Kolenka
Pooh-Bah
Reged: 06/01/08
Loc: Seattle Area, WA, USA
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Re: ADM vs Losmandy
[Re: TheMenace]
#2954980 - 02/28/09 01:57 PM Attachment (52 downloads)
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Try again.
If you align the blocks and use the two outer center holes,you should see that they fit the ota perfectly,but they will not line up with the larger blocks.
Attaching the heavy dove tail and blocks to a 10" ota,using only one screw is a big accident waiting to happen.
You might get by on the 8" ota,but why risk dropping my telescope by using only one mounting screw.
By sending a matched set of blocks,this could easily be avoided.
Maybe the newer LX 200 R has different spacing and hole placement?
LX200R has the same placement dating back to the Classic. Otherwise all the lovely accessories that date back to that era wouldn't mount on the newer tubes. While I understand Celestron has changed things from time to time, in this case, Meade has not changed the placement of their screws. Partly because of Meade's own accessories they sell that attach to them.
I've attached the diagram provided with the dovetail plate that I received, which is how the blocks are designed to attach to the tube. While I do understand your concern of a single screw holding in the small block, I don't think you would get enough torque if the screw came loose to snap the rest of the dovetail off the rear block or OTA. You wouldn't even get much side-play once the rail itself is firmly attached.
If you are really that concerned and refuse to use it as designed, I'd use the two larger blocks instead of the smaller ones. You will get a much better hold on the OTA than using the small blocks. It will do a much better job at preventing side-play if one of the two mounting blocks do come loose than using the two small blocks (which were really only meant to be mounted on the corrector end, and not designed to be mounted to the rear cell where most of the weight is).
Edited by Kolenka (02/28/09 02:00 PM)
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TheMenace
sage
Reged: 10/21/08
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Re: ADM vs Losmandy
[Re: Kolenka]
#2955239 - 02/28/09 05:03 PM
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Thanks for the diagram,I never received one.
I still don't understand why the blocks just don't match each other?
Why all the extra holes drilled into the radius block?
I'm using the larger blocks on the 10",the smaller on the 8".
I just wanted to show that they do interchange,the only difference being the length of the dove tail.
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Kolenka
Pooh-Bah
Reged: 06/01/08
Loc: Seattle Area, WA, USA
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Re: ADM vs Losmandy
[Re: TheMenace]
#2955264 - 02/28/09 05:12 PM
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Thanks for the diagram,I never received one.
I still don't understand why the blocks just don't match each other?
Why all the extra holes drilled into the radius block?
I'm using the larger blocks on the 10",the smaller on the 8".
I just wanted to show that they do interchange,the only difference being the length of the dove tail.
Cost and different tubes, is what I'd suspect. I'd bet you the large blocks are specific for Meade tubes, while the smaller ones fit both Celestron and Meade tubes. But, as you say yourself, it by itself isn't good enough to hold a D-type dovetail in place. They might save a bit on materials cost.
If I recall correctly, some of the larger dovetails for the Meade that Losmandy makes do use two larger blocks for extra stability. On the 8/10" tubes, it saves a tiny bit of money (without sacrificing too much stability) to use one of each.
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Ido Graiman
member
Reged: 09/26/07
Loc: Israel
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Re: ADM vs Losmandy
[Re: Kolenka]
#2973638 - 03/09/09 12:52 PM
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Hi guys, hope my question is not too much off topic...
I'm looking to remove my meade LX10 (8" SCT) from it's fork and mount it on my HEQ5 mount.
I'm looking for a dovetail rail of some sort that will attach to the mount on one end and to the OTA on the other end.
One of the options is the Losmandy (or ADM) dovetail you are talking about here.
From what I see here, this dovetail is meant to be used for mounting / piggybacking things on top of the OTA, but what I'm looking for is a dovetail that the OTA can be mounted on top of.
Now even if this dovetail is the right choice, how does it mount to the mount itself? from what I can see (please correct me if I'm wrong), it does not have the vixen-style attachment on it.
Any insights?
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Kolenka
Pooh-Bah
Reged: 06/01/08
Loc: Seattle Area, WA, USA
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Re: ADM vs Losmandy
[Re: Ido Graiman]
#2973704 - 03/09/09 01:20 PM
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Losmandy-style rails are meant to attach to Losmandy-style saddles. To mount an OTA onto a Vixen-style saddle, you need a Vixen-style dovetail.
Losmandy saddles/rails tend to do a better job holding heavier OTAs in place (10-14") than Vixen saddles/rails, and that is why you see a difference.
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TheMenace
sage
Reged: 10/21/08
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Re: ADM vs Losmandy
[Re: Kolenka]
#2973721 - 03/09/09 01:28 PM
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The dove tail is used to mount the ota on my atlas.
The vixen style just uses one screw on each end to mount the dove tail to the ota,rather than the blocks shown in the photo above..
You'll need the vixen version.
http://admaccessories.com/ADM%20Products/VC8.htm
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Ido Graiman
member
Reged: 09/26/07
Loc: Israel
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Re: ADM vs Losmandy
[Re: TheMenace]
#2973874 - 03/09/09 02:33 PM
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But then my OTA will be held by two screws! (one on each side of the OTA). It doesn't seems to be safe...
Isn't there a way to attache the vixen-style dovetail (I have both the 8" and the 13" one - from Orion) to the Losmandy dovetail?
Also - doesn't the Atlas comes with vixen-style head?
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mclewis1
Thread Killer
Reged: 02/25/06
Loc: New Brunswick, Canada
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Re: ADM vs Losmandy
[Re: Ido Graiman]
#2973977 - 03/09/09 03:23 PM
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Yes the Atlas uses a Vixen compatible saddle. The similar to the Atlas new CGEM and NEQ-6 mounts apparently use Losmandy D compatible saddles.
Vixen compatible dovetail rails are 1.75" in width. Losmandy D type plates are ~4" wide (the actual dovetail is 3" wide at its narrowest point). Careful with the nomenclature as Losmandy also makes a V or Vixen compatible rail as well.
Either the Vixen dovetail rail or the Losmandy D type plates should IMHO be on some form of "base". This can take the form of small radius blocks at each end of the rail/plate or a full length plate that the dovetail rail bolts onto (see Scopestuff http://www.scopestuff.com/ss_mpc8.htm for a picture and better explanation).
The exception to the idea of using separate blocks or plates is the Celestron CGE rail ... it is a Losmandy D compatible rail that because of it's unique shape can be bolted directly to the OTA.
Ido, I'm with you ... I'd never want my scope held to the dovetail rail by only two bolts unless it was sitting on a flat surface (like that provided by the radius blocks or full length plate). When a dovetail rail is bolted down to the blocks it can make use of a much heavier bolt.
Edited by mclewis1 (03/09/09 03:26 PM)
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Ido Graiman
member
Reged: 09/26/07
Loc: Israel
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Re: ADM vs Losmandy
[Re: mclewis1]
#2974033 - 03/09/09 03:51 PM
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So, this brings me to the logic conclusion (at least in my mind) that a combination of both the Losmandy D dovtail and a vixen-style dovetail is probably the best solution; The Losmandy dovetail providing enough 'traction', and the vixen-style dovetail attached to the Losmandy dovetail with more then two bolts (4, in case of the dovetail provided by Orion).
The question is - is there a way to connect the two different types of dovetails, or do I need to replace my HEQ5 mount head so that it can work with Losmandy D type dovetail?
Am I the only 8" SCT owner encountering this problem?
BTW, the plate scopestuff sell doesn't solve the problem since it's flat. Therefore - again, there can be only 1 screw at either side of the OTA attaching the two. They do not provide some radius blocks...
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DaveJ
Pooh-Bah
Reged: 01/07/05
Loc: NE Ohio
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Re: ADM vs Losmandy
[Re: Ido Graiman]
#2974121 - 03/09/09 04:25 PM Attachment (47 downloads)
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Hi Ido,
Here are three photos that I believe will clear things up for you.
All three show the mounting techniques for a C-11 using Losmandy "D" plate and saddle.
Here's the first showing the "D" saddle. The "V" saddle (Vixen, CG5, etc) is similar, but much smaller and less robust...
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DaveJ
Pooh-Bah
Reged: 01/07/05
Loc: NE Ohio
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Re: ADM vs Losmandy
[Re: DaveJ]
#2974127 - 03/09/09 04:27 PM Attachment (46 downloads)
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Here's a photo showing the Losmandy "D" rail and radius blocks I use on my C-11:
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DaveJ
Pooh-Bah
Reged: 01/07/05
Loc: NE Ohio
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Re: ADM vs Losmandy
[Re: DaveJ]
#2974134 - 03/09/09 04:29 PM Attachment (44 downloads)
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and one more:
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Ido Graiman
member
Reged: 09/26/07
Loc: Israel
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Re: ADM vs Losmandy
[Re: DaveJ]
#2974138 - 03/09/09 04:31 PM
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Thanks Dave. Still, as I previously said - it means I have to either find a way to replace the saddle on my mount to work with a D type dovetail, or I have to find a way to attach the V type dovetail to the D type dovetail (since no matter how hard I googled, I wasn't able to find any V type dovetail that comes with radius blocks).
Or am I still missing something?
Thanks 
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DaveJ
Pooh-Bah
Reged: 01/07/05
Loc: NE Ohio
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Re: ADM vs Losmandy
[Re: DaveJ]
#2974149 - 03/09/09 04:36 PM
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Each of the radius blocks are held to the OTA with two screws. The rail is held to each radius block with two more screws. The whole system is pretty secure and I never worry about something coming loose. This same system is available for most any OTA in either the "D" (larger) or "V" (smaller) rails/saddle. Losmandy and ADM both provide most anything you would require for any OTA, to my knowledge. My refractor has rings that attach to a Losmandy style plate so it can be placed in the saddle instead of the C-11. Also available from Losmandy & ADM are dual-saddle arrangements that allow both the C-11 and refractor to be mounted simultaneously.
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DaveJ
Pooh-Bah
Reged: 01/07/05
Loc: NE Ohio
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Re: ADM vs Losmandy
[Re: Ido Graiman]
#2974295 - 03/09/09 05:40 PM
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I wasn't able to find any V type dovetail that comes with radius blocks).
Take a look at the VCB8 here. If I'm not mistaken, this is what you're looking for, but you'd have to call Losmandy and see if those radius blocks will work for an 8" Meade or if he's making radius blocks compatible with Meade and hasn't yet updated his web page. Do you know any machinists?
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Ido Graiman
member
Reged: 09/26/07
Loc: Israel
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Re: ADM vs Losmandy
[Re: DaveJ]
#2974337 - 03/09/09 06:02 PM
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Thanks again Dave.
From what I know, the VCB8 exist only for Celestron, but I guess I'll have to give Losmandy a call and ask him. Otherwise, it seems that VSCT13 is the only thing for my OTA, meaning that it will be attached to the OTA by one bolt on each end. Maybe it's enough. Maybe it's not. I have to say that I can't see myself putting my trust in a single bolt 
So again, it's either getting some radius blocks for Meade (and I actually talked with 2 machinists today, and none of them gave wanted to produce a solution for me), or getting the D dovetail and finding a way to attach it to my mount (I am curious to see how TheMenace did it).
Thanks again
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DaveJ
Pooh-Bah
Reged: 01/07/05
Loc: NE Ohio
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Re: ADM vs Losmandy
[Re: Ido Graiman]
#2974362 - 03/09/09 06:12 PM
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Ido, I would not hang an OTA from a mount with a dovetail plate held by a single screw at each end...I'm with you there. Could be the single screw idea is meant for a counterweight rail but that's just conjecture on my part. I believe a call to Scott at Losmandy is in order here. Good luck.
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TheMenace
sage
Reged: 10/21/08
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Re: ADM vs Losmandy
[Re: DaveJ]
#2974423 - 03/09/09 06:35 PM
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Adm makes a dual saddle plate that accepts both dove tails.
The 8" should work fine with one screw on each end as the ota does not weigh enough to cause any problems.
I would call ADM and see about the dual saddle.
The losmandy radius blocks caused me quite a few headaches,as they didn't match up with my ota.
I needed to buy 2 complete dove tails to get a set that match.
The losmandy radius blocks only use 1 screw on the corrector end of the ota,in their stock configuration,even for the 10" ota.
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Ido Graiman
member
Reged: 09/26/07
Loc: Israel
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Re: ADM vs Losmandy
[Re: TheMenace]
#2974561 - 03/09/09 07:39 PM
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dual saddle plate! Aha! that was the missing link
I'll check ADM's saddle
The 8" OTA weighs about 12lbs (I assume), which still seems a lot for these screws. I'll feel a lot better with the radius blocks holding my OTA...
As for the frustration with the Losmandy blocks - I just had a talk with a friend who spent a LOT of time trying to figure out how to attach these blocks to the OTA along with the dovetail, so this story is quite familiar
Thanks for the insight!
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Troys
member
Reged: 02/22/09
Loc: Hudson, FL
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Re: ADM vs Losmandy
[Re: Ido Graiman]
#2976555 - 03/10/09 08:39 PM
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I just bought the ADM VM8 to attach my 8" LX10 OTA to the CG5. It only has 1 screw at each end. They give you longer screws to replace the screws that are there now. I was surprised but the cells are thicker then I thought they woud be.
It's only been a week but it is still tight and have had no problems.
If you look in either the classified section or the swap section someone is selling the one you need for $50.00.
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