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Orion SkyView EQ Deluxe for astrophotography

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#26 Mert

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Posted 11 December 2008 - 05:35 PM

Hi Keith,

Sorry I wass off thread but now i'm back again.
Saw you asked on the EQMOD forum as well :-)
The DC motors will not interface with a stepper controller
since they do not step or have discrete movements.
They run faster with more voltage and that's about it.
If you want to use DC-motors like servo-motors, then you
need to attach encoders as well, which apart from costly
also complicates the whole thing.

Hope that answers your question.

#27 kwits

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Posted 11 December 2008 - 07:52 PM

Good Day,

I just purchased from ebay last night a, Meade 492 DS Drive Kit with a 429 hand controller for less than $60.00; it is brand new, still within its package. The seller claims that it is GoTo upgradeable. However, I am not quite sure that that means. I suppose its description inferred the use of a AutoStar 495 or 497. I hope that I will be able to retrofit my GEM to accommodate this stepper motor design but also know, I will need a stepper controller and TTL-RS232 converter cable.

Best Regards,
Keith

#28 MtnGoat

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Posted 11 December 2008 - 09:25 PM

i believe you mean a 492 handset, and I think this is the manual slewing handset. no database, arrow keys and speeds and thats about it.

the connector panel all the motors plug into will accept either the 495 or 497, I recommend just jumping right to the 497 for its full numerical keypad which really speeds things up, as well as it's much larger database.

#29 kwits

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Posted 11 December 2008 - 09:38 PM

But do I really need to go the route of the 497 controller when I can use EQMOD with a wireless USB hub communicating with my remote stepper controller, connecting in my drive motors?

#30 MtnGoat

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Posted 12 December 2008 - 11:56 AM

On that one, you're out of my range. The motors you purchased are not stepper motors, they are geared down DC servo motors with encoders mounted on the shafts. As far as I know, they do not use stepper control functions and are serially controlled via a Meade serial protocol, which may be industry standard for serial commands but I'm pretty sure is not a stepper interface.

#31 kwits

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Posted 12 December 2008 - 01:13 PM

This is a big surprise to me! Are you saying I need a servo controller instead of a stepper controller? Should I return my order in your opinion? Is there a better option available? I heard that the Meade 492 DS drive system was a high-precision setup from my GEM that could be retrofitted for GoTo operation. Is this assumption correct?

#32 MtnGoat

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Posted 12 December 2008 - 01:39 PM

I hope someone else will chime in here, but I believe your statement is correct...you need the servo controller system compatible with meade serial protocol. These are not just motors, inside the case is a DC motor control board and serial interface to actually run the motor. Whatever controller there is sends the commands, and then the motor control board executes them.

If you already intended to use DS motors you already decided you could mechanically interface them, so all we're talking about is one of the Meade handsets for control vs the stepper controllers. Me, I'd go through with the order and just search for a used 497. Cut rate option is a $50 495 new from Telescope Warehouse. You can still change gear ratios in the 495, and that is the only crucial thing you need to make this mount work with those motors and a meade handset.

In my opinion, you are still on the road for the simplest GOTO retrofit.

#33 MtnGoat

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Posted 12 December 2008 - 01:45 PM

Ok, I just did a bit of digging and need to make a small revision. What you want is the 494 handset as the cheap option, and the 497 as the better one. (The 497 is the lastest upgrade of the 495).

Here's the lineup..

494 - Full Goto basic handset, scroll keys for selecting parameters, no keypad, limited database (but you can still add objects.) This one comes with the baseline ETX models I believe. Telescope Warehouse has new ones. The only question with this model is, does the list of mounts include a GEM, since all ETX's are fork mount.

495- Old top of the line handset with large library and full numeric keypad

497 - current top of the line handset with large library and full numeric keypad



#34 kwits

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Posted 12 December 2008 - 08:31 PM

Okay, I have decided to purchase a Meade 497 AutoStar controller for $75.00. Is this a good price and should it be programmed for a GEM? Does the AutoStar suffice as a servo controller or do I need a separate device?

#35 MtnGoat

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Posted 12 December 2008 - 10:01 PM

that is a good price

it has multiple scopes in it and will have a GEM of the LXD55/75 type, which will work fine.

the autostar handset is the complete controller package.

you will plug the motors into a connector panel and the handset as well, thats about it, except for figuring out your gear ratios and mounting up the motors

#36 kwits

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Posted 12 December 2008 - 10:11 PM

Have you heard of AutoStar Suite? If so, do you know where to purchase this product? It would appear that this software package drives the AutoStar 497.

http://www.meade.com...r/as_suite.html

#37 MtnGoat

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Posted 12 December 2008 - 11:26 PM

i believe you just download it for free. And it comes with the DSI imagers.

to drive the 497, you will also need a serial port on your laptop and the correct cable assembly, which I believe is a #502 but don't take that for granted, look it up.

Also, go to Weasner's site and start reading up on autostar. and be sure to dig around at the site I presented, he has more examples of Meade conversions and a page on how to figure out your new gear ratio.

#38 kwits

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Posted 15 December 2008 - 01:35 PM

Is an AutoStar #505 cable the same as a standard, RS232 to USB, TTL converter?

#39 jrcrilly

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Posted 15 December 2008 - 02:01 PM

Is an AutoStar #505 cable the same as a standard, RS232 to USB, TTL converter?


It is merely a cable. It can be used to connect an Autostar #495/497 to a PC or laptop RS-232 compatible serial port.

#40 MtnGoat

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Posted 15 December 2008 - 04:00 PM

Is an AutoStar #505 cable the same as a standard, RS232 to USB, TTL converter?


I don't think it has any USB functionality at all. It is a serial cable with the phone jack style connector on one end and a 7 pin standard serial D-SUB on the other. To USB it, you'll still need a serial-USB converter.

#41 kwits

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Posted 15 December 2008 - 04:47 PM

I plan to use a Wireless USB hub as a communications link between my AutoStar 497 at the telescope end to my PC. I am also looking for a USB amplifier that can extend the range beyond the standard 30 feet limit.

#42 kwits

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Posted 27 December 2008 - 02:04 PM

I hope everyone has had a safe and blessed, Merry Christmas this year and thank you sincerely for all of your feedback on this discussion thread.

Well, I finally have all of my hardware together now since I am finally back home from a 4 month, work assignment. I have a question about configuring the AutoStar 497 for my SkyView EQ Deluxe GEM. There are several options listed for the LXD55/75 but I am unsure of the best for my GEM's configuration using the 492 DS drive system. Here are the options listed for the latest firmware load (43Eg):

127 Ac
152 Ac
6 new
8 new
10 New
8 SC

#43 MtnGoat

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Posted 28 December 2008 - 03:58 PM

The only thing that may differ may be aiming restrictions for the various sizes of OTA's. Since you're running an entirely different GEM, I don't think it matters much. Just pick one and start from there.

One thing I did need to do in addition to gear ratio changes to get the LXD parameters to drive my 4504 mount was to reverse the polarity of one of the gear ratios, I think it was the RA drive.

First order of bidness...figure out how to get those motors mounted and coupled. After that, sorting out the gear ratios and signs shouldn't be too bad.

#44 kwits

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Posted 28 December 2008 - 07:11 PM

Thanks for your feedback. I have my AutoStar 497 connected to my laptop's USB port via a RS232 converter adapter; I installed the latest Meade driver to support this connection. I have Meade's AutoStar Suite v5.0 installed and it works great while my AutoStar is connected via its 505 cable but not when emulating a virtual port like COM10. The ASU finds the virtual port with no problem but the Suite throws an error. Have you observed this issue under your setup?

#45 MtnGoat

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Posted 29 December 2008 - 01:23 PM

I have had serious issues trying to use virtual ports to get Envisage/Drizzle guiding to interface to Autostar Suite for guiding. I have no problem at all connecting to the scope from the suite, but I have not yet been successful in getting Envisage to connect. I've tried numerous COM ports, virtual ports, and internal IP sockets....nothing works.

#46 kwits

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Posted 29 December 2008 - 02:00 PM

I use Windows XP Professional (SP-3) on my laptop and the Meade Serial to USB driver is installed with no flagged conditions as COM10. It does not make any sense for the ASU to auto-detect this port with no problem while the Suite throws an error. I have sent an email to Meade on this issue.

#47 kwits

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Posted 29 December 2008 - 03:04 PM

I just found a fix for using the AutoStar 497 with AutoStar Suite via a USB connection by setting the telescope protocol for Network. Read this website for details!

http://www.weasner.c...008/remote.html

#48 kwits

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Posted 22 January 2009 - 12:09 PM

I hope you are well. Right before I was able to bring my new GEM mod online, I noticed that I had significant damage to my RA gear and minor damage to my DEC gear. Evidently, during my trial run, the worm gear jumped its teeth alignment with its respective round gear. I am not sure what caused this failure. I greased the gear assemblies with lithium grease. Evidently, when I reassembled the worm gear box and mounted my drive assembly, the teeth were not in proper alignment or maybe there was a balancing issue. My GEM is at a machinist shop now for assessment. I am planning on having the round gears turned 180 degrees so the damaged area will most likely not be used. Another option is to repair the gears which I believe will be expensive if I cannot replace them entirely from a vendor.
1. Have you observed this issue under your previous setup?
2. Do you know how many teeth are for the DEC and RA round gears?

#49 MtnGoat

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Posted 23 February 2009 - 12:05 PM

Just refound the thread.

I finally got my mount and am working on the GOTO as of last night. I had to remove the DEC assembly as it was binding...the DEC head would not turn relative to the DEC gear.

The usual chinese finger puzzle of getting these things apart...there is a hex screw next to the DEC clutch knob that you remove, to get access to another set screw on the inner collar. You need to rotate the head while peeking through the hole to find the second screw. Undo this screw, then put the outer one back in and use it to fix the inner collar in place. At this point the dec head unscrews, shaft and all, from the end collar.

Turned out a piece of grit had snuck into the *very* closely machined bearing surfaces between shaft and gear. It gouged up the gear bearing surface a bit in addition to locking it in place. I hit it with some 2000 grit emery paper, then retouched the inner and outer gear bearing surfaces.

Everything came out nice and smooth, they really did a pretty nice job of close tolerances on this, when the shaft is in place there is no sideplay or wiggle that I can see, very nice for non ball bearing bushing style bearings. I am also impressed by the nice large diameter worms.

My other issue is someone was reefing too hard on the worm screw locking bolts and pretty much tore through the thin metal in the mount holes. They're supposed to be slots to allow moving the worm block in and out a bit, mine are huge holes with barely enough left to even have enough for the bolts to tighten on. I'm fabricating a small piece of aluminum to redo the mounting plate.

I counted teeth on the DEC axis and came up with 120 teeth. haven't done the RA yet, I suspect it is 144 teeth but read somewhere it was 142. Not sure I believe that, it's an odd number in a world of standardized gears for this use, I suspect someone counted wrong.

You shouldn't need a machinist to turn the gear around for you, it spins inside the housing relative to everything when the worm block is removed. You can just turn it around to the good side yourself, and this should work just fine since the DEC axis will always remain within 90 degrees of where it starts at German North/home.






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