Jump to content


Photo

ASA DDM85X-SL - Keeps getting better

  • Please log in to reply
32 replies to this topic

#1 SL63 AMG

SL63 AMG

    Viking 1

  • *****
  • Posts: 864
  • Joined: 21 Dec 2009
  • Loc: Williamson, Arizona

Posted 18 September 2012 - 03:18 PM

A year and a half ago I purchased an ASA DDM85XL-S.

It was a big leap for me, not so much due to the cost, but mostly due to the learning curve. Not only was there a huge learning curve for the mount, but I started from scratch knowing little to nothing about astronomy, astrophotography, mounts, collimation, cameras, filter wheels and most of all, image processing.

I kid you not; there were no gradients in my knowledge, just pure green (me)!

Enough of that, let's talk about the mount.

First, I encourage you to read my review of the ASA DDM85XL-S Direct Drive GEM

It's not the best writing in the world, but I think it gets the point across...this is an excellent mount for astrophotography!

So I find myself, a year and a half later, becoming quite knowledgeable on this mount...and it keeps getting better.

I recently upgraded my Autoslew software that controls the mount with version 5.1.0.0 and the plate solving software to Sequence version 9 by Dipl. Phys. Dr. Philipp Keller.

Dr. Keller has made major improvements to the software, specifically in the Advanced Pointing model of Autoslew and the Multipoint Local Precision Tracking portion of Sequence.

What seemed like required an advanced degree in astrophysics to operate and understand can now be down quite easily by a greenhorn like me. All of the advanced pointing and modeling functions are now completely automated.

I am now consistently able to achieve polar alignments equal to or less than 6 arcseconds in both axis in about a half hour after setting up the mount and then create a substantial pointing model within another 30-45 minutes. Once completed, I can select an object, create a MLPT model in 2-12 minutes depending upon the length of my exposures and the number of iterations I select and then I can achieve 20-30 minute subs with no periodic error, no backlash and most importantly, no guiding.

The pointing accuracy is very good but it is the tracking capabilities that are absolutely amazing.

When I am done imaging for the night, I simply park the scope, cover it and it's ready for the next evening of imaging.

If I need to shut off the power or remove the laptop for any reason, that's cool too. I make sure I point the scope at a star in the eastern horizon, synch to that star and then Autoslew calculates the angular offset between the synched star and the encoders home position. It then uses your coordinates, date and time and that angular offset to determine exactly where to point after you power up and perform a HomeFind. In other words, it never forgets where it is positioned once a 30 second home find is performed on power up.

Here are some images of the mount and some taken using the mount. They are a combination of 10 and 20 minutes subs with no periodic error, no backlash and most importantly, no guiding.

Posted Image Posted Image
Posted Image
Posted Image
Posted Image Posted Image
Posted Image

#2 Alph

Alph

    Surveyor 1

  • -----
  • Posts: 1769
  • Joined: 23 Nov 2006
  • Loc: Melmac

Posted 18 September 2012 - 04:12 PM

I have written off the ASA DDM mounts for a couple of reasons:
- Payload capacity, DDM60 too little, DDM85 too heavy
- Subpaar machining. Those mounts don’t look they are worth the money.
- Difficult to operate mechanically. The azimuth adjustment range is too small. The lack of easy axes locking mechanism makes OTA mounting a royal pain in the …
- Frequent problems with PID parameters. Many users reported tracking errors after 10 minutes or so of continues tracking (no manual axis movement). ASA has no fix yet.
- Price is way too high
- Poor customer support.
- Shipping the DDM85 to ASA for repairs is very expensive.

#3 Peter in Reno

Peter in Reno

    Fly Me to the Moon

  • *****
  • Posts: 6195
  • Joined: 15 Jul 2008
  • Loc: Reno, NV

Posted 18 September 2012 - 04:34 PM

Thanks for the well written report. It looks like you got a great mount.

Peter

#4 SL63 AMG

SL63 AMG

    Viking 1

  • *****
  • Posts: 864
  • Joined: 21 Dec 2009
  • Loc: Williamson, Arizona

Posted 18 September 2012 - 04:45 PM

I think you need to do your homework, or at least keep up with the progress of ASA.

I have written off the ASA DDM mounts for a couple of reasons:
- Payload capacity, DDM60 too little, DDM85 too heavy

ASA DDM60 - 55lbs
ASA DDM85 Basic - 100lbs
ASA DDM85 Standard - 143lbs
ASA DDM85 Premium - 220lbs


- Subpaar machining. Those mounts don’t look they are worth the money.

Subpar? Based upon looks? These mounts are CNC machined and high quality.

- Difficult to operate mechanically. The azimuth adjustment range is too small.

Not sure how much you think you need, but after pointing the mount near polaris, lighting polaris up with the laser, there really isn't much adjustment needed. I think what they offer is overkill. I simply hold up my pinky finger at arms length against polaris on the Kochab side and spot the laser to the other side of my pinky. I find myself polar aligned within 5 to 8 arc minutes every time, then run a sequence plate solving 10-15 stars and my polar alignment is typically less than an arc minute and often within 6 arc seconds if I am really maticulous about centering stars in the crosshairs of the CCD image.

The lack of easy axes locking mechanism makes OTA mounting a royal pain in the …

Using a metric #8 hex tool to tighten a locking bolt is a pain? Seriously? I have no trouble mounting my Astrotech 12" RC all by myself. I find it much easier then setting up a Celestron CPC1100 for mount, especially on a wedge!

- Frequent problems with PID parameters.

This issue is fixed in Autoslew 5.1.0.0. There are now presets depending on the size and weight of your system. Only minor adjustments are needed from the preset. Once you set the values and balance the scope using the wicked cool software balancing system, you save your scope to a profile and forget it. I change scopes and with a click all my settings are spot on.

Many users reported tracking errors after 10 minutes or so of continues tracking (no manual axis movement). ASA has no fix yet.

I am not sure what you mean by "no manual axis movement" but if people are having tracking issues after 10 minutes, then they aren't setting up properly. If you do a good polar alignment (30 minutes) and make a good pointing model (30-45 minutes) then use MLPT for tracking, you can't miss. 20 minute unguided subs are easily attainable even for a beginner like me. The images in my post speak for themselves. For those that need to autoguide, you can do that too, but really, it is unecessary unless you want subs greater than 40 minutes.

- Price is way too high

Too high is relative. By the time you buy any other mount, add all your guiding accessories, you'll spend as much as a DDM60. My images speak for themselves. It's worth every penny!

- Poor customer support.

My experience is different. There is a time zone difference and a language barrier, but when I had an issue with an early model DDM60, I traded up and ASA brought my DDM85 NEAF, used it as a demo and gave me a great discount!

- Shipping the DDM85 to ASA for repairs is very expensive.

You got me here!


If you have never owned one, how can you comment on service and support, machining, etc, etc?

#5 herrointment

herrointment

    Aurora

  • *****
  • Posts: 4942
  • Joined: 12 Mar 2011
  • Loc: East of Poskin

Posted 18 September 2012 - 05:46 PM

We all have opinions....

#6 SL63 AMG

SL63 AMG

    Viking 1

  • *****
  • Posts: 864
  • Joined: 21 Dec 2009
  • Loc: Williamson, Arizona

Posted 18 September 2012 - 06:01 PM

We all have opinions....


True, but which opinions have value? Opinions based on actual use and fact or opinions based on heresay and conjecture?

I don't mind anyone giving an opinion even if it is negative, but when that opinion is given as a deliberate attempt to completely discredit a product when it is obvious the person giving the opinion has no direct experience with that product, that opinion has little value.

I wanted to be sure to make that clear my rebuttle above.

If you look at the images it's quite obvious the product does exactly what it is designed to do and does so even while in the hands of an inexperienced operator...like me.

#7 psandelle

psandelle

    Viking 1

  • -----
  • Posts: 697
  • Joined: 18 Jun 2008
  • Loc: Los Angeles

Posted 18 September 2012 - 06:24 PM

Hats off to you for having a great mount. I've been keeping my eye on the ASA mounts (and their scopes) for a while, but always thought that using them mobile might be a bit much. You've shown it not only can be done, but that it's working very well.

Cool and congrats!

Paul

#8 Psyire

Psyire

    Apollo

  • *****
  • Posts: 1339
  • Joined: 24 Jun 2007
  • Loc: 55* North

Posted 19 September 2012 - 12:06 PM

Dave, Thanks for the update/review! I've been watching these mounts for quite awhile as I'm seriously thinking about a 'big' upgrade in the near future. ASA is definately on my list..

#9 orion69

orion69

    Viking 1

  • -----
  • Posts: 998
  • Joined: 09 May 2010
  • Loc: Croatia

Posted 19 September 2012 - 01:34 PM

Dave, I'm very interested in ASA DDM60 mount, price is NOT that high for mount of that quality, payload capacity is enough for me (max 6" refractor) and Austria is not very far.
So probably my next mount, thanks for review!

Knez

#10 petely

petely

    Lift Off

  • -----
  • Posts: 15
  • Joined: 06 Jan 2011
  • Loc: England

Posted 19 September 2012 - 03:53 PM

- Price is way too high

I suppose all things are relative. Where I am the DDM85 compares favourably with the paramount ME in terms of payload and price.

#11 Nezar H

Nezar H

    Sputnik

  • -----
  • Posts: 44
  • Joined: 11 Aug 2011

Posted 08 October 2012 - 02:11 PM

It was a big leap for me, not so much due to the cost, but mostly due to the learning curve. Not only was there a huge learning curve for the mount, but I started from scratch knowing little to nothing about astronomy, astrophotography, mounts, collimation, cameras, filter wheels and most of all, image processing.

I kid you not; there were no gradients in my knowledge, just pure green

So I find myself, a year and a half later, becoming quite knowledgeable on this mount...and it keeps getting better.


I expect that your IQ is very high .. I'm very pleased with your participation and your comments! and really motivated me to rather more effort to get to a better level than I am now.

GoodLuck and I wish for you all the Best.

Nezar.

#12 Mkofski

Mkofski

    Surveyor 1

  • *****
  • Posts: 1548
  • Joined: 19 Jul 2011
  • Loc: Greenfield, Indiana, USA

Posted 08 October 2012 - 02:30 PM

No way to argue with the results! Your pictures are stunning! If I am ever in the position to spend $20K on a mount, I'd certainly consider one of the ASA offerings. That reminds me I need to start buying lottery tickets.

#13 korborh

korborh

    Viking 1

  • *****
  • Posts: 895
  • Joined: 29 Jan 2011
  • Loc: Arizona

Posted 09 October 2012 - 01:10 AM

SL63, congrats on the mount and those great images!

How long have you been able to image unguided and how well is flexure modeled ? Do you find it worth the time and effort of modeling rather than autoguiding? Do you see any flexure in 30min images?

#14 SL63 AMG

SL63 AMG

    Viking 1

  • *****
  • Posts: 864
  • Joined: 21 Dec 2009
  • Loc: Williamson, Arizona

Posted 09 October 2012 - 11:52 AM

At this time, the longest unguided subs I have taken with the mount are 1200s (20m) using the MLPT tracking with Sequence 9.

I am confident I can do 30 minute unguided subs and I may very well try it next week during the new moon cycle. I just need to find an object like my LBN438 image where I need deep exposures.

I am using a complete ASA system and I don't have much flexure. All of the components are either screwed together or attached using 6 screws. Everything is very well machined and fits tightly.

Sequence 9 and Autoslew will measure the flexure and collimation error of the system. I have never seen these numbers very high. The neat part is unlike hysteresis; flexure and collimation error can both be measured and thus corrected by software. That's exactly what the ASA software does!

With regards to the time spent modeling the system versus guiding, I definitely find it worth the time. In fact, this wouldn't even be a question if I were in a permanent observatory because I would do it once and forget it. Unfortunately, I have to setup every new moon cycle but I leave the system setup for up to 10 days at a time.

It takes me just a few hours the first night to setup, dial in my polar alignment, model the system with a large pointing file and then I only have to run an MLPT model for each object I image. The MLPT model takes less than 15 minutes for about 30-40 images.

So the answer to your question is, yes I think it is worth the time. I never have to worry about finding a guide star, thin clouds blocking my guide star of any of the guiding issues. They simply do not exist for me. There is, however, a bit of a steep learning curve to figure all this stuff out, but with more people using the ASA mounts, there are a lot more helpers out there to get the next guy started.

Personally, I think someone spending two nights with me could learn this system quite well. There are a lot of steps each with many details that must be remembered, but none of it is so complicated that the average guy cannot understand it, figure it out and repeat it.

Here is an image of LBN438 that was made with 20 minute unguided LRGB subs binned 1x1

LBN438 High Resolution

#15 johne

johne

    Messenger

  • *****
  • Posts: 471
  • Joined: 10 Nov 2006
  • Loc: Prescott, AZ.

Posted 10 October 2012 - 09:14 AM

Just sticking my nose in here for a second...

I happened to have the pleasure of spending some time with Dave and his ASA system last night. I have a Paramount ME (which I am very satisfied with), but Dave's ASA is simply amazing and accurate. The mount is incredibly fast and whisper quiet when performing slews, expecially when compared to the ME. LOL, the focuser was louder than the mount. I'd say you need to be alert and keep your wits about you when slewing, lest you get "whacked in the head", if you're not paying attention.

#16 jmiele

jmiele

    Patron Saint?

  • *****
  • Posts: 4331
  • Joined: 04 Dec 2010

Posted 10 October 2012 - 09:25 AM

This is great to hear. These mounts have shown great potential in the hardware for some time. Now that the software is sorted, it seems they are performing wonderfully. Dave's results are stunning. BTW Dave, the processing is also super! Getting solid data is just the first part. His images are great.

Best, Joe

#17 morten

morten

    Vostok 1

  • -----
  • Posts: 157
  • Joined: 22 Jul 2008
  • Loc: Denmark

Posted 17 October 2012 - 05:01 PM

Kudos Dave. What excellent photos. I considered the ddm60 in 2010, but felt that it was immature and went conservative with a ap900. Your description of your journey is a fantastic read.
It seems that you set up on a tripod on each session. How long does it take you to get the mount aligned and running?

#18 BPO

BPO

    Ranger 4

  • -----
  • Posts: 371
  • Joined: 23 Feb 2010
  • Loc: South Island, NZ

Posted 19 October 2012 - 03:08 AM

Nice write up and images.

#19 jjongmans

jjongmans

    Vostok 1

  • -----
  • Posts: 183
  • Joined: 11 Feb 2012
  • Loc: The Netherlands

Posted 23 October 2012 - 03:13 AM

I ordered an ASA DDM60 PRO 7 weeks ago to update my EQ6. I did a lot of research and also looked at other mounts like 10Micron, Mesu, Paramount and Astro-Physics. The improving results of the ASA pioneers (like SL63 AMG) helped me decide to choose the ASA. I'll receive it in the next 2 weeks, when the custom pier is ready.
I'm going to use it with an GSO 10" RC, with a FL of 2000mm@f/8. I hope to get 30 min. unguided subs with this setup.

#20 morten

morten

    Vostok 1

  • -----
  • Posts: 157
  • Joined: 22 Jul 2008
  • Loc: Denmark

Posted 23 October 2012 - 01:03 PM

congratulations!! I can't wait to hear about your experiences.

#21 SL63 AMG

SL63 AMG

    Viking 1

  • *****
  • Posts: 864
  • Joined: 21 Dec 2009
  • Loc: Williamson, Arizona

Posted 26 October 2012 - 05:18 AM

Thanks for all the kind comments. I am really enjoying the ASA DDM85 mount. I think ASA has made a huge improvement to the DDM60 with the addition of fixed encoders on the axis. I had my DDM60Pro prior to this improvement and wasn't really happy with it, but I am sure the DDM60Pro is a fine mount with fixed encoders.

Knowing my experience with the DDM series mounts, I would not start out with a FL length greater than 1000mm. JJ, I think you may set yourself up for some frustration expecting to achieve 30 minute unguided subs at 2000mm FL right away. It's possible, but you'll need to really know the system well first.

I highly reccommend that you start with a simple telescope under 1000mm FL and first work on obtaining a very good polar alignment and achieving 5 minute unguided subs. As you get to know the software, particularly Sequence 9, plate solving and it's interaction with Autoslew, you can then venture into 10m subs and longer, Sometimes I still struggle with 20m unguided subs at 950mm FL f/3.6, yet I have on several occasions been able to shoot 20m unguided subs as 2432mm FL F/8 using my AT12RC.

At the longer focal lengths every error in your system is amplified greatly.

There are many things that come into play that can ruin an unguided sub, particulaly at higher FL. For example, I believe I have some flexure issues with my AT12RC which currently utilizes a FeatherTouch focuser. While I like the FeatherTouch focusers and MicroTouch controller system, I do not like the way it attaches to the AT12RC telescope and I believe it is likely the cause of both flexure and tilt in my current system.

I am replacing the FeatherTouch with an FLI Atlas focuser and a precision adapter for both my FLI ML8300, a future PL16803 and a TAK collimator.

It is critical to obtain precise collimation and it really isn't possible with my current focuser and even if I did obtian critical collimation there is no way to ensure the collimator and the camera chipset will both be aligned with the same optical axis.

Once I replace the focuser with the precision couplers for both the camera and the collimater, I am pretty sure this issue will be resolved and I'll be able to shoot 20-30m subs at 2432 with repeatable results.

So basically, I am telling you the mount is perfectly capable of the results you seek, but that doesn't necesssarily mean you will get those results everytime you setup your mount, but if you keep the FL shorter while you are learning how to deal with all of the issues you are sure to encounter, you'll keep your sanity.

Morten, it takes me about two hours to setup all my gear prior to sunset, then another two hours to get everything polar aligned to within 6-12 arc seconds. If I were only shooting subs at 5m, I could have everything polar aligned and a pointing model built in about 30 minutes, but since I leave my system setup for an entire new moon session, I tend to count the first night as a setup and test night and I am willing to spend most of the night tweaking the entire system for perfection.

If I had a permanent setup, I would dedicated several days to this process to get it perfect and then be done with it.

Of course you have to take into a account that I have done this process over and over again for almost two years now, so I am very good at setting up the system in a portable environment.

It takes time to learn the system, then more time to practice the process of setting it up and aligning everything in a repeatable without making a lot of mistakes.

Personally, I like the challenge. This whole astrophotography hobby is a very technically challenging endeavor and that is what keeps me interested.

JJ, congrats on your new mount. I just wrote some procedures for getting started with tuning the motors and balancing. You can find the information on the Yahoo group. Read it carefully and it will save you some time when you first setup your DDM60Pro. Getting the servo motors properly tuned and balancing the system using the provided tools is also critical to achieving long unguided exposres.

JJ, I notice you have a QSI683wsg camera. Since this camera has a pick off prism mounted in front of the filters, I highly recommend that you purchase a Lodestar camera to use for autoguiding at long FL. While the mount is perfectly capable of unguided exposres, having an OAG and autoguiding at FL's greater than 1500mm will ensure perfect results, especially for subs >=20m, such as may be necessary for Ha, SII, NII and OIII narrowband imaging.

I intend to purchase an OAG for use with my AT12RC for 30-40m subs. Although I have not yet tried autoguiding with the DDM series mounts, I have read about it and it seems to be straight forward and relatively simple to do.

Enjoy your new mount and let me know if you have any issues with which you need help.

#22 jjongmans

jjongmans

    Vostok 1

  • -----
  • Posts: 183
  • Joined: 11 Feb 2012
  • Loc: The Netherlands

Posted 26 October 2012 - 05:52 AM

Hi Dave, I'm not completely new to astrophotography and I also know a few things about PID controllers, but it will be hard to get good results in the beginning. I already have the Lodestar, so I can switch to guided imaging if the unguided results are no good. I managed to get good results on a EQ6 with 2000mm FL. I upgraded my focuser with a Moonlite high resolution stepper focuser, so I can use FocusMax to autofocus in an automated setup with CCDAutoPilot.
I already read your procedures on the Yahoo group :)

#23 SL63 AMG

SL63 AMG

    Viking 1

  • *****
  • Posts: 864
  • Joined: 21 Dec 2009
  • Loc: Williamson, Arizona

Posted 26 October 2012 - 01:02 PM

I understand. I apologize if I implied in any way that you were new to astrophotography. I only meant to imply that with the mount coming with a bit of a steep learning curve it may be less frustrating to get started using a shorter focal length telescope in the beginning.

I visited your web site. Not only are your images remarkable, but also quite informative about each of the objects displayed.

I hope you enjoy the new mount.

#24 jjongmans

jjongmans

    Vostok 1

  • -----
  • Posts: 183
  • Joined: 11 Feb 2012
  • Loc: The Netherlands

Posted 26 October 2012 - 02:10 PM

Hi Dave, you don't have to apologize! I am new to it, I started 2 years ago. I really enjoy reading your stories about this DDM, I think I can learn a lot from your experiences! Keep up the good work :)

#25 orion69

orion69

    Viking 1

  • -----
  • Posts: 998
  • Joined: 09 May 2010
  • Loc: Croatia

Posted 26 October 2012 - 04:55 PM

Are there any differences or advatages between guided and unguided tracking (and vice versa) if mount is correctly polar aligned?
Why would I shoot unguided if I can guide (disregarding you don't have to worry about guiding star or seeing)?






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics