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Equipment Discussions >> Mounts

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Steblaj
member


Reged: 07/27/12

ASA DDM 60, anybody a proud owner?
      #5615932 - 01/10/13 05:39 PM

I've been thinking about "going pro" and the direct drive seems the way to go.

On the other side, I've read on several places complaints about the reliability of the mounts? Although, all these complaints were from a year ago at least.

Any experiences?


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jjongmans
super member


Reged: 02/11/12

Loc: The Netherlands
Re: ASA DDM 60, anybody a proud owner? new [Re: Steblaj]
      #5616701 - 01/11/13 05:09 AM

I received my DDM60 Pro in november 2012. I read the same complaints, but I believed direct drive was the way to go, so I just ordered it. I'm really happy with it, it looks and it works great. The software (Autoslew) is improved and almost all complaints are fixed. I was able to take 20 minute unguided images with 1380mm fl within three nights of testing. The workflow is pretty straightforward nowadays and isn't complex:
1) PA with the laser
2) Balance the scope, this is very critical!
3) Tune motorparameters, automatic with AutoTune, No PID control knowledge needed anymore.
4) PA improvement with 3-star pointing model, fully automated with Sequence (and Maxim and PinPoint)
5) In a permanent setup create a full sky pointing model, also fully automated with Sequence. In a mobile setup create a MLTP (tracking) pointing file for specific object.
6) Point and shoot your object unguided.

No more Periodic Error, Backlash, Guiding issues (seeing dependent, clouds interrupts), silent (fans of the CCD make more noise when slewing with 15°/sec), 100 corrections p/s (able to compensate for wind gusts).

If your going to use the mount in a mobile way you need some time to setup. In a permanent setup it's just a power on switch and a homing routine (2 min) and you're good to go.

I'm confident that I can image 30 minutes unguided at 1380mm, but the weather is very bad over here so I'm not able to prove it...

I haven't got regrets, no way! And the steep learning curve isn't that steep anymore (lots of improvements and automation since the introduction).

You must join the ASA Yahoo group, great info there. Feel free to ask more.


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jjongmans
super member


Reged: 02/11/12

Loc: The Netherlands
Re: ASA DDM 60, anybody a proud owner? new [Re: jjongmans]
      #5616705 - 01/11/13 05:16 AM

Here is a first unguided attempt: test

Edited by jjongmans (01/11/13 01:58 PM)


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Steblaj
member


Reged: 07/27/12

Re: ASA DDM 60, anybody a proud owner? new [Re: jjongmans]
      #5617020 - 01/11/13 10:51 AM

Actually, I was looking at your posts and web page the other night - just after posting my question here.

As I will be a mobile astrophotographer I'd like to get some idea as how much time woulg go on accurate PA since there is no guiding? Somewhere in the drift alignment time-region?

Also, I've seen that the payload for the DDM60 is 28 kg, but on ASA's webpage is a confusing statement that with counterweights you can go up to 56 kg??

Thanx for the help.

(Of course, I've been reading ASA Yahoo group)


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neptun2
scholastic sledgehammer


Reged: 03/04/07

Loc: Bulgaria
Re: ASA DDM 60, anybody a proud owner? new [Re: Steblaj]
      #5617049 - 01/11/13 11:07 AM

Hello. I would like to also thank you for the detailed nformation. ASA DDM60 is also on my list of future upgrades and from what i see it is definitely a very good mount and deserves the money. Also obviously it is not so complex to operate like in the beginning when it was introduced. About the capacity - as i know the max payload is 28 kg and total weight can reach 56 kg with the counterweights included.

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Steblaj
member


Reged: 07/27/12

Re: ASA DDM 60, anybody a proud owner? new [Re: neptun2]
      #5617135 - 01/11/13 11:52 AM

Ok, that makes more sense than what I have understood from the web site. Thank you!

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Alph
Carpal Tunnel


Reged: 11/23/06

Loc: Melmac
Re: ASA DDM 60, anybody a proud owner? new [Re: jjongmans]
      #5617159 - 01/11/13 12:10 PM

Quote:

100 corrections p/s (able to compensate for wind gusts).



Yet balancing is very critical!


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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: ASA DDM 60, anybody a proud owner? new [Re: Alph]
      #5617326 - 01/11/13 01:56 PM

Alph - the way I heard it from the ASA guys (though jj would know first hand) is that balance is critical because not only is it balance (and off-balance is NEVER good), but it also gives a baseline for compensation (when there are wind gusts and such). It's pretty logical: how can you know were to "zero out" if you don't set an accurate "zero out?"

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jjongmans
super member


Reged: 02/11/12

Loc: The Netherlands
Re: ASA DDM 60, anybody a proud owner? new [Re: Alph]
      #5617327 - 01/11/13 01:57 PM

Balance is important to have the same performance over the full sky, that isn't related to wind gusts.

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Alph
Carpal Tunnel


Reged: 11/23/06

Loc: Melmac
Re: ASA DDM 60, anybody a proud owner? new [Re: psandelle]
      #5617413 - 01/11/13 02:59 PM

Quote:

It's pretty logical: how can you know were to "zero out" if you don't set an accurate "zero out?"



It's pretty illogical. So your are saying that the controller can't be trained for off-balance condition. Wind gust and off-balance should look the same to the controller. Force is force, no matter where it comes from. I can't see how the controller can differentiate between them unless it does frequency analysis on the fly.


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jjongmans
super member


Reged: 02/11/12

Loc: The Netherlands
Re: ASA DDM 60, anybody a proud owner? new [Re: Alph]
      #5617479 - 01/11/13 03:40 PM

Unbalance is low frequent (one direction constant force not changing) and wind gusts high frequent (different directions, different forces, fast changing)

If the mount is balanced I can achieve 20 minutes unguided images, I think that's impressive... If I ever get clear skies again I'm confident I can reach 30 min unguided subs.

Edited by jjongmans (01/11/13 03:46 PM)


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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: ASA DDM 60, anybody a proud owner? new [Re: jjongmans]
      #5617568 - 01/11/13 04:35 PM

Alph - sounds like you need to contact the ASA guys to have them explain it to you. They'll be able to walk you through it better than I can. Also, any other questions you have on the mount, since it seems like you're interested (I always see you post when the ASA mount threads come up). It's a good price for a quality mount that has its own particular way of accomplishing fine tracking. You should definitely get one.

Paul


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BPO
sage


Reged: 02/23/10

Loc: South Island, NZ
Re: ASA DDM 60, anybody a proud owner? new [Re: psandelle]
      #5617849 - 01/11/13 07:31 PM

Don't worry. There are a few people out there who want to believe that these mounts are "no good". One or two constantly troll ASA's Yahoo! Group trying to paint the DDM mount concept as being inherently flawed. Usually they are people who spent a lot of money on mounts based upon geared tech.

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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: ASA DDM 60, anybody a proud owner? new [Re: BPO]
      #5617934 - 01/11/13 08:15 PM

There are some pretty amazing mounts at this price range and above (geared and not), and they all have their little "quirks" (the ASA mounts surely had teething problems at the beginning), but they ALL seem to do excellent jobs once they're understood and put to their best use. There may be personal reasons for picking one over the other, but I'd be tickled to have any of them (and, one of these days, when I settle down to an observatory, I will).

It's good to point out possible friction areas in mounts (especially new ones coming to market), but to dismiss any of these mounts just seems silly.

Paul


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frolinmod
Carpal Tunnel


Reged: 08/06/10

Loc: Southern California
Re: ASA DDM 60, anybody a proud owner? new [Re: psandelle]
      #5618211 - 01/11/13 11:24 PM

Someone named Alph appears to own a Paramount MX. Not sure if it's the same Alph or an unrelated Alph. My hat's off to the furry little guy, whomever he is.

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Steblaj
member


Reged: 07/27/12

Re: ASA DDM 60, anybody a proud owner? new [Re: Steblaj]
      #5619107 - 01/12/13 01:50 PM

Quote:


As I will be a mobile astrophotographer I'd like to get some idea as how much time woulg go on accurate PA since there is no guiding? Somewhere in the drift alignment time-region?





Again, I'd like to get an answer on the above question. I've been researching available information and it looks like a time consuming effort for a mobile setup?


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korborh
professor emeritus
*****

Reged: 01/29/11

Re: ASA DDM 60, anybody a proud owner? new [Re: Steblaj]
      #5619266 - 01/12/13 03:23 PM

Simplicity is very important for mobile setup. Tak/AP mounts are the simplest to use in the field. So I recommend these proven, reliable geared mounts for field use rather than a complicated one like DDM.

Autoguiding high-end geared mounts like AP/Tak is very easy. AP mounts can also do un-guided with additional modeling software if needed. However, auto-guiding is not that difficult on these mounts, and it is really the only way to get the highest quality data for ANY mount.


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jjongmans
super member


Reged: 02/11/12

Loc: The Netherlands
Re: ASA DDM 60, anybody a proud owner? new [Re: korborh]
      #5619313 - 01/12/13 03:46 PM

Setting up the DDM will take less than 60 min. You'll need 2 automated pointing models; one for the polar alignment (with the model you can easily get within 1 arcmin of the pole) and one for the object you want to track.

Btw, I'm using the DDM with auto guiding at the moment. I changed some things and didn't take the time to remodel it, so I just decided to autoguide. No corrections seen in 20 min subs!

Edited by jjongmans (01/12/13 03:53 PM)


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Per Frejvall
sage


Reged: 09/28/12

Loc: Saltsjöbaden, Sweden
Re: ASA DDM 60, anybody a proud owner? new [Re: korborh]
      #5620376 - 01/13/13 09:44 AM

Quote:

Tak/AP mounts are the simplest to use in the field.




Don't forget the 10Micron mounts. Polar aligned in a few minutes, very transportable and I get half an hour unguided performance at focal length 1470mm from my GM2000HPS. I have a GM1000HPS on the way in and it will be interesting to see if it is as good as the 2000.

/per


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Steblaj
member


Reged: 07/27/12

Re: ASA DDM 60, anybody a proud owner? new [Re: Per Frejvall]
      #5620402 - 01/13/13 09:57 AM

I don't think we should be comparing Astro-physics and 10 micron mounts with the ddm60, as they are not in the same price range?

Otherwise I would be choosing between the new Paramount and ddm85.

60 minutes sounds reasonable, not so great but reasonable.


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