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Any DDM160 users out there?


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#1 Chocolate Elephant

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Posted 25 August 2013 - 08:10 AM

Hi.

 

Has anyone used an ASA DDM160 mount? If so, what are your impressions and opinions of it?

 

Thanks.



#2 DDM160_user

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Posted 30 August 2013 - 09:08 PM

I am a soon-to-be DDM160 user. It is still in its crate. By the end of November it should be on the pier.


Robert W. Williams
website: http://www.dinium.net/english

#3 nakbrooks

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Posted 31 August 2013 - 08:45 AM

What are you mounting on it?
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#4 DDM160_user

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Posted 31 August 2013 - 01:58 PM

I'm putting this on it (attached image). 62 cm f/3.4 - f/10.4. ASA made the tube and prime focus corrector for my optics.

Attached File  62cmCass.jpg   25.76KB   5 downloads


Robert W. Williams
website: http://www.dinium.net/english

#5 Chocolate Elephant

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Posted 01 September 2013 - 06:13 AM

I'm eager to hear about your experiences with this equipment. Please keep us posted.



#6 DDM160_user

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Posted 02 September 2013 - 07:50 PM

Thanks. I will keep you posted. I update my website with the construction progress once a week or so: 

http://www.dinium.net/english/

 

I am usually behind schedule because of the day job and the weather. If I am extremely lucky with both, I may have the dome and mount in place by the end of November, in time for the arrival of comet ISON to the northern hemisphere.


Robert W. Williams
website: http://www.dinium.net/english

#7 nakbrooks

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Posted 02 September 2013 - 07:55 PM

I see you are using a ScopeDome. I have just installed a 4 metre ScopeDome. Went reasonably well but there are some lessons to be learned so if you haven't started installing it yet I may be able to give you a few tips.

I'm not using a DDM160 but I am using the DDMXL premium which has a smaller version of the same (equatorial) pier and is configured the same way as the DDM160 in Autoslew, so our systems are quite similar.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#8 DDM160_user

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Posted 02 September 2013 - 08:13 PM

I would very much appreciate any tips you can give me. Many thanks! I haven't yet started installing it, but weather providing, I may start during the weekend.


Robert W. Williams
website: http://www.dinium.net/english

#9 nakbrooks

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Posted 03 September 2013 - 12:12 PM

Do you have an email Robert - the ScopeDome tips are a bit off-topic here.


Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#10 DDM160_user

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Posted 03 September 2013 - 03:43 PM

Agreed. To put it back on topic, my first impression of the DDM160 is that it is 220 kg of solid, well thought-out engineering.

 

Instrument to Declination axis distance

The distance from the mounting plate to the declination axis is extremely short, keeping the counterweight mass to a minimum. This short distance is possible because of the absence of a polar axis drive gear, which on an "old-fashioned" gear-driven mount would have a diameter of at least 60 cm in a drive with the capacity of the DDM160.

 

Mounting plate and pier

The mounting plate for the ASA truss tube is massive, as is the pier. The latter was custom-made for a lattitude of 59 degrees. The base plate of the pier is also massive, with ten holes for anchoring bolts. Considering that the center of mass of the entire mount + instrument load + counterweights + pier is almost exactly over the center of the base plate of the pier, there is practically zero torque on the base plate. To be more precise, the intersection of the declination and polar axis is positioned only 9 cm north of the center of the pier's base plate. This is a very stable configuration.

 

Packaging and crating

Very well done. Can tolerate harsh shipping conditions without damage.


Robert W. Williams
website: http://www.dinium.net/english

#11 lukepower

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Posted 03 September 2013 - 04:27 PM

Nigel,

 

I know it's off-topic, but I used to have a ScopeDome 3m version, which I ultimately sold as I had too many issues with it to use it remotely as planned. Is the 4m version better in that regard? To be specific, I had trouble with the cable connecting the fix to the moving part getting messed up at some point during the nights, and also the gear driving the cog-rim sometimes "jumping" from the rim, ultimatively leaving the dome un-motorized. For the remainder, I also go with a DDM85XL and a soon-to-be-installed 50cm-Cassegrain-Newton :)

 

Lukas


Lukas Demetz
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www.skygemsobservatories.com
Astro Dolomites Observatory, Skygems Network
Santa Cristina Valgardena, Italy
20" Cassegrain-Newton on ASA DDM85XL


#12 nakbrooks

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Posted 03 September 2013 - 04:33 PM

Current versions (of the 4M anyway) do not use a cable.  They use electrical contacts on the two rings to transfer power (rollers on the lower ring touching contacts on the upper ring) and wireless to enable the fixed controller to talk to the dome controller.

 

Getting the cog wheel to mesh properly with the teeth on the ring is a matter of careful alignment. The upper ring has to be absolutely level (to within a few mm).  I did have to play around with this after construction (mostly because I didn't spend enough time on getting perfect alignment prior to adding the dome to the ring) but it seems to work OK now.  Time will tell of course - I've yet to use it in anger as I am still testing and configuring.


Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory




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