Mesu mount (all versions) owner's thread

[Jonk]

Nope, maybe some larger professional observatories have them.

Email Lucas and ask him, he might tell you!

[dan_adi]

21 hours ago, Jonk said:

Nope, maybe some larger professional observatories have them.

Email Lucas and ask him, he might tell you!

He did mention it once, but I didn't ask details. But I guess it's been built for pro observatories. 

Last week I used the mount every night and it worked without a glitch all night.

Do you guys platesolve and recenter after 1 hours or so? Usually after 1 hour I refocus, re-platesolve and re center. 

I wonder how the mount will behave with absolute encoders. 

[steppenwolf]

1 hour ago, dan_adi said:

Do you guys platesolve and recenter after 1 hours or so? Usually after 1 hour I refocus, re-platesolve and re center. 

I refocus every hour but if you are autoguiding as I do then there would never be a need to re-centre

[mrpizza]

It's been a couple of weeks and between Sci-Tech and Voyager it's been a learning experience.  I recorded a video of me mounting the Meade LX650 14" on the mount.  I did this for a size comparison of the mount.  

https://youtu.be/kdr1s1uDn1M

So far I never get tired of the flat guide graph!

[Jonk]

23 hours ago, mrpizza said:

It's been a couple of weeks and between Sci-Tech and Voyager it's been a learning experience.  I recorded a video of me mounting the Meade LX650 14" on the mount.  I did this for a size comparison of the mount.  

https://youtu.be/kdr1s1uDn1M

So far I never get tired of the flat guide graph!

Very nice, except I would lock the DEC axis before attempting that again! One slip and it's gone.

[ZS1RA]

On 24/07/2021 at 11:54, dan_adi said:

Mesu 200 autoguiding very well last night. The total RMS varied between 0.14-0.25 ". I find that amazing!

Software: Prism v.10: the autoguiding tab has both centroid and full frame guiding, I used full frame guiding

Parameters: Aggression RA+DEC: 0.6, Minimum move: 0.2 pixel

Guider image scale: 1.27 "/pixel

Image scale: 0.92"/pixel

In the Calculations Tab look at "Both Error (current exposure:)" 

In the Distribution Tab, the white square is 1x1 pixel !

Wow, that’s really amazing. I’m just getting started and still getting to grips with Scitech. I’ve achieved Polar Alignment of 3 arc minutes. With a Esprit 100 refractor and a 50mm Orion guidescope with Starshoot Autoguide camera I’m at double your guiding resolution. I think that PA is playing a part in this but I’m also of the opinion that the Orion guidescope isn’t rigid enough in the mount ring as it has 2 screws to adjust the guide to main scope alignment and a third spring loaded floating pin. I suspect that this is introducing flexure into the system as I get unexpected blips in my guiding every few samples.

 

[gorann]

2 hours ago, ZS1RA said:

Wow, that’s really amazing. I’m just getting started and still getting to grips with Scitech. I’ve achieved Polar Alignment of 3 arc minutes. With a Esprit 100 refractor and a 50mm Orion guidescope with Starshoot Autoguide camera I’m at double your guiding resolution. I think that PA is playing a part in this but I’m also of the opinion that the Orion guidescope isn’t rigid enough in the mount ring as it has 2 screws to adjust the guide to main scope alignment and a third spring loaded floating pin. I suspect that this is introducing flexure into the system as I get unexpected blips in my guiding every few samples.

 

It could also be seeing. My Mesu can give me 0.3 - 0.4" RMS on good nights but other nights I get 0.8". Both are usually ok for the pixel scale I work at. However, it is evident that I get better guiding when I use OAGs instead of a guide scope, but when I have a RASA on the mount OAG is not an option and then guiding is rarely better than 0.7".

[ZS1RA]

4 hours ago, gorann said:

It could also be seeing. My Mesu can give me 0.3 - 0.4" RMS on good nights but other nights I get 0.8". Both are usually ok for the pixel scale I work at. However, it is evident that I get better guiding when I use OAGs instead of a guide scope, but when I have a RASA on the mount OAG is not an option and then guiding is rarely better than 0.7".

Hi,

 

that’s good to know. I’m just so envious of all these flat graphs with a 2” scale and I have to resort to 8” scale 🤣😂😂

There’s is a Facebook group for Mesu owners.

https://www.facebook.com/groups/220611292974183

Cheers

[tomato]

My Mesu  dual Esprit 150 rig guiding performance seems to be susceptible to both seeing conditions and scope orientation, which probably means the balance needs work. Nevertheless it can vary from 0.35-0.7” total RMS.

My experience concurs with @gorann, RASA8 with separate guidescope is not as good as OAG on the 1050mm FL refractor.

[david_taurus83]

RMS only tells you the average guiding. My CEM25 can have 2 arc seconds peak to peak but an average RMS of 0.6". What is the usual peak to peak errors on the Mesu? For £6k or so I'd want pretty good performance night after night. Asking as I'll finally be moving house this week and maybe looking for a forever mount within the next 12 months.

[gorann]

2 minutes ago, david_taurus83 said:

RMS only tells you the average guiding. My CEM25 can have 2 arc seconds peak to peak but an average RMS of 0.6". What is the usual peak to peak errors on the Mesu? For £6k or so I'd want pretty good performance night after night. Asking as I'll finally be moving house this week and maybe looking for a forever mount within the next 12 months.

Since there is no backlash on a Mesu (being a friction drive) it is essentially all up to your guiding, and then mainly your seeing. Then of course a Mesu 200 can hold 100 kg of scopes.

[gorann]

1 hour ago, tomato said:

My Mesu  dual Esprit 150 rig guiding performance seems to be susceptible to both seeing conditions and scope orientation, which probably means the balance needs work. Nevertheless it can vary from 0.35-0.7” total RMS.

My experience concurs with @gorann, RASA8 with separate guidescope is not as good as OAG on the 1050mm FL refractor.

And with a RASA8 at 400 mm focal lenght, any guiding below 1" RMS is overkill😁

[tomato]

1 minute ago, gorann said:

And with a RASA8 at 400 mm focal lenght, any guiding below 1" RMS is overkill😁

Indeed, but RASAs have lots of other ways of producing dodgy stars, at least in the corners.😉

[ollypenrice]

On 10/06/2021 at 19:53, steppenwolf said:

To that end, I have a really  heavy duty Manfrotto 143 tripod that I have modified with a central bolt for placing the mount on whenever I need to work on it not in the observatory. Of course, none of this helps our unfortunate friend  but it might well help others in the future.

When I first got my mount, I had it sitting on the carpet test tracking and it gently over-balanced onto it’s side but it could so easily have been on a bench with catastrophic consequences. Not a Mesu issue at all but definitely something to be aware of! 

My Mesu 200 (Sitech II controller) bought new in 2013 continues to work faultlessly in my automated observatory - one of the best purchases I have ever made!

I can't believe your mount is so old! I remember talking to you on the phone while you were considering this purchase. It was the first time we spoke. That means that the mount which Yves brought here, and which I subsequently bought from him for my own use, must be significantly older than that. It is still working perfectly, as it always does. Since it was installed it has never been moved, adjusted or anything else. I just use it. It has to be the best astro-purchase I ever made. If it has any rivals they would be a second Mesu I bought second hand, just as good, and my second hand TEC 140. I do have a few other favourites but, in the name of progress, I may be selling some of them so I won't mention them here because I don't want to use this thread for promotional purposes.

I really think it is dead simple. The Mesu 200 is a work of genius.

Olly

[steppenwolf]

58 minutes ago, ollypenrice said:

I can't believe your mount is so old! I remember talking to you on the phone while you were considering this purchase. It was the first time we spoke. That means that the mount which Yves brought here, and which I subsequently bought from him for my own use, must be significantly older than that.

Crazy how time flies - the Mesu and my Esprit 150 are my best ever purchases and I can only echo your satisfaction with the Mesu - quirky design but it simply works 👍

[tomato]

Thanks to advice received here shortly after joining SGL I purchased a Mesu 200, and would agree it’s the best Astro imaging equipment purchase I have made.

I heard a comment today that Mesu mounts are purchased by folks who like to tinker with their mounts, I would venture the precise opposite is true. 

[dan_adi]

23 hours ago, ZS1RA said:

Wow, that’s really amazing. I’m just getting started and still getting to grips with Scitech. I’ve achieved Polar Alignment of 3 arc minutes. With a Esprit 100 refractor and a 50mm Orion guidescope with Starshoot Autoguide camera I’m at double your guiding resolution. I think that PA is playing a part in this but I’m also of the opinion that the Orion guidescope isn’t rigid enough in the mount ring as it has 2 screws to adjust the guide to main scope alignment and a third spring loaded floating pin. I suspect that this is introducing flexure into the system as I get unexpected blips in my guiding every few samples.

 

My polar alignment was 0.1 arc min, tested with phd assistant, and I use an Optec OAG. My seeing is on average 2-3 arc sec.

Bellow some results from that night. As you can see the seeing wasn't all that great but still the mount guided excellent.

I'm not sure, but I've read somewhere that below 20% elongation the stars are perfectly round for the human eye. We can't detect a change below that threshold. 

Edited August 3, 2021 by dan_adi

[ollypenrice]

11 hours ago, tomato said:

Thanks to advice received here shortly after joining SGL I purchased a Mesu 200, and would agree it’s the best Astro imaging equipment purchase I have made.

I heard a comment today that Mesu mounts are purchased by folks who like to tinker with their mounts, I would venture the precise opposite is true. 

I agree. I have two, have had them for years, and have spent precisely no time whatever tinkering with them.

Olly

[dan_adi]

Great night, Auto guiding for 4 hours straight RMS 0.1-0.25 ". I am seriously thinking of getting another Mesu

Edited August 9, 2021 by dan_adi

[Jonk]

12 hours ago, dan_adi said:

I am seriously thinking of getting another Mesu

Do it if you can / need to! I wouldn't mind another, maybe a project for the future, time, space and finances permitted.

[dan_adi]

On 10/08/2021 at 14:42, Jonk said:

Do it if you can / need to! I wouldn't mind another, maybe a project for the future, time, space and finances permitted.

I didn't get to use it much, because I slowly build my little obsy, but now that everything is working and I am using the mount regularly (good weather lately) I am very impressed with it. I wonder why other companies overlooked the friction drive system, and still build with gear and worms ... 

Just the other day I saw a guide graph for a 10 micron on CN. The RMS was almost identical to what I get with the Mesu. Of course the corrections were far fewer for the 10 micron, but still ...  

 

[tomato]

I think the design and manufacturing costs probably rule out a friction drive from the likes of SW and Ioptron, but you never know. There are a couple of similar friction mounts out there but nothing like in the numbers of Mesu units that have been supplied.

[dan_adi]

On 02/08/2021 at 21:49, david_taurus83 said:

RMS only tells you the average guiding. My CEM25 can have 2 arc seconds peak to peak but an average RMS of 0.6". What is the usual peak to peak errors on the Mesu? For £6k or so I'd want pretty good performance night after night. Asking as I'll finally be moving house this week and maybe looking for a forever mount within the next 12 months.

My dotted lines in the guiding inspector are +/- 1.5 pixels. The peak to peak variation is bellow that

[dan_adi]

For users who use a Mesu mount with Prism software. The autoguiding module doesn't automatically calculate the minimum move (in pixels).

Bellow is the formula I found to calculate the min move. 

   
    image_scale = (206 * CCD_pixel_size)/FL
    guider_scale = (206 * Guider_pixel_size)/FL
    total_allowable_error = 0.8 * image_scale
    min_move = total_allowable_error/guider_scale*0.5

 

[Xsubmariner]

Hi dan-Asi, may I enquire what application you used to create the Seeing and star elongation graphs?

This week I acquired a Mesu 200 non MK2, from a very nice gentleman who stored the mount for 5 years having acquired another premium mount prior to the Mesu delivery.  I was unsure if a “never used” Mesu stored for that time would have some stiction problems, I needn't have worried. Commissioning the mount yesterday with a 12” Meade ACF load everything is working as it should. I will never tire of watching these mounts move large loads so effortlessly, smooth and quiet. Now looking forward to seeing how this mounts operational performance compares to my 2 Mk2 mounts.

After the challenges of my first premium mount, CEM120EC2 and then the PEC, T Point, re-greasing and worm drive adjustment demands of a Paramount MX. I love the fact that the Mesu needs no more than an initial plate-solve on startup and then it centres on DSOs to within 3 pixels in 2 or less plate-solves.  The guiding is excellent with the apparent limiting factor being the PA and seeing. If my Mesu’s deliver the long reliability experienced by Olly I will be a very contented man. Bring on the longer nights.