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Posts Made By: daniel gillis

January 17, 2003 10:28 PM Forum: Equipment Talk

Curved Spiders

Posted By daniel gillis

Hello Tom,

I have built a curved support for my homebuilt 12.5"
dob (Parks primary). I prefer the lack of spikes in the images I see--especially when the seeing is steady.
I must also say that some ATMers I have talked to think that the first defraction ring is enhanced as well as increased "glow" from having a curved vane. I do not think so from my limited experience.

I know that ProtoStar sells secondary mounts w/o the supports that you can then add a curved vane to. Sky&Telescope had an article in the April 2002 issue (I believe) that described building a whole assembly. I built my whole secondary assembly out of wood, some bolts, a nylon screw, and a stainless steel strip. Its not too hard especially if you have built four scopes--this 12.5" was my first.

Daniel

February 22, 2004 10:58 PM Forum: Telescope Making

Has anyone made a break down refractor?

Posted By daniel gillis

Hello Bill,

About two years ago I built an optical tube intended for a D&G f15 refractor that could break down into two sections for transport. After getting it constructed I decided that the 75" tube was too long for my tastes--my alt-az mount was not very good.

Still the ota was about 10 pounds without the objective but with a 1 1/4" refractor focuser, homemade rings with altitude bearings, and 30mm finder. I used a product called Hollowood (32" long 6" outside diameter, 30" long 4" outside diameter, and a smaller diameter Hollowood tube holding the focuser. The two largest tubes were held together using large pvc plumbing fittings which were glued with Plumber's Goop to the Hollowood tubes. It was quite rigid and allowed the tubes to be unscrewed apart for shorter transport.

Food for thought,

Daniel

July 18, 2004 08:40 PM Forum: Telescope Making

Bearings for Alt Az

Posted By daniel gillis

Hello Ian,

I have built a couple of dob mounts for refractors. An excellent material for the alt bearings is 6" PVC pipe glued to 3/4" thick wood. This is in turn bolted directly to the tube rings or bolted to another board that is bolted to the tube rings. The cradle used Carpet Glides purchased from one of several retailers. This can provide for a nice movement in altitude. I have a picture of one such project on an old ad for a folded refractor listed awhile back on Astromart.

Daniel

February 6, 2005 06:46 PM Forum: Telescope Making

New home built 12" ultralight dob

Posted By daniel gillis

Hello Alan,

Congratulations on a nice design! Elegant yet simple. I especially like the secondary mount using wire.

I have a two plus year old lightweight homemade 12" dob--a little dated now. There is an article at cloudynights describing its construction. I am in the process of replacing the original 20 pound mirror with a 10 pound 1" thick custom mirror to further reduce weight to around 35 pounds.

I have had luck with using felt sheeting as a baffle material for the upper assembly. A simple tube formed of felt held in place with velcro might work without adding much weight.

Again, nice scope.

Daniel

February 17, 2005 06:18 PM Forum: Beginning Astronomy?

WHy doesnt my view of Saturn look like the picture

Posted By daniel gillis

Hello Ben,

I like the suggestions concerning using a little higher magnification and just plain practice.

You might also want to do some mooching off of other people's scopes to compare what they see with what you see at the same eyepiece. An experienced observer can sometimes point out subtle details to look for that might otherwise go unnoticed.

February 20, 2005 05:57 PM Forum: Telescope Making

Dob base and bearing?

Posted By daniel gillis

Hello Nate,

There is a good article on dob bearing materials in the October 2003 Sky&Telescope issue.

I have tried various combinations of materials on dob mounts of various sizes. From personal experience, I think PFA (perfluoroalkoxy fluorocarbon) used with ebony star is excellent. The PFA is more expensive than regular teflon though. I like PFA especially for lightweight applications like on my lightweight 12" dob.

Good luck,
Daniel

July 7, 2006 02:33 PM Forum: Reflectors

Sky Designs

Posted By daniel gillis

Hello Darian,

My good observing buddy has a 14.1" Sky Design with a wonderful primary mirror. The scope has passed through a couple of club members hands since it was built. It did indeed have a very annoying secondary mounting system. The primary mount was not much better with three triangles glued to a leather cover. But the woodworking is very solid.

After one Copper Breaks Star Walk when the wind actually knocked it over and broke the focuser, we decided to do a major remodel of the scope. It lives on with a homemade curved secondary support, a Moonlight focuser, four quick setup truss poles, new ventilation holes in the primary box, a new primary mirror mount with four collimation adjustments in front of the mirror, and fitted with an Argo Navis.

The scope keeps working--a real deepsky workhorse. As I said a wonderful mirror.

Daniel

April 12, 2009 07:31 PM Forum: Telescope Making

Folded Refractor

Posted By daniel gillis

Nicely executed.

I built two folded refractors several years ago. The first one had an excellent 5" f15 doublet objective. I cheated somewhat and had just one fold in the ota. You could either look down the focuser or use a regular refractor diagonal to redirect the light to a 90 degree angle from the scope.

Daniel

May 7, 2009 05:01 PM Forum: Digital SLR AstroPhotography

A question about computers

Posted By daniel gillis

Thanks for the feedback. I will pass it on to my daughter.