| helf circle | 1 1/2 circle | 2 1/2 circle | 3 1/2 circle | 4 1/2 circle | 5 1/2 circle | 6 1/2 circle | 7 1/2 circle | 8 1/2 circle | 9 1/2 circle | 10 1/2 circle | 11 1/2 circle | 12 1/2 circle | 13 1/2 circle | 14 1/2 circle | 15 1/2 circle | 16 1/2 circle | 17 1/2 circle | 18 1/2 circle | 19 1/2 circle | 20 1/2 circle | 21 1/2 circle | 22 1/2 circle | 23 1/2 circle | 24 1/2 circle | 25 1/2 circle | 26 1/2 circle | 27 1/2 circle | 28 1/2 circle | 29 1/2 circle | 30 1/2 circle | 31 1/2 circle | 32 1/2 circle | 33 1/2 circle | 34 1/2 circle | 35 1/2 circle | 36 1/2 circle | 37 1/2 circle | 38 1/2 circle | 39 1/2 circle | 40 1/2 circle | 41 1/2 circle | 42 1/2 circle | 43 1/2 circle | 44 1/2 circle | 45 1/2 circle | 46 1/2 circle | 47 1/2 circle | 48 1/2 circle | 49 1/2 circle | 50 1/2 circle | 51 1/2 circle | 52 1/2 circle | 53 1/2 circle | 54 1/2 circle | 55 1/2 circle | 56 1/2 circle | 57 1/2 circle | 58 1/2 circle | 59 1/2 circle | 60 1/2 circle | 61 1/2 circle | 62 1/2 circle | 63 1/2 circle | 64 1/2 circle | 65 1/2 circle | 66 1/2 circle | 67 1/2 circle | 68 1/2 circle | 69 1/2 circle | 70 1/2 circle | 71 1/2 circle | 72 1/2 circle | 73 1/2 circle | 74 1/2 circle | 75 1/2 circle | 76 1/2 circle | 77 1/2 circle | 78 1/2 circle | 79 1/2 circle | 80 1/2 circle | 81 1/2 circle | 82 1/2 circle | 83 1/2 circle | 84 1/2 circle | 85 1/2 circle | 86 1/2 circle | 87 1/2 circle | 88 1/2 circle | 89 1/2 circle | 90 1/2 circle | 91 1/2 circle | 92 1/2 circle | 93 1/2 circle | 94 1/2 circle | 95 1/2 circle | 96 1/2 circle | 97 1/2 circle | 98 1/2 circle | 99 1/2 circle | 100 1/2 circle |
| arcsecond | 648 000 " | 1 296 000 " | 1 944 000 " | 2 592 000 " | 3 240 000 " | 3 888 000 " | 4 536 000 " | 5 184 000 " | 5 832 000 " | 6 480 000 " | 7 128 000 " | 7 776 000 " | 8 424 000 " | 9 072 000 " | 9 720 000 " | 10 368 000 " | 11 016 000 " | 11 664 000 " | 12 312 000 " | 12 960 000 " | 13 608 000 " | 14 256 000 " | 14 904 000 " | 15 552 000 " | 16 200 000 " | 16 848 000 " | 17 496 000 " | 18 144 000 " | 18 792 000 " | 19 440 000 " | 20 088 000 " | 20 736 000 " | 21 384 000 " | 22 032 000 " | 22 680 000 " | 23 328 000 " | 23 976 000 " | 24 624 000 " | 25 272 000 " | 25 920 000 " | 26 568 000 " | 27 216 000 " | 27 864 000 " | 28 512 000 " | 29 160 000 " | 29 808 000 " | 30 456 000 " | 31 104 000 " | 31 752 000 " | 32 400 000 " | 33 048 000 " | 33 696 000 " | 34 344 000 " | 34 992 000 " | 35 640 000 " | 36 288 000 " | 36 936 000 " | 37 584 000 " | 38 232 000 " | 38 880 000 " | 39 528 000 " | 40 176 000 " | 40 824 000 " | 41 472 000 " | 42 120 000 " | 42 768 000 " | 43 416 000 " | 44 064 000 " | 44 712 000 " | 45 360 000 " | 46 008 000 " | 46 656 000 " | 47 304 000 " | 47 952 000 " | 48 600 000 " | 49 248 000 " | 49 896 000 " | 50 544 000 " | 51 192 000 " | 51 840 000 " | 52 488 000 " | 53 136 000 " | 53 784 000 " | 54 432 000 " | 55 080 000 " | 55 728 000 " | 56 376 000 " | 57 024 000 " | 57 672 000 " | 58 320 000 " | 58 968 000 " | 59 616 000 " | 60 264 000 " | 60 912 000 " | 61 560 000 " | 62 208 000 " | 62 856 000 " | 63 504 000 " | 64 152 000 " | 64 800 000 " |
1/2 circle or half circle is equal to 360°/2 = 180°. Plural name is helf circles.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| helf circle | 1/2 circle | ≡ 180 ° | = 3.1415926 rad | Metric system SI |
| helf circles | arcseconds | helf circles | arcseconds |
|---|---|---|---|
| 1 | ≈ 648000 | 6 | ≈ 3888000 |
| 2 | ≈ 1296000 | 7 | ≈ 4536000 |
| 3 | ≈ 1944000 | 8 | ≈ 5184000 |
| 4 | ≈ 2592000 | 9 | ≈ 5832000 |
| 5 | ≈ 3240000 | 10 | ≈ 6480000 |
A second of arc, arcsecond (arcsec), arc second, or second arc is a unit of angular measurement equal to 1/3600 of one degree.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| arcsecond | " | ≡ 1°⁄3600 | ≈ 4.848137×10−6 rad | Metric system SI |
| arcseconds | helf circles | arcseconds | helf circles |
|---|---|---|---|
| 1 | ≈ 1.5432098765432E-6 | 6 | ≈ 9.2592592592593E-6 |
| 2 | ≈ 3.0864197530864E-6 | 7 | ≈ 1.0802469135802E-5 |
| 3 | ≈ 4.6296296296296E-6 | 8 | ≈ 1.2345679012346E-5 |
| 4 | ≈ 6.1728395061728E-6 | 9 | ≈ 1.3888888888889E-5 |
| 5 | ≈ 7.716049382716E-6 | 10 | ≈ 1.5432098765432E-5 |
| helf circles | arcseconds |
|---|---|
| 1 | ≈ 648 000 |
| 1.5432098765432 × 10-6 | ≈ 1 |
| Symbol | Definition |
|---|---|
| ≡ | exactly equal |
| ≈ | approximately equal to |
| = | equal to |
| digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |