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More on the Mesu 2 mount.


ollypenrice
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Now that I've used this mount a bit more I can add a few comments on what it's like to use. To recap briefly in case it's a new one on you the mount is a big observatory class GEM made by a small astronomical engineering setup in the Netherlands, Mesu Optics. It uses friction drive, steel on steel, rather than a worm so has no backlash, has a claimed payload of 90 Kg (!) and a PE roughly comparable with Paramount and AP. This one is installed long term in our new roll-off observatory and belongs to SGL member Yves, the lucky chap. It is currently carryng a 14 inch Orion Optics ODK with focal length of 2.4 metres.

An evening goes like this;

1) The mount has no clutches but moves easily by hand (you do htis slowly) so you roughly point the scope at an alignment star by hand. I shine a laser through the finder for speed and simplicity.

2) Switch on the mount's Servocat drives and Argo Navis GoTo. They each have their own handset, something I'll describe in a moment. In the Argo Navis handset select Mode Align Star and scroll to your preferred alignment star. Use the small Servocat handset with NSEW buttons to centre the star in the finder and OK that on the Argo Navis handset. All this is in the open area of the observatory.

3) Go into the warm room with the Servo Cat handset, fire up the camera and use the handset to precisely align the star onto the centre of the crosshair on your capture screen. Pop out and OK this refined alignment on the Argo Navis handset which lives on a stand by the mount. (I always OK the rough finder scope alignment before the accurate camera-based one in case I dopily slew away from the alignment star. I know what I'm like...)

4) Select 'Catalogue' in the Argo Navis handset and go back into the warm room. Hit Go To on the Servo Cat handset and the mount swishes with a pleasing and very posh-sounding whirr to the target, which is always on the chip. Centre and then set the Servo Cat to slow guide speed.

5) Open PHD and run the calibration in 1 second subs. Then switch to 5 second subs. This mount has very low PE and deviates very slowly so long guide subs help beat the seeing. It thrives on these long subs.

Some might consider the two handsets a complication and opt to control the lot via the computer. Not me. Give me handsets any day. (Only this week a guest went out to use our Takahashi mount which is controlled by TheSky 6. It has been working perfectly for about a year but this time it won't play. The Sky 6 opens correctly but when the mount is connected it leaps to the wrong part of the sky. We jackass around trying to find out why and in the end we have to swap to a different planetarium to get going. When something doesn't work in imaging it is, almost invariably, a software nonesense. Handsets every time for me. Whenever I switch on the planetarium-controlled mounts I have a pang of stress; will they work? Remember, I have an obligation, I'm not just doing this for myself.)

The Argo Navis handset is brilliant. It has only 2 buttons and a large wheel used for scrolling. Once you are used t it I doubt you'd want anything else. Scroll the wheel the choose a menu, eg Catalogue.

Press Enter. Scroll the wheel to choose a sub catalogue (Messier, IC, etc etc.) Press Enter. Scroll to the first digit. Enter. Scroll to next digit. Enter. Etc. You then use the little Servo Cat handset and press Go To.

The Servo Cat is a small NSEW affair with a set of buttons for slew speed (Slew, Jog, Fast Guide, Slow Guide.) It also has a GoTo button which ignores the chosen speed and triggers a fast slew to whatever is on the Argo Navis.

The mount has overload protection in the case of a pier collision which is very reassuring, especially for Yves!! :D

I've probably done about sixty hours imaging with this mount and it has performed magnificently. On the last project, for instance, I took 24 consecutive Ha subs of thirty minutes on consecutive nights and evry one had perfectly tight little stars.

I would buy a Mesu 2 tomorrow if I were in the market for an observatory mount. The price is fantastic, the quality is fantastic and you can speak to the boss if you need to. Not even the European importers can speak to Takahashi...

The Mesu is now available from Telescope Service.

Olly

Edited by ollypenrice
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Hi Olly,

Very glad to hear the mount is working so well as this mount and scope sound a lovely combination :):). Can't wait to see some images with that intoxicating mix of accurate mount, big scope and fantastic skies :(.

Do you think that this set up will endear you to AP at longer focal lenghs ? :D:)

Clear Skies

Paul

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Hi Olly,

Very glad to hear the mount is working so well as this mount and scope sound a lovely combination :):). Can't wait to see some images with that intoxicating mix of accurate mount, big scope and fantastic skies :(.

Do you think that this set up will endear you to AP at longer focal lenghs ? :D:)

Clear Skies

Paul

Consider me enamoured, Pau! I wouldn't get involved in any kind of imaging in which I was asking more of the mount that it wanted to deliver. Here the Mesu has no trouble with 2.4 metres.

Olly

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Sounds like you're having a wonderful time with that mount Olly and creating more than a bit of jealousy I can tell you :D

Regarding the Tak. I always used Chucks Temma Driver with Maxim. It's certainly the best thing that happened to the Temma II and makes the Sky controlled telescope look like hard work.

BW

Robert

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Im intrigued by the steel on steel drive, how does it deal with expansion and contracton due to temperature changes?

Not a clue!

Since we have a working temperature range here of 40 degrees C taken over the year a problem will occur here if anywhere. I think we'll be fine though.

Olly

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Not a clue!

Since we have a working temperature range here of 40 degrees C taken over the year a problem will occur here if anywhere. I think we'll be fine though.

Olly

Im guessing its spring loaded, still can't work out how they don't slip, like a train wheel on a track?

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I'm not sure, Earl. Yves is a Mac man so he has Sky Safari on the computer he installed here. I expect all mount the software will be ASCOM compatible. It should be straightforward enough but it didn't want to work straight away and in the brief spell during which he brought the gear down and we put it together Yves didn't get it to work. To be honest it was a low priority since I wouldn't use it anyway!!!

Olly

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Hi Olly,

Undoubtedly this mount has been on my list as an upgrade option so thank you for the further details.

From your description above, it sounds like you haven't slewed from a home position and that you just point to a nominated star and align. Do I infer from this that Mesu doesn't have a "park to home" facility and that everything is based on the initial star alignment? Presumably there is the option to do multiple alignments for greater accuracy?

Also, you don't mention polar alignment. Does your star alignment procedure effectively deal with this, eg, something similar to Alignmaster?

Thanks, Alistair

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Hi Olly,

Undoubtedly this mount has been on my list as an upgrade option so thank you for the further details.

From your description above, it sounds like you haven't slewed from a home position and that you just point to a nominated star and align. Do I infer from this that Mesu doesn't have a "park to home" facility and that everything is based on the initial star alignment? Presumably there is the option to do multiple alignments for greater accuracy?

Also, you don't mention polar alignment. Does your star alignment procedure effectively deal with this, eg, something similar to Alignmaster?

Thanks, Alistair

To be honest, Alistair, I don't know if there's a Home Park position or not. I'll have to look into that. It will be in the Argo Navis manual, I guess. It's so fast to do a single star alignment that it hadn't occurred to me to find out. Likewise multi star alignment. Since a one-star puts the target on the chip every time that's all I've ever done.

We polar aligned the old way, just held a laser pen alongside the polar axis to get somewhere near Polaris then did a drift. It took about than ten minutes and seems to be very accurate indeed based on the lack of image shift over a long run. Yves and I were both bemused by how quickly we did the alignment and felt certain that we'd somehow missed something, it went so well.

Olly

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Argo navis is a very powerful handset, it can build complex sky models so pointing accuracy is even enhanced ... most of the softwares out there can interface with ArgoNavis ...

It did work on the mac, but there was an offset between the aligned position between handset and computer ... as Olly mentioned we didn't bother in finding out as this is not a remote site, thanks to Olly ...

Maybe one day when internet speed is high and Olly is busy with guests I could jump in and help, for now that's not on the list.

For all info on the handset and computer download the pdf manual from ArgoNavis ... it's a very very capable handset, simple in use and very robust.

On the friction drive, it is not spring loaded it's adjusted at assembly time.

Our experience is not even 2 month's but my guess is it's going to be the best mount out there in this price range and the one above. Other Benefit, I know Lucas and if there is an issue it's fixed asap ... (we never had one so that's maybe optimistic, but I talk regulary with him and he is very responsive)

Yves.

Edited by vdb
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thanks Olly, and Yves.

If you get 2 minutes, could you give me an idea of dimensions please; specifically height (I am assuming it won't vary too much by latitude looking at the 0 and 90 degrees pictures on the Mesu website) and also the diameter of the base.

thanks very much

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..or do they sell a pier / head for it?

Probably, but I already have a pier in my observatory which will need to be reworked. As it is sunk into the concrete I will cut the top off and get a new top section machined and welded on.

The top of my pier was not built how I wanted but as my father in law did it for free and it does work I can`t complain. But I will re-do it properly when I get this mount and add a custom universal mounting plate.

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Probably, but I already have a pier in my observatory which will need to be reworked. As it is sunk into the concrete I will cut the top off and get a new top section machined and welded on.

The top of my pier was not built how I wanted but as my father in law did it for free and it does work I can`t complain. But I will re-do it properly when I get this mount and add a custom universal mounting plate.

Sounds good to me - I'm just in process of installing a dome (my wife prefered the look of the Pulsar dome to a roll off shed) - and I'm debating whether to cast a concrete plinth and pier for my current EQ6 and then modify it if (when) I upgrade the mount - or just cast a concrete plinth base and then bolt a steel pier to it, then change the whole pier to suit a new mount.

Steve

Edited by Steve 1962
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Olly,

What is the approximate diameter of the base of the mount head where it attaches to the tripod/pier. I am just trying to think what I would need to do to my pier to accomodate this mount.

Thanks

Neil C

Hi Neil, It's a 20cm flat metal circle on top of the pier, which is also made by Mesu in this case.

Olly

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Hi Olly,

I got my Mesu 2 mount last week with a Mesu pier especially made for mounting my Orion Optics 350 SPX. Mesu also provided an adapter for my (higher) Losmandy tripod so I can use this one for mounting my C14. I mounted everything and indeed this mounting is sturdy . However, since I got it,the bad weather curse struck. So am am desperately waiting for clear skies to give it its first light.

Roger

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