Online Star Charts & Planetarium Software

To help find your way around the night sky, Skymaps.com makes available for free each month The Evening Sky Map — a 2-page monthly guide to the night skies of the northern and southern hemispheres. Each issue contains a detailed sky map, a monthly sky calendar, and a descriptive list of the best objects to see with binoculars, a telescope, or using just your eyes.

Sky View Café is a Java applet that lets you use your web browser to see many types of astronomical information, in both graphical and numerical form. You can see which stars and planets will be out tonight in the sky above your home town, see how the next solar or lunar eclipse will look from Los Angeles, or find out when the Moon rose over Sydney on your birthday ten years ago. Sky View Café includes star charts, a 3-D orrery, displays of the moons of Jupiter and Saturn, an astronomical event calendar, an ephemeris generator, and many other features.

Heavens-Above.com generates customizable sky charts for the time and location you choose. Planets appear on sky charts, but not deep-sky objects. Heavens-Above also provides locater charts for comets and asteroids, as well as times for observing man-made satellites.

Wikisky.org provides an interface similar to google maps for exploring the night sky. It supports a variety of photographic views: visible spectra, infrared, and hydrogen-alpha, in addition to the standard chart style.

Your Sky is an interactive, highly technical planetarium of the Web. You can produce maps in different forms for any time and date, viewpoint, and observing location. If you enter the orbital elements of an asteroid or comet, Your Sky will compute its current position and plot it on the map. Each map is accompanied by an ephemeris for the Sun, Moon, planets, and any tracked asteroid or comet. A control panel permits customisation of which objects are plotted, limiting magnitudes, colour scheme, image size, and other parameters.

Lunar Observing

Take a Moon Walk Tonight, an article by Alan Macrobert, will help you explore the moon with binoculars or a telescope using their lunar map.

The Universty of Iowa’s Modern Astronomy Laboratory Project is an outline for lunar observations and includes a copy of a map of the Moon available from Sky Publishing Corporation. A higher resolution version of the map is available at The Moon page on Astro-Tom.

Atmospheric Seeing

Having trouble understanding Atmospheric Seeing? Have a look at some of these sites:

• Damian Peach has generated an animated version of the Pickering Seeing Scale for rating atmospheric turbulence.
• telescope-optics.net provides a detail description of the effects of atmospheric turbulence, including an illustrated Pickering scale (a ten-point scale) and a comparative illustration of the effect of turbulence as seen through telescopes of different apertures.
• University College London provides a concise summary of diffraction effects, including an illustrated Danjon scale (a five-point scale).

Photometry

Read about Basic Photometry information from the Department of Physics at Durham University. This same information is presented in a more conversational tone on Cornell University’s “Ask an Astronomer” page about apparent magnitude.