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Telescope magnification, orbital period, escape velocity, habitable zone, and rocket equation calculators.
Find visible constellations by month and hemisphere.
Calculate telescope magnification from focal lengths.
ISS pass reference and satellite visibility educational guide.
Calculate how long light takes to travel any distance.
Star apparent magnitude scale with brightness comparisons.
Calculate orbital period from semi-major axis using Kepler third law.
Calculate escape velocity from mass and radius. All planets reference.
Calculate redshift z from observed and emitted wavelengths with distance estimate.
Calculate habitable zone boundaries from star luminosity.
Tsiolkovsky rocket equation: exhaust velocity and mass ratio to delta-v.
Convert light seconds to kilometers.
Convert kilometers to light seconds.
Convert modern dates to Roman calendar notation with AUC year.
Convert Gregorian dates to Mayan Long Count and Tzolkin/Haab.
Convert Gregorian dates to Chinese lunar calendar with zodiac animal.
Convert calendar dates to Julian Day Number used in astronomy.
Convert calendar dates to Modified Julian Day used in satellite tracking.
Calculate GPS week number and day of week from a calendar date.
Calculate local sidereal time from date, time, and longitude.
Calculate solar noon time for a given date and longitude.
Calculate the equation of time correction for a given date.
Calculate analemma figure-eight sun position for a given location.
Convert right ascension between hours-minutes-seconds and decimal degrees.
Convert declination between degrees-minutes-seconds and decimal degrees.
Calculate hour angle from local sidereal time and right ascension.
Convert equatorial coordinates to horizontal altitude and azimuth.
Reference for stellar classification: O, B, A, F, G, K, M spectral types.
Reference for galaxy morphology: spiral, elliptical, irregular, and lenticular.
Reference for nebula classification: emission, reflection, planetary, and dark.
Reference for planet classification: terrestrial, gas giant, ice giant, and dwarf.
Reference for asteroid classification: C-type, S-type, M-type, and near-Earth objects.
Reference for comet structure, orbital types, and notable periodic comets.
Annual calendar of major meteor showers with peak dates and viewing tips.
Calendar of upcoming solar and lunar eclipses with visibility and timing data.
Reference for lunar phases, synodic month, and moon phase identification.
Detailed reference for the 12 zodiac constellations with notable stars and mythology.
Complete reference for all 110 Messier objects with coordinates and descriptions.
Reference for IAU-named stars with magnitudes, distances, and constellations.
Reference for binary star systems: visual, spectroscopic, and eclipsing types.
Reference for variable star types: Cepheid, RR Lyrae, Mira, and cataclysmic.
Reference for supernova classification: Type Ia, Type II, and their light curves.
Reference for black hole types: stellar, intermediate, supermassive, and primordial.
Reference for pulsar types, rotation periods, and notable discovered pulsars.
Reference for quasar properties, active galactic nuclei, and redshift records.
Reference guide for dark matter evidence, candidates, and detection methods.
Reference guide for dark energy, accelerating expansion, and cosmological constant.
Reference for the cosmic microwave background radiation and its implications.
Reference for the Hubble constant, expansion rate, and the tension problem.
Interactive Drake Equation calculator for estimating communicative civilizations.
Reference guide for the Fermi Paradox, proposed solutions, and implications.
Reference for notable space missions: Apollo, Voyager, Mars rovers, and JWST.
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