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Need equatorial mount for 8-inch f/4 newt

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#1 starhacker

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Posted 14 August 2013 - 02:05 PM

While I'm building my 12.5 inch scope I've decided it's time to finally get a decent mount for my older 8-inch. Right now I have a clever but embarrassingly cheap looking collection of large gas pipes and elbows screwed together, with a couple bearings installed. It even has clock-drive. I don't need to do AP with this scope but I would like the right trade-off between sturdiness and portability. Fully decked-out with Nagler and finder scope the OTA weighs in at 23 pounds and is 38 inches long. I'm looking at the Orion Atlas EQ mount, but I'm wondering if that's a little overkill. There seem quite a few options out there. Whatever money I spend of this is less money I have for the 12.5-inch. Any advice is welcome.

#2 Stew57

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Posted 14 August 2013 - 02:19 PM

The Atlas is a good choice especially if you think you may try AP or live video in the future. I would think the VX would be enough for just visual however.

#3 starhacker

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Posted 15 August 2013 - 09:22 AM

Thanks for the advice. I just placed an order for the Atlas at telescope.com.

#4 starhacker

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Posted 21 August 2013 - 09:54 AM

The brand new Atlas mount arrived yesterday and does not work. The hand-controller says it can't talk to the head. I see from the forums I'm not the first person to encounter this problem. Tech support is sending me a new hand unit and cable. We'll hope that's where the problem is as I don't want to have to ship back the whole head assembly (although maybe I can get them to just send a replacement "motherboard" in that case as it doesn't look that hard to swap out).

#5 Jesus Munoz

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Posted 21 August 2013 - 10:02 PM

I think the cable is the problem. I bought a Skyview pro upgrade kit for my Vixen GP mount and had the same problem but just got a second cable and the mount worked fine.

Good luck!

#6 starhacker

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Posted 22 August 2013 - 11:48 AM

We'll hope it is the cable, it does look kind of low-end. It's probably not the hand controller as I just now followed the instructions in the manual for creating loopback cables and running the self-test. It passed, so it is able to transmit and receive to itself. BTW, this is easy to do if anyone finds the need for doing it themselves. You just need a sacrificial modular phone cord (4 or 6 wire), a sacrificial ethernet cable, wire cutters, and a google of RJ-12 or RJ-45 to indentify pin 1 on the plugs. Then follow the instrucitons in the SynScan manual.

#7 starhacker

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Posted 22 August 2013 - 12:30 PM

I just found the wiring diagram for the interface cable in the mount manual (the Atlas cable has RJ-45 on one end and DB9 on the other). The diagram is wrong since it says the cable is RJ-12 to DB9, but it still identifies the necessary signals on the DB9 connector. TD and RD are in their customary locations. Using that information I was able to include the original cable in the loopback test and it does indeed look like that is where the problem lays. So I have high hopes the replacement cable they shipped out with the controller today will fix the problem.

#8 Jesus Munoz

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Posted 22 August 2013 - 07:19 PM

Dave, where did you get the wiring diagram? It's good to know your equipment.

Thanks

#9 starhacker

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Posted 22 August 2013 - 09:28 PM

The diagram for the RJ-45 (and RJ-12) jack(s) in the hand controller are in the "SynScan GoTo Hand Controller" manual, which I think you can find online as a PDF either at the Orion website or through googling.

The diagram for the Atlas DB9 (and RJ-11) connector(s) are in the "Orion Atlas EQ-G Equatorial Mount" manual, which I think is also online. It shows the DB9 going to a DB9/RJ-12 cable in that diagram which is wrong for the Atlas/SynScan combo, but you can still identify the DB9 signals.

There is no (correct) diagram for the actual cable itself, but I mapped mine out with a continuity tester. It's clearly wrong since nothing is connected to one of the data lines. I will repeat that procedure with the replacement, in case I need to eventually replace it too (with a homemade one). Maybe when I next talk to tech support they can point me to the missing wiring diagram for the cable.

Both manuals come with the Atlas EQ-G.

#10 starhacker

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Posted 26 August 2013 - 01:12 PM

In case anyone cares, the cable was indeed the problem. The mount is now working with a replacement cable. Oddly, the new cable tested out as being the same as the old cable, so I am at a loss in explaining exactly what was wrong. It also confuses me when I see how at least one (presumably important) signal does not go through the cable. Possibly the documentation on the DB9 connector is wrong.

Orion customer service was very responsive in getting this problem fixed.

#11 DanlB

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Posted 30 August 2013 - 08:36 PM

A couple of things commonly cause problems with RJ45 connectors. The first is the conductors don't always get crimped well causing intermittent opens. The second is the slots that hold the little copper springy fingers are too narrow or have a small piece of flashing preventing the finger from making contact with the mating connector. Really hard to see, especially if it is a dimensional defect. Usually replacing the connector solves the problem unless you get a batch of bad connectors or have a cheap, worn out crimping tool (I have a boxful of them and can never decide which is least worn out ;-)
Soldered db9s almost never fail unless you are a sloppy solderer. Crimp ones suffer the same malady as the rj45s except one doesn't have to worry so much about springy fingers.
Glad you got things working.

#12 Startraffic

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Posted 02 September 2013 - 04:11 PM

DanlB,
Toss your old worn out connector tools & invest in an AMP. I've have mine set (RJ-11, 45, & DB pin) for 20+ years & have made literally 1000's of crimps. Perfect every time. It ain't cheap (+$65) but it just works. I've have to replace the dies for the RJ45 once.

Clear Dark Skies
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#13 starhacker

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Posted 06 September 2013 - 11:49 AM

Thanks for all the info. BTW, just bought a 12AH/12V SLA (gel cell) battery and charger. Hopefully that has the capacity to get me through a long evening of observing with the Atlas mount. I haven't tried to measure the average draw of the scope, I only know they specify a 2A minimum supply.

#14 Jesus Munoz

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Posted 06 September 2013 - 12:04 PM

Good news to read you've solve your problems. Same as my problem: cable.






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