Slashdot Mirror

This particular eclipse is an Annular, where the Moon's shadow is somewhat smaller than the Sun's disk. From the right location, it appears as a bright ring around a dark Moon. I've not seen one, but I've heard some Umbraphiles say "I wouldn't cross the street for an Annular Eclipse."

First of all, as for binoculars (a very good idea, IMO) they are described by a two number 'code' such as 7x50 or 10x70, where the first number represents the magnification and the second the size of the 'input' lenses (in mm). Surprisingly to most newbies, it's the second number that matters the most. The challenge in seeing many astronomical objects is not in making them bigger, but in making them brighter (there are exceptions, of course).

There's a catch, in that if you make the objective lenses too big without increasing the magnification accordingly you end up throwing a wider beam of light at your eye than can actually fit through your iris. The width of this beam of light is called the 'exit pupil' and you can figure it by dividing the objective size (the second number) by the magnification (the first).

So, for many years, astronomers were advised to get binocs that had this measurement as close as possible to 7mm, that being about as large as young, healthy pupils can get. Any larger and you'd be wasting light, any smaller and your magnification would be higher than optimal, spreading all that light your glass worked so hard to gather over a larger area, and thus lowering the brightness of any one part.

Nowdays, however, more experienced binocular observers than I have determined that some magnification is a good thing to have, too. They suggest different binoculars will show roughly the same amount if the product of the two description numbers is the same. Check the link above for details. I'm not sure I'm convinced, but I know one way to satisfy both criteria- I'll buy binoculars with a traditional exit pupil, but the very biggest one's I can handle.

Which brings us to the other numbers that describe a pair of binoculars. The price, about which no more needs to be said (except perhaps the occasional 'yikes!' form the underpaid sysape), and the weight. Larger binoculars are, of course, heavier. Heavier binoculars are really hard to hold steady enough to see things with when looking up. 7x50's seem to be about the limit for hand holding by most people. Maybe 10X70's if you're Conan. Anything much beyond that and you'll be looking for a photographer's tripod, or a beanbag perched atop a wall, or any of the other myriad gadgets astronomers have cooked up to hold their binoculars steady.

Gee, what a saga. I hope it's usefull to someone. Think I'll ramble about scopes such in another post.

The annual Persied shower is one of the best showers of the year and the best summer shower. The peak is around Aug 12-13 with upwards to 80 or so meteors visible per hour from a dark sky site.

A good source of info for coming astronomical events is Sky and Telescope magazine. You can find online info from S&T here.

a blue moon is when two full moons occur in the same month

BZZZZT. Wrong.

A blue moon is the third full moon in a season that has four full moons, instead of the usual three.

see this for an explanation.

This actually was a big thing a few years ago. Thus you have goodies like the Sky and Telescope Impact Hazards website, along with this nifty cosmic impact calulator.

To be fair, there is this article about a scientist that thinks mass extinctions are a myth. ( I am skeptical of this.

And not that a ten mile wide asteroid would make a mess, but that an asteroid needed to wipe out and actually destroy the earth would likely be much much large, maybe 1,000 miles across or more.

10 miles across is like a bug on the windshield. Note that humans are living on the outside of the windshield.

So it sounds like you get to have fun researching impact craters on google, etc.

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.

We will get our treat in December when Geminids (Dec. 12-14) hit us. :)

http://www.skypub.com/sights/meteors/meteors.shtml

Firstly, photo.net's search engine returns a few results:

1. The search results

2. This article is a good pick from the above search.

This site is supposed to have a very good article about meteor photography, but I haven't found the link yet. In any case it has a reasonable amount of information on meteors in general and how to best observe them. You'll find this information on this link.

Of course, if any body else has other links to similar information I'd love to see them. I haven't gone out myself to take these types of shots before, so any help I can get is good.

Finally, for a bit of inspiration - here is a photo (although not of a meteor shower, just star trails) that is just amazing.

Firstly, photo.net's search engine returns a few results:

1. The search results

2. This article is a good pick from the above search.

This site is supposed to have a very good article about meteor photography, but I haven't found the link yet. In any case it has a reasonable amount of information on meteors in general and how to best observe them. You'll find this information on this link.

Of course, if any body else has other links to similar information I'd love to see them. I haven't gone out myself to take these types of shots before, so any help I can get is good.

Finally, for a bit of inspiration - here is a photo (although not of a meteor shower, just star trails) that is just amazing.

Now days we call the 2nd full moon in a calender month a blue moon. But that was not the original definition.

Usually a season has 3 full moons, the last one often being called the harvest moon. On occasion, a season has 4 full moons. The last moon in the season is still the harvest moon. The 3rd full moon in a season with 4 full moons is the Blue Moon.

You can find this history in Sky and Telescope

According to them, it was originally defined as an extra moon within a season - since all 12 full moons within the year have a specific name relative to their season, this extra moon was the blue one.

So, (as has been pointed out) with our more recent definition, every Halloween full moon will be a blue moon, but with the old definition it would would be blue. (blue moons could only be in Feb/March, May/June, Aug/Sept or Nov/Dec - at the end of the season)

There was an article in the August 2000 Sky and Telescope mag about Automated Asteroid Hunting.

Here's the blurb from the online index:

Automatic Asteroid Hunting
Off-the-shelf software can help your telescope and computer do all the work of looking for minor planets.
COMPUTERS IN ASTRONOMY | By Jeff Medkeff

Here are other links:

software for telescope control

more links to robotic scopes

I doubt the problem of cataloging new asteroids lies with the actual finding of them. A simple image blinking discovery method would consume a trivial amount of computing resources. I'd suspect the tedious portions of the cataloging are due to the measurement of the angle/direction the asteroid moves in relation to the imaged field, it's correlation to the orientation the telescope was in at the instant it took the image, the time of year it was taken, the location of the observer, etc. and the calculations required to derive the asteroids actual orbit from these data. However I don't see why all that cant be computerized and automated with sensors (gps, atomic clock time, telescope orientation sensors, orbit calculation algorythms etc.) so that people are only needed to maintain the equipment. All that really needs to be invented is the software.

Keep in mind that these kind of things only make noise on TV and in the movies.

Depends on what you mean by "these kinds of things". The large fireball that was seen over Pennsylvania a few weeks ago "[i]n its final moments the fireball created a deafening sonic boom that shook the ground."

From a report from Sky and Telescope you can read here.

Steve M

Go out around 4am any clear night this week. Don't worry about the peak of the shower. Keep your unaided eyes open and be very patient. Since you're new at this and close to the city, consider 5 meteors per hour a success.

In the evening this month, the bright orange "star" in the south is Mars. The dimmer one to its right is Antares. Use a sky map to identify whatever else you can see. Sky and Telescope has a good general article for beginners.

Go out around 4am any clear night this week. Don't worry about the peak of the shower. Keep your unaided eyes open and be very patient. Since you're new at this and close to the city, consider 5 meteors per hour a success.

In the evening this month, the bright orange "star" in the south is Mars. The dimmer one to its right is Antares. Use a sky map to identify whatever else you can see. Sky and Telescope has a good general article for beginners.

You're just one more person with an agenda claiming unrelated benefits for compliance ... After reading this story, almost everyone will forget about it, because it's really not very important.

Perhaps you should stay more in tune with current events. Like the power crisis in California. Using less energy is not an unrelated but a pretty direct benefit.

The folks up in Clagary thought so, as you can read here. They expect significant savings in energy by changing to full cutoff light fixtures.

A similar law recently passed in Connecticut and another is awaiting the governer's signature in New York.

Light pollution also takes its toll on the environment in more subtle ways then wasted energy.

From a story at ABCNews.com:

"Darkness for Health

Scientists have now discovered that only when it's really dark can your body produce the hormone called melatonin. Melatonin fights diseases, including breast and prostate cancer. "It turns off the cancer cells from growing," says Joan Roberts, a photo biologist. But if there's even a little light around your bed at night, your melatonin production switches off. "So there may be this natural way that Mother Nature has given us, that is, dark night to keep certain cancers under control," Roberts says. Even watching TV turns on other immune system hormones that should be active only in daytime. They get depleted, and you're more likely to get a cold. Nature needs darkness, too. The immune systems of animals grow weak if there's artificial light at night."

Not getting cancer seems like a pretty significant benefit.

Light pollution also has adverse effects on migrating birds and plant life (the plants can't track the natural light curve and don't properly prepare for winter).

Interested readers my wish to check out the International Dark-Sky Association for more info on light pollution and its effects.

Steve M

--

Smog isn't the problem so much as light. It does have an effect, but most places that have smog have a lot of light pollution as well. I remember a friend who grew up in L.A. who freaked out the first time he went out to the desert at night and actually saw the Milky Way.

Chuckle. My first thought was: Many people already believe this, and that's why we have so much light pollution.

Hmmm, I was just reading some SETI stuff in the current Sky & Telescope (Bah, they don't have the currrent issue online... this is the closest thing I can find...) ... where they discuss using telescopes to broadcast optical stuff to alien SETI hunters.
--
If the good lord had meant me to live in Los Angeles

But the next leap forward is going to be European... ESO (European Southern Observatory) are constructing two identical telescopes in Chile and Hawaii (project Gemini.) How's that for a long baseline? ;p

And for bluesky "gee whizz" quotient, check out the Overwhelmingly Large Telescope (OWL)...

I've seen a chart somewhere (can't find a link - anyone?) charting aperture (light collecting capacity) of telescopes since Galileo. The Keck and other 10m class telescopes have moved the curve from a nice straight line to an exponetial curve - and that's not allowing for vastly increased computer power, active optics, and out-of-visible band stuff. Truly this is a fantastic time to be interested in astronomy, even (especially?) as an amateur. For a couple of thousand dollars you can do stuff in your yard that was the province of professionals only a few decades ago.
--
If the good lord had meant me to live in Los Angeles

To my mind a planet is something that is made round by its own gravity, and is in orbit around a star.

Clearly under that definition Pluto counts as a planet. Pluto even has a moon called Charon.

There are a whole bunch of reasons to not consider Pluto to be a planet:

• Pluto has a composition unlike any other planet. It most closely resembles Triton (a moon of Neptune).
• Pluto has an orbit which is unlike any other planet. It's orbit is inclined 17 degrees, and is high eccentric - it is sometimes closer to the Sun than Neptune. It's orbit is similar to at least 70 other Kuiper belt objects.
• It's "moon", Charon, is in a synchronous orbit (it's position is fixed relative to Pluto's surface). No (other) planet in the solar system has a natural satelitte in synchronous orbit.
• Pluto is far smaller than any other planet. It is half the size of Mercury and only two-thirds the size of our Moon. It is likely that many other Kuiper belt objects will be of similar size.
• Pluto is also very light in terms of mass. Current estimates put it's mass at around 1/500 of Earth's.

The fact that Pluto is made of ice is irrelevant- Jupiter is made of gas. Does that mean Jupiter isn't a planet?

For reference, here is the 2 year old CNN article about how the International Astronomical Union was/is considering reclassifying Pluto as a minor planet (like many asteriods). They decided against it. This is a really good article from Sky and Telescope covering the debate.

On the other hand, the spectacle of viewing 100,000 meteors per hour might grind society to a halt for a day or so.

Sky and Telescope magazine has a better article on the eclipse, with a bigger copy of the maximum eclipse map.

Sky and Telescope magazine has a better article on the eclipse, with a bigger copy of the maximum eclipse map.

Sky and Telescope magazine has a better article on the eclipse, with a bigger copy of the maximum eclipse map.

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).
• 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).
  • 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).&nbs 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).
• 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).

http://www.ee.surrey.ac.uk/

http://www.skypub.com/

Especially useful and entertaining is this Solar System Impact Calculator, where you if you are lucky, you can help Marvin the Martian get rid of the pesky planet blocking his view of Venus. :) You can check out effects of impacts on other planets as well. Just don't make Marvin mad ...

:)

- - - - - - - -
"Never apply a Star Trek solution to a Babylon 5 problem."

Especially useful and entertaining is this Solar System Impact Calculator, where you if you are lucky, you can help Marvin the Martian get rid of the pesky planet blocking his view of Venus. :) You can check out effects of impacts on other planets as well. Just don't make Marvin mad ...

:)

- - - - - - - -
"Never apply a Star Trek solution to a Babylon 5 problem."

Sky and Telecope Magazine has a neat asteroid and comet information page here. And to make things more interesting, there is an excellent online impact calulator here, complete with comments by "Marvin the Martian" if the interplanetary object you dial in is sufficiently large.

Sky and Telecope Magazine has a neat asteroid and comet information page here. And to make things more interesting, there is an excellent online impact calulator here, complete with comments by "Marvin the Martian" if the interplanetary object you dial in is sufficiently large.

?

Try this link. Where it says "Select Product Categories" at the top, pop open the combo box and select "Hubble Space Telescope". I'm sure there are others; if you e-mail me, I can probably track down some more for you.

Any Leonid activity you see will originate from the east, after the radiant rises, which will be aprox. midnight, EST.

Check here for info

These calculations have been done, and the result is that the best achievable resolution is on the order of 10 centimeters. Enough to read tail numbers on airplanes, not enough to read license plates or newspapers.

Not so fast.

Astronomers have found a way to overcome the atmosphere's turbulence: adaptive optics. If I recall correctly, they shine a laser upwards to create an artificial star, and then by monitoring the twinkling of the artificial star, the telescope mirror is dynamically distorted hundreds of times per second to compensate.

Such a mirror is now in place at Mauna Kea... the resolution rivals Hubble's, at a fraction of the cost. See Gemini North Sees the Light (scroll down to "Friday, June 25"), or the media fact sheet from the Gemini Project.

See also this picture of Pluto and Charon.

Now, the question is: can adaptive optics be used in the other direction, to observe the ground from space?

Did astronomers actually invent adaptive optics, or is it just another Cold War technology spinoff? Makes you go Hmmmmm.....