SW ED80 long dovetail bar

[luka]

Hi,

Any ideas where to find a longer dovetail bar for my ED80. Something like this (https://www.bintel.com.au/product/skywatcher-dovetail-bar-30cm) but at least 35cm (14") long. I need the extra length to attach counterweights to the front to balance the mount.

I have found this (https://www.bintel.com.au/product/losmandy-vixen-universal-plate-14-inch) but unlike the dovetail I linked above it is not possible to use the two extra screws on each tube ring to improve the mounting stability of the OTA. In other words, only the middle screw will be pressing each tube ring while the SW dovetail allows 3 screws on each tube ring.

And then there are these (https://www.bintel.com.au/product/farpoint-vixen-style-dovetail-bar-celestron-8-sct-ota) Farpoint dovetail bars which may require drilling & tapping of holes but there is no info how long they are.

Confused. Does any Vixen type dovetail bar fit and where to find a long one?

:thanx:

[Benjamin]

I added an ankle weight (I think from Target) to the end of my ED80 for balance. Adjustable, stays put and keeps the dew shield nice and stable as well.

[ab1963]

Hi Luka
All you need to do is go to Rebel sports and buy the velcro attaching ankle weights and attach to the front end of the scope and you will not need to worry about a longer dovetail bar to balance out ,I use one with a Vixen SD81S with a Ethos 21mm and 2x powermate and balances no problem ,If you need more info pm me

[luka]

Thank you Ben and Andrew, excellent idea.

Got the ankle strap, now I just have to find a Velcro strap that is long enough to go around the front of the scope/dew shield to secure it. Pity that Velcro that is part of the ankle strap is not long enough.

:thanx:

[ab1963]

These are the ankle weights you need here one is around a 100mm refractor and works the same around my 80mm also

[Benjamin]

These ones worked for me:
https://www.kmart.com.au/product/2-pack-ankle-weights/719362?&gclid=EAIaIQobChMIn7iPopSR5gIVwyMrC h32JQBWEAUYASABEgIPt_D_BwE&gclsrc=aw.ds
No extra Velcro needed for the ED80

[Tulloch]

That's a really neat solution, I hadn't thought about ankle weights!

I have the opposite problem, I have a C9.25 on an Evolution altaz mount which is top heavy. Moving it further back into the mount means I can't attach the Barlow and camera I need at high elevation angles. I've tried strapping a hand weight onto the handle but that didn't hold securely enough, and last week I drilled some holes out of a 20cm long Aluminium bar from Bunnings, attached a plastic coated diving weight to it and screwed it into the dovetail holes. It's very industrial looking at the moment but it does help the balance.

Anyone got any other ideas for back weighting the OTA? There'e not a lot a space to move back there.

Thanks, Andrew

[luka]

Thank you Andrew and Ben. I joined two of my old ankle weights and got it around the dew shield, but with an extra 1kg of weight. The guiding looks better than ever (in a short test), I suppose the mount does not have to "fight" the imbalance any more.

Considering that the Kmart ones are cheaper, Ben, did you use just one to go around? They look suspiciously similar to the ones I have here.

Regarding the back-weighting Andrew, not sure. It looks quite good what you did, as long as it does not shift. I assume that there is no dovetail bar on that side of the OTA, otherwise this (https://www.bintel.com.au/product/losmandy-dvdws-counterweight-2-5lb) could help. Someone else may have better suggestions.

[Tulloch]

Hi Luka, thanks for that. Yes, no dovetail on that side as fitted, and it uses the wider CGE dovetail on that side. So like you, I would need a longer dovetail (http://www.sirius-optics.com.au/celestron-14in-dovetail-bar-cge-wide.html?gclid=EAIaIQobChMI39_UyJu V5gIVSgwrCh1ncQCVEAQYAiABEgLPaPD_Bw E) to fit the scope, plus the weight and attachment (https://www.bintel.com.au/product/losmandy-dvdws-counterweight-2-5lb/?v=6cc98ba2045f), adding up to a cost of over $220.

Sure, it would look pretty (although I'd still have to drill holes in the dovetail to fit my 9.25), but for $40 and an afternoon drilling some holes in some Aluminium (https://www.bunnings.com.au/metal-mate-60-x-3-0mm-1m-aluminium-section-fluted-strip_p1109984)from Bunnings and a diving weight (https://scubadiving.com.au/products/pvc-coated-1500g-weight), my solution seems to work OK right now.

Maybe one day I'll stump up for the more expensive solution, but just wondering if anyone had any other ideas.

Andrew

[Merlin66]

I also need a longer bar - to support a spectrograph behind an ED80 (to use as a spectroheliograph)
Found 40 x 10 mm aluminium bar x 600 mm long available from Just Aluminium (local distributor for Direct Aluminium in Geelong) for $12......
http://www.directaluminium.com.au/2017-catalogue/

[luka]

To answer my own question if anyone else comes looking for an answer, the Kmart ankle weights that Ben posted above seem to be the cheapest solution ($6.50) that will just reach around the ED80 dew shield.

Anything larger and you should get the one Andrew suggested above from Rebel sports.

Also I have possibly found a longer Vixen-style dovetail bars, 400mm long here (https://www.aliexpress.com/item/32957065108.html) for example. However, I am not so sure about the stability because of the long cut along the length.

:thanx: everybody!