MicroHelp Library A Compendium of Information Required by the + Observer of the Belted Planet (c) L. Abbey, 1990, 1991 + Version 2.0 . . . . . . . * . . . . : . " . . . . . . . .: * . . :. Date: / / Time: : Zone: Diameter: Rotation Period 9.842 hrs Equatorial 142,800 km (Sidereal) ! Polar 134,200 km Z Density 1.32 Inclination 3.12 \ Escape Velocity 59.6 km/sec Reciprocal Mass 1,047.355 ] Volume (Earths) 1,323 Mass (Grams) 1.899x10^27 ] Surface Gravity 2.69 Geometric Albedo 0.52 ] Mean Magnitude -2.3 F1 - Help F3 - Definitions Any Other Key to Proceed DEFINITIONS - 1 BELTS (South) SEB - South Equatorial Belt. Prominent belt immediately above (South of) the Equatorial Zone. Often seen separated into North and South components. STB - South Temperate Belt. Immediately South of the SEB. The Red Spot frequently interacts with this belt, especially with the many white ovals which appear on it's southern edge. SSTB - South South Temperate Belt. South of the STB. There is little activity here. EB - Equatorial Belt. This belt is rarely seen, and is probably composed of the connected tops of the many loops and festoons which are found in the Equatorial Zone. This belt, if it is a belt, is unstable and very elusive. - Exit Any Key to Proceed DEFINITIONS - Exit or Highlighted Key to Select DEFINITIONS - 2 BELTS (North) NEB - North Equatorial Belt. Prominent belt immediately below (North of) the Equatorial Zone. Often seen separated into North and South components. It is almost always the most prominent marking on the planet. NTB - North Temperate Belt. Immediately North of the NEB. This belt usually contains many dark knots and light streaks. NNTB - North North Temperate Belt. North of the NTB. There is little activity here. In general, the Northern Hemisphere of the planet is not as active or interesting as the Southern one. - Exit PgUp - Previous Screen Any Key to Proceed DEFINITIONS - 3 Zones (South) EZ - Equatorial Zone. The most prominent zone. It spans the middle of the planet, and contains many delicate features. STrZ - South Tropical Zone. Prominent zone immediately above (South of) the South Equatorial Belt. This zone is famous as the home of the Great Red Spot. STZ - South Temperate Zone. Immediately South of the STB. Though this zone is usually placid, the light ovals of the STB project into it, producing many intricate patterns and interactions. SSTZ - South South Temperate Zone. South of the SSTB. There is little activity here. - Exit Any Key to Proceed DEFINITIONS - 4 Zones (North) EZ - Equatorial Zone. The most prominent zone. It spans the middle of the planet, and contains many delicate features. NTrZ - North Tropical Zone. Prominent zone immediately below (North of) the North Equatorial Belt. NTZ - North Temperate Zone. Immediately North of the NTB. NNTZ - North North Temperate Zone. North of the NNTB. In general, the Northern Hemisphere of the planet is not as active or interesting as the Southern one. - Exit PgUp - Previous Screen Any Key to Proceed DEFINITIONS - 5 OTHER FEATURES SPR - South Polar Region. The dark "Polar Cap" of the planet. Very little observable change occurs here, but occasionally small light or dark spots appear, especially near the northern edge. NPR - North Polar Region. Immediately North of the NTB. Similar to the SPR, but less active. Limb Darkening is not usually noticed by visual observers, yet it is an important aspect of the planet's appearance. Limb darkening appears as a slightly darker crescent-shaped border to the planet's disk, located on the limb opposite to the Sun. When prominent enough to be noticed, it gives a "3-D" effect. - Exit Any Key to Proceed DEFINITIONS - 6 RED SPOT RS - The Great Red Spot. Slightly larger than the Earth, the Red Spot is the planet's most interesting feature. It varies in intensity from a dark brick red to a pale rose. Occasionally some structure is visible within the spot. At other times it disappears for months, or even years. The spot usually appears as an appendage hanging from the northern edge of the STB. RSH - The Red Spot Hollow. The hollow is an oval which is slightly larger than the spot. The spot lies within it, and when the spot is in it's quiescent phase, only the pale white hollow is seen. Sometimes the hollow is bordered by a darker swirl of clouds. - Exit Any Key to Proceed HELP - GENERAL You may customize the program for your time zone by using a command-line switch. For instance if you are in time zone 7 invoke the program as follows: C> jupe 7 Choose from the menu items by either moving the cursor with the arrow keys, or by pressing the highlighted letter for the selection desired. Any Key to Proceed HELP - LONGITUDES There are five images for the simulation of the Red Spot's predicted location. Each of these covers a zone 30 wide (plus one blank). The longitude of the spot is assumed to be 30 (II). This is a reasonable approximation for the next several years. The percent of the disk which is illuminated by the Sun is shown. Due to Jupiter's phase angle of up to 12 this can vary between 98.9% and 100%. Any Key to Proceed DEFINITIONS - 7 LONGITUDES Longitude Systems. Two longitude systems are used by visual observers. System I. This system is used for observations in the equatorial region of the planet. It extends from the southern edge of the northern component of the SEB to the northern edge of the southern component of the NEB. It includes the Equatorial Zone. System I has a rotation period of 9h 50m 30.003s. System II. This system is used for the rest of the planet. System II has a period of 9h 55m 40.632s. System III. Used for radio sources only. Central Meridian. The central meridian for any of the two visual systems is the longitude which passes through the center of the disk. - Exit Any Key to Proceed HELP - SATELLITES - 1 The satellite screen initially displays the configuration of the Galilean Satellites for the date and time entered. Pressing any key other than or F1 causes the display to animate the satellite system for the next six hours, in thirty-minute increments. This should be sufficient for most observing sessions. The time and date of the animated display are shown. Any Key to Proceed HELP - SATELLITES - 2 The satellites are shown as black dots whenever they pass in front of or behind the disk. This is not to be interpreted as a prediction of transit or occultation. The program does not take into account the small inclination of the plane of the satellite's orbit. The size of the planet's disk in relation to the satellite's orbits (and size) is approximate. Any Key to Proceed HELP - SATELLITES - 3 The satellites are identified beneath the display as follows: C - Callisto E - Europa G - Ganymede I - Io Any Key to Proceed HELP - GENERAL This program uses the current date and time as the default for central meridian and satellite predictions. It is therefore important that the computer's clock be set before the program is run. The times and dates which are entered should be local. Times should always be entered in the 24-hour system. Any Key to Proceed Unable to locate graphics library JUPE.GXL INTRO ABBEY FACTS DEFINE1$ DEFINE DEFINE2# DEFINE3 DEFINE4 DEFINE5 DEFINE6 HELP1y! HELP2 DEFINE7d& HELP3#* HELP4 HELP5@/ HELP1A NOLIB