10Micron GM2000HPS

[perfrej]

10MICRON GM2000HPS

My journey into the high end market started a little over two years ago. I was imaging with an NEQ6 from my balcony at home under reasonable skies and wanted to go automatic and possibly remote, a task that the NEQ6 is not really suitable for. The search began. I had managed to absorb some information about what properties in a mount are good and what properties are not. Let me just briefly go through some of my base criteria.

Stability and payload

The mount should be mechanically very stable and without slack up to the specified payload. A lot of mounts can perform well by using tricks like shaft heavy balancing, but I really felt that it should be a base property and not something that has to be worked around.

Encoders and homing and guiding

Obviously, encoders are an added benefit for any high end mount and something that could very well lead me to the goal of unguided imaging. Guiding is not one of my favourite pastimes, and even though I never had any real issues with it I find that it sometimes fails and always steals valuable imaging time.

Automatic homing is something that can solve many of the remote operation issues, but also something that can be seen as a bolt-on solution to the problem of not having absolute encoders. If the latter are present, there should be no need for homing, and if there still is, something is fundamentally wrong with the encoder design.

Computer dependency and software

One may ask why I raise this issue as I am an imaging only person who never does visual observing. The answer lies in my background with electronic systems engineering and the fact that everything I have designed over the past 35 years has been based on distributed intelligence and part-autonomous components. So, my mount needed to do well on its own in order for me to be calm. Having written software since the early to mid 1970’s I have very strong opinions about software. In order to be flexible, ASCOM should be the path of choice.

My choice

I finally fell for an Italian job with ridiculously good looks and specifications; 10Micron GM2000HPS. Having booked a week at Olly Penrice’s Les Granges Astronomy in Provence, I decided to order a mount and pick it up at Baader Planetarium on the way to Provence. Apart from a mishap with a transport damaged cable that created a problem with the control box, the trip was a success. Real first light for the mount would come at a later stage.

Brief overview

The mount was, at the time of purchase, available in two versions with two different control boxes. The monolithic version of the mount has the complete head as one unit, while the “Ultra Portable” version (ha!) can be easily split in two. The UP version, that I ended up getting, can be put into a set of three flight cases for travel and transport.

The mount base with right ascension axis and the declination head are easily assembled to a unit, which is then put on top of the control box. Cables between the box and he mount head number three; one for the encoders and one for each motor. All attach to the base of the Ra housing. The boxes available at that time were a round one acting as a pier extension, and a square, smaller one on the side.

The drive system consists of AC servo motors with incremental encoders, a belt-driver first reduction stage and finally a traditional pre-loaded worm design. An absolute encoder with more than ten million ticks per revolution is fitted to each axis, and the information from the encoder is included in the feedback control loop of the motor control. With the two stage feedback (motor and final axis), periodic error is virtually eliminated and PEC is not necessary. As the encoders are absolute, they do not lose their position information when powered off, so you can move the mount around by hand, power off or power on, and they will know exactly where they are when power is reapplied without the need for homing – for which there are no procedures or sensors as the concept of homing the mount simply does not exist.

With absolute encoders present, unguided imaging starts to enter the scene, especially considering that the mount control system tracks not only in right ascension, but also in declination. Enter the model. 

Alignment and modelling

With absolute encoders and an in-mount controller system, the concept of pointing and tracking models are implemented in the mount itself without need for external software. Standard polar alignment is performed by roughly aligning the mount to the north and syncing on three stars. After that procedure is taken care of the mount knows approximately how much of a polar alignment error is present, and the hand controller gives instructions as to how much to turn the elevation and azimuth knobs (in decimal turns, like 0.15 right, meaning 0.15 turns on the knob that moves the mount to the right). There is also a procedure in the hand controller where a star is centred by means of the adjustment knobs, all to the same end and from the same information obtained from the three (or more) alignment points.

Having polar aligned the mount with one or two iterations, the polar alignment error is usually under one arc minute, which definitely is good enough for most situations. Further iterations can bring it down to single digit arc seconds, but at that accuracy the precision of your knob turns are beginning to disturb the process.

By adding alignment points, or stars, to the mount by means of syncing, the model is refined. The mount hand controller is always ready to tell you what kind of accuracy you can expect from the present model. The modelling in itself is similar to T-Point and concerns both tracking and pointing. The tracking part is not handled by nudging the mount, but rather directly in the motor control loop.

First light

For the first light of the GM2000HPS I used the 10Micron Centaur tripod that I got with the mount kit. It is a steady beast by all standards and very difficult to disturb (and haul around). I used a William Optics FLT-98 mounted on it and did around 10 to 15 alignment points after the polar iteration. I then exposed, by means of Nebulosity 3, a five minute exposure without guiding and found, pleasantly surprised, perfectly round stars in the image. Increasing the exposure to ten minutes made no difference to the star shape.

Further on

When I bought the mount, 10Micron relied on the fact that the controller supports more or less the complete LX200 and AP command sets. I did, however, find that the ASCOM drivers for LX200 and AP where not perfectly suited, a fact that prompted me to quickly learn ASCOM development and write my own ASCOM driver for the mount. I also started on an application to automatically build the models by means of repeated plate solving, a tool I find essential when operating a mount of this calibre.

10Micron released their own ASCOM driver eventually and have implemented many new features in the firmware. The model can now consist of up to 100 points, while the firmware two years ago only supported 25.

Present day use

After having served on my balcony for a year and a half, the mount is now housed in a permanent remote observatory in Provence, south of France. It has never been guided for imaging and has produced wonderful results. In Provence, it has a Takahashi FSQ-106 mounted, a telescope that is about to be replaced with a TEC-140 this coming summer. The Tak is going back home to sit on my newest mount, a 10Micron GM1000HPS, the smaller brother of the GM2000HPS. That combo will go into my next remote observatory to be built on an island in the Stockholm archipelago this summer.

Things to consider

Unguided imaging requires a rock steady rig. There can be now unpredictable flexure or any other form of instability. Some telescopes are simply not stable enough for modelling. I had to rebuild my Skywatcher 190MN primary mirror cell in order to make it work on the GM2000. The FLT-98 worked initially, but as my models became bigger and required even more rigidity from the telescope and imaging system, it had to go.

Getting unguided imaging to work can be a tedious task, but the way it is implemented in the 10Micron mounts makes it a breeze – provided you give it a stable enough telescope.

IN SUMMARY

This is a high end mount that delivers extraordinary performance and unguided imaging. It does not come cheap, but when comparing to other offerings it is important to note that this has absolute encoders – and they don’t come cheap.

Positive

• The 10Micron GM2000HPS has been a wonderful companion so far. It has never failed to provide unguided imaging and it has been easy to use.
  
• The mechanical design is excellent with nice finish and absolutely no slack what so ever.
  
• Absolute encoders are wonderful to have.
  
• The frictions are top notch and very reliable.
  
• Power up and go capability – no realignment
  
• Extreme slewing – 20°/s – good for satellite hunting
  
• Points exactly on target after a meridian flip
  

Negative

• It is a bit heavy to lug around to say the least, but it is luggable and very quick to set up in the field.
  
• I initially found the lack of software problematic. That has since been corrected, but the offer could still be better.
  
• They discontinued the round control box. Now you have to choose the square detached one.
  
• You need a good telescope system in order to enjoy it fully.
  

Facts

Mount type     German equatorial, monolithic or divisible head

Weight         28 kg (13 + 15 for ultra portable version)

Payload        60 kg (imaging)

Lat range      23°-70° N or S

Azimuth adjust +/- 10°

CW shaft       40mm stainless steel

Axes           50mm alloy steel

Motors         AC servo motors, encoders

Transmission   Nylon timing belt

Worm           215 teth, 172mm B14 bronze

Power          24V DC 0.7 – 5A

Slew speed     2°/s to 20°/s

[NickK]

What about meridian flips?

[perfrej]

Nick!

Positive points, last one: "points exactly on target after a meridian flip"

It flips on demand, has settable limits as to when it is OK to flip and supports ASCOM's SetDestinationSideOfPier, which means you can flip it before the meridian if you have set the limits to allow it.

I made a movie ages ago about it flipping: http://filer.frejvall.se/Flip.m4v I think it is set to 15 or 17 degrees per second...

Meridian flips are a non-issue. There is no slack anywhere, no play or anything mechanical that makes flipping a bad idea. And the model makes the mount point exactly at the target again without re-centering.

/per

[Steve Ward]

I think you forgot one minor negative Per .... the £10,000+ price tag may just be out of most folks reach ... 

Very nice review though , look forward to seeing the results from it ... 

PS ... Your movie link throws up a 404 ... ?

[perfrej]

Ah, thanks! Link's fixed.

It is not a negative per se, rather a fact that may be unpleasant. Try an AP with similar capacity and encoders, or a Paramount. They charge between $3000 and $4000 per encoder! The price of the GM2000HPS includes the encoders - in fact, you cannot get it without them as they are an integral part of the mount.

/per

[Tinker1947]

Nice write up, anybody want to buy a wife.....

[perfrej]

Haha! I've got one already. You may want to interrogate me as to how I manage to own a bunch of astro equipment without loosing the wife! Or perhaps you are thinking strictly financially and really need the cash she could bring... Only you know!

/per

[pete_l]

What a great advertisement review. If only the UK astro mags would carry content of this quality and obvious experience - I might go back to buying them again   and buying the kit they feature.

[perfrej]

I think most reviews can be seen as some form of advertisement, with the possible exception of someone who is really annoyed and dissatisfied wanting to rant. Humans were probably conceived with sales in mind because we really do want people to make the same choice as ourselves, most likely in order to boost our egos and get us the recognition we think we deserve Some even get insulted if other people don't get the stuff they recommend.

The smaller mount, GM1000HPS, that I also have, is slated for a more detailed review soon. I am collecting stuff for it right now, and it will be very detailed. Then there is the very interesting small 95mm refractor that I have bought and am waiting for. I'll definitely review that!

/per

[ChrisLX200]

This mount was top of my list of potential replacements for my G11 even before reading this, but buying one is not likely for another 12 months yet. I was wondering about the 'portable' aspects and whether it would benefit me personally, I don't travel to dark(er) sites much but it may still be a useful feature if it doesn't compromise stability/accuracy at all. 28KG is not that heavy I suppose but at my age I have to calculate how much longer I can toss such weights around

ChrisH

[perfrej]

Yes, I got the UP version so that I could be portable and the price difference is not that great, but I find that as I do not like to stay up late I will be automated anyway and probably always in permanent setups. But still, going to a dark site (with a cabin) and setting up a good tripod and mount for a few nights of imaging is something that I could do. In that case I would still use automated capture so that I could get my well deserved rest...

/per

[Roberto Coleschi]

I think that, for a remote obs, 10 Micron is one of the best choices that you can make. For the unguided pose, at longest focal lenght, the limits that you can have, are a poor mechanical construction of the OTA (mirror flop, shift). Two nights ago, I have the last three subframes on M51 ruined, maybe due the flop of my Meade ACF 10" at full fl (2500 mm), but I have blocked the mirror. Perhaps may have been a change in temperature to cause a blur in my images ( I don't have a TC focuser). But my mount have done the work very well (I got an Avalon Linear FR)..

So, anyway, have fun, and clear skies ..

[FLO]

I think most reviews can be seen as some form of advertisement, with the possible exception of someone who is really annoyed and dissatisfied wanting to rant. Humans were probably conceived with sales in mind because we really do want people to make the same choice as ourselves, most likely in order to boost our egos and get us the recognition we think we deserve Some even get insulted if other people don't get the stuff they recommend.

You might be right per 

Nice review too. 

... will go into my next remote observatory to be built on an island in the Stockholm archipelago this summer.

I am not often jealous but... 

[perfrej]

Roberto,

That Avalon thing is an interesting conception. One of these days I am going to look closer at it.

Steve (is it?),

Thanks

/per

[FLO]

Steve (is it?),

Well, it is an 'advertorial' but a good read 

[Earl]

I was planning on the 10micron but life got in the way, I have a CGE now and it will have to do until im in a posistion to work like a dog again HAH

[NickK]

Ahh bullet points, my eyes Glaze over from PowerPointitis!

Whereas every review could be construed as advertising, personally I think it's good to see a positive long standing review.

What is missing is a high end mount shoot out to compare and contrast..

[perfrej]

Yes, "Death by PowerPoint", or, as it was known in the 80's: "Foil-flipping contest". Ah, the days of over-head projectors and transparencies!

I'd love to do a shoot-out! The only problem is which to shoot against each other. Most of the American offerings are on an older technological level, and comparing, for instance, a direct drive ASA to a belt/worm thing like 10Micron is not really correct either. I guess he shoot-out would be more on usability and features like that. How about these points:

• Set it up in the field - time and ease
• Get balanced - time and ease
• Get polar aligned - time and ease
• Get aligned or modeled - time and ease
• Shoot guided images
• Shoot unguided images
• Test pointing accuracy
• Test tracking accuracy
• Test recovery after power-loss and homing (if need for it)

All video recorded and published here on SGL! Who's on?

/per

[NickK]

Hmm I think just a band of budgets and a objective measurement of results. No excuses and no marketing regurgitated performance data..

As a separate discussion have the surjective discussion on fit to type of imaging, etc.

[pete_l]

I'd love to do a shoot-out! The only problem is which to shoot against each other.

I'm not sure a shoot out would be that helpful. I've recently - over the past year or so - formed the view that pretty much any of the closed-loop control system mounts are basically "it" and comparing them against the old-fashioned worm-and-cog    mounts that rely on machining accuracy for their performance would only confirm that. 

So the only points to ponder are price, load capacity, usability / software - and possibly the  weight of the mount if you really *are* going to drag it around some muddy fields.

Oh, and what colour it is.

[Dark Matter]

Nice setup Per, but I don't think this mount would swing my next setup...two C14 OTA's - one either side of mount centre saddle + g/scope in middle + SXM25C  + Canon 60Da + f/scopes total p/load ~120 kgs.

Anyone got a mount suggestion for this kit?

Jim

[perfrej]

Well, if you want to swing it unguided and with the same spirit as I swing my little scope, I'd say the GM3000HPS (100 kg) or the GM4000HPS (150 kg). The C14 only weighs in at about 20 kg, how do you get it up to 125?

/per

[Dark Matter]

Well, if you want to swing it unguided and with the same spirit as I swing my little scope, I'd say the GM3000HPS (100 kg) or the GM4000HPS (150 kg). The C14 only weighs in at about 20 kg, how do you get it up to 125?

/per

In that estimate includes the Parallax rings for the OTA's,  back to back D Losmandy plates to hold the tubes + other saddle plates to hold the g/scope.

So by the time I add all the bits and pieces to carry all this stuff,I think it would  come close to 100 + kgs,

I'd rather have a bigger mount just in case I want to change the scopes to a larger single one...20 - 24" RC + CCD. 

[Dark Matter]

In that estimate includes the Parallax rings for the OTA's,  back to back D Losmandy plates to hold the tubes + other saddle plates to hold the g/scope.

So by the time I add all the bits and pieces to carry all this stuff,I think it would  come close to 100 + kgs,

I'd rather have a bigger mount just in case I want to change the scopes to a larger single one...20 - 24" RC + CCD. 

Looks like the 4000HPS should do the trick.

[pete_l]

Well, if you want to swing it unguided and with the same spirit as I swing my little scope, I'd say the GM3000HPS (100 kg) or the GM4000HPS (150 kg). The C14 only weighs in at about 20 kg, how do you get it up to 125?

/per

I an unreliably informed that from April 1 2015 there will be a new accessory for this mount.

It will consist of a reclining chair with a Losmandy wedge. You will be able to "goto" yourself with a pair of binoculars. There will even be a roller-coaster style harness so you don't fall out during a meridian flip.

If it's successful, there's a rumour of a further attachment for Dobsonian owners.