| astronomical unit | 1 AU | 2 AU | 3 AU | 4 AU | 5 AU | 6 AU | 7 AU | 8 AU | 9 AU | 10 AU | 11 AU | 12 AU | 13 AU | 14 AU | 15 AU | 16 AU | 17 AU | 18 AU | 19 AU | 20 AU | 21 AU | 22 AU | 23 AU | 24 AU | 25 AU | 26 AU | 27 AU | 28 AU | 29 AU | 30 AU | 31 AU | 32 AU | 33 AU | 34 AU | 35 AU | 36 AU | 37 AU | 38 AU | 39 AU | 40 AU | 41 AU | 42 AU | 43 AU | 44 AU | 45 AU | 46 AU | 47 AU | 48 AU | 49 AU | 50 AU | 51 AU | 52 AU | 53 AU | 54 AU | 55 AU | 56 AU | 57 AU | 58 AU | 59 AU | 60 AU | 61 AU | 62 AU | 63 AU | 64 AU | 65 AU | 66 AU | 67 AU | 68 AU | 69 AU | 70 AU | 71 AU | 72 AU | 73 AU | 74 AU | 75 AU | 76 AU | 77 AU | 78 AU | 79 AU | 80 AU | 81 AU | 82 AU | 83 AU | 84 AU | 85 AU | 86 AU | 87 AU | 88 AU | 89 AU | 90 AU | 91 AU | 92 AU | 93 AU | 94 AU | 95 AU | 96 AU | 97 AU | 98 AU | 99 AU | 100 AU |
| light-day | 0.0057755 ly | 0.0115510 ly | 0.0173266 ly | 0.0231021 ly | 0.0288776 ly | 0.0346531 ly | 0.0404286 ly | 0.0462041 ly | 0.0519797 ly | 0.0577552 ly | 0.0635307 ly | 0.0693062 ly | 0.0750817 ly | 0.0808573 ly | 0.0866328 ly | 0.0924083 ly | 0.0981838 ly | 0.1039593 ly | 0.1097348 ly | 0.1155104 ly | 0.1212859 ly | 0.1270614 ly | 0.1328369 ly | 0.1386124 ly | 0.1443880 ly | 0.1501635 ly | 0.1559390 ly | 0.1617145 ly | 0.1674900 ly | 0.1732655 ly | 0.1790411 ly | 0.1848166 ly | 0.1905921 ly | 0.1963676 ly | 0.2021431 ly | 0.2079187 ly | 0.2136942 ly | 0.2194697 ly | 0.2252452 ly | 0.2310207 ly | 0.2367963 ly | 0.2425718 ly | 0.2483473 ly | 0.2541228 ly | 0.2598983 ly | 0.2656738 ly | 0.2714494 ly | 0.2772249 ly | 0.2830004 ly | 0.2887759 ly | 0.2945514 ly | 0.3003270 ly | 0.3061025 ly | 0.3118780 ly | 0.3176535 ly | 0.3234290 ly | 0.3292045 ly | 0.3349801 ly | 0.3407556 ly | 0.3465311 ly | 0.3523066 ly | 0.3580821 ly | 0.3638577 ly | 0.3696332 ly | 0.3754087 ly | 0.3811842 ly | 0.3869597 ly | 0.3927352 ly | 0.3985108 ly | 0.4042863 ly | 0.4100618 ly | 0.4158373 ly | 0.4216128 ly | 0.4273884 ly | 0.4331639 ly | 0.4389394 ly | 0.4447149 ly | 0.4504904 ly | 0.4562659 ly | 0.4620415 ly | 0.4678170 ly | 0.4735925 ly | 0.4793680 ly | 0.4851435 ly | 0.4909191 ly | 0.4966946 ly | 0.5024701 ly | 0.5082456 ly | 0.5140211 ly | 0.5197966 ly | 0.5255722 ly | 0.5313477 ly | 0.5371232 ly | 0.5428987 ly | 0.5486742 ly | 0.5544498 ly | 0.5602253 ly | 0.5660008 ly | 0.5717763 ly | 0.5775518 ly |
The astronomical unit (symbol: au or ua) is a unit of length, roughly the distance from Earth to the Sun. However, that distance varies as Earth orbits the Sun, from a maximum (aphelion) to a minimum (perihelion) and back again once a year. Originally conceived as the average of Earth's aphelion and perihelion, it is now defined as exactly 149 597 870 700 metres (about 150 million kilometres, or 93 million miles). The astronomical unit is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars. However, it is also a fundamental component in the definition of another unit of astronomical length, the parsec.
| 1 astronomical units ≡ 0.005775518331437 light-days | 4 astronomical units ≡ 0.023102073325748 light-days |
| 1.5 astronomical units ≡ 0.0086632774971555 light-days | 4.5 astronomical units ≡ 0.025989832491466 light-days |
| 2 astronomical units ≡ 0.011551036662874 light-days | 5 astronomical units ≡ 0.028877591657185 light-days |
| 2.5 astronomical units ≡ 0.014438795828592 light-days | 5.5 astronomical units ≡ 0.031765350822903 light-days |
| 3 astronomical units ≡ 0.017326554994311 light-days | 6 astronomical units ≡ 0.034653109988622 light-days |
The light-day is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in oneday, and is equal to exactly 2.59020683712×1013 metres.
| 1 light-days ≡ 173.14463267424 astronomical units | 4 light-days ≡ 692.57853069696 astronomical units |
| 1.5 light-days ≡ 259.71694901136 astronomical units | 4.5 light-days ≡ 779.15084703408 astronomical units |
| 2 light-days ≡ 346.28926534848 astronomical units | 5 light-days ≡ 865.7231633712 astronomical units |
| 2.5 light-days ≡ 432.8615816856 astronomical units | 5.5 light-days ≡ 952.29547970832 astronomical units |
| 3 light-days ≡ 519.43389802272 astronomical units | 6 light-days ≡ 1038.8677960454 astronomical units |
| 1 astronomical units ≡ 0.0057755 light-days |
| 1 light-days ≡ 173.1446327 astronomical units |