Sean over at Visual Astronomy has a number of useful tips for observers filed under Astronomy Tips. These include topics like: care and maintenance of telescopes, as well as tips on objects you may want to look at. Monday, February 23, 2009
Astronomy Tips for the Observer
Sean over at Visual Astronomy has a number of useful tips for observers filed under Astronomy Tips. These include topics like: care and maintenance of telescopes, as well as tips on objects you may want to look at. 
Friday, February 20, 2009
Carnival of Space #91 @ Next Big Future
Monday, February 16, 2009
Make Your Stargazing Events Shine
Keep it Comfortable
Lying in a clearing, gazing up at the stars can be a wonderful experience. Use ground sheets or camp mattresses to keep away the damp. Mug up (a snack and drink) afterwards is always welcome.
Can’t see the Constellations for the Stars?
Switching from urban to dark sky observing can be almost overwhelming the first few times. Stars that you could easily find in the city can get lost in the vivid background of the Milky Way. If you’re looking for something specific, try getting out for a practice look or allow extra time. If you have a telescope, make sure the finder and main scope are properly aligned or you may find yourself lost in space.
Planning your Event
Before you go out, consider building planispheres (star wheels) and practicing with them at a meeting. Free templates for cardboard ones can be found on-line (or on my blog). You could also prepare some astronomical flashlights. Attach several layers of red cellophane over the ends of flashlights, holding them on with elastic bands. Try and see how little light you need to read.
Sites such as http://www.skyandtelescope.com/observing/ataglance provide information about what planets are visible in the night sky. For satellites and observing forecasts, you need location specific information. Two sites I recommend for this are:
- Clear Sky Charts http://cleardarksky.com/csk/ provides the best observing forecasts for over 3,500 locations. These charts give much more information than cloud cover and precipitation.
- Heavens Above http://www.heavens-above.com/ provides information on satellites including the Space Station, Shuttle, Iridium flares, and others. You do need to configure your latitude, longitude and altitude to get accurate predictions.
Tailor your event to your age group. Organize parallel events to keep attention and events manageable (especially if equipment is involved).
If you are using equipment, such as a telescope that requires setup, get to your site before your group and leave enough time to set up and adapt your eyes to the dark. Remember to keep the lens and eyepieces covered until use to prevent dew buildup on them.
Have other leaders take your group on a pre-watch night hike. Keep flashlights off to get their eyes adapted for night vision (about 20 minutes).
Break into smaller groups and rotate through the activities. One group can look at constellations, the Milky Way, and perhaps meteors and satellites. Another can use their planispheres. A binocular group can look at nebula, open clusters, the Andromeda Galaxy, and perhaps a comet. Use the telescope to look at planets, binary stars, globular clusters, smaller nebula, and galaxies. Take care to have the youth move their eye to the eyepiece and not touch the scope. Telescopes will need to be adjusted every few minutes to compensate for the Earth’s rotation unless they are capable of tracking.
Clear skies everyone!
— David Gamey is an enthusiastic Scouter with the 433rd Toronto Scouting Group, who has developed his own ScoutBlog with articles on compassless navigation, building planispheres, choosing binoculars and telescopes, integrated SkyForecast charts for some Scout camps, ringed planets, Earth’s other moons, and much more. Check out the site using category labels such as http://mangsbatpage.433rd.com/search/label/Astronomy or http://mangsbatpage.433rd.com/search/label/SkyForecast.
This article by David Gamey previously appeared in Scouting Life Magazine and is reprinted with permission of Scouts Canada.
Super Astronomy Books
- Night Watch: A Practical Guide to Viewing the Universe by Terence Dickinson
- Celestial Sites, Celestial Splendors by Herve Burillier
- Turn Left at Orion: A Hundred Night Sky Objects to See in a Small Telescope – and How to Find Them by Guy Consolmagno, et al
- The Backyard Astronomer’s Guide by Dickinson& Dyer.
This is the year with all kinds of educational and awareness events happening on a global and local level. For more information and resources see http://www.astronomy2009.org/. Look for sites and events sporting their official logo.
There are 11 cornerstone projects — something for everyone!
Earth Hour – March 28, 2009
Earth Hour will allow us to appreciate dark skies and how we can help the environment. See http://www.earthhour.org/. Plan on joining in now, and watch for ideas on how to do so in the March/April issue of Scouting Life.
Related Articles
Explore the Night Sky
— Ptolemy, c.150 A.D.
A night sky studded with stars has fascinated humankind for millennia. Thinking they were deities, the ancient Babylonians, Egyptians and Chinese organized them into constellations; making star maps to predict cataclysmic events or planting and harvest times, and to mark religious celebrations. Amazingly, some of these same constellations remain as part of astrology and modern astronomy. So, when taking your youth stargazing, you are doing more than earning a badge; you are engaging in a wondrous experience, as old as humanity itself.
Sky Maps
There are 88 constellations spread across the northern and southern hemispheric sky. To locate the ones overhead in your area, think of the night sky as a huge dome with stars stuck on its inside surface. Just as you need a map when exploring an unfamiliar landscape, use a sky map as your guide. Star maps can be purchased at a local book/magazine store or downloaded from several astronomy-related web sites on-line. Some of the on-line versions can even be customized to your exact longitude and latitude!
Since sky maps are held over your head when looking skyward, they will show the east/west cardinal points switched around when laid on your lap. To use the map properly, hold it printed side up, then rotate it clockwise 180 degrees. Keeping the face of the map visible, lift it over your head. With N on the map pointing northward, east and west will now be properly aligned. The center of the map is the part of the sky nearly or directly overhead. The outer circle of the sky map corresponds to the horizon.
You may need a flashlight to read a printed sky map. Cover the lens with red cellophane or a red sock to produce a red light that makes reading the map possible without affecting your night vision. Better yet, use commercial “glow-in-the-dark” maps.
Like all areas of study, astronomy has its own language. Understanding and using its vocabulary is essential when searching for constellations. See “Words You Gotta Know” (www.skyandtelescope.com/howto/basics/Words_Ya_Gotta_Know.html) for a great list.
Let’s Get Started
- Start your stargazing adventure indoors first. Become familiar with a good star guide book and sky map for the current season as well as your location on earth. Pick one or two constellations to look for and learn how to find them.
- When ready, find a high spot of ground away from any light source and where the horizon is visible.
- Allow a half hour for your eyes to adjust to the darkness. (See Star Myths sidebar for one way to pass the time.)
- Lie on your back with your feet pointed towards one of the cardinal points of the compass. Most stargazers begin by pointing north to find Polaris.
- Orient the sky map.
- Find Ursa Major (the Big Dipper), as a starting point.
- From there, focus your attention on finding the popular constellations (Ursa Minor - containing the Little Dipper), Orion (completely visible in winter), Cassiopeia, Leo and
VegaVirgo. Some star maps show star alignments you can use to find other stars and constellations. For example, after you locate the Big Dipper, look at the two stars that mark the outer edge of its bowl. Connect these two stars with an imaginary line and extend itbelowbeyond the dipper’s bowl. Polaris, the North Star, lies along this line, about five times the distance between the two pointers. No matter where the Big Dipper is in our sky, these two pointer stars always point to Polaris. - Be patient. There is a lot in the night sky to study. Wait for a clear night.
Sources of Printable Sky Maps
Skymaps
www.skymaps.com/downloads.html
Starry Night Online
www.space.com/snserver/snweb.php
(Type in your postal code and receive an up-to-the-minute, on-line sky map for your exact location.)
Star Bright, Star Light
On a perfectly clear and pitch-black night, only 1,500 stars are visible overhead. Most stargazers focus on just the 26 brightest, working through them one constellation at a time.
Most stars are suns and no two are exactly alike. They either glow dull red, blue, yellow or white. Varying from a few to several million kilometres in diameter, they are basically huge balls of mostly hydrogen gas held together by their own mass and producing enough gravity to create a constant fusion reaction in their cores.
The study of a specific star begins by first finding the constellation in which it appears and then locating where in the constellation it is positioned. To find Betelgeuse (pronounced beetle juice) for example, find Orion first. Betelgeuse is in the upper left hand corner and marks Orion’s right shoulder. Being a red supergiant, it is the ninth brightest star in the night sky. While cooler than our sun, it is more massive and over 1000 times larger. If placed at the center of our Solar System, it would extend past the orbit of Jupiter.
Orion has more surprises. Another of its stars is a binary — two stars appearing as one as they revolve around one another. Another star is actually a star cluster. A star-like object located in Orion’s sword hanging straight down from the middle star of his three starred belt and visible with the naked eye is actually a nebulae — a huge gaseous cloud.
The Planets
Of course, not all of the points of light in the night sky are stars, nebulae or galaxies. Five of them (Mercury, Venus, Mars, Jupiter and Saturn), move among the “fixed” stars and were named “planets” (wanderers) by the ancient astronomers. The three remaining planets (Pluto recently lost its planetary status) are not visible with the naked eye. It was Galileo who discovered the planets were not rogue stars but worlds like our own. By noting the changing positions of stars and planets over the course of two or more nights, you can witness how the Earth’s yearly motion around the sun alters the position of objects in the night sky. With the aid of a binoculars or a telescope, features such as phases, moons, rings and surface storms may also be visible. This site provides a good guide to the Solar System: www.astronomytoday.com/astronomy/solarsystem.html.
Shooting Stars
“Shooting star” is the name used to describe a meteor — an intense streak of light across the night sky. Meteors form when small bits of interplanetary rock and debris called meteoroids burn as they pass through the Earth’s upper atmosphere. The rare few meteors that survive the plunge and hit the earth are known as meteorites. While it’s possible to see a” shooting star” any clear night, there are times of the year when they seem to” shower” the earth.
Meteor showers are named after the constellations from which they seem to appear. One of the most spectacular showers is the Perseid which produces between 40 to 60meteors per hour around August 12/13 each year. Other strong meteor showers are listed in a calendar at: www.meteorshowersonline.com/calendar.html.
Artificial Stars
Unlike meteors which streak quickly and for only a short distance, some points of light move gracefully west to east from horizon to horizon. These are satellites — man-made objects launched into space for relaying messages, observing the weather, mapping the earth’s surface and even spying on other countries. Satellites can be best seen during the two hours right after sunset and two hours before sunrise when they best reflect the light of the setting/rising sun. You can tell where the satellites are orbiting by their speeds and brightness. Satellites orbiting on lower levels usually move faster and brighter than those located higher above the earth. One of these moving lights could be the International Space Station (ISS). To learn of possible IS sighting times for your area of Canada, visit: www.spaceflight1.nasa.gov/realdata/sightings/cities/skywatch.cgi?country=Canada.
Just Look Up
From believing that the stars and planets are gods and goddesses and that Earth is the center of the universe to now knowing that our sun is just one of hundreds of billions of stars that make up just our own galaxy in a vast universe of galaxies, human knowledge has taken an amazing journey over the past 5000 years. And like the great earthly and heavenly explorers of the Renaissance who separated fact from fiction, astronomers today continue to venture into unimaginable places. Just where this journey will take us, no one knows, yet we can share part of it by just looking up.
— Jim Cornish is a 5th grade science teacher in
Cubs – Astronomer Badge, #1 - 4
Star Myths
Reading aloud the myths of the constellations passes the time while waiting for eyes to adjust to the darkness. Tailor the story to the age of the youth and the constellation you are going to find. For instance, read aloud the story of Orion, and then find Orion in the sky.
Indoor Stargazing Activities
Make Your Own Constellations
Make Constellations in a Canister @ About.com
and www.wnit.org/outdoorelements/pdf/Constellation_Canisters.pdf
Mythology of the Constellations @ ComfyChair.org
Make a Star Finder @ NASA's Spaceplace for Kids
Orion the Hunter
See http://stardate.org/nightsky/constellations/orion.html
Give Me More
More interesting star web sites can be found on Scouts Canada’s web site, under Scouting Life’s current (January 2009) issue, as an additional page.
This article by Jim Cornish previously appeared in Scouting Life Magazine and is reprinted with permission of Scouts Canada and the author.
Related Articles
Sunday, February 15, 2009
Thursday, February 12, 2009
Easy "Red Eye" Exit Pupil Method
Astronomers talk about the "Exit Pupil" of their optical systems. Most commonly it's used with binoculars but it also applies to telescopes. It's used in two ways, (1) to find the best match between the lowest power of your system and your eye's pupils, and (2) in binoculars which have a fixed magnification to get the maximum light available into your eye.The rule of thumb used is that the exit pupil should be 7 mm. In binoculars, a 7x50 (7 power x 50 mm lens) is considered a near perfect fit for star gazing because it matches the exit pupil. A 10x70 would also be an excellent fit, but an 8x25 wouldn't provide enough light.
For more on this see Visual Astronomy on The Effects of Exit Pupil.
My son recently completed a Science Fair project on night vision which looked at pupil size and age. To get enough data he needed a quick, easy, and reliable method of measuring pupil size in the dark. They couldn't take everyone to an eye doctor and the "slit" method was neither easy nor quick.
What he came up with was the "red eye" method. By taking a flash photo with a digital camera after about a minute of darkness you can then use software like Photoshop or GIMP to measure the diameter of the red eye in pixels. The only other thing you need is an object of known size to find the number of pixels per mm. For this he used a dime (18 mm) on a Popsicle stick.
The photo above shows a 7 year old with an amazing 9mm pupil!
Later, I'll provide more about pupil size and age.
Related Articles
Thursday, February 5, 2009
Astronomy Links from Jan/Feb 2009 Scouting Life Magazine
Explore the Night Sky
- Words Ya Gotta Know from Sky and Telescope
- Printable Sky Maps from Skymaps.com
- Printable Sky Maps from Starry Night Online
- The Planets and Solar System from Astronomy Today
- A Shooting Star Calendar from Meteorshowers Online
- Artificial Stars from NASA Orbital Tracking
- Make your own Constellations (in a Canister) from About.com Space
- The Mythology of the Constellations from Comfy Chair
- Make a Star Finder from NASA's Space Place for Kids
Make Your Stargazing Events Shine
- This Week's Sky at a Glance from Sky and Telescope
- Observing Forecasts for over 3,500 locations from Clear Sky Charts
- Charts on Satellite, Space Station, Shuttle flights and others from Heaven's Above
More Astronomy Links (Scouting Life Website)
- Night Sky from Space.com
- Night Sky Video from the Hubble Site
- The 10 Brightest Stars from SPACE.com
- The 26 Brightest Stars from WISC
- Welcome to the Planets from NASA's JPL (corrected)
- Shoebox Planetarium from Middleschool Science
- Tin Can Planetarium from Familyfun (note: article is at the very bottom of the page)
- Cyberchase Games Star Gazing from PBS Kids
- Star Journey from National Geographic
- The Hubble Space Telescope Site from NASA
- Stargazing Basics from Sky and Telescope
- Windows to the Universe from UCAR
- Sky Almanac from StarDate Online
- Stargazing Weather for Canadian Cities from The Weather Network
- 2009 Monthly Sky Guides from About.com Space (updated)
- Constellations by Month from WISC
- Your Sky from Formilab
- Sky Map from Sky Map
- Sky Cafe Interactive Planetarium from Sky View Cafe
- Google Sky
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