10Micron GM2000HPS

[perfrej]

That's not an altogether crazy idea... You will need the 3000 for starters, preferably the 4000 if you want to bring a case of beer and the heavier type of binoculars...

/per

[Dark Matter]

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.

 I'm sure the makers of the 10Microns GM000HPS will see your remarks as a being immature and insulting. Grow up if you have any fertilizer left in the garden.  

[ChrisLX200]

 I'm sure the makers of the 10Microns GM000HPS will see your remarks as a being immature and insulting. Grow up if you have any fertilizer left in the garden.  

It's not that daft, I once saw an article about an equatorially mounted shed the whole thing rotated on an axis together with anything inside of it... in S&T IIRC.

ChrisH

[Uplooker]

 I'm sure the makers of the 10Microns GM000HPS will see your remarks as a being immature and insulting. Grow up if you have any fertilizer left in the garden.  

[Earl]

the idea of a goto bino viewing chair all be it somewhat lazy boy territory is not a bad one either

[GuillermoBarrancos]

[perfrej]

A friend is building one... Arduino controlled!

/per

[ian_bird]

Hi Per

Out of interest - what was the problem with the WO FLT 98? Did you have the Starlight Instruments Feathertouch focuser on it?

Regards

Ian

[perfrej]

Hi Ian!

Yes, it was a Starlight Feathertouch large R&P. It should be stable enough but never made a good model. I never did tweak it though, and may or may not have made a difference. Also, you never know the actual status of the cell, which may well be slightly loose in order not to pinch. I don't know...

The Tak 106 is the best I have tried so far and I have tweaked the focuser on that.

/per

[alan potts]

Per,

Very well writen and interesting review.

Alan.

[perfrej]

Thanks, Alan!

/per

[buzz]

I'm slightly wondering about this GM2000 review and why it does not mention any of the recent issues with 10 Micron or the GM1000 / GM2000 mounts, of which the OP is aware and involved. Choosing a mount of this expense is a big deal. I do not feel comfortable with Per's review and think it is important that a account is required that includes the full user experience.

There are always issues with every product for sure. For those of you who are not 10 Micron users, a group of about a dozen of us all over Europe have been struggling with tracking and guiding issues that affect GM1000 and GM2000 HPS mounts. The mount's ethos is certainly one that is best suited in a permanent setup, where lavish care and attention may deliver fantastic unguided performance.  In my view, it still has some way to go in less than perfect conditions, that is, portable setups. Apart from the clutch knobs on the GM1000, which require Herculean strength to get a good grip, the mechanicals are generally very well executed. The external electronics in a handbag as Per says, is an accident waiting to happen.

Achieving great results certainly requires extremely good stability. Even when you have that, success is not guaranteed.  The firmware has some 'growing pains', especially in the guiding department. These are not rants. We're a bunch of 80:20 guys. We expect this mount, with a little care delivers low PE and 80% of the tracking accuracy. We can mop up the 20% with autoguiding, or spend more time on building models and hope to go unguided. Either way, a group of us have spent most of the winter testing successive beta versions to find a happy medium between guiding oscillations of several arc seconds and a guiding response that is so laid back it causes a Maxim dither command to take 2 minutes to move 2 arc seconds.  These issues occur on regular setups, pier or tripod and with users challenging each other to ensure everything is just so.

10Micron are not alone in the 'there is nothing wrong with our product, it must be something you are doing' camp but their support has considerable room for improvement. Their lack of openness means that the customers are left guessing on best practices, what has been fixed and when remaining items will be addressed etc. You are never quite certain if your problem is being taken seriously. Check out the free PHD2 webpage. They do a better job at keeping you in the picture.

This is not a rant. The other users realize that although these are very technically advanced mounts, they are not turnkey solutions and invest considerable attention on their setups and providing support to each other. The latest beta release is usable for guiding and dither but has not yet been publicly released. A number of users are experiencing and investigating intermittent tracking errors that have the look and feel of another software related issue. Since we feel that were are not believed, we are collaborating in a number of experiments to isolate the issue and present it to 10 Micron.

There are some users that consistently report excellent results, Per being one. Admittedly, forums are often places of complaint but Per is outnumbered. Our collective complaints have got 10 Micron moving but I cannot tell you when 10 Micron are going to release a new firmware or if they take our remaining issues seriously, as they simply keep their customers in the dark. We're told that things are changing, so these sentiments may change in the future...

[ollypenrice]

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

I suspect that this is not a workable rig on any mount. What will kill it, in my view, is mirror flop. Now the word 'flop' is probably not the right one because Celestron have curtailed mirror movement pretty well, from what what we read, but at this kind of focal length it needs to be eliminated almost entirely and no engineers like that kind of problem! Yves and I tried two large reflectors in tandem, one of them carrying an OAG. The guided scope was fine and the Mesu could deliver round stars on that scope. But the other one always trailed. We also wondered about geometric issues at long focal lengths. We wondered if you had to eliminate cone error on both scopes and guide on a star near the middle of the field. Not easy and we don't know if it really is necessary. Some web searching produced others who had tried and failed to make big reflector tandems work. ASA also claim that there embarrassing failure to get their unguided mounts to work for the Observatoire de Haute Provence was due to mirror movement in the Celestron SCT.

I don't think you can reliably run a C14 unguided. The FL and mirror movement are pretty daunting. Running two on one mount would be even harder. If I were you I'd run them on two mounts, both with OAG. It is more work to get two mounts running but I do it a lot and it can be done. Three is one too many but I've been there as well! Guiding has its virtues.

Chris, in a nutshell you're saying that the 10 Microns sometimes respond badly to autoguiding? I see basic accuracy and response to the autoguider as two quite separate issues and Per introduces a third when, effectively, guiding off the encoders. Do I have this straight?

Olly

[perfrej]

Chris,

I think you are missing something here; this review is for the GM2000HPS, not the GM1000HPS. The only firmware issues I have seen with the GM2000HPS concerned a non-essential bug in the handset reporting of alignment point errors, and a not so trivial one which involved an unstability after a slew. The latter was discovered by me from activities in Provence and I bypassed it by introducing an  extra slew settle time of 10-15s after a slew. Subsequently, that issue was solved rapidly by the firmware team of 10Micron and tested by myself.

The guiding and tracking issues you mention, and that are being discussed on the 10Micron forum, all concern the GM1000HPS, which again is not on review here. My GM1000HPS tracks fine for 20 minutes unguided at FL 1000 mm, but recent firmwares have introduced a tendency to not always get perfectly round stars. Since I do not guide it I am not going to say anything about how well it guides. The only guiding I have done, which is in the guiding test thread on the forum, is with the GM1000HPS under non-imaging use and produced reasonable results. The tests going on involve so many parameters that I have subsequently lost track of what is what. Some measure with a model in the mount, some without. Some have flex in their rigs, some don't. It is simply very, very, difficult to make head or tails on what is going on. The mount workings are very complex and even having different expected RMS error in the model is going to create differences in tracking behavior. I am quite confident this issue will be resolved one way or another.

Anyway, this is the GM2000HPS. The review is mine and I stand by it, and my rig delivers - unguided. Again, I have not guided the GM2000HPS and do not feel the need for it. One hour long subs at FL 1000 mm is enough for me

/per

[perfrej]

Olly, the mount uses the absolute encoders directly in the motor control loop, just as it uses the motors' relative encoders to do the basic control of the servo AC motors (not steppers!). After modeling the mount behavior, a model is used to control tracking in both Ra and Dec. This is maths that are very similar to TPoint and MaxPoint, but 10Micron uses a proprietary rotational matrix which is far more accurate than TPoint's.

Any mathematically describable anomaly that is found is mapped to parameters in predefined formulas. For instance, if your focuser sags really nicely and predictably from gravity, the model will include a term for how much it flexes by using the cosine of the alt angle and the parameter calculated. There are up to 11 of these in a model, and if the rig behaves differently on one side of the pier the terms will double and each half is treated with a separate set of complex model terms.

The 11 terms include things like polar error, ortho error and adds, on top of all the model terms, the actual refraction calculation derived from the ambient air pressure and the temperature.

Phew!

/per

[Velvet]

i was surprised to read the post of the problems with the 10 micron.  I agree having the controls in the separate square box caused me a few issues but i sorted that by requesting a 1.5 mm longer cable so it now sits in a box at the base of the tripod,

problem solved.  I only use my GM1000 as a portable set up and so far have done mostly unguided, which if you get your PA done well is a treat to run.  takes a little more time and effort to set up but it is worth it as you dont get the swearing when it

loses a guide star.  As for the clutch knobs, that was sorted by a plastic tool that helps me tighten them and i have no problems with them now

I have guided with the mount with PHD and everything seemed to go well.  I am no expert, in fact a real beginner.  That is probably the best testament for this mount, if a novice 'blonde' like me can have success, anyone can

would be interested to hear the results of the tests so i know if i have to look out for any pitfalls i have not found yet

Velvet

[perfrej]

Velvet,

That agrees mostly with my take on the GM1000HPS. I just got a 2.5m cable for the mount so I have now eliminated that problem. My GM2000HPS does not suffer from the same problem as it has the round control box which is truly fixed - it should be, shouldn't it, being part of the base

/per

[buzz]

I understand that the review is of the GM2000 but the firmware release is common to both mounts. So is the attitude and response of the supplier to a normal customer, which is relevant to any review of a piece of technology.

Like you I'm committed to the mount and believe the software quirks will be ironed out.  It is easy to forget about the good bits, like minuscule PE and effortless polar alignment.

In comparing the two mount types, I beg to differ on the assertion that it is only the GM1000 that has guiding issues: If you have never auto guided the GM2000....how do you know if it works? The same applies to the dither response issues. I have had face to face discussions with other GM2000 users and they have auto guiding issues that match the GM1000 user's experience. 

As you say - it is a sophisticated mount and it is difficult to nail issues down. Right now about 6 users have a drift issue which comes and goes. When it comes, we have found our drift rates are the same within a few percent. It could be a coincidence but statistically that does not tally with user and setup variables. We are starting with basics: Our reasoning is if this issue is not apparent in a basic mount mode (polar aligned, nothing fancy) and only occurs when we apply dual tracking, models and refraction, then the issue is probably software.

[buzz]

I finished my GM1000 drift tests over the weekend and rather than hijack this thread,  for an issue that may/may not affect GM2000 owners, I have posted the results of my drift analysis in the 10 Micron forum. It confirms there is a problem, probably in the firmware. This has been present in the two mounts I have owned and at least 3 others users'.

http://forum.10micron.eu

[pete_l]

Yves and I tried two large reflectors in tandem, one of them carrying an OAG. The guided scope was fine and the Mesu could deliver round stars on that scope. But the other one always trailed.

That is always going to be a problem, no matter what (big) reflectors or mount you use.

OAG-ing will correct for tracking errors in the mount and also a whole slew of other errors, generated within the OTA. However, if you add a second OTA, all the flops, rattles, loose components and thermal effects in that mount will receive the correction as the first mount. Whether those correctionss "work" for tube #2 would be down to random chance. Some will, to some extent, others won't - and some will be worsened.

Given the size of a 14 inch OTA and the weight of its mirror, I doubt you'd ever get a reliably accurate mechanical match between 2 of them.

[buzz]

I finished my GM1000 drift tests over the weekend and rather than hijack this thread,  for an issue that may/may not affect GM2000 owners, I have posted the results of my drift analysis in the 10 Micron forum. It confirms there is a problem, probably in the firmware. This has been present in the two mounts I have owned and at least 3 others users'.

http://forum.10micron.eu

update: My friends report the issues from early 2014 have been fixed now. The firmware has moved on since last year and according to them they are tracking with either no guiding or minimal 'safety net' guiding. Judging from the forum, they are now going after even longer sub exposures, enabled with frequent weather and web based clock updates to account for atmospheric conditions and clock drift. 

[perfrej]

And I am lobbying for direct firmware support for a USB-stick weather station, simply to get said parameters into the mount as efficiently as possible.

/per

[buzz]

Per - I have tried and given up on using Temperhum devices (with sequence generator pro). I'm not getting consistent results and their supplied drivers crash on my Win 7-64 bit platform. There also seems to be two distinct calibrations in an otherwise identical package, which throws it entirely.  Some of the Arduino projects look promising - there is one with pressure, temperature and humidity and can take wind/light too.  Is the intent to propose an Ascom interface?

[perfrej]

The ASCOM interface already has support for general sensor devices, but there is no strict standard for the pressure and temperature specifically. I'll lobby for that, though

/per