Posts Made By: Bruce N Nyquist

I am a bit confused on how to figure the best size eliptical secondary for my Edmund White 6" f8 scope. I have heard 15% to 20% obstruction but not sure how you figure that with an eliptical vs. a round primary.

What quality should I be looking for?? Will a 1/10th wave be OK or are substantially better results had with higher quality.

Thanks

Bruce

Yikes...... I am in the process of changing the old single stalk secondary out to a spider on my 6" f8 Edmund white tube.

I ordered a spider and holder from Sky Instruments (very nice by the way and $20!!). I had decided to change the mirror to a 1.1" MA after recent posts regarding that.

Question: After talking with the folks at Sky Inst. he talked about a ray trace to determine optimum secondary placement. Is there a place on the web that can walk me thru this??

He said that going to a 1.1" may not work out as the light cone may move the secondary out quite a bit and reduce focusor travel???

I obviously need to do some reading on this.

Thanks

Bruce

It is 8" ....... name that scope.

Herb,

Who has random access to my and others user info?? Like address, phone, etc.

Hopefully that is restricted to you.

I am going to put together a 4.25" f10 newt.

Questions:

Do they make Sonotube in a 5" ID?? If not what material do you recommend?

The spider assy I got for my 6" had a 1.3" secondary hold and it is apparently the smallest made??

Thanks

What size secondary would be best?? A 0.8"??

My thanks to Walter for the tip on the felt from McMasters.

Very good stuff!! I got the non-adheasive backed stuff.

After pondering how to apply the felt to my 6" f8 tube the light went on.

1. Cut the felt full length plus 2" (1" over on each end).

2. Clean inside tube with alcohol.

3. I used 3M spray adhesive for headliners, etc. (available at body shop supply store).

4. Using a broom handle.... Roll the felt onto the handle rather tightly. At the end, secure the felt with double sided tape in 2 or 3 spots. (tape on the inside surfaces, this ensures the tape will not contact tube. Tape is easily removed after.)

5. Spray interior of tube with adhesive and wait as directed. You could use brush on cement as well.

6. I used a helper for this. Put handle with rolled felt into tube (suspended in center). After the felt extends 1" on either end make contact with tube and roll firmly. Go slow taking care to keep it square. Double sided tape will release. Felt is applied without seams, or wrinkles.

7. With exacto trim ends and focusor opening.

Works very slick!!

What are you talking about??

I am looking into a used 4" refractor. This would be my first and I was wondering if the cell and lens can be sent out to be striped and recoated with better quality coatings??

If yes...... How much?

Thanks

My puter crashed!!! Lost all my links. Does anyone have the name of the place that I think Arthur got felt from?? Not Protostar...

Thanks

Does anyone have instructions on how to collimate an Astroscan by Edmund??

Thanks