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Old 12-04-2018, 02:35 PM
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Losmandy -style plate

I have an idea how to make a cheap saddle for Losmandy bar... see the sketch attached.

I have one extra bar.. so it is easy to cut it to a smaller size (to reduce weight). The other bar (on the scope) is held in place by means of two bolts and appropriate nuts and washers (I am trying to find something suitable, otherwise I will have to have them milled).

It will be way cheaper than what's available.. and even good looking...

Anyone knows of something like that? Angles are 60°.
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Old 12-04-2018, 05:06 PM
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Hi Bojan,

If the extra bar is from the scope I think it would be a shame to remove and cut it, rather than keep it as an accessory bar for piggyback or finders etc.... I'd wait a bit as saddles sometimes come up in the classifieds. If it is for mounting to your mount, then possibly you could use a Skywatcher dual style (Vixen & Losmandy) replacement saddle for about $60 as in the ebay advert below here, but be careful with the mounting collar base recess to your mount as there are two types as shown in the cross-section in the image attached. You obviously wouldn't want the wrong one and the advert I attached doesn't show that detail unfortunately.

https://www.ebay.com.au/itm/SKYWATCH...4AAOSwl9RZ-qHl

Best
JA
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Last edited by JA; 12-04-2018 at 05:18 PM.
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Old 12-04-2018, 05:26 PM
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The bar I mentioned was collecting dust in one of my cupboards.. so I thought to put it to some use...
Thank you for the link, it seems right for me (my old (black) EQ6 used "standard" profile). I will check with seller asap.

BTW.. I found something on Alibaba ( I have the mounting collar):
https://www.aliexpress.com/store/pro...68e76fdcTBFlaK

Last edited by bojan; 12-04-2018 at 05:52 PM.
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Old 13-04-2018, 01:28 PM
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Solution found: it is standard aluminium extrusion available at Aluminium Trading Centre).
https://www.aluminiumtc.com.au/store...3-id-14mm-152/
Bolts (3 or 4 or even more) could be M6, 120mm long (they could also be threaded rods (Bunnings), with nuts&washers at each end).
The structure can be reinforceda bit further by number of countersink screws (M4~M5, shown on the second picture).

The whole thing will cost me around $20... ($15 for 1.6m channel, $5 for screws) with some leftovers for another project (I will have to use ~0.5m or a bit more).
I even do not need to shorten the bar, I can leave it as it is (while waiting for better solution.... but we all know that temporary solutions usualy last the longest time...)
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Last edited by bojan; 13-04-2018 at 02:43 PM.
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  #5  
Old 13-04-2018, 02:42 PM
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Bojan,
I don't think the added c'sunk screws would do much; the al section is in compression due to the wedges.
Possibly a 6mm(or what your CAD says) spacer between the bolts and the two Losmandy plates.
Do a plan view showing the bolt spacing and a "packer" between them.
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Old 13-04-2018, 02:46 PM
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Quote:
Originally Posted by Merlin66 View Post
Bojan,
I don't think the added c'sunk screws would do much; the al section is in compression due to the wedges.
Possibly a 6mm(or what your CAD says) spacer between the bolts and the two Losmandy plates.
Do a plan view showing the bolt spacing and a "packer" between them.
You are right, it will be compression as long as scope is above the mount.
Probably it would be a good idea to mill the al channel (60°) so it can go deeper between the plates.
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Old 13-04-2018, 06:17 PM
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Actually Ken, you are only half right - there are scope positions where one side of the bar is under compression, and at the same time the other side is under pulling stress.. so those screws will be helpful
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Old 13-04-2018, 06:21 PM
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No, I think the wedges in in the plates will pull the sections tight.
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Old 13-04-2018, 06:29 PM
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This is the situation I am talking about.
Of course, the residual amount of pressure will be dependent on bolts and how tight they are.
Also, when scope is pointing upwards (towards zenith is the extreme case), half of the channel is under compression, the other half is pulled apart.

Anyway... I found the suitable piece of 20x20x3 channel in my shed.. so tomorrow I am putting the whole thing together.
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Old 14-04-2018, 07:45 AM
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Quote:
Originally Posted by JA View Post
Hi Bojan,

If the extra bar is from the scope I think it would be a shame to remove and cut it, rather than keep it as an accessory bar for piggyback or finders etc.... I'd wait a bit as saddles sometimes come up in the classifieds. If it is for mounting to your mount, then possibly you could use a Skywatcher dual style (Vixen & Losmandy) replacement saddle for about $60 as in the ebay advert below here, but be careful with the mounting collar base recess to your mount as there are two types as shown in the cross-section in the image attached. You obviously wouldn't want the wrong one and the advert I attached doesn't show that detail unfortunately.

https://www.ebay.com.au/itm/SKYWATCH...4AAOSwl9RZ-qHl

Best
JA
Tried to get some more info from seller, but they do not know (??).

Does anybody have a drawing with dimensions of both styles, maybe it is possible to machine the "wrong"one into right shape?
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Old 14-04-2018, 08:02 AM
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SW changed the shape of the mating puck on the NEQ6 in 2008.
See the illustration:
https://www.altairastro.com/puck-to-...q5-mounts.html
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Old 14-04-2018, 08:31 AM
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Quote:
Originally Posted by bojan View Post
Tried to get some more info from seller, but they do not know (??).

Does anybody have a drawing with dimensions of both styles, maybe it is possible to machine the "wrong"one into right shape?
Hi Bojan,

You could ask them for a close up photo of the side AND bottom of the the mounting clamp? You should be able to tell from a good close photo.

Best
JA
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Old 14-04-2018, 08:43 AM
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Bojan,
If your mount is post 2008 then all the currently available puck/ saddles should work.
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Old 14-04-2018, 09:08 AM
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Quote:
Originally Posted by JA View Post
Hi Bojan,

You could ask them for a close up photo of the side AND bottom of the the mounting clamp? You should be able to tell from a good close photo.

Best
JA
I did .. no reply yet.
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Old 14-04-2018, 09:11 AM
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Well, in the meantime, that's it, more or less... proof of the concept, at least. I decided to mount EQ6 puck on the other bar (that was from the top of the scope... without cutting, just 4x6mm countersink holes were drilled for that), as my losmandy bar is not identical to ADM bars that came with the scope (it is couple of mm wider.. standards, standards....).

And I have plenty of space for accessories - they will be "under" OTA, but that is actually better because the imbalance caused by additions weight will be smaller.
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Last edited by bojan; 17-04-2018 at 07:03 AM.
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Old 14-04-2018, 01:01 PM
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Quote:
Originally Posted by Merlin66 View Post
SW changed the shape of the mating puck on the NEQ6 in 2008.
See the illustration:
https://www.altairastro.com/puck-to-...q5-mounts.html
I need the old style, before '08.
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Old 15-04-2018, 08:49 AM
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Drawing for milling 20mm square aluminium bar is attached.
I will try to have it done at some point in time... or someone can do it for me?
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Last edited by bojan; 15-04-2018 at 09:50 AM.
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Old 18-04-2018, 02:41 PM
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I decided to buy the Skywatcher saddle from ebay... and machine it to fit it to my EQ6 if necessary.

Drawings of "old" and "new" saddles are attached, together with necessary machining to fit "new" style to old EQ6.
I will also add ring to further reinforce the saddle when it sits inside EQ6 head.
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Last edited by bojan; 20-04-2018 at 06:19 AM.
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Old 22-04-2018, 02:46 PM
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Here it is on the mount, using temporary solution (while waiting for new saddle).
In total, ~30kg of weight.
Hopefully weather in Melbourne will hold for the first light

And it did...
The hardest part was to remove the OTA from mount - I had to use the support crutch which held the counterweight in horizontal position while I was sliding the OTA out from the improvised saddle.. it is really heavy, and one clumsy move (and unfortunately they are happening more often recently) and the damage can be fatal (for scope or for me).
I will definitely need that Skywatcher thing (expecting it next week, then I have to organise machining next Saturday)
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Last edited by bojan; 22-04-2018 at 06:32 PM.
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  #20  
Old 24-04-2018, 06:32 PM
gb44 (Glenn)
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Hi
So, with the counterweight bar supported horizontal, and the vertical OTA seated objective down on some sort of table ( height adjustable observing seat maybe), cant you open up the dovetail clamp to release the OTA?
Glenn
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