]

Commissioning the dual rig this last week has been a challenge, with slow progress principally due to the weather.  The usual software and communication glitches surfaced as with any new imaging system combination, thankfully these have settled down now thanks to tie wraps. USB connections without securing clamps suck.

Having reflected on feedback from other Mesu users I plan on operating my mount without a sky or PEC modelling. My modus operandi is to control the mount through SGPro with an initial plate solve after un-parking the mount.  PHD2 will be used with an OAG setup to guide the system.

A schoolboy error with OAG spacing didn't help, but last night I finally managed to conduct a couple of short tracking runs between rain showers.  While not perfect, the seeing was reasonable and the best I have experienced with this mount, to date. 

Bearing in mind I am still using default PHD settings, I have been very impressed with the performance and ease of using this mount. Also using the Polar Alignment completed following initial mount installation, last nights runs indicated alignment error between 0.3-0.6 arc/sec, acceptable but will adjust when time allows.

With a 40+KG load the mount slewed to target and plate-solved to within 1 pixel of my chosen target (SGP) within 2 iterations.

While guiding runs were short due to cloud disruption, the MESU achieved guiding of 0.5 RMS total error at start and I am sure this figure will settle on longer runs following some grooming of PHD settings.

PHD guiding assistant indicated Declination Backlash to be 0.  While it is a limited sample base, the absence of backlash is clear testament to the engineering quality of my MESU mount and certainly reflects the experience of other users.

At this time I could not be happier with my new mount, roll on clear skies.

 

 

 

 

 

[tooth_dr]

Hi Martin

Glad to hear things are heading the right direction.  There is a peak to peak RA error of 1.8" - is this higher than expected?  Due to that dip perhaps on the graph?   

[Xsubmariner]

Hi Adam,

Yes it is higher than I would hope with average seeing.   Last night the passing clouds were not helpful and I was experiencing “star lost” a lot of the time.  The backlash results were nice to see and I am confident the mount will meet my needs once commissioning is complete.  Once I get PHD and PA refined I am sure the figures will better reflect this mounts true performance.

[ZS1RA]

On 26/02/2020 at 15:39, Xsubmariner said:

Hi Adam,

Yes it is higher than I would hope with average seeing.   Last night the passing clouds were not helpful and I was experiencing “star lost” a lot of the time.  The backlash results were nice to see and I am confident the mount will meet my needs once commissioning is complete.  Once I get PHD and PA refined I am sure the figures will better reflect this mounts true performance.

I dream of this level of guiding, it’s superb. I’d like to see more detailed pics of your side by side configuration if you ever find the time. Well done on your installation.

On 22/01/2020 at 11:50, WanderingEye said:

Yes it does intrigue me that such a high end mount with superb engineering, uses such a simple and “old fashioned” for want of a better expression, way of adjusting PA... but if it works....... 😀

I was wondering about this very issue, once I made a rough model by holding a batinov mask at an angle and rotating it, it made perfect sense to me. I think it’s wonderfully simplistic and will ensure rigidity. I plan to use mine for semi portable use on a tripod as I don’t have an observatory. I would move my setup when there’s inclement weather so I would have to setup at least a few times a year. I’m thinking I’m going to need knurled nuts so I can turn it by hand instead of fiddling with spanners to do this task repeatedly.

On 22/01/2020 at 12:02, tooth_dr said:

I know that you asked the same questions on this thread, and got the same answers.  It might be better dropping Lucas Mesu an email directly if you need more info?

 

 

I actually emailed him this morning to ask this very question. I feel foolish now that I found this thread.