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Deforking a Meade 2120

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#1 SJLAN

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Posted 08 April 2021 - 11:10 AM

Hello!
I have a Meade 2120 10” SCT, and it mounts on an old school equatorial wedge with tracking. With accurate drift alignment I can get just 45 seconds to 1 minute camera exposures because the mount is so old and used, and it’s frustrating to use at times. I am wondering if someone can give me a link to any in depth guides to deforking old SCTs? I am looking to get a nice new German equatorial mount for this scope, but I’m not sure how to defork and attach the correct dovetail bar for a German equatorial mount. 2500mm focal length is great for small DSOs and I love this scope. 
Any help is appreciated, thanks!

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#2 CltFlyboy

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Posted 08 April 2021 - 02:55 PM

Like this? It's my 2120 I deforked last year.

 

https://www.cloudyni...gem/?p=10745084

 

The actual deforking took no more than a few minutes. Adding the Losmandy plate another few. Really, really simple on the 2120.


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#3 SJLAN

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Posted 08 April 2021 - 03:08 PM

Like this? It's my 2120 I deforked last year.

 

https://www.cloudyni...gem/?p=10745084

 

The actual deforking took no more than a few minutes. Adding the Losmandy plate another few. Really, really simple on the 2120.

Yes! I have this same exact telescope. The only difference is that there is some added insulation around my telescope. I’m just confused as to where and how to attach a losmandy plate because there doesn’t seem to be anywhere to fit one on the scope


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#4 jdupton

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Posted 08 April 2021 - 04:29 PM

SJLAN,

 

   If you don't mind spending some money on high quality machined fittings, you cannot do much better than ADM accessories. The following link will do exactly what you want.

 

https://www.admaccessories.com/product/dm10-d-series-dovetail-bar-fits-meade-10-otas/

 

   If you have access to any machine shop equipment, you can make your own. They are pretty easy and the specifications for dimensions are available on the Web. I made my own about eight years ago but they the ADM dovetail and radius bar set put mine to shame.

 

   If you search around, there may be some cheaper sets available for other suppliers. If you have a Losmandy dovetail plate long enough to fit the scope, I think you can purchase only the radius blocks from some suppliers

 

 

John


Edited by jdupton, 08 April 2021 - 04:34 PM.

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#5 SJLAN

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Posted 08 April 2021 - 05:22 PM

SJLAN,

 

   If you don't mind spending some money on high quality machined fittings, you cannot do much better than ADM accessories. The following link will do exactly what you want.

 

https://www.admaccessories.com/product/dm10-d-series-dovetail-bar-fits-meade-10-otas/

 

   If you have access to any machine shop equipment, you can make your own. They are pretty easy and the specifications for dimensions are available on the Web. I made my own about eight years ago but they the ADM dovetail and radius bar set put mine to shame.

 

   If you search around, there may be some cheaper sets available for other suppliers. If you have a Losmandy dovetail plate long enough to fit the scope, I think you can purchase only the radius blocks from some suppliers

 

 

John

Thanks John! I will be sure to check them out



#6 CltFlyboy

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Posted 09 April 2021 - 10:50 AM

Yes! I have this same exact telescope. The only difference is that there is some added insulation around my telescope. I’m just confused as to where and how to attach a losmandy plate because there doesn’t seem to be anywhere to fit one on the scope

Losmandy makes the tube adapters (radius blocks) as well as the plates, as long as you select Meade 10" SCT you'll get the right one. The Celestron ones, while the same diameter, have mounting holes in different locations ands will not work. Once y ou get the right one it's a piece of cake. The ADM ones are really great too...


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#7 CltFlyboy

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Posted 09 April 2021 - 10:52 AM

I forgot - several of the Losmandy crew are on this forum - look for them, PM them with your request and they'll tell you exactly what you need and then you can order from them directly. They are an excellent, reliable bunch of folks!


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#8 carolinaskies

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Posted 09 April 2021 - 11:14 AM

Hello!
I have a Meade 2120 10” SCT, and it mounts on an old school equatorial wedge with tracking. With accurate drift alignment I can get just 45 seconds to 1 minute camera exposures because the mount is so old and used, and it’s frustrating to use at times. I am wondering if someone can give me a link to any in depth guides to deforking old SCTs? I am looking to get a nice new German equatorial mount for this scope, but I’m not sure how to defork and attach the correct dovetail bar for a German equatorial mount. 2500mm focal length is great for small DSOs and I love this scope. 
Any help is appreciated, thanks!

Deforking Meade SCTs

Step one, precure ball-head allen wrenches.  These allow angled access to allen bolts as necessary. Good allen wrenches are essential, so don't buy the cheapest chromed set.

Step two, using appropriate size allen wrench loosen and remove the smallest allen bolt(2 total for the OTA) of the three bolts on either side of the OTA which connect the OTA to the fork arm carrier adapter.  Typically it's easiest to access from the OTA pointed straight down, but some models you may need to rotate the OTA around for best access with ball-head allen wrench.  BE AWARE these bolts if never removed before may resound with a 'crack' when initially breaking them loose.  

Step three, break loose the two remaing allen bolts(4 total) on either side of the OTA but don't remove them yet.  Lay the telescope on it's side on a soft blanket.  

 

Step four, mark the outline of the support fork arm location on the telescope base with a marker then break loose the four large allen bolts on the support fork arm side of the telescope.  Again these will have a resounding 'crack' when broken loose.  Marking is done so if you want to remount the OTA you can put the fork in the factory location to aid in recentering the OTA. 

Step five, remove the allen bolts from step three.  If the OTA will slide out from between the forks you're done. Otherwise, loosen by 1/4" the four bolts from step four, but do not remove them... there is no necessity to remove them. 

 


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#9 jgraham

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Posted 09 April 2021 - 01:28 PM

Step 6; don't put the screws that held the fork to the tube back in the tube, they may reach far enough in to bear on the mirror. Instead, buy a set of slightly shorter screws to replace them. Plan-B, put the original screws back in with a couple of washers under them to stand them off a bit. When you are finished take a peek inside the tube using a flashlight to make sure that there is clearance between the mirror and screws.
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#10 carolinaskies

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Posted 09 April 2021 - 06:44 PM

Step 6; don't put the screws that held the fork to the tube back in the tube, they may reach far enough in to bear on the mirror. Instead, buy a set of slightly shorter screws to replace them. Plan-B, put the original screws back in with a couple of washers under them to stand them off a bit. When you are finished take a peek inside the tube using a flashlight to make sure that there is clearance between the mirror and screws.

There are silcone hole plugs which are much safer to use...   https://www.stockcap...tore/plugs.html




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