Astronomical Constants and Tables

The following is a compilation of various useful astronomical constants and solar system statistics. We cannot guarantee their accuracy.

Numerical and Physical Constants

Value Symbol Explanation

71°39'49.1"W Frosty Drew Observatory Longitude

41°22'01.5"N Frosty Drew Observatory Latitude

4.88 meters Frosty Drew Observatory Altitude

3.141592654 π Ratio of circumference to diameter of a circle

0.017453293 π/180° Degree in radian measure

57.29577951 180°/π Radian in degree measure

1.609344 Mile in kilometers *

0.621371192 Kilometer in miles

299792458 m/s c Speed of light in a vacuum *

0.01720209895 k Gaussian gravitational constant

66.72×10^-12m³/(kg×s²) G Constant of Gravitation

149597870.691 km AU Astronomical Unit

2451544.5 J2000 Julian date for midnight January 1, 2000 *

10.0×10^-9 m Å Angstrom *

206264.8062 AU pc Parsec (1 pc = 3.269866 ly = 30.93532×10¹² km)

63080.5 AU ly Light Year (1 ly = 9.460730×10¹² km)

9192631770 # s Standard second *

60 s m Standard minute *

3600 s h Standard hour *

86400 s d Standard day *

36525 d C Julian century *

365.25 d y Julian year *

365.242191 Tropical year (equinoxes)

365.256363 Sidereal year (360°)

365.259635 Anomalistic year (nodes)

346.620072 Eclipse year

23h 56m 04s.1 Sidereal day

0.99726968 Sidereal day in solar units

1.0027377795 Solar day in sidereal day units

29.530588 Lunar synodic month

27.321660 Lunar siderial month
5029.0966 General precession (arc seconds per century)
* Value is exact by definition

Numerical and Physical Constants
Value	Symbol	Explanation
71°39'49.1"W		Frosty Drew Observatory Longitude
41°22'01.5"N		Frosty Drew Observatory Latitude
4.88 meters		Frosty Drew Observatory Altitude
3.141592654	π	Ratio of circumference to diameter of a circle
0.017453293	π/180°	Degree in radian measure
57.29577951	180°/π	Radian in degree measure
1.609344		Mile in kilometers *
0.621371192		Kilometer in miles
299792458 m/s	c	Speed of light in a vacuum *
0.01720209895	k	Gaussian gravitational constant
66.72×10^-12m³/(kg×s²)	G	Constant of Gravitation
149597870.691 km	AU	Astronomical Unit
2451544.5	J2000	Julian date for midnight January 1, 2000 *
10.0×10^-9 m	Å	Angstrom *
206264.8062 AU	pc	Parsec (1 pc = 3.269866 ly = 30.93532×10¹² km)
63080.5 AU	ly	Light Year (1 ly = 9.460730×10¹² km)
9192631770 #	s	Standard second *
60 s	m	Standard minute *
3600 s	h	Standard hour *
86400 s	d	Standard day *
36525 d	C	Julian century *
365.25 d	y	Julian year *
365.242191		Tropical year (equinoxes)
365.256363		Sidereal year (360°)
365.259635		Anomalistic year (nodes)
346.620072		Eclipse year
23h 56m 04s.1		Sidereal day
0.99726968		Sidereal day in solar units
1.0027377795		Solar day in sidereal day units
29.530588		Lunar synodic month
27.321660		Lunar siderial month
5029.0966		General precession (arc seconds per century)

# In 1967 the second was defined as: "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of ground state of the cesium 133 atom." Effectively, this says the second is exactly what the atomic clock in the National Institute of Standards and Technology says is a second.

Solar Data

Value Explanation

5800°K Temperature of Photosphere

5.0 Absolute Magnitude

-26.8 Apparent Magnitude

1.989x10³⁰ Mass [kilograms]

3.83x10²⁶ Luminosity [watts]

1.37x10³ Constant [watts/m²] at 1 AU

G2V Spectra classification

1392000 km Diameter

25.66 d Period

Solar Data
Value	Explanation
5800°K	Temperature of Photosphere
5.0	Absolute Magnitude
-26.8	Apparent Magnitude
1.989x10³⁰	Mass [kilograms]
3.83x10²⁶	Luminosity [watts]
1.37x10³	Constant [watts/m²] at 1 AU
G2V	Spectra classification
1392000 km	Diameter
25.66 d	Period

Planetary Orbital Elements

Planet Epoch date Inclination Semimajor Axis Period (years) Eccentricity Longitude Epoch Longitude Perihelion Ascending Node Equatorial Diameter Magnitude Siderial period Obliquity Albedo Color B-V Color U-V

Mercury 1998.0000 7.0049 0.387099 0.240842 0.205625 138.6783 77.424 48.310 4879 -0.42 58.656200 0.01 11% 0.41 0.41

Venus 1998.0000 3.3946 0.723332 0.615186 0.006785 89.9963 131.680 76.660 12104 -4.40 -243.01850 177.36 65% 0.50 0.50

Earth 1998.0000 0.0000 1.000000 1.000000 0.016720 99.4616 102.970 0.000 12756 -3.86 0.997277 23.44 37%

Moon 1975.0000 5.1453 0.002569 0.074803 0.054900 124.8756 145.960 248.640 3475 0.21 27.321660 0.92 06% 0.46

Mars 1998.0000 1.8498 1.523691 1.880812 0.093382 332.0970 336.016 49.540 6794 -1.52 1.025958 25.19 15% 1.36 0.58

Ceres 1995.7748 10.6010 2.766900 4.599200 0.076000 37.9240 71.530 80.660 1003 4.50

Pallas 1994.6790 34.8070 2.771700 4.679000 0.234000 298.5430 309.692 173.310 608 5.00

Vesta 1994.6790 7.1350 2.361600 3.677800 0.089600 172.2150 150.205 103.970 538 4.30

Jupiter 1998.0000 1.3047 5.202804 11.867417 0.048460 333.5863 15.695 100.460 142984 -9.40 0.413540 3.13 52% 0.83 0.48

Saturn 1998.0000 2.4854 9.538844 29.460748 0.054079 25.3840 88.620 113.610 120536 -8.88 0.444010 26.73 47% 1.04 0.58

Uranus 1998.0000 0.7733 19.181854 84.010945 0.042862 304.7550 174.919 74.080 51118 -7.19 -0.718330 97.77 51% 0.56 0.28

Neptune 1998.0000 1.7680 30.057960 164.793187 0.010819 300.6749 11.030 131.770 49764 -6.87 0.671250 28.32 41% 0.41 0.21

Pluto 1998.0000 17.1248 39.299760 246.368310 0.247625 236.2673 224.706 110.345 2390 -1.00 -6.287200 22.53 30% 0.80 0.31

Planetary Orbital Elements
Planet	Epoch date	Inclination	Semimajor Axis	Period (years)	Eccentricity	Longitude Epoch	Longitude Perihelion	Ascending Node	Equatorial Diameter	Magnitude	Siderial period	Obliquity	Albedo	Color B-V	Color U-V
Mercury	1998.0000	7.0049	0.387099	0.240842	0.205625	138.6783	77.424	48.310	4879	-0.42	58.656200	0.01	11%	0.41	0.41
Venus	1998.0000	3.3946	0.723332	0.615186	0.006785	89.9963	131.680	76.660	12104	-4.40	-243.01850	177.36	65%	0.50	0.50
Earth	1998.0000	0.0000	1.000000	1.000000	0.016720	99.4616	102.970	0.000	12756	-3.86	0.997277	23.44	37%
Moon	1975.0000	5.1453	0.002569	0.074803	0.054900	124.8756	145.960	248.640	3475	0.21	27.321660	0.92	06%	0.46
Mars	1998.0000	1.8498	1.523691	1.880812	0.093382	332.0970	336.016	49.540	6794	-1.52	1.025958	25.19	15%	1.36	0.58
Ceres	1995.7748	10.6010	2.766900	4.599200	0.076000	37.9240	71.530	80.660	1003	4.50
Pallas	1994.6790	34.8070	2.771700	4.679000	0.234000	298.5430	309.692	173.310	608	5.00
Vesta	1994.6790	7.1350	2.361600	3.677800	0.089600	172.2150	150.205	103.970	538	4.30
Jupiter	1998.0000	1.3047	5.202804	11.867417	0.048460	333.5863	15.695	100.460	142984	-9.40	0.413540	3.13	52%	0.83	0.48
Saturn	1998.0000	2.4854	9.538844	29.460748	0.054079	25.3840	88.620	113.610	120536	-8.88	0.444010	26.73	47%	1.04	0.58
Uranus	1998.0000	0.7733	19.181854	84.010945	0.042862	304.7550	174.919	74.080	51118	-7.19	-0.718330	97.77	51%	0.56	0.28
Neptune	1998.0000	1.7680	30.057960	164.793187	0.010819	300.6749	11.030	131.770	49764	-6.87	0.671250	28.32	41%	0.41	0.21
Pluto	1998.0000	17.1248	39.299760	246.368310	0.247625	236.2673	224.706	110.345	2390	-1.00	-6.287200	22.53	30%	0.80	0.31

Natural Satellite Elements

Satellite name Period (days) Semimajor
Axis Eccentricity Inclination Radius
(kilometers) Ratio
Satellite/planet

Earth
Moon 27.3217 384400 0.05490 18.28 1738 1.23×10^-02

Mars
Phobos 0.3189 9380 0.01500 1.00 13.5-11-9.5 1.50×10^-08

Deimos 1.2624 23460 0.00050 0.9 7.5-6-5.5 3.00×10^-09

Jupiter
Metis 0.2948 128000 20 5.00×10^-11

Adrastea 0.2983 129000 12.5-10-7.5 1.00×10^-11

Amalthea 0.4918 181000 0.00300 0.40 135-83-75 3.80×10^-09

Thebe 0.6745 222000 0.01500 0.80 55-45 4.00×10^-10

Io 1.7691 422000 0.00400 0.04 1815 4.68×10^-05

Europa 3.5512 671000 0.00900 0.47 1569 2.52×10^-05

Ganymede 7.1546 1070000 0.00200 0.21 2631 7.80×10^-05

Callisto 16.6890 1883000 0.00700 0.51 2400 5.66×10^-05

Leda 238.7200 11094000 0.14762 26.07 8 3.00×10^-12

Himalia 250.5662 11480000 0.15798 27.63 93 5.00×10^-09

Lysithea 259.2200 11720000 0.10700 29.02 18 4.00×10^-11

Elara 259.6528 11737000 0.20719 24.77 38 4.00×10^-10

Ananke -631.00 21200000 0.168 147.00 15 2.00×10^-11

Carme -692.00 22600000 0.206 164.00 20 5.00×10^-11

Pasiphae -735.0000 23500000 0.378 145.00 25 1.00×10^-10

Sinope -758.0000 23700000 0.275 153.00 18 4.00×10^-11

Saturn
Pan 0.5750 133580 10

Atlas 0.6019 137670 0.00000 0.30 20-10

Prometheus 0.6130 139350 0.00300 0.00 70-50-40

Pandora 0.6285 141700 0.00400 0.00 55-45-35

Epimetheus 0.6942 151420 0.00900 0.34 70-60-50

Janus 0.6945 151470 0.00700 0.14 110-100-80

Mimas 0.9424 185520 0.02020 1.53 196 8.00×10^-08

Enceladus 1.3702 238020 0.00452 0.00 250 1.30×10^-07

Tethys 1.8878 294660 0.00000 1.86 530 1.30×10^-06

Telesto 1.8878 294660 17-14-13

Calypso 1.8878 294660 17-11-11

Dione 2.7369 377400 0.00223 0.02 560 1.85×10^-06

Helene 2.7369 377400 0.00500 0.00 18-16-15

Rhea 4.5175 527040 0.00100 0.35 765 4.40×10^-06

Titan 15.9454 1221830 0.02919 0.33 2575 2.38×10^-04

Hyperion 21.2766 1481100 0.10400 0.43 205-130-110 3.00×10^-08

Iapetus 79.3302 3561300 0.02828 14.72 730 3.30×10^-06

Phoebe -550.4800 12952000 0.163 177.00 110 7.00×10^-10

Uranus
Cordelia 0.3350 49770 0.00100 0.10 13

Ophelia 0.3764 53790 0.01000 0.10 15

Bianca 0.4346 59170 0.00100 0.20 21

Cressida 0.4636 61780 0.00100 0.00 31

Desdemona 0.4737 62680 0.00100 0.20 27

Juliet 0.4931 64350 0.00100 0.10 42

Portia 0.5132 66090 0.00100 0.10 54

Rosalind 0.5585 69940 0.00100 0.30 27

Belinda 0.6235 75260 0.00100 0.00 33

Puck 0.7618 86010 0.00100 0.31 77

Miranda 1.4135 129390 0.00270 4.20 240 8.00×10^-07

Ariel 2.5204 191020 0.00340 0.30 579 1.56×10^-05

Umbriel 4.1442 266300 0.00500 0.36 586 1.35×10^-05

Titania 8.7059 435910 0.00220 0.14 790 4.06×10^-05

Oberon 13.4632 583520 0.00080 0.10 762 3.47×10^-05

Neptune
Naiad 0.2944 48230 0.00100 4.74 29

Thalassa 0.3115 50070 0.00100 0.21 40

Despina 0.3347 52530 0.00100 0.07 74

Galatea 0.4287 61950 0.00100 0.05 79

Larissa 0.5546 73550 0.00140 0.20 104-89

Proteus 1.1223 117650 0.00100 0.55 218-208-201

Triton -5.8769 354760 0.00002 157.35 1353 2.09×10^-04

Nereid 360.1362 5513400 0.75120 27.30 170 2.00×10^-07

Pluto
Charon 6.3872 19600 0.00100 99.00 593 2.20×10^-01

Satellite name	Period (days)	Semimajor Axis	Eccentricity	Inclination	Radius (kilometers)	Ratio Satellite/planet
Earth
Moon	27.3217	384400	0.05490	18.28	1738	1.23×10^-02
Mars
Phobos	0.3189	9380	0.01500	1.00	13.5-11-9.5	1.50×10^-08
Deimos	1.2624	23460	0.00050	0.9	7.5-6-5.5	3.00×10^-09
Jupiter
Metis	0.2948	128000			20	5.00×10^-11
Adrastea	0.2983	129000			12.5-10-7.5	1.00×10^-11
Amalthea	0.4918	181000	0.00300	0.40	135-83-75	3.80×10^-09
Thebe	0.6745	222000	0.01500	0.80	55-45	4.00×10^-10
Io	1.7691	422000	0.00400	0.04	1815	4.68×10^-05
Europa	3.5512	671000	0.00900	0.47	1569	2.52×10^-05
Ganymede	7.1546	1070000	0.00200	0.21	2631	7.80×10^-05
Callisto	16.6890	1883000	0.00700	0.51	2400	5.66×10^-05
Leda	238.7200	11094000	0.14762	26.07	8	3.00×10^-12
Himalia	250.5662	11480000	0.15798	27.63	93	5.00×10^-09
Lysithea	259.2200	11720000	0.10700	29.02	18	4.00×10^-11
Elara	259.6528	11737000	0.20719	24.77	38	4.00×10^-10
Ananke	-631.00	21200000	0.168	147.00	15	2.00×10^-11
Carme	-692.00	22600000	0.206	164.00	20	5.00×10^-11
Pasiphae	-735.0000	23500000	0.378	145.00	25	1.00×10^-10
Sinope	-758.0000	23700000	0.275	153.00	18	4.00×10^-11
Saturn
Pan	0.5750	133580			10
Atlas	0.6019	137670	0.00000	0.30	20-10
Prometheus	0.6130	139350	0.00300	0.00	70-50-40
Pandora	0.6285	141700	0.00400	0.00	55-45-35
Epimetheus	0.6942	151420	0.00900	0.34	70-60-50
Janus	0.6945	151470	0.00700	0.14	110-100-80
Mimas	0.9424	185520	0.02020	1.53	196	8.00×10^-08
Enceladus	1.3702	238020	0.00452	0.00	250	1.30×10^-07
Tethys	1.8878	294660	0.00000	1.86	530	1.30×10^-06
Telesto	1.8878	294660			17-14-13
Calypso	1.8878	294660			17-11-11
Dione	2.7369	377400	0.00223	0.02	560	1.85×10^-06
Helene	2.7369	377400	0.00500	0.00	18-16-15
Rhea	4.5175	527040	0.00100	0.35	765	4.40×10^-06
Titan	15.9454	1221830	0.02919	0.33	2575	2.38×10^-04
Hyperion	21.2766	1481100	0.10400	0.43	205-130-110	3.00×10^-08
Iapetus	79.3302	3561300	0.02828	14.72	730	3.30×10^-06
Phoebe	-550.4800	12952000	0.163	177.00	110	7.00×10^-10
Uranus
Cordelia	0.3350	49770	0.00100	0.10	13
Ophelia	0.3764	53790	0.01000	0.10	15
Bianca	0.4346	59170	0.00100	0.20	21
Cressida	0.4636	61780	0.00100	0.00	31
Desdemona	0.4737	62680	0.00100	0.20	27
Juliet	0.4931	64350	0.00100	0.10	42
Portia	0.5132	66090	0.00100	0.10	54
Rosalind	0.5585	69940	0.00100	0.30	27
Belinda	0.6235	75260	0.00100	0.00	33
Puck	0.7618	86010	0.00100	0.31	77
Miranda	1.4135	129390	0.00270	4.20	240	8.00×10^-07
Ariel	2.5204	191020	0.00340	0.30	579	1.56×10^-05
Umbriel	4.1442	266300	0.00500	0.36	586	1.35×10^-05
Titania	8.7059	435910	0.00220	0.14	790	4.06×10^-05
Oberon	13.4632	583520	0.00080	0.10	762	3.47×10^-05
Neptune
Naiad	0.2944	48230	0.00100	4.74	29
Thalassa	0.3115	50070	0.00100	0.21	40
Despina	0.3347	52530	0.00100	0.07	74
Galatea	0.4287	61950	0.00100	0.05	79
Larissa	0.5546	73550	0.00140	0.20	104-89
Proteus	1.1223	117650	0.00100	0.55	218-208-201
Triton	-5.8769	354760	0.00002	157.35	1353	2.09×10^-04
Nereid	360.1362	5513400	0.75120	27.30	170	2.00×10^-07
Pluto
Charon	6.3872	19600	0.00100	99.00	593	2.20×10^-01