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Absolute encoder upgrade


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#1 nakbrooks

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Posted 03 September 2017 - 09:21 PM

I am considering upgrading my DDM85XL to use absolute encoders. ASA have given me a quote which is expensive, although a lot cheaper than buying a new mount.

I am considering this because I intend to move to a hosted facility and need trouble-free remote operation.

Can anyone advise me whether the benefits of absolute encoders are worthwhile for remote operation, given the upgrade cost of several thousand euros.

Thanks

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

#2 GeorgeCarey

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Posted 04 September 2017 - 10:44 AM

No experience myself (I have a DDM60), but I have heard of someone who tried a DDM85 remotely in Nerpio, Spain.

It did not have absolute encoders and the result was that they sold the DDM85 and bought a Paramount.

Remote operation was too difficult without abs. encoders.


ASA DDM60Pro, homemade 8" and 10" reflectors, QSI 683 camera, Astrodon 5nm filters, Pulsar dome observatory. Website: http://www.geoastro.co.uk


#3 lukepower

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Posted 04 September 2017 - 04:49 PM

I am using two ASA's with the old encoders remotely at Nerpio, without serious issues.

The only thing you will need is some sort of remote IP camera to check the mount position before doing a homefind. I also added two marks (with duct tape) to know where the encoder reference marks are located, so that I can move the mount in the right position easily.

 

If you have the bucks, do the upgrade. Othwise buy a decent IP camera.


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


#4 nakbrooks

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Posted 04 September 2017 - 05:01 PM

Thanks Luke. I'll have 2 IP cameras so think I'll stick with the old encoders for now.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#5 ChristerS

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Posted 05 September 2017 - 12:06 AM

Hi Nigel, I second Lucas stick with the encoders and use the cams, also use a park position after each session to be in the right position for the next run.

The DDM85 should have gyros built in to try to find the zenit-east position before atemting a homefind, this worked excelent at first but after a while, perhaps some software change, they was not reliable so I now use the cames when homefind after parked close to zenit-east. 


Cheers,
//Christer

www.astropix.se


#6 nakbrooks

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Posted 05 September 2017 - 07:46 AM

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

#7 Jay

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Posted 05 September 2017 - 05:57 PM

Hi Nigel,

 

I've been using my DDM60 remotely for 3 years with the IP cam, and so far no problems. I'm doing the homefind from Park 1 every time before the session.

 

Jay

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#8 nakbrooks

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Posted 05 September 2017 - 06:03 PM

Thanks. I've also been using my DDM85XL remotely (albeit from the comfort of the adjacent house, not a thousand miles away). I've had a couple of occasions where the mount has lost track of its position and got into a very strange position but have managed to get it back using the cameras. Think I'll continue to rely on that, although I may need to rethink if I automate an entire night session using ACP without any visual supervision.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#9 Jay

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Posted 05 September 2017 - 06:26 PM

Nigel,

 

My observatory is fully automated with Firefly, Seletek, AAG... and bunch of astrosoftware (MaxPilote, MaximDL, Pinpoint, etc)

It can be used from anywhere with internet connection.

 

Jay



#10 ChristerS

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Posted 06 September 2017 - 08:27 PM

Nigel, one other thing after it started to not find home using the gyro was that it often even after I placed it at zenit-east I noticed the pier side was west not east witch made the homefind fail, so now I always check and set correct pier side, since then I have not hade any problems.


Cheers,
//Christer

www.astropix.se


#11 Josch

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Posted 06 September 2017 - 10:17 PM

Hi Nigel,

I am running a DDM85 from a remote site in Chile since 2011. If you park the mount and do not power down but only switch off the motors, then there is no need to do a homefind every night before the start of the session.

Only if you loose power a homefind using an IP Cam is necessary. No need for aboslute encoders.

I run literally every night and am sleeping when the whole system starts and gte data.

Of ocurse nothging is fool proof and sometimes the annoying thing is that MAXIM looses connection to the CCD randomly (like last night) and I loose half of the night as I check when getting up in the morning.

 

Josch



#12 nakbrooks

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Posted 07 September 2017 - 08:50 AM

Thanks Josch, that's reassuring.

Incidentally I've had problems with Maxim losing the camera connection almost every session for years. I have to reconnect the camera. I've not been able to diagnose the problem but I suspect USB issues.

In the new observatory I will have new cables and a new PC and will not need to use an extra USB hub so I'm hoping that will solve my problem.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#13 GeorgeCarey

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Posted 07 September 2017 - 09:07 AM

Do those of you with IP cameras switch them off while imaging?

I used a camera some years ago and found that the infra red light messed up the images.


ASA DDM60Pro, homemade 8" and 10" reflectors, QSI 683 camera, Astrodon 5nm filters, Pulsar dome observatory. Website: http://www.geoastro.co.uk


#14 john32712

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Posted 07 September 2017 - 09:00 PM

Hi George,

 

I upgraded my mount, DDM85XL, to the new absolute encoders. Best thing I ever did! You won't regret it....

 

John Nemcik



#15 nakbrooks

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Posted 08 September 2017 - 02:35 PM

John, what did you find were the major benefits. It's several thousand euros so a difficult decision. Also how long did it take ASA to do the upgrade?

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

#16 lukepower

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Posted 09 September 2017 - 12:19 PM

I usually power down the IP camera, as the infrared light (which fortunately I can turn off) definitively causes some odd artifacts on the images.


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


#17 Jay

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Posted 09 September 2017 - 05:30 PM

George,

 

Yes, I'll power down the IP camera during the session. Infrared light will mess up the images quite easily...



#18 john32712

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Posted 20 September 2017 - 01:50 AM

Nigel,

 

Apologies for the slow response! I live on Marco Island Florida where the recent hurricane has devastated the area.

 

Anyway, regarding the benefits....

1. In my opinion, for the level of sophistication of the drive system, it made no sense to me to have a mount that could lose its position if power was lost or various other reasons. Let's face it, even the lowest level of consumer mounts has a home find routine that "counts" from the initialized position. I'm sure this comment will not sit well with some. But I love that the position of the mount is known always and extremely accurately

2. It might be my imagination, but the mount appears to track better and slews seem more accurate

3. If I remember correctly, it took about 5 weeks to get my mount back

 

What you probably want to know the most, is it worth it? I would say a resounding yes! Startups are a breeze and home finds are a distant memory

 

John



#19 nakbrooks

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Posted 20 September 2017 - 04:15 PM

Thanks for yours reply John, particularly given your other priorities at this time.

I'm still undecided. It's very tempting to get the upgrade now while everything is disassembled as I move it to e-eye in Spain. However the cost is significant so I may wait and see how it goes.

I never had major problems in the past - just a couple of excursions following power outages mid-session, but I was able to resolve those ok using cctv.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#20 john32712

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Posted Yesterday, 01:37 AM

Hi Nigel,

 

No worries! Yes the upgrade is not cheap and I'm sure you'll be able to function well without it. 

 

Now that I have taken the plunge and have experience the difference, I'll never own another mount without absolute encoders. 

 

Warmest regards






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