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Equipment Discussions >> Mounts

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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking new [Re: OzAndrewJ]
      #5355471 - 08/06/12 08:51 PM Attachment (37 downloads)

You ask for info (and pics) and i can deliver...
Here are two view of the top of the leg.
As you can see, the answer to your question is "Yes.. and NO..."
There are set screws, which i assume (gets me into LOTS of trouble) are the "blocks" or "stops". And on these, as well as the other two legs, the screws are turned all the way in... thus, the do NOTHING!


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking new [Re: dmdouglass]
      #5355473 - 08/06/12 08:52 PM Attachment (25 downloads)

And pic #2 from the opposite view...

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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA Tracking new [Re: dmdouglass]
      #5355485 - 08/06/12 09:05 PM

Gday David

Quote:

There are set screws, which i assume (gets me into LOTS of trouble) are the "blocks" or "stops".




Not sure what they are, but its not the stop,
and looking closer, it looks like they are digging into the top casting, ( which isnt good practice )
Basically, the whole casting in the top of the leg becomes the stop.
Ie if you turn your tripod upside down, the legs will fall outwards freely, then stop. The thing stopping them is the design of the casting in the head of the leg. On the LX200s, if the lower spreader unit isnt in place, the legs will swing completely through 180degrees.

Andrew


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neilson
professor emeritus


Reged: 08/22/10

Re: LX80 RA Tracking new [Re: dmdouglass]
      #5355510 - 08/06/12 09:16 PM

Hi David, Meade doesn't seem to take action until enough people have complained.
I think the nut to keep from over tightening the spreader is a great Ideal. When I tighten mine all the way there's not alot of pressure though. I measured just under 3/16" from contact to full tighten on mine. A nut would prevent the spreader from full contact on mine. Others might be different though.
I wonder why Meade hasn't asked for the broken parts. I would expect they would want to verify why it broke. Maybe they already know why. I hope they look into it and take action if needed.
If you have one that's going to break from bad casting or bad design its just a matter of time. I hope that it was just that one tripod defective, but it would be nice to know for sure.
neilson
I just noticed y'all have already started checking all this out above, great

Edited by neilson (08/06/12 09:29 PM)


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking new [Re: neilson]
      #5355517 - 08/06/12 09:27 PM

Andrew...

Well, you made me go look again, and I think you may be right. I was thinking there were four screws, two on each side.

Without dismanteling the leg (which i will have to do anyway), i cannot tell for sure. As i reexamine the patterns, it does appear that the "inside" screws are actually imprints from the stress.....

I will have to find a couple of wrenches, and have a closer look. Will do that this evening. I did examine closely the other two legs, and i have the same pattern there.


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking new [Re: dmdouglass]
      #5355540 - 08/06/12 09:39 PM

Andrew...(and Rich...)

Well, its confirmed. I have it apart.
There are only two screws, and they are on the "leg" portion. They are exposed "maybe" one thread, i think probably less. They are also NOT evenly set (meaning the holes are not in a nice "pattern"...

The "screws" in/on the inside piece are actually imprints from the leg when extended. Holy cow.... that's would be a lot of force.

Ed: I should probably add that the screws seem to serve no other usful purpose.

Edited by dmdouglass (08/06/12 09:41 PM)


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Jared
Postmaster
*****

Reged: 10/11/05

Loc: Piedmont, California, U.S.
Re: LX80 RA Tracking new [Re: OzAndrewJ]
      #5355551 - 08/06/12 09:46 PM

Quote:

Gday Rich

Quote:

I am an engineer. Are there rotation stops on the tripod legs at the top? It seems that's where the load could be coming from.




Got my Mech Engineer hat on now.
If you look at Davids original pictures of the "top" of the tripod, you can clearly see the top of the legs are designed to be the rotation stop. There are no lower spreaders to take any load.
As such, as the tripod gets tensioned, the outward force on the legs can put a very high moment into the top joint, hence explaining the fracture mode David got.
Again, this is OK if the design and materials are suitable,
but how good is the metal in the head????

Andrew




Andrew, if the top of the legs themselves were applying the leverage that caused the fracture, wouldn't the tabs that contain the tripod leg bolts have broken off rather than the entire flange? It seems to me that if the leg were applying a large amount of force due to the lack of a rotation stop, then the fracture(s) would have been farther out. Much of the force applied from an over-extended tripod leg would have been inwards against the flange, wouldn't it? I'm thinking a bad casting is still the most likely explanation.


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greju
Carpal Tunnel
*****

Reged: 10/13/05

Re: LX80 RA Tracking new [Re: Jared]
      #5355583 - 08/06/12 10:00 PM Attachment (19 downloads)

A comparison shot of the LXD-75. I do not know if anything can be gleamed from this but I do know that there are no reports, to my knowledge, of spontaneous breakage occuring with these. Breaking after someone trips over a tripod leg, all the time. And since we really do not know how this breakage occured, at this point I am leaning towards a fall, everyone, includeing me, is just speculateing.

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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA Tracking new [Re: Jared]
      #5355587 - 08/06/12 10:03 PM

Gday Jared

Quote:

Andrew, if the top of the legs themselves were applying the leverage that caused the fracture, wouldn't the tabs that contain the tripod leg bolts have broken off rather than the entire flange? It seems to me that if the leg were applying a large amount of force due to the lack of a rotation stop, then the fracture(s) would have been farther out. Much of the force applied from an over-extended tripod leg would have been inwards against the flange, wouldn't it? I'm thinking a bad casting is still the most likely explanation.




As designed, with the leg being loaded by the spreader, you get an outward force and a restraining "moment" in the joint.
It is the moment portion of this that is the major player.
In an earlier picture, we can see there are no internal gussets going to the outer edges of the lugs, hence cant transfer and strength into the skirt at the connection points.
Thus, when under load, the bottom edge of the skirt casting will be under a high shearing load, which isnt good for thin castings.

Andrew


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greju
Carpal Tunnel
*****

Reged: 10/13/05

Re: LX80 RA Tracking new [Re: OzAndrewJ]
      #5355597 - 08/06/12 10:11 PM Attachment (11 downloads)

Correct me if I am wrong but the LXD-75 seems to have pretty close to the same mechanics concerning the leg spreader.

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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking new [Re: greju]
      #5355607 - 08/06/12 10:20 PM

Hello Greju...

I will defer the comparison of the two to the engineers. I do, however, see several "differences". They are NOT the same.

As to "trip" or "fall over", that has been referenced already. No, that did NOT happen. Can i prove it? Not really, I just told the story as it happened. As best as I can tell (and recall), the leg apparently seperated from the mount, and the mount collasped at my feet.


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA Tracking new [Re: greju]
      #5355618 - 08/06/12 10:25 PM

Gday Greju

Quote:

Correct me if I am wrong but the LXD-75 seems to have pretty close to the same mechanics concerning the leg spreader.




Similar concept but different design and probably different materials.
Just looking at the LXD75 head i can see its a "meatier" design.
Again, as i mentioned earlier, the mechanism should work if designed correctly and correct materials are used.
Unless you crunch the numbers, you cant say one way or another.
We are currently just discussing possible causes
( as David specifically said it wasnt a fall or a kick of the tripod ).

Andrew


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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: LX80 RA Tracking new [Re: OzAndrewJ]
      #5355782 - 08/07/12 12:19 AM

G'day all,

It's a much deeper section on the other LX mounts. There's just a bigger stress concentration on the LX80. Generally castings are fairly brittle, and the fracture on this part looks pretty brittle. I'd guess the broken piece will fit the spot it came from perfectly. They can send you a new part. I suggest treating it gently. Consider putting in a spreader at the bottom of the legs.

-Rich


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OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: LX80 RA Tracking new [Re: dmdouglass]
      #5355954 - 08/07/12 05:45 AM

Gday David

Quote:

Several times in this thread, people have asked or wondered if the LX80 mount could be used for imaging. I have stated many times, that I expect to do so. I was hoping to be able to do so in Alt/AZ, both guided, and unguided.




Do you wanna be a crash test dummy for AltAz pulse guiding?
I think i have patched the firmware to allow it,
but i have to say, i suspect it wont work well if you are in a region
where one of the motors is almost stationary.
For other areas, it should work, but i suspect you would have to recalibrate
for each new location.
It wont hurt anything, but not sure how good it will work.

Andrew


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TALK2KEV
sage


Reged: 03/08/06

Loc: Oklahoma
Re: LX80 RA Tracking new [Re: OzAndrewJ]
      #5356081 - 08/07/12 08:46 AM

peter D
Thanks for the kind words, As you can see we started out very small using the Equipment we had on hand. If fact i have heard more than once why would you use that scope to shoot through, because we had it on hand so stick a camera on it we went through web cam mods everyone has that eyepiece a 4mm you never use take the barrel off take a part your web cam hot glue the barrel on and point the thing at the moon. the best thing hot glue comes off easy so you can reclaim the barrel for the eyepiece or the next project.We try to show the Equipment we use with the photos taken, Its a learning process but for the most part it's fun. I would like you to share some of you photos and pic of Equipment used to take the photos You can contact me through the site
or via PM


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deSitter
Still in Old School


Reged: 12/09/04

Re: LX80 RA Tracking new [Re: greju]
      #5356181 - 08/07/12 09:48 AM

Quote:

A comparison shot of the LXD-75. I do not know if anything can be gleamed from this but I do know that there are no reports, to my knowledge, of spontaneous breakage occuring with these. Breaking after someone trips over a tripod leg, all the time. And since we really do not know how this breakage occured, at this point I am leaning towards a fall, everyone, includeing me, is just speculateing.




Look at the difference - the box structure behind the leg bosses is super-rigid and distributes the stress. It's a vastly better design than the LX80's head. Meade need to get on this immediately and redesign the head. Or Scopestuff

-drl


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TALK2KEV
sage


Reged: 03/08/06

Loc: Oklahoma
Re: LX80 RA Tracking new [Re: deSitter]
      #5356217 - 08/07/12 10:11 AM

Has anyone tried pulse guiding with a old 497 HC on the Lx80 I know the tracking rate would have to be changed

never mind the old tracking error problem would pop back up , unless we could force feed it a firmware update.

Neilson

Thanks for the feedback on Altitude lock screws if you are standing in front of the mount which would put the lock bolt on the left side or east side that is the same as mine it never get tight. Confirm left side when standing in front of the mount correct?


Edited by TALK2KEV (08/07/12 10:53 AM)


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking new [Re: TALK2KEV]
      #5356320 - 08/07/12 11:28 AM

Hi Kevin and Nielson...

Perhaps another way to say it would be...
The lock slider arm on the side of the base where the "N" is...

This lock is for the Azimuth adjustment. It controls or locks the "minor adjustment for azimuth" when you use the "tool key" on the lower adjustment screw on the front. When you make that adjustment, the entire mount turns on the base, and only by about 15 or 20 degrees (best guess) in either direction.

Mine gets tight. However, i can still use the tool to turn (adjust) the mount in that condition. The real concern should be is the base secure (you cannot turn it manually) during operation.


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dmdouglass
professor emeritus


Reged: 12/23/07

Loc: Tempe, AZ
Re: LX80 RA Tracking [Re: dmdouglass]
      #5356328 - 08/07/12 11:33 AM

Hi Andrew...

Hmmmmm "Crash Test Dummy"

Yup ! That's Me !!!

UPS reports expected delivery on Wednesday.


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deSitter
Still in Old School


Reged: 12/09/04

Re: LX80 RA Tracking [Re: dmdouglass]
      #5356365 - 08/07/12 11:55 AM

Here's David testing his new rig for transportability to remote sites:

http://www.youtube.com/watch?v=xpw0QvAYngA

Good humor, David.

-drl


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