Posts Made By: Mark Bernhardt

According to the December Sky and Telescope, the 10 inch LXD 55 model OTA weighs 29 lbs and the counterweights 30 (8 inch is 23+20). Dampening time is 6-7 seconds and vibration isolation pads reduce that by 2.

Sounds like it will be fine for visual use if you're not in high winds and keep the tube balanced.

Mark

Found an interesting article about a guy who is into making huge blanks in his garage. Pretty interesting stuff!

http://home.europa.com/~telscope/stadlem.txt

I would set some concrete goals before proceeding with the project. Since this is a class, maybe the equipment should be looked at like you'd look at football uniforms or something of that nature.

The goals I would set are at minimum the following.

1. One telescope per pair of students. This would include eyepiece sets, a mount and a chart.

2. The telescopes must have a fair chance of surviving ten years or more of use. This is an important goal, especially when it comes to acquiring funding.

3. The collection should be easily transportable.

Since you stated you are travelling to the dark sky site, I think refractors are your only option. I would shoot for a five inch refractor for each setup with a long and short FL eyepiece. A refractor also is very durable. The kids probably won't wreck it unless they knock the mount over. A dob has a delicate spider and a mirror that can break. Nose rings and things can fall down the tubes. They also need to be collimated which can cause stripped mirror cell holes, etc. A particle board mounted dob is close to the ground and would show wear sooner than a refractor. In ten years time with complete novices, everything will start going wrong with the dobs.

Mounts for the refractors could be obtained cheaply by the wood shop classes. Submit a blueprint for a simple alt-az mount, give the kids extra credit and they'd probably love to make them. They don't even have to look good. If one gets broken in the field just order another one from the shop teacher.

Tripods might be a problem. Maybe some piers could be made in metal shop with removable feet. There is a scrapyard around here that sells huge lengths of 3" stainless tubing by the pound. Again, they don't have to look that great. They just have to work.

The Orion Astroview 120 might be a good choice at F/5. It comes with two eyepieces. Or maybe something longer. You wouldn't need tube rings with this setup.

Also a couple of demonstrator scopes would be great like a larger dob and a SCT. Solar filters for daytime use might also be a good option. A couple of green laser pointers might help. Of couse a Ha solar filter would be awesome but you could blow your budget on that one alone!

Just a couple of ideas,
Mark Bernhardt

The ultimate star testing book is "Star Testing Astronomical Telescopes" by Suiter. You can find it at http://www.willbell.com/tm/index.htm and it is one thing I didn't get for Christmas even though I asked for it!

The two hole mask I believe is used as a focusing aid for astrophotography.

Mark Bernhardt

The Surplus Shed had some pinholes in metal plate for sale but it looks like they were all bought up. Maybe they ended up here..

http://www.sunflower.com/%7Eclafever/bezt/html/ezstar.html

Anyway, these are a .003mm pinhole in a metal plate. The above link used to say you had to place the 'star' 60 feet away from the telescope.

Another interesting write up on making your own..

http://www.mapug.com/AstroDesigns/MAPUG/StarTest.htm

Mark Bernhardt

They are out of business but many of them migrated to a new one called High Point Scientific.

http://www.highpointscientific.com/

Mark Bernhardt

No it's not just you. Bugs the heck out of me too!

Mark

I'm not sure about if it is true or not but I will say that all creationists are not created equal. I have an uncle who believes in creation and that it took literaly six days to create the universe. I've met others who are creationists but think that when God said "Let there be light" the big bang occured. The story of creation was explained to the prophet types in terms they could understand.

I think a professional astronomer would have trouble understanding God's motive in going to all that effort to create this universe in six days. A universe that under scrutiny appears billions of years old. Where light was created in mid-stream millions of years from its source. A universe with 3 degrees kelvin of background radiation for no purpose but to fool us. To me this reduces God to some kind of trickster like Loki.

I'd rather think that God created a particle that exploded, causing the birth of our universe. In this case I could see where an astronomer might think that anything so beautiful and complex had to be created.

Mark

I would just like to mention that someone is always saying the kids are all going to hell. Consider that the power brokers of today were students in the 60's.

And about the creation thing. Scientists are not theologians. If they wanted to study folklore they would have gone to seminary, the shaolin temple or anywhere far from MIT. Even if they decided to, how would they choose between thousands of religions and hundreds of creation theories? Where would they even start if the church leaders can't agree on anything?

Not to get too far off topic but why should a christian feel slighted because scientists aren't out there proving buddhism and palentology are false?

Mark Bernhardt

Here are a few to get you started. Without a cheshire eyepiece and/or a laser you won't get perfect collimation but the diagrams found in the links below can give you an idea if your project is on the right track.

http://gilstrap.home.texas.net/collimat/NoTools.html

http://www.efn.org/~mbartels/tm/collimat.html

http://home.earthlink.net/~flyj/mccluney.html

Mark Bernhardt