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GIR
super member


Reged: 01/02/10

Loc: Finland
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6108554 - 09/30/13 01:17 AM

Quote:

I've just posted a separate thread on the consequences of a pier crash - the results was NO loss of pointing accuracy even though the mount was driving the camera against the pier plate for 30 seconds before I got my wits back into gear and found the stop button (the original error is mine - I still need to set slew limits).






Sorry to hear about your pier crash. I've been pretty close myself couple of times, and now make sure that the slew limits are always in place.

In ASA mounts the Autoslew program will register a rapid rise in motor current if the mount hits the pier and switch off the motors. Of course setting the limits correctly will always a better option


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tomcody
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: GIR]
      #6108620 - 09/30/13 02:53 AM

One Big difference between these mounts is that the micron is old standard worm and gear technology, with all the wear , damage ( to the gear teeth) and adjustments that a precession gear drive needs. The ASA has no parts to adjust or wear except the main shaft bearings. Big difference in long term maintenance! As for where the computer is housed? who cares? both need one, does it really matter where the box is located?
Given a choice, I would take the direct drive system any day just from a maintenance standpoint.
The long time argument against direct drive was high power use in the field, as ASA seems to have solved that issue, there basicly is no downside to direct drive.
Rex


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Beerologist
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Reged: 07/29/11

Re: ASA DDM60 Pro vs. GM1000HPS new [Re: tomcody]
      #6108652 - 09/30/13 03:40 AM

"The long time argument against direct drive was high power use in the field, as ASA seems to have solved that issue, there basicly is no downside to direct drive."

As I recall that false argument about power consumption was made repeatedly by a fan of another mount mfgr (one that doesn't use direct drive tech) even though it was explained to him several times by different people that he was knowingly talking guff to try to make the direct drive mounts look bad.

Far as I know the ASA mounts have never had a high power consumption problem. They seem pretty darn slick to me and I'd be happy to own one.


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Hilmi
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Beerologist]
      #6108657 - 09/30/13 03:49 AM

Guys, I appreciate all the feedback, but I think this discussion would have more value if the users talked about the mount they had without making assumptions about mounts they don't have. For example assuming that a certain mount would wear out pre-maturely. Plenty of high precision worm gear driven mounts are going strong after more than 10 years of use and considering worms are replaceable parts, I don't feel 10 years is so bad.

I really just wanted the personal experiences with the individual mounts. Any frustrations faced during the learning phase, ease of setup in the field. Any failures failed. Any downsides you see to the mount you have (admit it, everything has a down side, nothing is perfect). I would rather hear about the downsides from people who own the equipment than from people for make assumptions about the equipment.

Think of it this way, it's not a competition to see which mount is better and who was the smarter person for choosing this one over that. This discussion is supposed to be reference material for people like me to make up their minds about purchase decisions based on objective evidence and subjective preferences as seen by the owners of these mounts. Then the buyer can see how the subjective and objective opinions fit in with their own criteria and make a purchasing decision based on some useful information. If we keep on trying to prove which mount is better we might not get anywhere. Such a dispute could take more than 10 years to resolve.


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famax
member


Reged: 07/01/07

Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Hilmi]
      #6108732 - 09/30/13 06:48 AM

Hello , just taking a little time to give more feedback about
the gm1000 full package.

The full package is now delivered with pelican cases type cases.. very solid. foam is grey and look durable;

The wood pier is from geoptik, hercule series.
I find mine a little to high , but one can ask for the short version of this pier.
Nothing to say about, it does well its job.

One downside of the 10µ is it is heavy : 19 kg and monoblock.
so taking it in the fields require a good back.

Something anoying is that you have to put the mount near polaris below 7° in azimuth.
A good compass allows it, but i would prefer a laser like solution for pre-positionning the mount.

The mount itself do not have major default, the tracking is very smooth, on of the best in its class.
and Once used two or three times , it is very easy to use.


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GIR
super member


Reged: 01/02/10

Loc: Finland
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Hilmi]
      #6108773 - 09/30/13 07:44 AM

Quote:

Guys, I appreciate all the feedback, but I think this discussion would have more value if the users talked about the mount they had without making assumptions about mounts they don't have. For example assuming that a certain mount would wear out pre-maturely. Plenty of high precision worm gear driven mounts are going strong after more than 10 years of use and considering worms are replaceable parts, I don't feel 10 years is so bad.

I really just wanted the personal experiences with the individual mounts. Any frustrations faced during the learning phase, ease of setup in the field. Any failures failed. Any downsides you see to the mount you have (admit it, everything has a down side, nothing is perfect). I would rather hear about the downsides from people who own the equipment than from people for make assumptions about the equipment.






Hilmi

I think you should listen to all kinds of arguments and decide yourself what is relevant and what is not. The fact is that both ASA and 10Micron are pretty newcomers and you'll have hard time to get comments of their longtime use from actual owners.

The other fact is that ASA direct drive technology is something that we haven't seen before or at least have heard very little about it. I can only tell about my own experience and don't really care if someone else is buying an ASA mount or not. If looking at the comments about ASA mounts, most of it is irrelevant, concentrating to some odd detail or simply doesn't make any sense. Besides most of the critical comments seem to come from people who have never even used the mount themselves, pure rumors and gossip. That is the main reason highlighting mainly downsides in a forum like this is quite useless.


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CounterWeight
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Reged: 10/05/08

Loc: Palo alto, CA.
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: GIR]
      #6108794 - 09/30/13 08:02 AM

Just wanting to chime in - great thread and initial OP question! (Thanks for asking it Hilmi) I am going to upgrade to something from my Mach1 pretty soon and find all this very interesting. Not long ago was near impossible here to discuss this / these without a huge noise level - this thread informative and a breath of fresh air. Again my thanks to those participating.

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Tonk
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Reged: 08/19/04

Loc: Leeds, UK, 54N
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: CounterWeight]
      #6108850 - 09/30/13 08:54 AM

Quote:

Plenty of high precision worm gear driven mounts are going strong after more than 10 years of use and considering worms are replaceable parts, I don't feel 10 years is so bad.





You might like to know that my 10Micron documentation says that no servicing of the mount will be required for up to 20 years though you can opt for a 10 year service if you wish. There is nothing for the user to adjust and the gearing is all sealed inside with "warranty void if broken" stickers.

Now I have only been running my mount 2 months so no way can I validate that the worms have such a lifetime. However you have to ask why Comec have such faith in their "old fashioned" worm gears if worm drives are truly that inferior to direct drive.

The only thing I can validate is the incredible pointing accuracy and highly successful long period unguided imaging I'm getting. Having the encoders on the shaft side of the worms means that the absolute shaft position can be monitored and stuff like backlash and PE corrected out by the firmware driven mount controller. This just leaves residuals in the corrected drive controller (very low), PA error and atmospheric refraction as your main enemies to unguided tracking.

One thing I have noticed is due to the absolute (shaft) encoder design, tracking has to accurately model atmospheric refraction for low altitude targets. Hence you need to input your height above sea level and the current atmospheric pressure to successfully track unguided for > 10 minutes when the target is below 25 degrees. (Consequently it might be nice if an electronic barometer could be attached - I need to ask the vendor if such optin exists). However at my dark sky site I'm in a clearing where the lower 30 degrees of sky are masked by trees - so it is not an major issue for me, though I have noticed a small tracking accuracy problem if I pick out an eastern target that just clearing the tree tops. As it rises the tracking gets better as refraction effects drop off.

I'm still learning how to use this mount, but from the go its been a blinder. Losmandy Gemini users would easily adapt to this mount and its controller as the pointing model building and PA correction procedures are very similar


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Tonk
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Reged: 08/19/04

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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6108868 - 09/30/13 09:04 AM

Quote:

Sorry to hear about your pier crash.




The point I was making in my other thread about the pier crash was no damage was done and pointing accuracy was maintained 100% even when the clutches slip. So the 10Micron design has that covered. It too does a current surge measurement and instantly backs off driving hard - it lets the internal clutches slip. I.e I had nothing to worry about!


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GIR
super member


Reged: 01/02/10

Loc: Finland
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6108923 - 09/30/13 09:31 AM

Quote:



However you have to ask why Comec have such faith in their "old fashioned" worm gears if worm drives are truly that inferior to direct drive.






Tonk

Glad to hear that you've been happy with your mount purchase. And I'm sure 10Micron is an excellent mount. However, comments like above just don't add any value when trying to compare different mounts. I doubt that people start calling to Comec (what ever that is) to ask why they're using worm gears in their products
And I'm sure the world is full of worm gear products but only few direct drives, especially implemented in the ASA way.


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tomcody
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Reged: 07/06/08

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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Beerologist]
      #6108987 - 09/30/13 10:10 AM

Quote:

"The long time argument against direct drive was high power use in the field, as ASA seems to have solved that issue, there basicly is no downside to direct drive."

As I recall that false argument about power consumption was made repeatedly by a fan of another mount mfgr (one that doesn't use direct drive tech) even though it was explained to him several times by different people that he was knowingly talking guff to try to make the direct drive mounts look bad.

Far as I know the ASA mounts have never had a high power consumption problem. They seem pretty darn slick to me and I'd be happy to own one.




I was referring to the fact that direct drive started out in professional observatories and was considered not usable in the field due to the high power consumption of systems at that time, now that ASA and other makers have designed low power consumption drives, there is no downside. You are just not looking back far enough to follow my statement.

Also as far as my statements about maintenance on gear /worm drives, it is a fact that they contain many precision machined and assembled parts and those parts are subject to wear and damage (just drop a gear/worm mount head in its crate with the clutches locked {which they should never be shipped locked as it transmits the shock of handling to the worm/gear matting point, but it does happen, both the shipping locked and the dropping} and you can damage a gear tooth and cause a periodic error at that tooth, or crash a mount into the pier and if the clutches or motor overload sensors do not work? do the same damage.
As there are no parts like that in a direct drive mount, that can't happen.

I am not trying to say which type of mount is better, just that the direct drive mounts change the game the same way a solid state wrist watch does compared to a old fashioned clock drive one.
Rex


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Tonk
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Reged: 08/19/04

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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: tomcody]
      #6109021 - 09/30/13 10:34 AM

Quote:

However, comments like above just don't add any value when trying to compare different mounts.




Should I remove it then??

All I've been telling you is exactly how my GM1000HPS performs for me so others can get some idea from a user of the mount. I just found it odd that mounts using worms were being down played as possibly inferior to direct drive when evidence from actually using the GM1000HPS says this is actually a top class mount.

How many worm drive mounts track accurately for 10 to 20 minutes so that you can go unguided that long??

The thing is how does this particular solution - (worm drive + absolute encoders) really compare to a direct drive solution?

As I have no experience of the latter I can't actually comment - all I can say is the GM100HPS vastly exceeded my expectations and the worm drive + absolute encoder combination really works well.

Quote:

And I'm sure the world is full of worm gear products but only few direct drives, especially implemented in the ASA way.




So you have totally missed the point about the use of absolute encoders - its not just any old worm drive. Absolute encoders means that the method of driving isn't that important as long as the feedback loop can correct drive errors fast enough by measuring the absolute position of the shafts and correcting the position in real time. The shaft position encoders have a resolution to better than 1 arc second (will have to check manual for actual value)

So there are equally very few worm + absolute encoder solutions as there are "ASA way" direct drives

Would you like to start again?


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GIR
super member


Reged: 01/02/10

Loc: Finland
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6109057 - 09/30/13 11:03 AM

Quote:


So you have totally missed the point about the use of absolute encoders - its not just any old worm drive. Absolute encoders means that the method of driving isn't that important as long as the feedback loop can correct drive errors fast enough by measuring the absolute position of the shafts and correcting the position in real time. The shaft position encoders have a resolution to better than 1 arc second (will have to check manual for actual value)

So there are equally very few worm + absolute encoder solutions as there are "ASA way" direct drives

Would you like to start again?




So 10Micron isn't just a worm drive but a worm drive with absolute encoders. I think I got it now


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tomcody
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6109068 - 09/30/13 11:14 AM

Quote:

So you have totally missed the point about the use of absolute encoders - its not just any old worm drive. Absolute encoders means that the method of driving isn't that important as long as the feedback loop can correct drive errors fast enough by measuring the absolute position of the shafts and correcting the position in real time. The shaft position encoders have a resolution to better than 1 arc second (will have to check manual for actual value)




One thing to remember, with absolute encoders, yes they can over come errors in the PE due to gear irregularities but they can not overcome mechanical looseness in the drive train. In the industry there is a truth that the position error you are trying to maintain, must be greater than the mechanical play in the drive train. (i.e. in your example if you are trying to hold 1 arc second of position, but you have 3 arc seconds of mechanical looseness in the drive train? then your system will hunt back and forth trying to hold a position. In 30+years of designing installing, and servicing servo drive CNC and robotic systems, whenever a machine would not hold position, (even with absolute encoders) it was almost always a mechanical looseness problem.
(which is why I say that a direct drive system has less fail points than a gear drive system).
And while I am still not saying which system is better, I am just pointing out the differences.

But if I were in a remote land and service was thousands of miles away, I would rather ship back a servo drive board or drive package , ( the most likely point of failure on a direct drive system) for repair rather than the entire mount head.

Rex

Edited by tomcody (09/30/13 09:03 PM)


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Tonk
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: tomcody]
      #6109393 - 09/30/13 02:49 PM

Quote:

Comec (what ever that is)




Ah! Comec Technology is the Italian company that make 10Micron mounts - hope that helps


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famax
member


Reged: 07/01/07

Re: ASA DDM60 Pro vs. GM1000HPS new [Re: tomcody]
      #6109407 - 09/30/13 02:55 PM

hi all,

A thing to consider , and maybe GIR could tell more about , is that the direct drive needs careful PID adjusment which is not an easytask, but has to be done only once, given the setup is not modified.
To say , balance has to be near perfect with DD technology (as i remember, maybe it evolved since first batch of ASA's mounts...)

By the way, here are some images about the 10µ











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Tonk
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6109425 - 09/30/13 03:07 PM

Quote:

One thing to remember, with absolute encoders, yes they can over come errors in the PE due to gear irregularities but they can not overcome mechanical looseness in the drive train.




Good point. My mount doesn't seem to have this problem (yet - crossed fingers). I can hear the motor whine and its tone changes on direction so you can hear when hunting is happening - does happen but its its is very infrequent and lasts less than a fraction of a second. The first time I heard the "hunting cry" it did startle me

One interesting thing caught my attention the first time I was setting up a pointing model. Switching to a star target on the western side of sky having done the 3-star initial alignment on the east was very accurate - within my astrometric eye piece bullseye.

I've been used to a Losmandy/Gemini system for 10 years and the first time switch to western side target when setting up this mount is usuatlly way off (a degree is normal) and the mount has to be repointed and the modeler in the Gemini controller updated to add a term for the east/west flip positioning error.

The GM1000HPS doesn't suffer this - so I assume this is a feature/benefit of using absolute encoders. Whatever the reason its nice not to have this pointing error term to deal with!


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Tonk
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6109439 - 09/30/13 03:15 PM

Two other useful features that come with the GM1000HPS

1) It can measure balance (by monitoring motor current) and guides you to the correct balance point. Does both RA and DEC balance.

2) You can elect to have RA tracking or RA + DEC tracking. The latter is useful for dealing with correcting out residual PA errors but obviously if your imaging time is too long field rotation will creep in. This is taking advantage of the absolute encoders and the measured PA error from the pointing model.


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Tonk
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Re: ASA DDM60 Pro vs. GM1000HPS new [Re: Tonk]
      #6109462 - 09/30/13 03:26 PM

Quote:

Hello , just taking a little time to give more feedback about
the gm1000 full package.

The full package is now delivered with pelican cases type cases.. very solid. foam is grey and look durable;






Bugger! Mine came in a (very sturdy) cardboard box.

I've just checked - the pelican case option is an extra cost option. You can also get a zippered "soft case" option that reuses the solid padding block that was inside the cardboard box.


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GIR
super member


Reged: 01/02/10

Loc: Finland
Re: ASA DDM60 Pro vs. GM1000HPS new [Re: famax]
      #6109493 - 09/30/13 03:42 PM

Quote:



A thing to consider , and maybe GIR could tell more about , is that the direct drive needs careful PID adjusment which is not an easytask, but has to be done only once, given the setup is not modified.
To say , balance has to be near perfect with DD technology (as i remember, maybe it evolved since first batch of ASA's mounts...)






famax

Yes, as has been said already before ASA mounts need a careful PID adjustment, which can be done most of the time with Autoslew automated process and sometime there is a need for some additional manual adjustment. However, even the manual tuning is done with the help of real time graphics, and really isn't that difficult.

The other critical thing is balancing the mount and again that can be done with the help of Autoslew. All this has to be done only once (if the system hasn't been changed) and isn't really any rocket science even though will require reading the manual.

Let me add one more comment and I'm done answering these kind of questions...
Most of the complains (even from ASA mount users) seem to origin from the fact that people are not taking couple of hours to learn how to use the direct drive mount properly. And the critique here is based mostly on rumors and hearsay from people who have never even seen an ASA mount.

So what was the point for your comment ?
Learning the basics of Photoshop is far more demanding than learning to tune ASA mounts. If that is too difficult then one should to reconsider if astrophotography is a right kind of hobby for him/her.


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