De-forking a 14 inch Meade LX200.

[ollypenrice]

I'll take this a step at a time as I do it, because there is some dire misinformation out there in Netland. Whether I've got to the bottom of it will be seen as the project continues!

Stage one is Google Homework. Most 'de-forkers' unscrew the tube from its Dec carrier-brackets and then abuse it as they try to drag it out between the fork tines which are too tight for it to pass. It ends up gouged or scratched. Some create more space by spreading the tines with a car jack!  Now hang on, did Meade assemble the thing by spreading the tines with a car jack? This makes no sense.

A better class of U-tuber discovers that one of the fork tines, despite all appearances, is not integral with the other but can be unbolted, creating removal-space. Now we're talking. However, different variants of of the LX200 have fork arms which detach in different ways. The 14 inch has only the upper end of one tine which detaches. I didn't find a video on this but a close look at the GPS arm showed how it should come off.

The take-away, however, is that one of the fork tines detaches and you don't have to scrape the OTA out between un-separated tines.

Olly

[gorann]

Sounds good @ollypenrice. One thing I heard to be careful of is not to put all screws back around the bottom after de-forking as some will now protrude longer in and will hit the mirror and maybe chip it.

Edited October 29, 2022 by gorann

[Alan White]

Olly, one thing I would expect you to be doing is your home work, so we’ll done on this. 

On the Netland information, yes you have to tread carefully as a lot of old twaddle is spouted as fact.
As you say Meade would have unlikely used a jack to spring apart in production, so why do this in reverse,?
This is like getting a bigger hammer to drive things apart, break it and then spot the hidden locking screw…. clearly that’s not my own exp erience talking 😉

I await your next instalment. 

Edited October 30, 2022 by Alan White

[ollypenrice]

Slightly nerve-wracking but it went well. I gave some thought to the order in which to do things and started off by putting the forked scope on a bed for safety during the de-fork process. If you aim to re-use or sell the mount, mark the position of the Dec clamps against the fork tines before you start.

The critical thing is to be able to loosen one of the tines. On the 14 inch it is done by removing the four bolts below on the GPS side, but at this stage I just gave them a turn to loosen them. Doing it in the following order proved perfect.

 

Next I removed two of the three bolts which hold the OTA to the mount's altitude clamps. The one I didn't loosen at this stage on either side is the one shown here. This would be accessible later when the others wouldn't. (To get to the others you need to swing the fork upwards. I wanted the tube stable in the clamps at this stage, hence leaving the two accessible screws till last.

Next I went back to the four big tine bolts in the second image and removed them. I could then free the tine completely and under good control when I removed the last of the three bolts holding the tube to the clamp (as per image 3).  I could lift the tine away without its being under any stress.

 

The last bolt to come out was the single remaining one of the three OTA bolts on the other side. It's all pretty obvious but if done in the wrong order might have the heavy mount bashing and scraping the OTA. Once cleaned up it is almost impossible to see where the mount attached to the fork on one side and on the other it literally is impossible. This scope, over twenty years old and a veteran of observatories in Britain, Italy and France looks no more than a gnat's crotchet short of brand new.

I'm now awaiting a dovetail to mount it on the Mesu and am working out how to attach a nice Altair Astro 80mm triplet to the top to give a widefield alternative to the big scope's 3.5 metre focal length.

To be continued.

Olly

 

 

 

Edited October 31, 2022 by ollypenrice
False click

[Alan White]

Good to see progress Olly. 👍

 

[gorann]

Liberated! Well done Olly!

[Cleetus]

Good job. Hope your mattress didn't suffer too much!! I was going to do the same to my 12 inch but decided to sell it in the end. What are your plans for the OTA?

 

EDIT: just read about your plans.

Edited November 3, 2022 by Cleetus

[ollypenrice]

10 minutes ago, Cleetus said:

Good job. Hope your mattress didn't suffer too much!! I was going to do the same to my 12 inch but decided to sell it in the end. What are your plans for the OTA?

 

EDIT: just read about your plans.

I'm going to use the OTA for visual observing, both for myself and with guests. It's going on a MESU 200 which has a payload sufficient for a second one.  I have a Moonlite focuser which came with another deal but which wouldn't fit in the fork mount, so I think the Meade will now do great stuff. Less vibration and a locked mirror with nice fine focus. EPs are 13mm Ethos and 26mm Nagler at the moment but I'm feeling the urge to splurge - on a Pentax 40mm. First it has to survive being lifted onto the mount, though, so I added a removable front lifting handle for such occasions. I'll do this with two helpers, for sure.

 

 

Olly

[Cleetus]

For the last three or four years I was waiting around for the electronics in my Meade to go belly up in order for me to justify de-forking. It never did, and I felt a bit guilty about de-forking a perfect working scope so I sold the whole lot. My idea was to use it with one of those fancy Vixen mounts. Have ordered the Vixen but now nothing to put on top of it. 😆

I also used a Moonlite and was really impressed with it. Great views using a Nag 22 and Pan 35. Tried an Ethos but sold it on as I just couldn't get used to it. Hope my next telescope, whatever it is, is equally impressive.

Anyway, your plan sounds a good one and best of luck with it.

[Magnum]

Hi Olly, I have a set of these for my 12" LX200 but looks like he has sold out of 12" & 14" versions

https://ensoptical.co.uk/index.php?route=product/product&path=126&product_id=13815

Though just found this rail and ring system on eBay which fit the 14" which include a cheap guide scope. If I had your scope I would snap these up fast 🙂

https://www.ebay.co.uk/itm/203925817273?hash=item2f7aed07b9:g:lvMAAOSwI9ViaByn&amdata=enc%3AAQAHAAAAsG%2FrUJ87uwu85svy6G%2FQ7RuVbCpcHjI0bg%2Bt1XxGIJriLvveM1KG3B7njz52%2Fbz0oURB5m9Cvn1mbdl2UL61Cam6yL9aDxG938i3SIO%2Fi%2Fuh2Eg7Ogb38hlNIZ6J272gpCrbQGMwk2cqxE4G0uPjRo%2Fx0osfTRUro3bKtOjC0vTrVv9Pi2UvTze0jmKOMTrEfPTyuT9wLJfj09N73MTUqCBsaJcJTYUd0Fc6j%2B7zDjza|tkp%3ABk9SR4St3NuHYQ

Lee

Edited November 3, 2022 by Magnum

[kirkster501]

The 14" Meade is a monstrous instrument, almost as big as one of the 1970's rubbish bins.  In a dark sky they are magnificent.  I had one of them and it was a great scope but my Bortle 4/5 skies do not do it justice and so I sold it.  They are too big and heavy for regular mounting/demounting.

[Magnum]

My  old 12" LX200 is still working fine on its original fork drive, but if it ever dies I will have to buy a 2nd EQ8 for it. 

you should do some planetary with the 14" once you have it mounted, the 12" is proving excellent for the task 

You can just see the Astro Engineering guide scope rings that I picked up as new old stock for from ENS for only £25.

It's a good idea to vacuum out the screw holes after de forking before you put the bolts back to avoid swarf going inside. the tinniest smear of grease on the bolt threads helps if you are going to be removing them a few times.

Edited November 3, 2022 by Magnum

[ollypenrice]

2 hours ago, Magnum said:

Hi Olly, I have a set of these for my 12" LX200 but looks like he has sold out of 12" & 14" versions

https://ensoptical.co.uk/index.php?route=product/product&path=126&product_id=13815

Though just found this rail and ring system on eBay which fit the 14" which include a cheap guide scope. If I had your scope I would snap these up fast 🙂

https://www.ebay.co.uk/itm/203925817273?hash=item2f7aed07b9:g:lvMAAOSwI9ViaByn&amdata=enc%3AAQAHAAAAsG%2FrUJ87uwu85svy6G%2FQ7RuVbCpcHjI0bg%2Bt1XxGIJriLvveM1KG3B7njz52%2Fbz0oURB5m9Cvn1mbdl2UL61Cam6yL9aDxG938i3SIO%2Fi%2Fuh2Eg7Ogb38hlNIZ6J272gpCrbQGMwk2cqxE4G0uPjRo%2Fx0osfTRUro3bKtOjC0vTrVv9Pi2UvTze0jmKOMTrEfPTyuT9wLJfj09N73MTUqCBsaJcJTYUd0Fc6j%2B7zDjza|tkp%3ABk9SR4St3NuHYQ

Lee

Thanks Lee, but I won't be guiding the 14 inch, which won't be doing DS imaging. You're right about a bit of planetary imaging, though. I've no idea what the current top camera choices are but it would be good to look into them.

2 hours ago, kirkster501 said:

The 14" Meade is a monstrous instrument, almost as big as one of the 1970's rubbish bins.  In a dark sky they are magnificent.  I had one of them and it was a great scope but my Bortle 4/5 skies do not do it justice and so I sold it.  They are too big and heavy for regular mounting/demounting.

I'm really impressed by the view in the 14 inch.  It was significantly better than I was expecting and I really can't fault it. As you say, it will go on and stay on except when something needs fixing.

3 hours ago, Cleetus said:

For the last three or four years I was waiting around for the electronics in my Meade to go belly up in order for me to justify de-forking. It never did, and I felt a bit guilty about de-forking a perfect working scope so I sold the whole lot. My idea was to use it with one of those fancy Vixen mounts. Have ordered the Vixen but now nothing to put on top of it. 😆

I also used a Moonlite and was really impressed with it. Great views using a Nag 22 and Pan 35. Tried an Ethos but sold it on as I just couldn't get used to it. Hope my next telescope, whatever it is, is equally impressive.

Anyway, your plan sounds a good one and best of luck with it.

Yes, my mount itself is OK, I think. It was working fine with its original handset but has proved not to work with the replacement, which is also called Autostar II. It goes in the right direction when I try to align it but misses by about 20 degrees and doesn't get any better when synched. I think it must have a different protocol and I hate faffing around with that kind of IT issue!  It wasn't very stable, either, with a long damping time. This isn't too good for beginners because they struggle to find focus when they're looking at a trembling star. I'm looking forward to having it on a stiff mount and to doing more visual observing again.

Olly

[Magnum]

4 minutes ago, ollypenrice said:

Thanks Lee, but I won't be guiding the 14 inch, which won't be doing DS imaging. You're right about a bit of planetary imaging, though. I've no idea what the current top camera choices are but it would be good to look into them.

 

Yes I know its for visual, but you said earlier in the thread you were looking for a way to mount your Altair 80mm to the top for wider views, so I thought these guide rings would be the easiest option as they have the correct curvature for mounting to the front and rear cells and include rails with sliding rings so you can balance it.

cheaper and more functional than buying another dovetail.

Lee

Edited November 3, 2022 by Magnum

[ollypenrice]

1 minute ago, Magnum said:

Yes I know its for visual, but you said earlier in the thread you were looking for a way to mount your Altair 80mm to the top for wider views, so I thought these guide rings would be the easiest option as they have the correct curvature for mounting to the front and rear cells and include rails with sliding rings so you can balance it

Ah, gotcha! Yes, that would be a good idea. Thanks,

Olly

[Magnum]

2 minutes ago, ollypenrice said:

Ah, gotcha! Yes, that would be a good idea. Thanks,

Olly

Though can’t tell what size the rings are from the listing so would need to ask to see if they are larger than your Altair 80 tube diameter.

[MarsG76]

On 31/10/2022 at 03:22, ollypenrice said:

Slightly nerve-wracking but it went well. I gave some thought to the order in which to do things and started off by putting the forked scope on a bed for safety during the de-fork process. If you aim to re-use or sell the mount, mark the position of the Dec clamps against the fork tines before you start.

The critical thing is to be able to loosen one of the tines. On the 14 inch it is done by removing the four bolts below on the GPS side, but at this stage I just gave them a turn to loosen them. Doing it in the following order proved perfect.

 

Next I removed two of the three bolts which hold the OTA to the mount's altitude clamps. The one I didn't loosen at this stage on either side is the one shown here. This would be accessible later when the others wouldn't. (To get to the others you need to swing the fork upwards. I wanted the tube stable in the clamps at this stage, hence leaving the two accessible screws till last.

Next I went back to the four big tine bolts in the second image and removed them. I could then free the tine completely and under good control when I removed the last of the three bolts holding the tube to the clamp (as per image 3).  I could lift the tine away without its being under any stress.

 

The last bolt to come out was the single remaining one of the three OTA bolts on the other side. It's all pretty obvious but if done in the wrong order might have the heavy mount bashing and scraping the OTA. Once cleaned up it is almost impossible to see where the mount attached to the fork on one side and on the other it literally is impossible. This scope, over twenty years old and a veteran of observatories in Britain, Italy and France looks no more than a gnat's crotchet short of brand new.

I'm now awaiting a dovetail to mount it on the Mesu and am working out how to attach a nice Altair Astro 80mm triplet to the top to give a widefield alternative to the big scope's 3.5 metre focal length.

To be continued.

Olly

 

 

 

Nice and tidy work Olly, well done.

 

[ollypenrice]

1 hour ago, MarsG76 said:

Nice and tidy work Olly, well done.

 

Thanks. The scope was a bequest from a friend, Alan Longstaff, and in showing it some respect I feel I'm doing the same for him, even if the handle will only serve occasionally.

Olly