Mounting guidescope on evostar 80ed

[Daf1983]

I've just received my evostar 80ed today, and was planning on mounting a dovetail on top of the rings, so I could piggyback my guidescope.

The allen bolts that come with the scope and dovetail don't seem to fit. Does anyone know what size bolts are needed?

Dafydd

 

 

[michael8554]

Could be the standard Tripod size for mounting a still camera,  1/4"-20 UNC

Michael

[Ouroboros]

1 hour ago, michael8554 said:

Could be the standard Tripod size for mounting a still camera,  1/4"-20 UNC

Michael

Yes, that’s exactly what they are. 

[Daf1983]

Thanks! I found some 1/4 20  bolts in the back of the shed last night, and you are indeed correct👍. 

Edited May 20, 2021 by Daf1983

[Ouroboros]

18 minutes ago, Daf1983 said:

Thanks! I found some 1/4 20  bolts in the back of the shed last night, and you are indeed correct👍. 

Good find. I had to buy some. 
 

In fact I’m trying to do exactly the same thing by mounting my SkyWatcher Evoguide-50 on top on the rings.  Trouble is the green bar in which the guide scope fits isn’t quite long enough. I can’t get the rings close enough together in other words. So I’m going to need yet another bar between the rings and fit the green dove tail to that somehow.

I will be interested to see how you fit your guidescope. 

 

[powerlord]

maybe this is me botching things, but the madness of some random holes being UNC/20, some M6 was doing my head in.

1. svbony do cheap bars on ebay at 210mm if that helps

and/or

- get a piilar drill. you'll save the cost after your second bar. then you can drill holes where you want, the size you want. get some SS nuts and bolts in metric sizes from ebay and you are no longer a slave to the madness of random threads and positions.

- for a 450mm long bar I needed for my 200p for the top (i.e. opposite vixen), I just got a bit of 2in, by 1/2 inch ali bar. about £15 for 1m. Drill holes where you want, lots spare for others, etc. solid as a rock.

Edited May 20, 2021 by powerlord

[Ouroboros]

@powerlord Thanks.  I think this 15 quid Astro Essentials 18cm bar from FLO will probably do the trick. I can bolt the green bar to it via bolts coming up through the slots and bolt through the slots to the rings, if that makes sense. 

 

https://www.firstlightoptics.com/dovetails-saddles-clamps/astro-essentials-dovetail-bars.html#about_this_product

[Daf1983]

2 hours ago, Ouroboros said:

Good find. I had to buy some. 
 

In fact I’m trying to do exactly the same thing by mounting my SkyWatcher Evoguide-50 on top on the rings.  Trouble is the green bar in which the guide scope fits isn’t quite long enough. I can’t get the rings close enough together in other words. So I’m going to need yet another bar between the rings and fit the green dove tail to that somehow.

I will be interested to see how you fit your guidescope. 

 

I bought a longer ADM dovetail to mount the 80ED, so I have the original skywatcher to mount on top for the guidescope, which is a cheap 50mm Svbony. I was planning bolting the dovetail on top of the 80ED, and then attaching the guidescope with the clamp, similar to this one.

https://www.ebay.co.uk/p/27028681810

Not sure if this will work well or not. 

 

[Daf1983]

2 hours ago, powerlord said:

maybe this is me botching things, but the madness of some random holes being UNC/20, some M6 was doing my head in.

1. svbony do cheap bars on ebay at 210mm if that helps

and/or

- get a piilar drill. you'll save the cost after your second bar. then you can drill holes where you want, the size you want. get some SS nuts and bolts in metric sizes from ebay and you are no longer a slave to the madness of random threads and positions.

- for a 450mm long bar I needed for my 200p for the top (i.e. opposite vixen), I just got a bit of 2in, by 1/2 inch ali bar. about £15 for 1m. Drill holes where you want, lots spare for others, etc. solid as a rock.

The different size bolts really annoy me as well, especially when you have a mix of metric and imperial units on the same product!

[Geoff Lister]

Unfortunately, consumer-grade tripod-mounted optical equipment is supplied with an internal 1/4" - 20 UNC thread. It would be a brave manufacturer that used an ISO metric thread form; the returns, under warranty would be huge.

I prefer Whitworth, but my tool box contains something suitable for most imperial and metric fastenings; and if necessary, 4 different-sized adjustable spanners, pump pliers, and a Stillson wrench. My "come in handy" box (well lots of boxes and biscuit tins) contains an assortment of nuts, bolts and washers. I also invested in a 1/4" - 20 UNC tap, so I can add tripod threads at various OTA balance points on a dovetail plate.

Geoff

[Daf1983]

Just posting to give an update. Managed to get 1/4 20 unc bolts from ebay, and mounted the dovetail on top of the 80ed. I then brought a svbony clamp which I mentioned above to attach to the guidescope. Seems quite solid, but haven't had a clear night to test it out yet.

Edited May 28, 2021 by Daf1983

[Richard_B]

Looking good Daf

[michael8554]

Not bad, but the rings are too close, big overhang.

Take advantage of the lovely green bar and move the rear ring as close to the guidecam as you can. 

You could mount the rings directly onto the green bar and remove another source of Flex.

Michael

[Daf1983]

30 minutes ago, michael8554 said:

Not bad, but the rings are too close, big overhang.

Take advantage of the lovely green bar and move the rear ring as close to the guidecam as you can. 

You could mount the rings directly onto the green bar and remove another source of Flex.

Michael

Thanks for the tip. Looking at it again, I totally agree.

With regards to mounting ring directly onto the bar; I did think of doing this, but because I store the scope and guidescope separately at present, it would mean bolting and unbolting the guidscope every time I set up. Hopefully this will work well enough so I don't have to do that!