Posts Made By: Sam Greenlaw

Came across this one. A simple, easy-centering jig for getting pipe or rod drilled accurately. If you're doing small rod, put a piece of 2" "L" in the vee.

The centering trick isn't all that hard to replicate. Good enough for most of what ATM's do.

Maybe applicable for other ATM drilling jigs ?

http://www.angelfire.com/az3/acorn/

I have to use a big needle and a stereo microscope to get drilling accuracy for flat pieces. PLOP supports, most recently.

Position the drill and work piece with a big sewing needle in the drill chuck. The point of the needle makes dead center. Lots easier for me to see than a drill point.

I had problems installing the SAC7. It's a 640x480 system that also can do microscope work.

Earlier postings mention alternatives to SAC software. Given that I had to reinstall W98, that sounds good.

Phillips camera system. The SAC-imaging.com site

Anybody got a good link and alternatives ???

This little thing has been in its box for a year.

Ring-and-brush systems work fine, but we're talking labor intensive construction. Spring loaded graphite is best to get really smooth long lasting connections. But who bothers ???

A slightly pricey alternative is the Mercotac line of rotator connectors. True professional quality stuff.

For ATM type volt/ohm levels their COAXIAL line is doable. The 3-wire coax connector costs $45 plus the cap.

www.mercotac.com

305 3 conductor Coax 45.00
305-L 3 conductor, low temp. 45.00
Accessory Terminal Parts for 305 models (required for wire connection)
553 Cap, 3 solder lugs 6.23
593 Receptacle, 3 wires, 6" 10.46

Their modular type stuff is much more expensive. Diagrams and specs download from the web site.

Radio Shack has a 1/4" Inline Phone Jack and Plug pair that work just fine for a rotary connector.

cost: $8.

Catalogue numbers: 274-1428 and 274-1546A.

This a "heavy-duty shielded" plug-in. Three wires: one ground wire and two signal wires.

Figuring that batteries for power (warming mirrors and running fans) can go on the rotating upper part of the scope, two signal wires sounds good enough. E.g., altitude stepper and a power focuser.

It's probably useful to have the voltage levels to the steppers similar, so the single ground wire can serve the two subsystems adequately.

The "shielded" part of the description is not kidding.

The socket part this thing is a piece of thin-wall metal pipe. Clamped in a 3/4" (or thicker) wood fitting, it will do fine as a center post.

There's an odd idea that recurs to me. Building a short FL Newt for a focuser.

Still one problem. How's to do a small secondary mirror ? Something down around a 1/2" or 5/8" minor axis ??

The little 2.5" and 3" mirrors come around with FL in the 10"-18" range.

Just want to see how this works as a finder. A spare 30mm EP and a 250mm FL sounds right.

But the little secondary isn't readily available.

Maybe just cut off a slightly large rectangle from a glass vanity mirror ?????

Thanks !

If this CCD camera at this secondary thing is doable, then maybe it's worth looking at correction programs. Camera as the one-and-only viewing system.... with a CCD and $200 eBay laptop computer...

A correction program should be able to undo distortions of most types.

Back during the Cold War it was common rumor that the C.I.A. could do near perfect ray tracing on camera lenses.

The spooks could take a photo and the camera that made it. Analysis of the camera let them get a corrected photo as good as the theoretical limit of the film.

So... point a telescope/camera at a known object. The full Moon comes to mind. The image is distorted by systemic telescope/camera errors.

Not to speak of atmospherics, but multiple overlays should cancel out that one. A 50-ply overlay image sounds good.

Then run a correction-determination program.

Compare the overlay thingy with a known "perfect" image. A Hubble moon image would do, most likely.

You get the idea...

The resulting correction mask would function mathematically to adjust for telescope/camera distortion.

A near-perfect optical system ??????

Vane spikes are a different issue. Seems to me that's more like a sampling problem. Preprocessing the image input looks good for spike eradication.

Anybody know beans about this stuff ?

I'm a database "guru"-guy. Not a scientific programmer, image processing supercoder, etc...... ;^)

I looked for "correction" in the CCD forum. And "image correction" with "software" overall. Not much.

This is a cheap, easy way to make triangles. Works with door plate aluminum.

The folding sides make the triangles remarkably rigid.

Got a PLOP 27-point (12 triangles) from one door plate and a piece of scrap.

Recommendation: put the PLOP dimensions for the pieces on cardboard and flesh it out to this type of design. Easy, easy, easy.

The 27-point is way forgiving of drilling errors. And strong.

The professionals have different ideas about what "complicated" means. Here's a folded thingie that is far beyond my comprehension:

http://map.gsfc.nasa.gov/m_mm/ob_techoptics.html

Results at:

http://antwrp.gsfc.nasa.gov/apod/ap031231.html

Age of the universe determined to +/- 4 seconds.... ;^)

Flexible spacer material for mirror cell triangles is available with FLEX-PLUS BLUE electrical tubing made by Carlon, Lamson, and Sessions.

This is a blue plastic tubing with discrete ribs (not spiraled). It is relatively easy to cut 90-degree surfaces with a hacksaw and a mitre box. I smoothed it off with 200-grit sandpaper, but that's not necessary; the cut is clean with a little WD-40 sprayed on the blade.

Temperature sensitivity appears to be minimal. I froze a section to 0-degrees and it was still flexible.

This material also doesn't compress much at all unless you put it in a vise and crank on it. Hand tight plus an 1/8th turn (with a lock nut) gets excellent results.

What is this stuff used for ?

To support mirror cell triangles. A 1/4-20 nut-and-bolt holds the triangle in place. This tubing goes around the bolt and works beautifully to allow the triangle to tilt. A 1" section seems to be just right.

I use a ring of clear fingernail polish on the base plywood to keep FLEX-PLUS BLUE section centered on the bolt. It works.

Horrible expense: a 10-foot length costs $2.50 including tax.... ;^)

That's $2.50 for 120 mirror cell triangles. $0.02 each.

Nice picture. The curved mirror holders do double duty.

That makes sense.

Adding a third holder at the bottom couldn't hurt. Doesn't seem to need it though.

This is another labor saving design alternative. Much easier to router a curve (taking 1/4" a pass) than to build a sling setup.