Use this window to select which objects and options to display.
Stars are identified in several ways. Common names, such as "Sirius", "Polaris" and "Vega", are shown by selecting "Star names". Many of these names are Arabic in origin. Other ways include Bayer and Flamsteed star labels (designations).
Bayer refers to the lower-case Greek letters assigned to stars within each constellation by German astronomer Johann Bayer (1572-1625; some sources list 1564-1617). When he ran out of Greek letters he continued with (upper case) "A" followed by (lower case) "b" through "z" (omitting "j" and "v"). Later astronomers have added additional (other case) letters and letter combinations. Selecting "Bayer star labels" includes all designations that begin with a letter, including some not normally associated with Bayer designations.
Flamsteed refers to numbers attributed to English astronomer John Flamsteed (1646-1719). This type of designation has also been extended by other astronomers. If both "Bayer" and "Flamsteed" are selected, and both labels are available for a star, then the Bayer label will be shown if it is a Greek letter, otherwise the Flamsteed label will be shown.
"Deep sky" refers to objects outside the solar system, such as galaxies, nebulas, and star clusters. The two sliders control the minimum magnitude shown when completely zoomed-out and zoomed-in. Higher magnitudes allow dimmer (and more) objects to be shown. By offseting these two sliders (i.e. keeping the lower one to the right of the upper one), more objects will begin to appear while zooming in.
"Milky Way" will display our galaxy as a shaded background. The outline is derived from the work of Dutch astronomer Antonie Pannekoek (1873-1960). This selection will also display the Large and Small Magellanic Clouds (which are satellite galaxies of our own Milky Way galaxy), and the Coalsack (a dark cloud in our galaxy).
"Constellation names" can either be full length, or the standard 3 character abbreviation.
"Celestial grid" refers to a grid of celestial longitude and latitude, which astronomers term as right ascension and declination, respectively. 0° declination coincides with the plane of earth's equator.
"Altitude/Azimuth grid" refers to a grid based on the user's perspective. Altitude (elevation) is latitude based on the horizon. Azimuth is longitude referenced from North (0°, East is 90°, South is 180°, West is 270°).
"Ecliptic" is the path the sun follows through the heavens.
"Horizon" refers to a tinting that is used to represent that part of the view that is blocked by the earth. This selection also displays compass directions ("N", "NE", "E", ...).
Note: Although the International Astronomical Union downgraded Pluto to "dwarf planet" status in August 2006, this program still shows it for historical reasons.
Pressing "OK" or "Apply" accepts new values.
Pressing "Cancel" rejects any changes.