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Some general questions regarding ASA DDM 60/Pro


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What is the periodic error of the mount DDM 60?
Because we use no gears due the direct drive we use, there is no periodic error to indicate and also no backlash. Encoders are mounted direct on the axis to read out 100 times per second and compare target and actual position. Failures are corrected via software in real time. This guaranteed a tracking which is unbelievable accurate.


Although the tracking is very accurate, can I connect an autoguider?
Naturally one can connect an autoguider via Software to control the mount.


What happens at power failure?
As you power on again after power failure the mount is searching for the so called Homing Position and is up to know updated for further imaging. That means that you can immediately continue your imaging session. This is a very important factor practice remote imaging.


How can I do polar alignments with the DDM60?
The DDM60 has a build in laser parallel to the RA-axis. If you turn your RA-axis, the laser will describe a circle on the sky. If you try to place the polar star on that place where Polaris should be actually in relation to the pole you have finalized a raw polar alignment. The fine adjustments are then taken with the assistance of the delivered Software.


Can I apply software like "The Sky", "CCD-Autopilot", "Maxim DL" etc.?
Naturally Autoslew communicates with all those software.


What is the current peak on the DDM60?
With maximum load slewing in both axes at maximum speed the current peak is 20 Amps (depending on the weight load). At Standard Operation 0,4 - 0,8 Amps.


Is it possible to set limits, so that the mount does not move into blocked zones?
Naturally you can set limits to avoid that the mount runs e.g. below the horizon or against a barrier inside the observatory.


Why is this mount tracking accuracy much better as other commercial mounts?

The secret is that ASA uses Renishaw Encoders, which are verified electronically and resolve to an unbelievable 0,01-0,02 seconds of arc. Positioning information is communicated by the mellow software developed by Philipp Keller. The tracking accuracy is accomplished by comparing the actual position of the system, 100 times per second in real time. This permits any required corrections to be applied immediately. Dependent on the diameter of the encoder a tracking accuracy of 0,2 - 0,4 seconds of arc is provided without guiding. The Torque motors (direct drives without gears and no backlash) we are using could operate in a range of one-hundredth of arc seconds.


Where is the difference between DDM 60 and DDM 60 PRO?
The difference is that the PRO-version guides the cable through hollow axle.


Is it possible to have a precise tracking, also when I can’t see the polar star for a polar alignment?
Yes, you will find a detailed description of the whole process in our manual. The rough direction to north will be found with a compass and the pole high with the latitude scale on the mount. The final fine adjustment will be done by our Software Autoslew.


What is the difference between a standard mount and ASA direct drive mounts?
Direct drive means that power and movement are done without conversion gear. This makes it possible to make a mount without coupler, shafts and other converter. The abdication of these parts has a lot of advantages for dynamic and precise applications in comparison to conventional gears. The result is a very precise tracking on long exposures.

The use of direct drive engines means a better precision, dynamic, flexibility, safety and compactness. Finally, they are extremely silent.


What are the advantages by using direct drive engines?
Positioning accuracy down to the nanometer range, high acceleration and top speeds; programmatic functionality and conversion; wear-free; uniform precision throughout the life cycle; overload protection of the motor and the machine, reducing the number of system components, very small designs; extremely quiet.


Has the DDM 60 a periodic error?
No. There are no worm gears. We are using torque motors; hence there is no periodic error!   


How precise is the tracking of the mount?

ASA mounts are so accurate that you can use them without autoguiding.
Here are the figures:

Pointing: RMS with Pointingfile
Tracking accuracy: Encoder Resolution: 0.03 "on the axis
Positioning speed: 15 ° / sec (25 ° / sec optional)


How long can the DDM 60 track without the use of an autoguider?

The precision of the DDM60 allows - depending on the focal length and accuracy of polar alignment a single exposure time of 10-15 minutes. In some cases, tracking times up to 30 minutes have been reported to us.


Is it possible to operate the DDM 60 with an autoguider?
The DDM60 does not have a separate autoguider port. Due to the tracking precision, single shots, depending on the focal length, with 10-15 minutes are no problem. In some cases it may be desirable to apply an autoguider method. In the following, we briefly describe how Autoslew in conjunction with MaximDL (or similar ASCOM compatible software) auto-guiding can be accomplished:

  1. Ensure that the following programs are already installed on your PC or Notebook: Autoslew, Maxim DL and correct driver for your guiding camera. Be sure that they are correctly installed and are working in a proper way.
  2. Ensure that Autoslew is running on the same PC/Notebook as your planetary program e.g. “The Sky X”
  3. Start Autoslew and make the polar alignment (if not already done)
  4. Start your planetary software and synchronize it with Autoslew.
  5. Select your webcam or guiding camera in Maxim DL and confirm it as your guiding camera
  6. In Maxim DL select “Telescope” as your autoguiding protocol.
  7. In Maxim DL connect to the telescope via the Observatory control window
  8. Make sure that in Autoslew “high accuracy tracking” is enabled.


How much power does the mount need?
The operating voltage is 12V/10 Amp. At normal tracking speed, the mount needs between 0,4 – 0,8 Amp. However, due to environmental influences it can occur that the mount will have a current peak from 8 – 10 ampere e.g. on wind gust or when it’s slewing.

With a car battery, you’ll be able to use your mount a whole night without any problems.


What power supply is recommended for the DDM 60?
The DDM60 requires a power supply of at least 12V and 10 amps. Laboratory power supplies are not recommended because it may cause a malfunction.

We have adequately tested the VOLTCRAFT FSP-11312 (13.8 V, 10 Amps) power supply.


Is there a manual for the DDM 60?

In the “download” section of the ASA website, you will find different manuals like these:

DDM 60 Product manual: Instructions for DDM 60
DDM 60 Pointing model manual: Instructions how to make Pointing models or files in Autoslew.
Sequence04 Manual: Introduction and guide for autopointing with Sequence.


What is the instrument weight capacity?
The DDM60 can handle 25 kg excluding counterweights. A higher weight of up to 27 kg or more can lead to disruptions in tracking e.g. on wind gusts.


Can I buy an original ASA tripod?
No, ASA currently not offer this.

Which tripod is recommended for ASA DDM 60?
We recommend the “G11 tripod” of the company Losmandy:
www.losmandy.com/access.html ASA provides an adapter to connect your mount with this tripod. We also recommend the tripod “Stativ Planet” of the company Berlebach www.berlebach.de They offer matching holes for our DDM 60 and DDM 85.

Both tripods are tested by ASA.


For which tripods/pillars does ASA offer adapters?
ASA provides an adapter for the Losmandy G11 tripod (and compatible products).
For using an EQ6 tripod, it’s necessary to drill three to six holes into the tripod plate.

Berlebach tripods offered with holes for the DDM 60/85. Thus, no adapters are required.


What is included in the scope of supply with the DDM 60?
The scope of supply includes the following items:
- Control
software Autoslew and Sequence of Dipl. Philipp Keller (designed for professional observatories)
- Two counterweights each with 2.6 kg
- Telescope mounting plate
- Base plate
- Cable


Is there for telescope with no ring systems (e.g. Schmidt cassegrain telescopes) with Losmandy/GP plate an adapter available?
Yes, you can order our optional Losmandy / GP adapter. The adapter is screwed directly off the top plate of the mount.
Price: 150 € (incl. VAT).

What cables/interfaces are led through the DDM 60 Pro?

Mounts delivered before May 2010:

A) Power supply cable with the following wiring
(The cables are provided with numbers that match the numbers listed below)

No 1: +12V1 + max.5A (fans, lasers, OK3, etc.) - Plus
No 2: - 12V1 (fans, lasers, OK3, etc.) - Minus

No. 3: + 0 to 48V2 max.5A (freely selectable, galvanically isolated) - Plus
No. 4: - 0 to 48V2 (freely selectable, galvanically isolated) - Minus

No. 5: + 12 max.10A (Mount control) - Plus
No. 6: - 12V (Mount control) - Minus 

8-pin shielded cable for data transmission, selectable (eg RS-232 - Serial)

C), USB cable (to connect the USB hub on the DEC axis of the mount, for example, a USB camera, a filter wheel or a focuser, etc.)

Mounts delivered after May 2010:

A) Power supply cable with banana plugs (red, black, with sub wiring as follows):
+ Gray: 0 to 48 V2 max. 5A (Voltage freely selectable as needed, galvanically isolated) – Plus
Yellow / Green - :0 to 48V2 (Voltage freely selectable as needed, galvanically isolated) - Minus

Brown +: + 12V max.10A (Mount controls) - Plus
Black -: - 12V max.10A (Mount controls) - Minus

K) USB Cable
(for the connection between the laptop / PC and your mount in the PRO version, this cable is used for the connection between the laptop / PC and the USB hub in the DEC axis of your mount.


 What is the slewing range in RA and DE – axis? Are there mechanical limits (internal stops)?

The slewing range is 355 degrees, secured with a mechanical stop.


Are the axes locked in case of a power blackout?
No, there are no breaks installed in the DDM 60. In a good balanced system there is no post-pulse oscillation till a speed up to 13 degrees per second. In a good balanced system, you will not have a problem also when strong wind gusts are blowing over the telescope.


What should I watch for an optimum performance of the laser?
The DDM60 laser for polar alignment is provided with an electric blanket to ensure an optimum operating temperature for the laser. At temperatures below 10 degrees, it can take up to 5 minutes after the start of the mount until the optimum temperature is reached and the laser will reach its full power.


Is it possible to see the mount „live“?
Yes, you can sign up for an on-site visit in the sales office and experience the ASA mount "live".

You can also check on our website about ASA fairs, conferences and workshops in the "Events" section.

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