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Defork a RCX400

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#51 JAT Observatory

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Posted 24 March 2007 - 08:57 AM

Marcus is there any kit you haven't got?


Yeah, I don't have the astro-photography talent kit :(

#52 Robin Lee

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Posted 24 March 2007 - 12:48 PM

I think there would need to be a study done on all these poor forks that will be put out of work. Where will they go? Can they be trained for other duties?
Just imagine, on the street corner there will be groups of forks congregating. They will be rotating back and forth getting all twisted while holding signs that read, "forks have feelings too" or "will work, for a while". :p
My LX200 forks have been sitting in my basement unused for 2 years since I pulled the OTA from it. I think I can still hear it weeping. :bawling:

Is it the GPS version? Is it for sale?

#53 Dave LoPresti

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Posted 24 March 2007 - 08:44 PM

Hi Kim. Yes, it is GPS but it's not for sale. I've kept it around so that I may someday use it as a solar platform. My intention is to put two piers in my observatory later this year with one dedicated to solar. The forks should do fine for webcamming but I need to replace one of the ribbon cables.

I really hope some folks figure out how to make a RCX OTA option with just an after market kit or something as easy. Meade could sell so many more scopes, IMO.

#54 Keith Howlett

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Posted 25 March 2007 - 01:25 AM

I'm pleased these forks are finding happy homes, you would almost feel obliged to buy a huge pair of binoculars just to cheer them up.

Hats off to the many poster who have kept my de-mounting partner and I entertained through the recent wet UK nights. :grin:

I think it is possible, thus...

1) Approach your RCX and flip it playfully onto it's back.

2) Remove covers and unplug stuff that you don't need (mostly motors) when de-mounted. See if RCX still responds to being turned on.

3) Modify Autostar firmware to get around boot problems (amazingly this is all possible - Dick Seymour has been very helpful).

4) Strip out mount boards, arm boards and wiring looms - check the OTA functions still work. Add connectors if required.

5) De-mount.

6) Feel very brave, take tube apart to retrive the DEC bearing cantilevers from inside the OTA. The four bolt holes either side of the rear cell will be needed for re-mounting. (I'm not too keen on this bit.)

Frank - any tips on re-mounting?

Cheers,

Keith

#55 Stephen R

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Posted 25 March 2007 - 02:55 AM

A vendor (no prizes) lists RCX 16" & 20" OTA in their price list.

#56 Frankv

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Posted 25 March 2007 - 09:49 AM

Frank - any tips on re-mounting?

Cheers,

Keith


:grin:

Hum……

Well Keith, this is one that I don’t want to even think about. If you do try this, as soon as you post pictures I think it’s safe to say that a lot of RCX forks will hit the market all at once.

I do find it interesting that right after Jerry’s introduction of the DSI Pro(peller), this thread went quickly back on topic.

I figure this has to be an industrial design issue…(Jerry?) :poke:

It certainly can’t be the technical writing. :silly: :stooges:

Best regards,

#57 Frankv

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Posted 25 March 2007 - 10:58 AM

At the risk of being on-topic

Just out of curiosity, how are you intending to mount a deforked RCX?

I was thinking about this and the following occurred to me.

The tube is carbon fiber and plastic. As far as I can tell, the mounting screws for a dovetail system (top or bottom) screw into the Carbon fiber. I’m really not sure that I would trust this system to hold the OTA in regular use.

So, my thinking is that you would need to have some sort of cradle fabricated for the tube. Lets say this weights about 10 LBS. Then you have the OTA its self; the 10-inch LX200R weights 36 lbs from what I have heard. I have to believe the RCX OTA has 5 to 10 lbs on the R.

So you would have somewhere around 40 to 45 pounds in the OTA alone. Then add cameras, finder scopes, etc.

Since the only reason to own a RCX over an R is for Astrophotography, you need a mount that is rated at, what, say …….65lbs (photographic load)? You would be talking Tak NJP or AP 900 minimum.

Maybe I am overestimating the weights, but this looks like a project that could get really expensive, really fast.

Of course having a NJP or a AP900 wouldn’t be a bad thing. ;)

Regards,

Added: Keith, I just noticed that you have the 14 inch. You and Nick would be looking at some pretty heavy duty GEMs.

#58 Keith Howlett

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Posted 25 March 2007 - 11:12 AM

Hi Frank,

I'm still not convinced the exercise is viable yet.

The accessory screws go into the aluminium castings at the front and rear of the tube in the same way that they do in the LX200 series.

The tube weight of the 14 inch RCX is estimated at 74lbs-ish elsewhere on the CN forum.

This is already beyond an AP900, and perhaps will cause flexure problems with a dovetail plate. The tube is not ring friendly either.

:tonofbricks:

Looking at the Max Mount pics Meade attach the cradle to the four side bolts on the rear cell - which is the attachment used for the RCX fork mount, albeit inside the tube.

I have asked myself the same question - if you have an AP1200 would you put a de-forked RCX400 on it?

Cheers,

Keith

#59 Frankv

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Posted 25 March 2007 - 11:54 AM

Still, its only a matter of time until someone tries this.

Let’s face it, all the bells and whistles are nice but it is the flat field and the F8 optics that make the RCX special.

If my RCX were to fail, I would be really tempted to give it a try. I would think that all you would need to do is find a way to control the three motors that give you focus and collimation control, and then find out how to control the dew heater.

This is where you wish our virtual community was a physical community. I can picture a bunch of us sitting in someone’s garage with hammers, welding machines, electrical testers, three miles of duct tape and a couple of case of beer “making” this project work. :smash: :smash:

Maybe there is another theatrical presentation to write up here? :shrug:

Regards,

#60 Joad

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Posted 25 March 2007 - 02:45 PM

Scene: A three story house on a lake in South Carolina. We enter a garage filled with men, hammers, welding machines, electrical testers, three miles of duct tape and a couple of cases of beer. A middle-aged blonde man wearing a DSI pro-peller beanie is busy at work hitting a 14 inch RCX400 on a fork mount with a sledgehammer.

Jerrywise: I'll have this puppy deforked in no time!

JAT Observatory: Dibs on the fork!

Keith Howlett: Are you sure you know what you are doing, Jerry?

JerryWise: Me? Of course not! Pass me one of those beer thingies.

Frankv: I've just run some calculations, Jerry. I think that when you get that RCX deforked, the Washington Monument would just be adequate as a pier mount for it.

Joseph Gillman: How on earth are we going to get that thing to the top of the Washington Monument?!

JerryWise: Ah, Joseph, you haven't seen my patented teleforklift device, have you? How do you think I got the Hubble Space Telescope into my roof observatory?

JAT Observatory: Jerry, I've been meaning to ask. I've counted 247 empty blue cylinders, each one about 10 to 14 inches in diameter, lying around your garage. Are they, um, what I think they are?

JerryWise: Well, I don't always buy the Sky Assurance plan, and sometimes a fellow just needs to experiment a little with his equipment.

Frankv: But what did you do with all the mirrors?!

JerryWise: I always did want to have a Palomar in my back yard. Look over there near the lakeshore. See the honeycomb of mirrors? That's going to be my 200 incher once I get the whole thing duct-taped together.

Nick Cook: Would someone please pass me another Guinness?

Ben Ritchie: Once you yank that motor out, Jerry, how are you going to collimate the RCX?

JerryWise: Collimate, shmollimate. None of these things is ever collimated anyway. Even that danged TMB 130SS wouldn't collimate.

Joseph Gillman: So why do you bother with all this, Jerry?

JerryWise: All my boats sunk. Nothing else to do.

Moggi: I've just had a look at your new TAK 152, Jerry. Do you always keep your refractors in a crib?

JerryWise: Yup. Hey, that reminds me. He's due for his bottle of baby formula now. Would you take over here while I see to that?

Moggi: There isn't much left of this OTO now, you know. Carbon tubes may have some thermal advantages but they really aren't very good for sledgehammering.

JerryWise: Oh shoot. Not again. It's back to Astromart, I guess. I'll look for a 20 incher this time. If it doesn't work out, I can use the tube as a garbage bin.

All the other men in the garage: :scared: :scared: :scared: :scared: :scared: :scared:


The curtain falls.

#61 Frankv

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Posted 25 March 2007 - 05:01 PM

Scene: It’s March 18th., 2007. A bueatufully cared for back yard in Northumberland, UK. :grin: :poke: :grin:

(A gentleman is putting the finishing touches on his 14inch RCX setup. Beaming with pride he takes a step back and takes in his pride and joy. His “collimation partner” walks up next to him looks at the RCX and then at him).

CP: What are you thinking about Keith?

KH: I was just thinking about how great the optics are on this scope. I couldn’t be happier. It’s just…….


CP: It’s just what?

KH Well, for proper astrophotography, you really need the stability of a German Equatorial Mount.

CP: Well, can you trade this one in and get one?

KH: Unfortunately, no, Meade doesn’t make one.

(Brief pause)

KH: Of course perhaps I could defork this one and put my RCX on a proper mount.

CP: Why don’t you try the Internet and see if someone else has done this.

KH: Good Idea.


(Walks into house and sits down at computer)

KH: Here is a site. Cloudy Nights. Amazing look at all of the forums and 10,000 members? Surely I can get intelligent thoughtful answers to my questions here.

(Signs up, dutifully reads the TOS)

KH: Ah here is the Meade LX / RCX forum. Lets see for my FIRST post.

(Types and then signs off)

(Turns to CP and saysJ

KH: CP these folks appear to be an intelligent and serious lot, I’m sure that I will get several proper answers to my questions.

(Curtain falls)

OK, Keith started this thread on his very first post. The poor guy asked an intelligent well though out question. (That will teach him.) :poke:

His thread morphed into what has to be one of the most meandering train wrecks the Meade LX RCX forum has ever seen. In all honesty, I'm not sure that anyone has really even answered his question. Top it all off, he hasn’t run for the door. :bow:

Many of us would spend years aspiring to a thread like this and never achieve it.

Mr. Howlett, you should be proud, and welcome to Cloudy Nights.

Best Regards,

#62 JAT Observatory

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Posted 25 March 2007 - 05:33 PM

Hi Frank,

I'm still not convinced the exercise is viable yet.

The accessory screws go into the aluminium castings at the front and rear of the tube in the same way that they do in the LX200 series.

The tube weight of the 14 inch RCX is estimated at 74lbs-ish elsewhere on the CN forum.

This is already beyond an AP900, and perhaps will cause flexure problems with a dovetail plate. The tube is not ring friendly either.

:tonofbricks:

Looking at the Max Mount pics Meade attach the cradle to the four side bolts on the rear cell - which is the attachment used for the RCX fork mount, albeit inside the tube.


Cheers,

Keith


This is why even with my 10" GPS when I deforked it I mounted it using a cradle. I decided the flexure with a dovetail plate would be unacceptable especially when I started hanging things off of it.

#63 JerryWise

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Posted 25 March 2007 - 09:59 PM

Good Lord Joad...... you know some of us too well.
As a quick aside, the Hunter 33.5 sailboat I caught before it sank. The prop shaft packing was leaking.

On this thread, there is tremendous interest in doing this. I'm also getting EMails about it from Astromart members. I'm sure glad you brought it up. I think it's doable and will be done soon. I'm too cheap to buy a new one and try it but there will be some on AM soon. I think 4 RCXs of each size haven't gone back and are in the field (all to members here on CN). Something will break soon.

Here is the freaky thing and what I think is driving this. The new Takahashi 152 is in a cradle (as Joad said) and is the apple of my eye. I was looking at Saturn and the Moon through it two nights ago. Saturn was perfect but the Moon was scary. It was so clear and stark it looked cold and frightning. It was so surprising I mumbled "good Lord, that looks like the RCX". That is how good I remember the views in the 10" RCX. Those OTAs are better than the LX200Rs I've tested. There's an excellent 10" LX200R mounted beside the Tak FS-152 and it just doesn't quite reach the clarity of the RCX or the large Tak APO.

The 12" will be the jewel of the crowd and likely the first to get defrocked. I've got the welder and chop saw ready.

#64 Keith Howlett

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Posted 26 March 2007 - 08:05 AM

Hi All,

I'm having a great time with this thread - and by making this gratuitous extra post I become a CN Member instead of a Journeyman. :grin:

Actually there is a point to this post and that's to find out how Meade stop the big RCX's from falling off their Max Mounts.

In the pictures on their website the cradle is clearly bolted onto the rear cell in the usual way but I can't make out what is going on underneath the tube.

Has anyone on CN had the good fortune to either take a peek up under the OTA or actually to own one of these monsters?

Cheers,

Keith

#65 Nick Cook

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Posted 26 March 2007 - 08:14 AM

Now Keith, trying to get this thread back on track, what are you thinking! ;)

Nick

#66 Keith Howlett

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Posted 26 March 2007 - 08:27 AM

Hi Nick,

I was wondering if a re-mounting cradle needs to go all the way to the front cell? :question:

(Probably does.)

Cheers,

Keith

#67 inaPICle

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Posted 26 March 2007 - 10:07 AM

Does anyone know if the focus/collimation motors are steppers or servos?

If they are steppers (and I would be surprised if they were not) then building a controller for them isn't hard. Something PIC or Atmel based with a serial port for intelligent PC control is very do-able.

As for the dew heater, it could be re-wired to use an external controller.

#68 jrcrilly

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Posted 26 March 2007 - 10:28 AM

Does anyone know if the focus/collimation motors are steppers or servos?


They are servos.

#69 Nick Cook

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Posted 26 March 2007 - 11:38 AM

As an interesting aside the common focus issue (please let it have gone away due to improved QA by now), isn't to do with the motors at all I believe. It is actually a failure in the sensor board at the front of the OTA. The stuck motor isn't actually stuck at all, but because of the failed sensor thinks it is at its limit. Honestly we're probably talking a component failure of a few pence/cents worth! Sigh.

I would have thought Keith, that a cradle all the way to the front would be unecessary. After all the existing OTA is supported from it's central weight axis (sort of). A yoke setup maybe, connected to the German Equatorial...

Cheers,

Nick

#70 Frankv

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Posted 26 March 2007 - 11:49 AM

As an interesting aside the common focus issue (please let it have gone away due to improved QA by now), isn't to do with the motors at all I believe. It is actually a failure in the sensor board at the front of the OTA. The stuck motor isn't actually stuck at all, but because of the failed sensor thinks it is at its limit. Honestly we're probably talking a component failure of a few pence/cents worth! Sigh.


I didn't have the issue with mine, (knock on wood), but I was under the impression that the issue was with "Run on". The motors started, and then would not shut off until they hit the stops.

#71 Nick Cook

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Posted 26 March 2007 - 11:53 AM

Sounds like a variation on the sensor not telling the motor to stop. My focus motor was stuck (failed sensor), rather than a run on.

#72 Frankv

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Posted 26 March 2007 - 12:14 PM

I think it is possible, thus...

1) Approach your RCX and flip it playfully onto it's back.

2) Remove covers and unplug stuff that you don't need (mostly motors) when de-mounted. See if RCX still responds to being turned on.

3) Modify Autostar firmware to get around boot problems (amazingly this is all possible - Dick Seymour has been very helpful).

4) Strip out mount boards, arm boards and wiring looms - check the OTA functions still work. Add connectors if required.

5) De-mount.

6) Feel very brave, take tube apart to retrive the DEC bearing cantilevers from inside the OTA. The four bolt holes either side of the rear cell will be needed for re-mounting. (I'm not too keen on this bit.)


Are we over-thinking this?

If you were to simply turn Smart Drive off, doesn’t the AutoStar issue go away?

Maybe to be safe, you would simply reset AutoStar to Alt/Az before you started the process. If you forgot to do this you could hit 999 at the welcome screen and this resets the system. I believe the default is Alt/Az.

So,

You would get the usually start up messages, and then the system asks you if you want to auto-align. You hit “Mode” instead of “0” and your at the top of the menu tree.

This would mean (at least in my mind) that the only issues are mechanical (physically removing the OTA) and psychological. All you are doing is relocating the controller boards, and carving up a really expensive telescope.

Hum.... got me thinking.

Regards,

#73 Ben Ritchie

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Posted 26 March 2007 - 12:36 PM

All you are doing is relocating the controller boards, and carving up a really expensive telescope.


Yeah, nothing to it. Oh, wait... :)

#74 Jeff Young

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Posted 26 March 2007 - 05:01 PM

Oh man, you guys are having too much fun here without me. (I've been talking to Keith via private messages, but I only just now wandered on to this thread.)

It appears that Keith has already hooked up with Dick Seymour, but if anyone else is looking for him the "LX200GPS" Yahoo group is a good place to go. (He and an Aussie by the name of Andrew Johansen helped me out quite a bit when my Meade fork was getting the better of me.)

Oh and Jerry, I've got upgrade fever. I was thinking about taking a page from your book and mounting a 165 lb Tak classical Cassegrain on my AP1200GTO. What do you think?

-- Jeff.

#75 JerryWise

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Posted 26 March 2007 - 07:29 PM

Hi Jeff. Good to have you back.

Ok, 165 pounds is too much for the AP1200. Yep, already Jeff (the Bird Man) Young has overloaded the un-overloadable. So now we have somebody to buy and tackle the "Max Mount". Yep, somebody too far away to send it back. That's what you need Jeff. Cheap, reliable and can handle the Hubble launch vehicle.

(Oh, for those that don't know, the "Bird Man" name came during ProDome Observatory lession 101. Let's just say you don't get an unbreakable grip on an unsecured shutter in a 40 knot wind.)


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