By: Charles Bowen
Many newspaper reporters work at night, so if they’re out looking at the stars on these fine spring evenings, they’re probably goofing off. By contrast, most of our readers are off in the evenings and many of them are out taking in the evening air. That’s why when they get home about 9:30 or so, some of them start calling the city desk to ask questions like, “What is that bright light just down left from the moon right now?”
Next time that happens, don’t growl at them. We really need all the readers we can get. Instead, put them on hold and then check the Web. A cool new site from Sky & Telescope magazine offers a simulated naked-eye view of the nighttime sky from any spot on Earth, including that patch of the heavens over your head. You also can examine the records for any time of the day or night, or any date in history or the future, from 1600 to 2400 A.D. Displayed on these Java-based maps are “charted stars and planets,” which is astronomy talk for those that are typically visible without optical aids under clear suburban skies. In addition, it also can plot some deep-sky objects that can be seen with ordinary binoculars.
To check it out, visit the site at http://skyandtelescope.com/observing/skychart/ where you are greeted with a screen asking you to pinpoint your location. Unlike many other astro-cyber guides that want you to indicate a longitude and a latitude, this highly civilized service will accept city and state names or even a ZIP code and do the necessary conversions itself. It will also need to know your time zone and whether your area observes daylight-saving time.
The site then displays its Interactive Sky Chart showing the sky visible tonight for your location at 9 p.m. local time. On the right side of the screen, labeled “All-Sky Chart,” is a circular map of the constellations with a green, four-sided frame near the edge labeled “West.” The portion of the sky inside this frame appears at a larger scale in the rectangular window labeled “Selected View” in the upper left corner of the screen. Under that you’ll find “Location” and “Date & Time” displays.
Online documentation notes that the All-Sky Chart’s center represents the part of the sky directly overhead. Its circular edge represents the horizon all around. Compass directions are labeled around the horizon/edge. So, a star that’s plotted on the map halfway from the edge to the center, therefore, can be found about halfway up the sky, that is, halfway from horizontal to straight up. On the other hand, the “Selected View” shows about as much sky as you can take in at once with your unaided eyes; the field of view is about 50 degrees wide by 40 degrees tall. Compass directions are abbreviated along the bottom, and two markers partway up the right edge of the window indicate your viewing altitude, from 0 degrees at the horizon to 90 degrees overhead.
Other considerations for using the Sky & Telescope service in your work:
1. You can change the Sky Chart’s date and time by simply clicking on the month, day, year, hour, or minute in the display at lower left in “Combined View” (under the “Date & Time” heading). When the selection is highlighted, use the plus (+) or minus (-) buttons to increase or decrease the values. The maps will be updated accordingly.
2. To change your location and time zone, click the “Change” button in the “Location” display area in the lower left of the “Combined View” display. This will take you back to the “Choose Location” page you saw when you visited the feature for the first time.
3. If you write about the service in your news columns, you might want to direct students and teachers to the “Advanced Display Options” button in the bottom left corner of the “Combined View” display. Here you can specify other things to view, such as deep-sky objects and special events like meteor showers.