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Warning: LXD75 SN Dovetail & Atlas

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#1 jgraham

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Posted 18 September 2012 - 09:40 PM

Just a warning to anyone using the Meade LXD75 SN dovetail and rings on an Atlas. Apparently the design of this dovetail limits how well it engages with the Atlas dovetail clamp. I've been using my SN6 on my Atlas without any problems until tonight. This was my first attempt to use a 90mm MCT guidescope on my Atlas (the one that I've been using with my LXD75), but the added overhung load was too much for the clamp. Three times the dovetail popped out of the clamp dumping my imaging gear onto the concrete. The total weight of my gear is less than 20 pounds so weight wasn't the issue. I don't think the SC8 dovetail will have the same problem.

Ugh. Rough night.

#2 jgraham

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Posted 18 September 2012 - 10:11 PM

I took a close look at the SN dovetail and the problem is that the base of the dovetail bar has a step that engages the top of the LXD75 and helps to keep the dovetail locked into the LXD75 receiver. However, this step also severly limits the grip of the Atlas receiver. I'm not puting my SN6 back onto my Atlas until I get this fixed.

#3 jgraham

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Posted 19 September 2012 - 08:59 AM

I looked at my AR-6 and it also uses the same dovetail as my SN6. The SC8 looks fine. Tonight I'll be moving the rings from my LXD75 dovetail over to the dovetail bar that came with the Atlas.

#4 Cliff Hipsher

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Posted 19 September 2012 - 09:03 AM

How about posting some pictures so we know what to look for?

#5 jgraham

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Posted 19 September 2012 - 10:09 AM

I'll do that as soon as I get a chance. I was up late last night taking a close look at it and I was really surprised at how limited the grip was between the LXD75 SN/AR dovetail and the Atlas dual mode receiver (the receiver being used on the latest model of the Atlas).

Ack! I lost a rare night of imaging and did some serious damage to my gear. Fortunately, it all looks fixable. The good news is that I was seriously considering putting my AR-6 on this mount. Now THAT would have been a disaster!

#6 dvb

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Posted 19 September 2012 - 10:38 AM

Scopestuff sell a nice replacement aluminum dovetail for LXD55/ 75 mounts to solve this problem.

http://www.scopestuff.com/ss_l5db.htm


I didn't find the extra dovetail retainer bolt was necessary.

(I had this problem with Meade SN8. )

#7 jgraham

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Posted 19 September 2012 - 12:13 PM

I was going to look at what ScopeStuff ahd to offer, but for some odd reason I can't access their web site. Ack! Fortunately, I can see their site from work. I just picked up the stainless steel bolts I need to move my SN6 rings over to the Orion dovetail bar, but I'll order two more bars from ScopeStuff for my other SN6 and my AR-6.

Thanks!

#8 Cliff Hipsher

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Posted 20 September 2012 - 09:28 AM

Scopestuff sell a nice replacement aluminum dovetail for LXD55/ 75 mounts to solve this problem.

http://www.scopestuff.com/ss_l5db.htm

That is exactly what I've getting (along with a set of rings) for my older (1989 vintage) Meade 2080.

It started out as an LX-5 fork mount. I deforked it, added a full length dove tail bar and mounted it on an LXD-75.

Then I realized I needed to adjust for cone error. I looked into getting OEM parts, but I've been told the Meade saddle plate (aka dove tail) is cheap pot metal and prone to failure.

Hopefully I'll have the new plate and rings in the next couple of weeks...




I didn't find the extra dovetail retainer bolt was necessary.

(I had this problem with Meade SN8. )



#9 jgraham

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Posted 20 September 2012 - 12:10 PM

I'll post picture when I get a chance. I'm still patching the pieces of my imaging gear back together. So far it looks like I lost a guide camera (I'll open it up to see if there's a chance of fixing it), a USB repeater cable (it looks like the scope landed on it), a USB port on my computer (it didn't like the end of the repeater getting smashed), damaged a guide scope (fixed), cracked the end ring near the mirror (scope looks okay though), damaged my imaging camera (seems to work though), cooling fan, finder, and dinged the end ring up by the corrector. I had most of this put back together last night riding on the Orion dovetail, but the images through my scope looked like the mirror or corrector may have gotten pranged. I'm going to pull the mirror tonight to see if it's pinched. In the worst case I've got a spare, but I hope that it doesn't come to that.

The Atlas is a nice mount, but compared to my LXD75 it's been a bit of a pain to get working smoothly. the LXD75 had it's quirks, but it was cheap, lightweight (relatively), and easy to work with. I'm sure the Atlas will grow on me once I get everything migrated over to it and the kinks worked out, but right now it's a bit of a mess.

One crisis at a time...






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