Domain: stellafane.com
Stories and comments across the archive that link to stellafane.com.
Comments · 7
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Re:Why not binoculars first?Tools can be made of a number of materials. From the Stellafane http://www.stellafane.com/atm/atm_grind/atm_tile_tool.htm tool page:
Alternative backing materials have been used - a concrete disk is shown at below. Two 3/4" plywood disks, bonded together, can also be used. But for low cost, light weight and all around good durability, Plaster of Paris can't be beat.
They mention using plaster. I prefer dental stone, but the process is very similar. Some amateurs even aluminize their own mirrors as well, but most do not. It actually can be fully DIY if you want. -
Re:Why not binoculars first?Ok my own post spurred my curiosity again and I clicked the link a few posts up. http://www.stellafane.com/atm/atm_myths.htm * How do two Flat Pieces of Glass grind into Spheres?
With the Mirror on top, the tool on the bottom, and coarse grit in between, we start grinding with the mirror overhanging the tool. We rub the center of mirror against the edge of the tool, and this wears a depression in the center of the mirror (the edge of the tool wears down also, so that the tool becomes convex (a "hill" in the center) and the mirror becomes concave (a shallow "bowl").
As grinding progresses, we grind with more center-over-center strokes, which will cause the mirror and tool to become matching spherical surfaces. So that makes it clear to me how you can do it with 2 glass blanks with one being the tool and the other being the mirror. Still doesn't explain to me how you do it with the porcelain tiles method. Unless there is enough thickness in the tiles to wear the tool down to the necessary sphericalness as well as the mirror.
I also forgot to mention the figuring process. The same link above also explains that the figuring is how you go from a spherical curve to a parabolic. I guess there is not much difference in shape if you can make these adjustments with the fine pastes & polishing compounds alone.
I so have to make me an 8" one of these babies. I do not have any astronomy gear yet and will, in about a year, be in a similar situation as the original poster with regards to getting started in astronomy and I just got my DSLR for that aspect of things. I wonder if making my own would be a worthy way of starting out... -
Re:Why not binoculars first?
Sure. It's not nearly as much equipment as one might think. The Stellafane ATM pages http://www.stellafane.com/atm/atm_main.htm are a good starting place to learn about how it's done. The best book I've found on the subject is How to Make a Telescope by Jean Texereau. Another fine set of books are Amateur Telescope Making - Volumes 1, 2, and 3 by Albert G. Ingalls (Editor).
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Some NASA dudeI accompanied my Dad to the Stellafane the weekend before last where some NASA dude talked about how amateur astronomers with small telescopes 6-12 inches might collect useful data on planets partially eclipsing ( transiting ) stars by measuring and graphing the brightness of the star using a CCD.
I am not really into astronomy, but I wonder if one of those guys found it..
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Amateur Astronomy and Telescope MakingLet me use this opportunity to plug a fascinating and intriguing hobby, Amateur Astronomy and Telescope Making.
I made several telescopes when I was a teenager, and have recently taken up grinding glass again after a long hiatus. I was also pleased to find the Central Maine Astronomical Society is in my area and joined last night while visiting their new observatory.
Telescope mirrors can be made by hand with suprisingly simple equipment. An eight-inch diameter telescope will run you about $250, maybe less if you're creative, for the mirror kit, eyepiece, aluminizing, and mounting.
There may be a telescope making or astronomy club in your area. A good way to find out is to subscribe to the ATM mailing list. Another way is to follow some of these links:
- Chabot Telescope Maker's Workshop (Oakland, California)
- Sidewalk Astronomers (Los Angeles and San Francisco)
- Amateur Telescope Makers of Boston
- Stellafane - Springfield Vermont, where the hobby was started in the USA
If you don't want to build a telescope, you can buy one. The telescopes made by Meade and Celestron are well known. You can find ads for dealers in the pages of Sky and Telescope Magazine, which you'll find in many bookstores.
A large number of astronomy products may be found through the Astronomy Mall.
Although the price differential for small telescopes like 6 or 8 inches is not that great between making it oneself and purchasing, the cost of purchasing really large instruments is really prohibitive, while large ones are actually affordable to make, comparable to purchasing a computer. If you start off making an 8 inch mirror, your next mirror can be much larger, say 16 inches, and amateurs commonly make mirrors from 20 to 30 inches, and I think there is a 72 inch mirror nearly complete made by some amateurs. My goal is to have a 40 inch observatory in my backyard.
Although I've listed U.S. organizations and companies, telescope making is practiced world-wide. A while back someone from Iraq subscribed to the ATM list and asked for help obtaining a kit. There are lots of subscribers from Europe and a number from Asia and Africa. Follow the links, and maybe you'll find a club in your home town, or at least within a reasonable distance!
I cannot describe the awe that comes from beholding the wonders of the heavens through a telescope made with one's own hands.
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Re:getting started young
Kinda reminds me of my first astronomy class. I hadn't even made it to my freshman year of high school and I had 4 credits of Astronomy from the local community college.
Many people have given good advice above. I'll mainly just second their comments. The order I'd proceed in is.
First item, a good beginners star atlas.
Second item, warm clothing.
Third item, many nights in the country just learning the stars and constelations.
After that go and get a good pair of binoculars or a good telescope.
Last, but not least. As your doughter is so young, you will need to be there as a source of infromation. You'll need to learn alot to help guide her in the early years.
Now for some Links. The first two have good beginners information. Some of the links below may be dead. I just quick cut and pasted them from the astronomy section of my Interesting Places page.
- Astronomy Mag. (www.astronomy.com/home.asp).
- Sky & Telescope Mag. (www.skypub.com).
- Minnesota Astronomical Society (MAS) (www.mnastro.org).
- The Telescope Shoppe (www.telescopeshop.com), 3402 Federal Dr., Eagan, MN, 651-688-7335. Yes this is a local Twin Cities telescope shop. They have a map on their site showing where they are. They are tucked in the lower level along the side of the strip mall they are in. The store is small and easy to miss. If your at the corner of Yankee Doodle RD and Federal Dr., park in the lot to the south east. They are a short stones throw from the intersection.
- Telescope making links
- Many good links on making AltAz mounts (zebu.uoregon.edu/~mbartels/altaz/altaz.html).
- ATM's resource List (www.freenet.tlh.fl.us/~blombard).
- Astronomy-Mall.com (www.astronomy-mall.com/Astronomy-Mall).
- Stellafane (www.stellafane.com).
- Terrestrial Planet Finder (tpf.jpl.nasa.gov).
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Many Images of the moon (www.seds.org/nineplanets/nineplanets/pxmoon.html
) . - Solar Views (www.solarviews.com).
- Planetary Image Atlas (www-pdsimage.JPL.NASA.GOV/PDS/public/Atlas).
- Hubble Space Telescope Archive (oposite.stsci.edu/pubinfo/pictures.html).
- Hummble Site (hubble.stsci.edu).
- StarStuff (www.starstuff.org).
- SpaceRef (www.spaceref.com), Your space refference.
- Astronomy Picture of the Day Archive (antwrp.gsfc.nasa.gov/apod/archivepix.html).
- SkyView (skyview.gsfc.nasa.gov) virtual observatory.
- 2MASS (www.ipac.caltech.edu/2mass/) and (pegasus.astro.umass.edu/GradProg/2mass.html) Two Micron All Sky Survey.
- Large Angle and Spectrometric Coronagraph Experiment (LASCO) (http://lasco-www.nrl.navy.mil/lasco.html).
- AAVSO Network to Search for Optical Counterparts of Gamma-Ray Bursts (www.aavso.org/grb.stm).
- High Altitude Observatory (www.hao.ucar.edu).
- Asteroid Comet Impact Hazards (impact.arc.nasa.gov).
- Unusual Minor Planets (cfa-www.harvard.edu/iau/lists/Unusual.html).
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Potentially Hazardous Asteroids (cfa-www.harvard.edu/iau/lists/PHACloseApp.html).
& nbsp; Of particular interest to me are LB16 and AN10 which will pass at a distance closer than the moon's orbit. LB16 currently only has one opposition charted so it's predicted orbit will likely change as new data comes in. It's expected to swing by in 2004. In 2027 AN10 will visit earth. It's orbit is calculated with three oppositions meaning it't much more likely to really showup ontime and in place. With further data LB16 could either get closer or farther away. When AN10's orbit was first predicted (only one opposition at the time) it's error envelope included earth. With further data it was found to just pass within the moon's orbit and miss the earth. -
Forthcoming Close Approaches To The Earth (cfa-www.harvard.edu/iau/lists/CloseApp.html).&nb
s p; This is the document to look at when you want to know who will visit next and how far away. It has all close approaches to 0.2 AU away from earth or within 20% of the distance of between the sun and earth. On Sep 19th, 2000 we will have a visiter at 0.0477 AU and on Oct 31st anotehr one will pass at 0.07386 AU. LB16 and AN10 are expected to pass at around 0.25% of the distance between the sun and earth.
- Mars Global Surveyor (mars.jpl.nasa.gov/mgs/index.html).
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Mars Orbiter Laser Altimeter (MOLA) (ltpwww.gsfc.nasa.gov/tharsis/mola.html).
There are full data on the shape of Mars including 1 degree and
.5 degree elevation data sets. - Planetary photojournal by JPL (photojournal.jpl.nasa.gov).
- NASA's Origins Program (origins.jpl.nasa.gov).
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stellafane
take her to the stellafane convention put on by the springfield telescope makers. i go every year and every year i learn more and more. check them out (http://www.stellafane.com)