Star Patterns in the Night Sky and Two Late Month Meteor Showers

Last month I talked about how a casual stargazer can identify the International Space Station, the Space Shuttle and Iridium Flares traversing the night time sky. While the appearance of these man-made objects change from night to night, the star patterns we observe have remained practically unchanged for thousands of years.

With that in mind, it shouldn't be a difficult task to learn how to identify the constellations that can be seen from here in southern New England.

While many people with even a basic knowledge of the night sky can at least identify Ursa Major (the Big Dipper), Taurus (the Bull), and possibly Orion (the Hunter), other star patterns may elude all but the keen observer.

The easy way to learn the constellations is to accompany a person who is already knowledgeable in this field of study. Let that individual be your guide to the beautiful star patterns our ancestors created in the heavens.

However, if an experienced guide is not readily available to you, there is a simple and inexpensive tool which can help you with constellation identification...it's called a planisphere.

A planisphere (star wheel) consists of a round rotating disc depicting the constellations and a calendar of dates. A fixed outer scale contains a time scale (8:00 pm, 9:00 pm, etc).

All one has to do is set the rotating disc to the corresponding month and time. There are four flanges on the planisphere corresponding to north, east, south and west. If you hold the south flange and face south, the stars in the sky will now match those shown in the star wheel's viewing area. You also have to imagine that the planisphere curves up around you like a planetarium dome. To view and identify constellations in other directions simply hold any of the other three flanges and face that direction.

After you've identified a few star patterns, a great family game would be to create your own constellations. All you have to do is have a good imagination and connect the dots (stars). This pastime can provide quite a few laughs.

Some of the local book stores have carried different versions of planispheres from time to time. There are some small ones and large ones. Today, most are made of plastic. Prices vary. Scientifics (www.scientificsonline.com) carries a thin cardboard, 8 «-inch square "Star and Planet Locator" star wheel for $2.95. It's a good deal.

But the best deal can be found at Uncle Al's Sky Wheels on the internet (http://www.lhs.berkeley.edu/StarClock/skywheel.html) From this website you can download free of charge the templates to assemble your own planisphere. Instructions for assembly and use are included. I suggest you print on the heaviest stock paper your printer can accommodate.

Start using your plansiphere on any clear night and you'll soon be able to identify all the constellations visible from the northern hemisphere over the course of a year. And one other suggestion. After you've become familiar with these star patterns, learn some of their mythology. The stories will add a different dimension to your knowledge of the heavens.

July Meteor Showers

In addition, at month's end there are a couple of minor meteor showers. While both are seen better from the southern hemisphere, at least during the peak nights you'll see a few more meteors than you would on a non-shower night.

The first one, the Delta Aquarids, peaks across several nights, from the 27th to 29th. The Moon will be a waning crescent in the early morning sky and will not hinder observing as many meteors as possible. Expect less than 10 bright, yellow and medium speed (25.5 miles per second) meteors at best per hour.

The second meteor shower, the Capricornids, come a day later on the night of July 28/29. The Capricornids are characterized by their often yellow coloration and their frequent brightness. They are relatively slow meteors, hitting our atmosphere at around 15 miles per second. An observer should expect no more than eight meteors per hour, though the Capricornids are noted for producing brilliant fireballs.

For both showers, direct your gaze towards the southern sky.

Don't forget to visit Seagrave Memorial Observatory on any clear Saturday night for a tour of the heavens. Visit our website for additional information: http://www.theskyscrapers.org