To buy or not to buy a 10Micron GM2000

[Datalord]

So, unsurprising to many people, I have found that the Celestron CGX is not really good enough for my telescope. I'm really struggling to get the PE under control while guiding and anywhere else than NE I have wild swings in RA. After consulting with the PHD2 forum it seems like I can't get it to where I need it to be because of the limitations in the mount.

So I look. And if I'm to change, I want something with absolute encoders. Which leads me to the 10Micron. With that mount I can even take the guider out of the equation, which would be amazing.

But, does anyone here have experience with the 10Microns? Is the unguided tracking good enough for 2400mm FL and 20 min subs? If not, how easy is it to get good guiding with the mount?

[Davey-T]

A few folk on here have 10Micron mounts if you check the imaging section , Barry Wilson and Peter Goodhew, Velvet  etc.

I have the GM1000HPS because it's light enough to take to dark sites, they do the GM2000 in 2 pieces which supposedly makes it portable.

Once you've figured out the plate solving / sky modelling thing then it can do 20 minute subs unguided no bother, I've done 30 minutes OK with mine just to test it and I seem to recall the late great Per did 60 minutes to test his.

Never tried guiding it but shouldn't be any different to other mounts.

Haven't used anything longer than 900mm focal length on it though, there are some Y'Tube vid's by Broke Astronomer using a Celestron SCT.

Like any other mount they are not without their occasional problems but the 10Micron service is pretty good just a pity you have to return stuff to Europe to be fixed so that may prove a problem in future.

Dave

 

[RolandKol]

Did I get it correctly, 10Micron  has no USB slots at all?
Even CEM120-EC2 looks more modern...

I constantly look for my next mount and simply cannot make up my mind....

[Datalord]

Another option is the ASA DDM85. If anyone has experience with that, I'm all ears.

[SamAndrew]

I believe you still need to guide to get the best out of the 10Micron GM2000, If you look at the results from Barry and Steve you can see they guide theirs when imaging at 980mm with the TEC 140. 

[Datalord]

1 hour ago, SamAndrew said:

I believe you still need to guide to get the best out of the 10Micron GM2000, If you look at the results from Barry and Steve you can see they guide theirs when imaging at 980mm with the TEC 140. 

I'm all cool with guiding, as long as it works. The CGX managed perfectly fine with the RASA at 600mm, but 2400mm is way too much for it.

[DaveS]

2 hours ago, Datalord said:

Another option is the ASA DDM85. If anyone has experience with that, I'm all ears.

Not the 85 (Yet), but I have used the 60, and would not willingly go back to something that wasn't direct drive.

It uses a whole sky model for pointing, then a local model for the tracking during the run. I've seen my RMS error down to 0.1" over a 2 hour run. And that was with less than perfect PA.

One thing to note is that your balance must be perfect around all 3 axes. Fortunately Autoslew provides a good tool to get it right.

Have a word with Rupert at Astrograph. I may be putting in an order too.

[DaveS]

I'll add that although the mount comes with its own software, Autoslew and Sequence, you do need to have Maxim DL and PinPoint for plate solving.

[Datalord]

3 hours ago, DaveS said:

Not the 85 (Yet), but I have used the 60, and would not willingly go back to something that wasn't direct drive.

That's a solid endorsement. One comment I saw somewhere was someone saying that when it is switched off, it loses position and is suddenly "floating". That seems a bit mad to me, is it true?

[Zcapd11]

Autoguiding is not necessary. There is one European/German GM2000 user with a C14 Edge HD who images without autoguiding and who very recently got an APOD: https://apod.nasa.gov/apod/ap190222.html?fbclid=IwAR3VjWp6Z7c4S97LKjacfvDBBSGA-_KjCXCBectHSEQR34Uuxy_kQpXKb-s

[Star101]

There is always the Mesu 200 

It is friction drive and can take a large payload, upto  around 100Kgs I believe.

Guiding is recommended. 

I have a C11 (FL 2800mm ) and a TS APO65Q with Filterwheeel, cameras and OAG Guider on mine.  Not what I would call portable as its fairly heavy for one person to carry but a excellent mount.

[Datalord]

16 minutes ago, Star101 said:

Guiding is recommended. 

I think I'm done with it. Seems to me that absolute encoders are the future and as the technology becomes cheaper, everyone will use them. So if I'm to change, I want that.

[Star101]

Just now, Datalord said:

I think I'm done with it. Seems to me that absolute encoders are the future and as the technology becomes cheaper, everyone will use them. So if I'm to change, I want that.

Fair enough. 

Just trying to save you some ££

[AKB]

5 hours ago, Star101 said:

Just trying to save you some ££ 

My favourite comment on this in relation to guiding comes from @ollypenrice

 

On 18/10/2018 at 07:53, ollypenrice said:

Autoguiding turns a £1000 mount into a £10,000 mount for most purposes. It's inexpensive, elegant, easy and effective.

 

[ollypenrice]

I have hosted three 10 micron mounts for unguided imaging and currently still host one of them. One was sold following the sad death of its owner, that great friend of us all, Per Freyjvall - and one was eventually returned for refund following a number of issues with it. The owner went back to guiding on a different mount. I think they can usually be made to work but I do not believe that a buyer should expect getting to this stage to be plain sailing. It may be, it may not be. Those who have found it not to be tend to be less vocal than those who have... 

From what I've seen here, guiding is easier than not guiding but those who have had an easy ride with unguided mounts won't agree, naturally enough. Like all highly IT intensive systems the inexplicable stumbling block is always round the corner.

What I do know is that about six years ago Yves Van den Broek and I set up a Mk1 (handset) Mesu 200 and ODK14 with 2.4 metre FL working at 0.64"PP. We took to using 30 minute subs, guiding via OAG in PHD2, and in the two years we were imaging with this setup we lost precisely zero subs to guiding error. After six years the count remains at zero but we are now using it at much coarser pixel scale. I then bought a second Mk1 Mesu and that, too, is stunningly reliable under guiding. I'm also persuaded that, while worm and wheel mounts can obviously be made to work, the other (backlash free) options are inherently better.

Olly

 

[DaveS]

8 hours ago, Datalord said:

That's a solid endorsement. One comment I saw somewhere was someone saying that when it is switched off, it loses position and is suddenly "floating". That seems a bit mad to me, is it true?

Only the DDM60 has relative encoders, the 85 has absolute encoders so always knows where it's pointing. Even with the 60, once you've powered up you do a homefind, at which point the mount recovers it's position.

Rupert has said that they run DDM60s at e-eye.

[ollypenrice]

1 hour ago, DaveS said:

Only the DDM60 has relative encoders, the 85 has absolute encoders so always knows where it's pointing. Even with the 60, once you've powered up you do a homefind, at which point the mount recovers it's position.

Rupert has said that they run DDM60s at e-eye.

But when not powered up is there anything to hold the mount still? The key question being, 'If you have a power outage are you at the mercy of the wind?' I think this used to be the case but I don't know if it still is.

Olly

 

[DaveS]

Yes, as far as I know they are still at the mercy of the wind when not powered up. Not a problem in an obsy, but can be if set up in the open with a cover, as I've found.

And what's with "outage" (Can barely bring myself to type it). We have "power cuts' too well remembered.

[JamesF]

14 minutes ago, DaveS said:

And what's with "outage" (Can barely bring myself to type it). We have "power cuts' too well remembered.

Blimey.  Picking an English teacher up on his English.  That's fighting talk, that is

James

[DaveS]

* Takes off cufflinks, rolls up sleeves and removes tie*

[Dinglem]

Just now, DaveS said:

* Takes off cufflinks, rolls up sleeves and removes tie*

At our age you should know better!!

Never take anything off as you'll put it down then spend the next two weeks trying to remember where we put them ?

[DaveS]

1 minute ago, Dinglem said:

At our age you should know better!!

Never take anything off as you'll put it down then spend the next two weeks trying to remember where we put them ?

Hehe. Been there done that. Now if I could remember where I left my marbles......

[JamesF]

3 minutes ago, DaveS said:

* Takes off cufflinks, rolls up sleeves and removes tie*

Reminds me of a line in "Endeavour" where Morse's boss (no stranger in his early police life to extracting confessions with menaces, it appears) is trying to get some information from a criminal who is clearly not willing to divulge what he knows.  "In that case," says DI Thursday, "I'm going to have to take off my hat."

James

[DaveS]

11 hours ago, Datalord said:

That's a solid endorsement. One comment I saw somewhere was someone saying that when it is switched off, it loses position and is suddenly "floating". That seems a bit mad to me, is it true?

 

1 hour ago, ollypenrice said:

But when not powered up is there anything to hold the mount still? The key question being, 'If you have a power outage are you at the mercy of the wind?' I think this used to be the case but I don't know if it still is.

Olly

 

I think this is what you were referring to?

Yes, when not powered there's nothing to hold any of the DDMs in position. Outside under a cover it can be a problem but probably not in an obsy. In any case the DDM85 mounts have absolute encoders so always know where they are pointing, even when powered off.

[Datalord]

43 minutes ago, DaveS said:

Yes, when not powered there's nothing to hold any of the DDMs in position. 

How is this not a problem? No matter how good you are at balancing, there will be one side or other with a few grams of weight.

I guess I'm wondering just how "floating" it is? Is it like a de-clutched mount? Is there some bit of friction to hold slight imbalance?