Skywatcher dob modifications

[Mokusatsu]

I got a Skywatcher 12" yesterday! Big upgrade from my 8" home made dob, but my dob had many features which I added over time which I miss now. It held all my eyepieces, it had handles in convenient places, I could slot my ipad into a place on the front of the rocker box, the tube cover velcroed onto the tube which not only kept it out of the dust but also helped with balance.

What are Skywatcher dob bases made out of? I'm guessing it's probably just melamine covered chip board or MDF, but I want to make sure before I start drilling a bunch of holes in it for attaching iPad and eyepiece holders etc I want to make sure it has the physical strength to hold them. It may make a difference to whether I use screws or dowels or something else.

I am thinking of doing the following mods. Has anyone else got one of these and has any tips, regrets or ideas?

- I want to make a more extensive eyepiece shelf, including for 2" eyepieces.
- I want to make a docking clip of some kind to hang the Synscan controller.
- I want to put wheels on one side of the dob, and mounting points for handles on the other, to make a wheelbarrow type arrangement for moving it around.
- I want to make a mounting point for placing a car battery (or later on maybe a jumpstarter) for powering the drive in the field.

I haven't done much to it yet except put a felt furniture foot pad inside the base where the tube knocks against it when it goes vertical, and replace the finderscope with a Telrad.

I'm planning on putting some baffles into the secondary tube (arcs made from aluminium sheets cut from a soft drink can, cut carefully to match the tube inside diameter, painted flat black, riveted in place) and doing a shroud. The focuser could be upgraded, without my glasses on it doesn't have enough inward travel to focus with some of my eyepieces when I use a filter wheel or something, so I'm going to swap in a low profile double speed crawford one.

I've seen mention of doing something to the azimuth bearing which apparently improves goto. Can anyone elaborate on that?

All ideas are welcome! I may eventually in fact just make my own custom base out of plywood, with all the features I need and with excess material cut out because this base is gratuitously heavy!

Travis

[astro_nutt]

Hi Travis.
I've recently brought a Bintel 12 inch dob, and like you,done a few mods. I have left the original mount intact for the scope when not in use. I have made another mount out of 16mm ply, and fitted a lazy sussan bearing with a fixed bottom pin to stop the mount from rocking. it also has a 150mm hole cut out from each side and a removable EP tray. This works out to be at least a kilo lighter than the original. I hope this helps.
Cheers.

[BeanerSA]

The factory bases are pretty sturdy, I've seen all sorts of things drilled in and mounted to them.

That said, using the existing pieces as templates, and recreating out of ply with extra cutoouts, will certainly result in a lighter, but sturdier base.

[Allan_L]

Hi Travis,
Greetings from the East Coast.
Congratulations on getting a really good scope.
I have similar, but I think an older model, of same.
Have you checked out the mods and project section of IIS. http://www.iceinspace.com.au/projects.html

I feel your pain about the weight of the base, but as yet I have not attempted to replace that. There are plenty of posts about replacing DOB bases with Marine Ply. But I have not yet had the urge to start this.

I have however done quite a few mods:

Replace Finder with Right angle Finder (skywatcher brand $99)
Added Red Dot Finder
Use a stubby holder with bottom removed for Dew shield for finder
Bob's Knobs for Secondary mirror
Dew Heater strap for secondary
Fan for primary mirror
Focuser modification to smooth action.
Addition of (skywatcher) electric focuser (excellent fine adjustments and no vibrations)
Levelling base (made from Form Ply, holes for legs to sit through, and Bunnings adjustable furniture legs) mine is a triangle base, 3 legs are easier to adjust than four) Also helps protect the DOB base from moisture in the ground/grass.
Home made shroud (based on Astrozap design)
Dew shield (home made from gym mat type material)
Tube Flocked
Bumper pad for tube meets dob base (as you already have done)
Magnetic counter weights (to offset big eps and TV paracorr etc)
A simple synscan controller holder made from a Bunnings foam paint pad with locking ball head, (held to dob base by a saddle clamp)
http://www.bunnings.com.au/monarch-180mm-interior-exterior-pad-painter_p1660526
so much more convenient, and removable for transport.
Velcro for attaching (slim line) 18 Amp/hour battery to front of dob base turntable.

You may be able to tell, we have a consistent problem with dew in these parts.:(

I have also done slip clutch adjustments you mention when needed, but I suggest you leave that until needed, as you can cause further complications when you start removing motor casings. I have some instructions that I have posted here a few times before.

Good luck, and enjoy.
It is really a nice instrument, and one I recomment without hesitation, even without the tinkering. ;)

[Mokusatsu]

Well I've solved the problem of mounting the synscan controller with three sticky backed velcro dots, and their opposites on the side of the rocker.

I also discovered that indeed I did have an appropriate tip for the scope to use with my Energizer XP18000 power pack, which should have enough juice if fully charged to last an overnight star party, and that too has been attached (to the inside of the box) with velcro dots.

I'm thinking maybe velcro won't be the ideal method for hanging up eyepieces, but it seems so far to be an excellent solution for various problems so I'm keeping an open mind. :P

Travis