Level  
LE I II III
Star database The star database contains stars limited to magnitude 11.0, with designations Hipparcos, Tycho, ACT, GSC, SAO, PPM, GCVS, WDS, HD, HDE, BD, CD, CP, HR, GC, Bayer's letters and Flamsteed's numbers, counting 980000 stelle.
Star database The star database is based on Hipparcos, Tycho, Tycho-II, ACT, GSC, SAO, PPM, GCVS, WDS catalogues, counting 18881123 stars. Includes also HD, HDE, BD, CD, CP, HR, GC names, Bayer's letters and Flamsteed's numbers.
USNO-A catalogue support Visualization of the stars contained in the USNO-A 1.0 or 2.0 catalogue (not included with Perseus)
Non-stellar objects database The database of non-stellar objects is based on Messier, NGC, IC, UGC, PGC-LEDA (maximum magnitude 16), Barnard, Abell, van den Bergh, Sharpless, Monella, etc catalogues, counting 207456 objects.
Solar System objects You can simulate the Sun, all the planets and the major satellites. You have also asteroids and comets, based on catalogues available on the internet and updated weekly on Perseus' site (you can find them also in other sites). You can import data in text format and insert orbital parameters manually. You can filter asteroids and comets using several parameters.
Artificial Satellites You can show on your screen the satellites' position. You need only to insert the orbital elements in TLE format. The TLE elements are not provided with Perseus because of their rapid variability.
Planets and satellites' visualization Polygonal texurized graphics, correct representation of shadows, phase, body's libration and rotation. Detailed surface maps when available.
Comets' visualization With RealDeep technology, with calculation of tail's direction and extension (approximated). Comets can also be indicated with symbols.
Asteroids' visualization Represented as stars with the correct magnitude, or as symbols.
Stars' visualization Maximum magnitude is automatically set according to magnification (customizable); stars are colored according to the spectrum type. Otherwise, they're white. More styles are available in order to get the desired effect. Contrast between brighter and darker stars is customizable.
Non-stellar objects' representation Standard symbology is correctly scaled ad oriented. Outline available for bigger objects. RealDeep Technology available for nebulae, galaxies and globular clusters. You can select the symbols you want to see according to catalogues and object's type.
Reference lines Equatorial, altazimuth and ecliptic coordinates. Galactic equator, meridian and customizable horizon with azimuth graduation. Names, borders and traditional reference lines of any constellation. Double stars' orbits. Star's and object's names (customizable). Catalogue number(s) for any object. Coordinate system, terminator and edge on planets and satellites.
Atmospheric effects Realistic simulation of dawn and sunset; limiting magnitude changes on dusk; refraction is calculated according to temperature and pressure. Local pressure is calculated according to elevation. .
Refraction Refraction is computed from the temperature and pressure conditions supplied by the user.
Stars and objects info Coordinates calculated in many different reference systems. Visibility. Names and catalogue numbers lists. Customizable descriptions. Elongation from the Sun and the Moon. References to Sky Atlas, Uranometria, Millennium atlases. Magnitude and spectrum, data on variability, distance, proper motion, apparent dimensions when available.
Annotations on the sky You can add text, fields of view of oculars or films/CCD by defining focal and sensor size (customizable database included). You can track any object in any reference system or relative to any other object. Contacts, entrance and exit time during Sun eclipses are displayed on the tracks.
Observation tools Night vision (in red)
Supernovae maps by Stefano Pesci
Night duration chart
Lunar calendar
Altitudes chart
Guide star search
Instant visibility
Inner planets chart
Calculation of solar and lunar eclipses
Telescope control Control of Meade LX200 and Autostar telescopes.
It is possible to use the drivers of the ASCOM platform to control these and other telescopes.
Time controls Observation time is set as local time, with automatic DST change according to the system's settings, and manual timezone setting. ΔT and UTC table can be updated via internet. Date visible as D/M/Y, M/D/Y, Y/M/D (by choice). Automatic setting of Julian/Gregorian calendar according to the date of the simulation (customizable to allow for different dates of the calendar reform). Real time animations. You can change the simulation time to the rising/culmination/setting of an object. Time interval -1000/+3000.
Automatic calculation of UTC from the local time; automatic DST change according to the system's settings; automatic or manual ΔT setting. ΔT and UTC table can be updated via internet. Date visible as D/M/Y, M/D/Y, Y/M/D (by choice). Automatic setting of Julian/Gregorian calendar according to the date of the simulation (customizable to allow for different dates of the calendar reform). Real time animations. You can change the simulation time to the rising/culmination/setting of an object. Time interval -1000000/+1000000 (the simulation can give an inaccurate view when far away from historical epochs).
Location of the observer Select your location from a database or enter geographical coordinates.
Ability to modify the location database, and observe from any planet or satellite or from an arbitraty point in space.
Printing You can print in B/W or using customizable colors, add a legend and get a print preview too.
Saving and "undo" Save and load program's situations using a file. You can redo/undo the last 100 given commands.
Image creation You can save the program's view using the resolution you want and choosing one of the following formats: JPEG, BMP, TGA.
Aiming You can aim at any object existing in the program's database, independently from reference system and observer's position, using any object designation recorded in the database; you can aim according to altazimuth or equatorial coordinates.
Field of view Field of view can be set from about 270° to about 1" (it depends on window's shape and size).
Orientation You can fix the orientation of the field of view relatively to the horizon, the celestial equator or the ecliptic. You can also set it free. You can keep any object at the center of your field of view.
Documentation Online help is available for any command. Documentation is updated on Perseus' site.
Paper manual is provided with several usage examples.
Script You can take any situation created with Perseus, animate it, add text, sounds and images. Perseus can automatically interpolate two different situations. Script is saved in a unique file. Some more scripts are available on this site.
It's possible to create AVI movies from the scripts.