DIY Dobsonian mount for 130mm Skywatcher.

[Gazereths]

Sorry if this is in the wrong section.

 

I have the 130m Skywatcher but am less than impressed with the cheap EQ mount, I was thinking of making a Dobsonian mount for it. I did a few quick designs on CAD but found that to get the eyepiece at a reasobale height the mount would have to be too tall and thin to be stable.

I saw this DIY one online but it seems you'd either have to table mount it or be on your knees to use it. Neither is really acceptable for me. (see pic at bottom of post)

How does the circumference/size of the bearings change the stability and smoothness of the mount?

D'ya think it's feasable for such a small scope or am I better off just saving up some pennies (and waiting for stock) and getting a purpose made 8 inch or above Dob?

 

 

Edited January 6, 2021 by Gazereths

[Spile]

I would give it a go and like you I would choose to go floor mount. I cannot see why raising the pivot would be an issue as long as you increase the base accordingly. Why not use the same dimensions as the Skywatcher?  

[Gazereths]

On 07/01/2021 at 16:24, Spile said:

I would give it a go and like you I would choose to go floor mount. I cannot see why raising the pivot would be an issue as long as you increase the base accordingly. Why not use the same dimensions as the Skywatcher?  

It just seemed like the mount would be very thin and top heavy on the drawing I made. The CAD drawing is on my office PC, when I get back there I'll grab a copy so I can show you what I mean. I think I might build one anyway as it's something to do during lockdown. I have the tools and skills, just need the materials (either MDF or PLY I'm thinking)

Edited January 9, 2021 by Gazereths

[johninderby]

Others have mounted a mini dob mount on a tripod which gives ypu height adjustment as well as portability.

 

 

Edited January 9, 2021 by johninderby

[Tiny Clanger]

On the cloudynights mega thread for the 130 heritage dob (they call it the OneSky Newtonian as that is how it is badged in the USA)  several folk have theirs on an IKEA 3 legged stool which is apparently just the right size , the name of the stool is KYRRE . Only cost about £10 last time I looked, cheap enough to not feel bad if you drill holes in it for the dob base feet , or some fixing bolts .

Heather

[Ricochet]

On 06/01/2021 at 23:09, Gazereths said:

I did a few quick designs on CAD but found that to get the eyepiece at a reasobale height the mount would have to be too tall and thin to be stable.

Did you make each design as a simple box? Did any of your designs flare out a bit towards the base? Instinctively, this feels like a more stable design, and your base board can then be of a similar size to those used on the 6-10" versions commercially available. Even with these larger versions, the telescope is too low to observe standing, and a height adjustable chair is required to observe.

On 06/01/2021 at 23:09, Gazereths said:

How does the circumference/size of the bearings change the stability and smoothness of the mount?

The larger the bearing size, the more stable the mount will be. If you have a small bearing, you may need high friction to keep the telescope from moving when you don't want it to, which will reduce smoothness.

If you do decide to make something like the picture that you have found, I would suggest that you alter the design so that both tube rings are used to hold the tube. On one ring I think there is the potential for the tube to want to flex in the ring when a force is exerted on the telescope (e.g. when you move it to find or track an object).

If you think a tripod mount might be more suitable (and affordable than a larger scope) then I would imagine that the Skywatcher AZ4 should hold your telescope well. I don't know if the long length of your telescope would have any issues pointing at the zenith with that sort of mount though.

[NGC 1502]

Some good solutions above, a tripod with alt-az mount is a viable option.  Or with a Dob mount if the eyepiece is too low for standing to observe then my own solution is a seat.  I use an adjustable height drummers stool, nice and comfy for extended sessions.

Ed.

[johninderby]

You could use thick aluminium bar on the base to mount the feet or castors which would allow you to make the base to fit the scope and the “outriggers” would give stability. You could even make the outriggers removeable to save space when transporting or storing.

I made this tall base for a bigger dob recently from 18mm marine ply.

Edited January 9, 2021 by johninderby