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ASA DDM60 Pro vs. GM1000HPS

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#1 Hilmi

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Posted 22 September 2013 - 05:55 AM

First of, I did not start this topic in order to start controversy. As I had mentioned earlier I am now saving up for a new mount and I have been looking at my alternatives. I already know the respective merits (and few shortcomings) of the Mach1GTO which are very well documented on the internet. On the other hand these two particular mounts have very little material on them available online (at least from what I could find). Most of the material I found is marketing material. I am trying to get feedback from people who have actually used these mounts at focal lengths similar to those a I am working at. I am currently working at 1680mm to 2000mm. I image with an STT-8300 which provides for a rather small pixel scale when not binned. I sometimes image with a DSLR, but mostly I use the CCD camera.

Therefore, keeping this in mind I am imaging with a laptop anyway, so bringing a laptop is not a big deal, I would like to know the experience (specifically for imaging at these focal lengths or higher) are. I am not too impressed when somebody tells me they can image at 600mm unguided. I can already image at short focal lengths unguided. I have no interest in short focal length imaging.

So far my limited research shows the following:

DDM60 Pro:
+Through the mount cabling
+Integrated laser pointer for rough alignment
+The ability to model tracking for the specific path of the object you are going to image
+Integrated USB hub and power connectors for accessories
-More expensive
-You have to sort out your own tripod
-100% computer dependent (no bigy but still a negative)

GM1000HPS
+Track satellites (not sure I would use this)
+Comes in a nice package that includes covers and carry bag and tripod (no need to hunt around for components to complete the package
+Works without computer (Nice to have, but not a must)
+Removable electronics
+Since the firmware is linux based, I am assuming that it is open to future 3rd party upgrades
-No through the mount cabling
-No polar alignment scope or laser for initial rough alignment

I will be spending a lot more money than last time. My last purchase did not meet my needs, I need to be ultra careful with my next purchase. That is not to say that I should stick to AP without any questions, I am willing to try other brands with their new interesting features, provided I find evidence to back that they are good enough to demand such a premium price tag.

#2 GIR

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Posted 22 September 2013 - 09:27 AM

...I am not too impressed when somebody tells me they can image at 600mm unguided...


Well, maybe you should be because the basic principles for doing it well with longer FLs are very much the same ;)

#3 Hilmi

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Posted 22 September 2013 - 09:43 AM

The reason is I can image unguided at shorter focal lengths already. I can with my G11 already image for 40 minutes (Ha) unguided at 400mm focal length. Only reason I couldn't use the images was because some parts where over saturated. I have the images to prove it too. Yet I still have difficulty with 1680 mm

At close to 3 times the price I want to see far more than 20 minutes 600 mm.

#4 GIR

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Posted 22 September 2013 - 09:47 AM


Good luck with your research :smirk:

#5 David Pavlich

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Posted 22 September 2013 - 10:09 AM

It seems from my readings of personal experiences here, the DDM series, once the quirks are conquered, is a top pick for unguided imaging for one reason; it is direct drive, no PE. At that point, it's up to you to get that polar alignment as close to perfection as possible.

However, I've seen some very impressive results with mounts not mentioned here, especially at the sub 1000mm focal length. APs, SBs, and a certain MI250 (not mine) that have done some outstanding unguided images at much longer focal lengths than 1000mm. But...these results come with added costs.

Add to that, your location, and then support becomes an issue. With that in mind, I'd stick with what is best for you in terms of service.

David

#6 Per Frejvall

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Posted 22 September 2013 - 10:23 AM

10Micron firmware is NOT open source or available for modification in any way.

I have never missed a polar scope. All that is needed is a compass bearing, a quick aim and three stars. After that you do he initial adjustment.

In order to reach unguided performance with a single-axis tracking mount (like the Losmandy - I assume it does not offer dual axis tracking as it lacks encoders) the polar alignment must be second to none. I do not think it is easily obtainable in the field.

10Micron and ASA mounts track in both axis and have absolute encoders. This means that you can have a much larger polar alignment error and still get away with unguided imaging. The mounts need good models in order to deliver unguided.

ASA's software has the path tracking option as you mention. The same is doable with a 10Micron mount if you just choose to model along the path of the intended target. Easily done with my model making software (you can read about that on my site).

/per

#7 Hilmi

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Posted 22 September 2013 - 11:03 AM

Per,

I thought all software based on Linux has to be open source or is in violation of the license agreement. Anyway, that doesn't affect me in any meaningful way.

You are right about polar alignment, when I took those 40 minute exposures I had spent several hours tuning my polar alignment using PEMPro.

Guiding is not an issue for me since my camera already has an off axis guider built in, my aim is to get the images so I don't care if it is done with or without guiding. I am just interested in getting images in the longer focal lengths. Defined in my dictionary as starting from 1680 mm going upwards from there.

#8 petely

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Posted 22 September 2013 - 11:49 AM

I've been casually considering the same kind of problem. One point that may be important to you: the DDM mount control software seems to be the creation of a single individual. If that guy gets bored, gets a better offer or his situation changes, would the company be able to keep supporting the mount? Without the control software, the mount is just a pile of highly machined metal.

#9 GIR

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Posted 22 September 2013 - 12:20 PM

Just have to comment on this :grin:

Yes ASA is using Dr. Keller as their main developer. However, if you'll check out what kind of a company ASA is, they should be able to hire a replacement for Mr. Keller if he gets hit by the truck.

And if you compare ASA to e.g. 10Micron who had problems to develop even proper ASCOM support without a help of a talented mount owner, not to even talk about other software development. I'd put my money on ASA ;)

#10 Per Frejvall

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Posted 22 September 2013 - 12:24 PM

Hilmi,

If that is your requirement then both mounts will do. I prefer the 10Micron for a number of reasons. I do not like the total PC dependancy, I do not like the fact that if power is cut the thing is loose as a goose and can continue its slew until it hits the pier, and I do not like motor control to be delegated to an external computer.

As for the Linux thing, all things Linux do not have to be open. It is the base embedded Linux kernel code that is open, not the firmware riding on it.

Now, if you are aiming for the longer focal lengths I would suggest you look at mounts "one step up". In 10Micron terms that would be the GM2000HPS. It is a formidable mount!

/per

#11 orion69

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Posted 22 September 2013 - 12:25 PM

Hilmi, can we see this 40 min unguided image with G11?

#12 Hilmi

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Posted 22 September 2013 - 12:38 PM

Will dig it up. I have the 20 minutes posted on astrobin. My g11 is upgraded with ovision worm and has a +/- 3 arc seconds pe. But it just won't guide properly and keeps on giving RA jumps larger than the PE. I thought it was seeing at first but dec axis plot is perfect.

Anyway. I'll go to my computer and dig up those 40 minute subs

#13 Hilmi

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Posted 22 September 2013 - 01:19 PM

I wish to retract my statement about 40 minutes unguided as I found I was using an auto-guider upon reviewing my images. I apologize for any shock and indignation I might have caused with that mistaken statement.

But I did manage 40 minutes guided

#14 GIR

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Posted 22 September 2013 - 01:33 PM

...I have the 20 minutes posted on astrobin...


Hilmi

Could you give a link to that 20min unguided exposure at the Astrobin. Could only find one 4 min unguided exposure.

#15 Hilmi

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Posted 22 September 2013 - 01:50 PM

Please look at the above statement. I made that statement out something I recalled incorrectly and I have posted an apology for my false statement.

That still doesn't change the fact that I want to see results from longer focal lengths.

Anyway, here is the picture I was referring to, it was not in the public area, it was in the staging area.

http://astrob.in/37174/

I will find the 40 minute sub and post it anyway.

#16 GIR

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Posted 22 September 2013 - 02:23 PM

Hilmi

Hope you'll find a good mount for your longer focal length plans. It shouldn't be a problem because doing longer focal length with autoguiding is quite manageable with all high end mounts.
Maybe you'll also find out one day that taking 20 min unguided exposures with a 600 mm scope isn't so trivial you seem to think.

#17 Hilmi

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Posted 22 September 2013 - 02:28 PM

Found the 40 minute raw sub. It's a 16 meg file so I am posting a link to drop box. As I have mentioned earlier, it is auto-guided and I had made a mistake when I thought it was not guided.

https://www.dropbox....gzy0/pW2m5V8mj8

#18 Hilmi

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Posted 22 September 2013 - 02:34 PM

Thanks GIR. I do not intend to trivialize the achievement I mean to say that I want to see results in the focal lengths I am working at.

When I purchased the G11, I was told that it can do 2000mm imaging, but I actually didnt see any results and now I am not happy at all with it's guiding performance. So I can't be blamed for looking to see actual evidence of performance at the same focal lengths I am working at.

I saw an image from a DDM85 at 4500mm that was unguided and very impressive. but a DDM85 is not a DDM60. While the principles of operation are the same, I would still like to see feedback from users of the same mounts I am considering.

Same goes for GM1000HPS. Lots of feedback on the GM2000HPS, very little on the GM1000HPS.

I found lots of information about the Paramount MX and The Mach1GTO. That was so easy to dig up.

#19 frolinmod

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Posted 22 September 2013 - 06:00 PM

I found lots of information about the Paramount MX and The Mach1GTO. That was so easy to dig up.

That should tell you something.

#20 orlyandico

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Posted 22 September 2013 - 07:25 PM

Hilmi, if I were you I'd find some friend traveling to the US who can get you a used AP900GTO. Certainly it can't do the 20-minute unguided trick of the 10Micron and ASA mounts, but as frolinmod just implied... it's a bulletproof and no surprises solution. Since you indicate you'll be guiding anyway.

#21 shams42

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Posted 22 September 2013 - 10:34 PM

I found myself in a similar quandry. I am fascinated by the 10Micron mount in particular and have read the instruction manual several times. It sounds amazing. Ultimately I ended up going with the Paramount MX due to all the information out there and the mature software integration. It also helps that the PMX can carry about twice the weight of the GM1000. I am hoping to try some unguided images via ProTrack and TPoint. The PMX arrives on Tuesday!

My Takahashi NJP has been an amazing mount for guided imaging and truthfully its only shortcoming is that it doesn't thrive in an automated environment.

#22 GIR

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Posted 23 September 2013 - 12:30 AM

...I saw an image from a DDM85 at 4500mm that was unguided and very impressive. but a DDM85 is not a DDM60. While the principles of operation are the same, I would still like to see feedback from users of the same mounts I am considering...


If you're seriously wanting to learn more about ASA mounts, you might want to check out some of the user experiences from their web site. It includes all kinds of set-ups. ASA forum is also a good place to ask what kind of results people are getting from their systems.

ASA

#23 Hilmi

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Posted 23 September 2013 - 02:16 AM

Gir,

Thanks for the link. I have now found the sort of samples I was looking for. I found images done on a 10" LX200 unguided and they looked very nice.

#24 Per Frejvall

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Posted 23 September 2013 - 04:27 AM

Just have to comment on this :grin:

nd if you compare ASA to e.g. 10Micron who had problems to develop even proper ASCOM support without a help of a talented mount owner, not to even talk about other software development. I'd put my money on ASA ;)


Well, they were late in releasing their ASCOM driver, that I can confirm. In the meantime I developed my own which is entirely mine and has nothing to do with 10Micron. Today both are available.

/per

#25 Hilmi

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Posted 23 September 2013 - 05:29 AM

I see there is some healthy rivalry between the mount owners.

Per,

Did you purchase your mount with the full kit including the tripod and carry cases? How good re these accessories? Do you feel they are good enough to be considered influential in the purchase decision?






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