Posts Made By: Ian Van Voorst

I have another question about the Dob Driver:

If you decide to forgo using the drive, how well does your scope work as a plain old dob?

Thanks in advance,

--Ian

Thanks! -- I just swiped it off of a colleague's desk

--Ian

Attached is the collapsed scope in its entirety.

Sorry for the bad pics btw. I only have a toy digital camera at the moment.

The main advantage of the string scope is fast set up and being able to have small poles that come apart. I didn't want to have to check an extra container with truss poles when I flew somewhere. The poles are taken from floor lamps and are unfortunately steel -- maybe someday I can replace them with custom made aluminum ones -- any suggestions for a source?

Things I would have done differently/may still change:

Lighter UTA: I should have used aluminum instead of dowels for the spacers and could get away with fewer spacers too. I considered a single ring UTA, but am glad I didn't do it -- I have already dropped it once and the two ring configuration saved my secondary.

larger secondary for better baffling. Still need to add a detachable baffle opposite the focuser.

The box that elevates the rocker makes observing while standing a little easier, but if I have a camp stool I don't think it will be that useful. It adds a lot of weight to the package and I may just make a regular ground board.

Better mirror cell??: I used the method of attaching the mirror with silicon adhesive (thick pads) to plywood a la Richard Berry. Many people including the guy who sold my mirror to me are adamantly against this. I chose an 8" mirror because it is about the largest mirror that can be mounted so simply. For a scope that will travel this much, the silicon adhesive seems like a good way to protect the mirror. Thoughts anyone?

Thanks to everyone on this message board -- I have garnered several ideas for this scope here.

--Ian

hmmm....

No one ever seems to mention Borg.

How about a Borg 100mm ED? I love the idea of a lightweight OTA that breaks down into pieces rather than being limited to a focal length that will fit into a carry on. More aperture, but it very lightweight so that you can get away with a lighter mount.

I don't own (yet), just like the idea in theory. Maybe someone out there who does can chime in.

--Ian

Making the altitude bearings larger will help as your friend mentioned. Of course the other solution is to add an easily adjustable counterweight, though balance may still be tricky.

I have a similar problem to yours. Aside from any problems with the center of the tube be balanced at the altitude bearings, I have a problem with the scope being too easy to move, so that balancing the scope is not possible for even a small variation in eyepiece weights. I am using altitude bearings which are slightly small because they are actually stored inside the mirror box of my scope, which is designed to be as compact as possible.

I think I will need to go with the spring-tension arrangement, similar to the commercial dobs. I would like to try PFA.

--Ian