# What is the brightest star in the night sky?

> Sirius is the brightest star in the night sky. Why it shines so brightly, how to find it from Orion's Belt, its white dwarf companion and the dog days.

HTML: https://www.theuniversecounts.com/stars/the-stars-you-can-see/sirius

Numbers as of 2026-11-04 15:06 UTC. Live ones keep changing on the HTML page.

The brightest star in the night sky is Sirius, the Dog Star. It shines so brightly for two reasons. It is close: its light takes 8.6 years to reach us. And it is bright in itself, giving out far more light than the Sun. From the north you see it on winter evenings, low in the south. From the south it rides high on summer evenings. Orion's Belt points the way to it.

- The Moon's distance from Earth right now: 382,273 km
- Venus's distance from Earth: 43,196,166 km
- Jupiter's distance from Earth: 814,476,503 km

## The brightest star of the night

How bright is Sirius?

Astronomers measure brightness in magnitudes, and the scale runs backwards: the lower the number, the brighter the star. Each step of one is about two and a half times brighter. Sirius has a magnitude of -1.46, which puts it below zero, brighter than any other star in our sky. The faintest stars you can see on a really dark night are about magnitude 6.5.

Only the Moon and some of the planets outshine it: Venus and Jupiter, and Mars and Mercury at their best. Venus can reach magnitude -4.92.

So when can you actually see it? From Europe, North America and the rest of the north, Sirius is an evening star from about December to March, low in the southern sky. From the far Arctic it never rises at all. From Australia, South Africa and South America it climbs high overhead on summer evenings. Sirius is bright enough to shine through the glare of a city, so you don't need a dark sky to find it.

## Follow Orion's Belt down

How do I find Sirius?

The easiest way to find Sirius is to start with Orion. On a winter evening in the north, face south and look for three bright stars in a short, straight row. That is Orion's Belt. Follow the line of the belt down and to the left, for a little over two fists held at arm's length, and the first very bright star you reach is Sirius. In the Southern Hemisphere the picture is the other way up, and the belt points up towards it.

Sirius is part of the constellation Canis Major, the Great Dog, which is why it is called the Dog Star. It follows Orion, the hunter, across the sky like a dog at his heels.

Like every star, Sirius rises in the east and sets in the west, because Earth turns beneath the sky. From northern Europe it stays low all night, never far above the southern horizon. Look for it after the sky is fully dark, when it has had time to climb clear of houses and trees.

## Why is Sirius so bright?

Close, and bright in itself

A star can look bright because it is powerful, or because it is near. Sirius is both. It gives out about 25 times as much light as the Sun, and it is one of our closest neighbours among the stars.

Many stars are far more powerful. Rigel, in Orion, pours out vastly more light than Sirius, but it is so much farther away that it looks fainter. Its light set out between 790 and 1,030 years ago. The light from Sirius left only 8.6 years ago.

Sirius is also getting closer. It is moving towards us at about 5.5 kilometres per second, fast enough to cross from London to New York in about 17 minutes. Since you opened this page, Sirius has come [counts up live on the page] kilometres closer.

## Why does Sirius flash colours?

Why does Sirius twinkle red and green?

On a cold night you may see Sirius flicker red, green and blue, several times a second. The colours are not coming from the star. Sirius is a white star, hotter than the Sun.

The flashing happens in our own air. Earth's atmosphere bends starlight a little, and it bends each colour by a slightly different amount, like a prism. Moving pockets of warmer and cooler air shift those colours in and out of your line of sight, so you see one colour, then another.

The effect is strongest close to the horizon, where starlight passes through much more air before it reaches you. That is why it is so striking from Europe and much of North America, where Sirius never climbs high. From a southern summer sky, with Sirius overhead, it shines far more steadily.

## The Pup, a hidden companion

Does Sirius have a companion?

Sirius is not alone. In 1844 the astronomer Friedrich Bessel found small, regular wobbles in its path across the sky, and realised that an unseen companion must be pulling on it. In 1862 Alvan Clark and his father saw the companion for the first time. It is called Sirius B, and sometimes the Pup.

The two stars circle each other once every 50.13 years. Sirius B is a white dwarf: the hot core left behind by a star that has run out of fuel. Long ago it was the heavier of the pair, so it aged faster, threw off its outer layers and shrank.

What is left is extraordinary. Sirius B holds about 1 times the mass of the Sun, yet it is only about 11,000 kilometres across. Earth is about 1.1 times as wide. Sirius B is so much fainter than Sirius that it is lost in its glare, and you need a large telescope to see it.

## The Dog Star and the dog days

Why is it called the Dog Star?

The ancient Greeks, Romans and Egyptians watched Sirius closely. In high summer it rose at the same time as the Sun, hidden in the dawn glare. They believed its heat added to the Sun's and made those weeks the hottest of the year. The Romans counted the dog days from 3 July to 11 August, the weeks around the time Sirius rose with the Sun.

The heat of summer has nothing to do with Sirius. It comes from the tilt of Earth's axis: in the northern summer, the North Pole leans towards the Sun. But the name has stayed, and so has the habit of looking for Sirius as the year turns.

Sirius may be a destination too, of a kind. Voyager 2, now in interstellar space, is heading in its direction. It will take hundreds of thousands of years to pass it, at a great distance.

## FAQ

### What are the three brightest stars in the night sky?

Sirius is the brightest, then Canopus, then Alpha Centauri, whose two bright stars look like one to the eye. Canopus and Alpha Centauri sit far down in the southern sky, so from northern Europe and most of North America you can't see them. From there, the next brightest star after Sirius is Arcturus.

### Is Sirius brighter than Venus?

No. Venus is far brighter, at up to magnitude -4.92, and Jupiter is brighter too. But Venus only shows in the west after sunset or the east before sunrise, while Sirius can be up in the middle of the night. If a bright light is flashing colours low in the south on a winter evening, it is probably Sirius.

### What is the brightest star in the sky tonight?

Whenever Sirius is above the horizon, it is the brightest star in the sky. When it isn't, as on summer evenings in the north, the brightest star is usually Arcturus or Vega, and from the south Canopus or Alpha Centauri. A light brighter than Sirius is the Moon or a planet, not a star.

### Can you see Sirius from the Southern Hemisphere?

Yes, and it looks even better. From Australia, South Africa or South America, Sirius climbs high on summer evenings, from about December to March, where it twinkles far less than it does low in a northern sky.

### Why is Sirius called the Dog Star?

Because it is the brightest star in Canis Major, the Great Dog, the constellation that follows Orion the hunter across the sky.

## Related

- [The age of starlight](https://www.theuniversecounts.com/stars/the-stars-you-can-see/old-starlight.md)
- [Planets visible tonight](https://www.theuniversecounts.com/you/your-sky/planets-tonight.md)
- [Orion, the hunter in the sky](https://www.theuniversecounts.com/stars/the-stars-you-can-see/orion.md)
- [Polaris, the North Star](https://www.theuniversecounts.com/stars/the-stars-you-can-see/polaris.md)

The light leaving Sirius tonight will reach Earth 8.6 years from now. Where will you be when it arrives?

## Sources

- Apparent visual magnitude of Polaris (Measured, with error): [arXiv (accepted, The Astrophysical Journal): Evans et al. 2024, The Orbit and Dynamical Mass of Polaris: Observations with the CHARA Array](https://arxiv.org/abs/2407.09641)
- Apparent visual magnitude of Sirius (Measured, with error): [SIMBAD, CDS Strasbourg (CfA mirror): SIMBAD basic data and V magnitudes for Sirius, Polaris, Betelgeuse, Rigel and other named stars](https://simbad.harvard.edu/simbad/sim-tap/sync?REQUEST=doQuery&LANG=ADQL&FORMAT=tsv&QUERY=SELECT%20i.id%2C%20b.main_id%2C%20b.pmra%2C%20b.pmdec%2C%20b.plx_value%2C%20b.plx_err%2C%20b.plx_bibcode%2C%20b.rvz_radvel%2C%20b.rvz_err%2C%20b.rvz_bibcode%2C%20b.sp_type%2C%20f.flux%2C%20f.flux_err%2C%20f.bibcode%20FROM%20ident%20AS%20i%20JOIN%20basic%20AS%20b%20ON%20b.oid%3Di.oidref%20LEFT%20JOIN%20flux%20AS%20f%20ON%20%28f.oidref%3Di.oidref%20AND%20f.filter%3D%27V%27%29%20WHERE%20i.id%20IN%20%28%27%2A%20alf%20CMa%27%2C%27%2A%20alf%20UMi%27%2C%27%2A%20alf%20Ori%27%2C%27%2A%20bet%20Ori%27%2C%27%2A%20alf%20Dra%27%2C%27%2A%20alf%20Lyr%27%2C%27%2A%20alf%20Car%27%2C%27%2A%20eps%20Ori%27%2C%27%2A%20sig%20Oct%27%2C%27%2A%20alf%20CMa%20B%27%2C%27%2A%20alf%20UMi%20B%27%2C%27M%2042%27%29); [NASA HEASARC: HEASARC TAP query of the BSC5P table: name, ra, dec, vmag for all 9,110 entries](https://heasarc.gsfc.nasa.gov/xamin/vo/tap/sync?REQUEST=doQuery&LANG=ADQL&MAXREC=20000&QUERY=SELECT%20name%2Cra%2Cdec%2Cvmag%20FROM%20bsc5p); [IAU WGSN: IAU Catalog of Star Names (IAU-CSN), IAU Division C Working Group on Star Names](https://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt)
- Apparent visual magnitude of Vega (Measured, with error): [SIMBAD, CDS Strasbourg (CfA mirror): SIMBAD basic data and V magnitudes for Sirius, Polaris, Betelgeuse, Rigel and other named stars](https://simbad.harvard.edu/simbad/sim-tap/sync?REQUEST=doQuery&LANG=ADQL&FORMAT=tsv&QUERY=SELECT%20i.id%2C%20b.main_id%2C%20b.pmra%2C%20b.pmdec%2C%20b.plx_value%2C%20b.plx_err%2C%20b.plx_bibcode%2C%20b.rvz_radvel%2C%20b.rvz_err%2C%20b.rvz_bibcode%2C%20b.sp_type%2C%20f.flux%2C%20f.flux_err%2C%20f.bibcode%20FROM%20ident%20AS%20i%20JOIN%20basic%20AS%20b%20ON%20b.oid%3Di.oidref%20LEFT%20JOIN%20flux%20AS%20f%20ON%20%28f.oidref%3Di.oidref%20AND%20f.filter%3D%27V%27%29%20WHERE%20i.id%20IN%20%28%27%2A%20alf%20CMa%27%2C%27%2A%20alf%20UMi%27%2C%27%2A%20alf%20Ori%27%2C%27%2A%20bet%20Ori%27%2C%27%2A%20alf%20Dra%27%2C%27%2A%20alf%20Lyr%27%2C%27%2A%20alf%20Car%27%2C%27%2A%20eps%20Ori%27%2C%27%2A%20sig%20Oct%27%2C%27%2A%20alf%20CMa%20B%27%2C%27%2A%20alf%20UMi%20B%27%2C%27M%2042%27%29); [NASA HEASARC: HEASARC TAP query of the BSC5P table: name, ra, dec, vmag for all 9,110 entries](https://heasarc.gsfc.nasa.gov/xamin/vo/tap/sync?REQUEST=doQuery&LANG=ADQL&MAXREC=20000&QUERY=SELECT%20name%2Cra%2Cdec%2Cvmag%20FROM%20bsc5p); [IAU WGSN: IAU Catalog of Star Names (IAU-CSN), IAU Division C Working Group on Star Names](https://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt)
- Diameter of Sirius B, the white dwarf companion of Sirius (Measured, with error): [The Astrophysical Journal: Bond et al. 2017, The Sirius System and its Astrophysical Puzzles: Hubble Space Telescope and Ground-Based Astrometry (ApJ 840, 70; doi:10.3847/1538-4357/aa6af8)](https://arxiv.org/abs/1703.10625); [International Astronomical Union / The Astronomical Journal: Prša et al. 2016, IAU 2015 Resolution B3 on Recommended Nominal Conversion Constants for Selected Solar and Planetary Properties](https://arxiv.org/abs/1510.07674)
- Distance to Rigel (Estimated): [Astronomy & Astrophysics: Validation of the new Hipparcos reduction (van Leeuwen 2007, A&A 474, 653)](https://arxiv.org/abs/0708.1752)
- Distance to Sirius (Measured, with error): [Astronomy & Astrophysics: Validation of the new Hipparcos reduction (van Leeuwen 2007, A&A 474, 653)](https://arxiv.org/abs/0708.1752)
- Earth's average distance from the Sun in kilometres (Measured): [NASA: Earth: Facts](https://science.nasa.gov/earth/facts/)
- Earth's diameter at the equator (Measured): [NASA NSSDCA: Earth Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html)
- Faintest star the eye can see from a city centre (limiting magnitude) (Debated): [U.S. National Park Service: Rate Your Night Sky](https://www.nps.gov/subjects/nightskies/rateyoursky.htm); [Sky & Telescope: Gauging Light Pollution: The Bortle Dark-Sky Scale (Bortle, Sky & Telescope, February 2001)](https://skyandtelescope.org/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/)
- Faintest star the eye can see from a suburb (limiting magnitude) (Debated): [U.S. National Park Service: Rate Your Night Sky](https://www.nps.gov/subjects/nightskies/rateyoursky.htm); [Sky & Telescope: Gauging Light Pollution: The Bortle Dark-Sky Scale (Bortle, Sky & Telescope, February 2001)](https://skyandtelescope.org/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/)
- Faintest star the eye can see in a perfectly dark sky (naked-eye limiting magnitude) (Estimated): [NASA Science (Night Sky Network): Check Your Sky Quality with Orion!](https://science.nasa.gov/solar-system/skywatching/night-sky-network/check-your-sky-quality-with-orion/); [NASA GSFC, Imagine the Universe!: Ask an Astrophysicist: The Night Sky](https://imagine.gsfc.nasa.gov/ask_astro/night_sky.html)
- Great-circle distance between London and New York (Measured, with error): [NASA NSSDCA: Earth Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html)
- Jupiter's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Jupiter from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27599%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Jupiter's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Jupiter's distance from Earth (Measured): [NASA NSSDCA: Jupiter Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/jupiterfact.html)
- Luminosity (total power output) of Sirius A (Measured, with error): [The Astrophysical Journal: Bond et al. 2017, The Sirius System and its Astrophysical Puzzles: Hubble Space Telescope and Ground-Based Astrometry (ApJ 840, 70; doi:10.3847/1538-4357/aa6af8)](https://arxiv.org/abs/1703.10625)
- Mars's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Mars from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27499%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Mars's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Mass of Sirius B, the white dwarf companion of Sirius (Measured, with error): [The Astrophysical Journal: Bond et al. 2017, The Sirius System and its Astrophysical Puzzles: Hubble Space Telescope and Ground-Based Astrometry (ApJ 840, 70; doi:10.3847/1538-4357/aa6af8)](https://arxiv.org/abs/1703.10625); [Monthly Notices of the Royal Astronomical Society: Joyce et al. 2018, The gravitational redshift of Sirius B (MNRAS 481, 2361; doi:10.1093/mnras/sty2404)](https://arxiv.org/abs/1809.01240)
- Mass of the Sun (Measured): [NASA NSSDCA: Sun Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html); [International Astronomical Union / The Astronomical Journal: Prša et al. 2016, IAU 2015 Resolution B3 on Recommended Nominal Conversion Constants for Selected Solar and Planetary Properties](https://arxiv.org/abs/1510.07674)
- Mercury's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Mercury from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27199%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Mercury's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Neptune's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Neptune from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27899%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Neptune's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Orbital period of Sirius A and Sirius B around each other (Measured): [The Astrophysical Journal: Bond et al. 2017, The Sirius System and its Astrophysical Puzzles: Hubble Space Telescope and Ground-Based Astrometry (ApJ 840, 70; doi:10.3847/1538-4357/aa6af8)](https://arxiv.org/abs/1703.10625)
- Saturn's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Saturn from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27699%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Saturn's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Speed at which Sirius is moving towards the Sun (radial velocity) (Measured, with error): [SIMBAD, CDS Strasbourg (CfA mirror): SIMBAD basic data and V magnitudes for Sirius, Polaris, Betelgeuse, Rigel and other named stars](https://simbad.harvard.edu/simbad/sim-tap/sync?REQUEST=doQuery&LANG=ADQL&FORMAT=tsv&QUERY=SELECT%20i.id%2C%20b.main_id%2C%20b.pmra%2C%20b.pmdec%2C%20b.plx_value%2C%20b.plx_err%2C%20b.plx_bibcode%2C%20b.rvz_radvel%2C%20b.rvz_err%2C%20b.rvz_bibcode%2C%20b.sp_type%2C%20f.flux%2C%20f.flux_err%2C%20f.bibcode%20FROM%20ident%20AS%20i%20JOIN%20basic%20AS%20b%20ON%20b.oid%3Di.oidref%20LEFT%20JOIN%20flux%20AS%20f%20ON%20%28f.oidref%3Di.oidref%20AND%20f.filter%3D%27V%27%29%20WHERE%20i.id%20IN%20%28%27%2A%20alf%20CMa%27%2C%27%2A%20alf%20UMi%27%2C%27%2A%20alf%20Ori%27%2C%27%2A%20bet%20Ori%27%2C%27%2A%20alf%20Dra%27%2C%27%2A%20alf%20Lyr%27%2C%27%2A%20alf%20Car%27%2C%27%2A%20eps%20Ori%27%2C%27%2A%20sig%20Oct%27%2C%27%2A%20alf%20CMa%20B%27%2C%27%2A%20alf%20UMi%20B%27%2C%27M%2042%27%29); [SIMBAD, CDS Strasbourg (CfA mirror): SIMBAD measured radial velocities of * alf CMa (Sirius)](https://simbad.harvard.edu/simbad/sim-tap/sync?REQUEST=doQuery&LANG=ADQL&FORMAT=tsv&QUERY=SELECT%20m.velValue%2C%20m.meanError%2C%20m.nbmes%2C%20m.bibcode%20FROM%20ident%20AS%20i%20JOIN%20mesVelocities%20AS%20m%20ON%20m.oidref%3Di.oidref%20WHERE%20i.id%3D%27%2A%20alf%20CMa%27)
- The Moon's average distance from Earth (Measured): [NASA: Moon Facts](https://science.nasa.gov/moon/facts/)
- The Moon's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [NASA JPL: JPL Horizons observer ephemeris of the Moon from Earth's centre (apparent magnitude, illuminated fraction and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27301%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C10%2C23%27); [NASA JPL: JPL Horizons observer ephemeris of the Moon, hourly around the new Moon of 2026-11-09](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27301%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-07%2000%3A00%27&STOP_TIME=%272026-11-11%2000%3A00%27&STEP_SIZE=%271h%27&QUANTITIES=%279%2C10%2C23%27)
- The Moon's distance from Earth right now (Measured): [NASA: Moon Facts](https://science.nasa.gov/moon/facts/)
- The Sun's total power output (luminosity) (Measured): [The Astronomical Journal (IAU): Nominal values for selected solar and planetary quantities: IAU 2015 Resolution B3 (Prša et al., AJ 152, 41, 2016; text also at arXiv:1510.07674)](https://doi.org/10.3847/0004-6256/152/2/41); [NASA NSSDCA: Sun Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html)
- Typical adult walking speed (Estimated): [Physiotherapy (Elsevier): Normal walking speed: a descriptive meta-analysis (Physiotherapy 97(3), 182–189)](https://doi.org/10.1016/j.physio.2010.12.004)
- Typical cruising speed of a long-haul airliner (Estimated): [EUROCONTROL: Aircraft Performance Database: B789 (Boeing 787-9)](https://contentzone.eurocontrol.int/aircraftperformance/details.aspx?ICAO=B789); [EUROCONTROL: Aircraft Performance Database: A388 (Airbus A380-800)](https://contentzone.eurocontrol.int/aircraftperformance/details.aspx?ICAO=A388)
- Uranus's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Uranus from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27799%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Uranus's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Venus's angle from the Sun in our sky right now (plus: evening sky, minus: morning sky) (Measured): [NASA JPL: JPL Horizons observer ephemeris of Venus from Earth's centre (apparent magnitude and solar elongation)](https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27299%27&OBJ_DATA=%27NO%27&MAKE_EPHEM=%27YES%27&EPHEM_TYPE=%27OBSERVER%27&CENTER=%27500%40399%27&START_TIME=%272026-11-04%2011%3A50%27&STOP_TIME=%272026-11-04%2012%3A00%27&STEP_SIZE=%2710m%27&QUANTITIES=%279%2C23%27)
- Venus's brightness at its brightest, seen from Earth (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973); [NASA NSSDCA: Venus Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html)
- Venus's brightness right now, seen from Earth's centre (apparent magnitude) (Measured, with error): [Astronomy and Computing (Elsevier); preprint on arXiv: Computing apparent planetary magnitudes for The Astronomical Almanac (Mallama & Hilton 2018, Astronomy and Computing 25, 10-24, doi:10.1016/j.ascom.2018.08.002)](https://arxiv.org/abs/1808.01973)
- Venus's distance from Earth (Measured): [NASA NSSDCA: Venus Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html)