Home » CEEFAX disks » telesoftware2.adl » 11_10_87/AST\INF
11_10_87/AST\INF
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » CEEFAX disks » telesoftware2.adl |
| Filename: | 11_10_87/AST\INF |
| Read OK: | ✔ |
| File size: | 070A bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
Duplicates
There is 1 duplicate copy of this file in the archive:
- CEEFAX disks » telesoftware2.adl » 11_10_87/AST\INF
- CEEFAX disks » telesoftware5.adl » 20-03-88/AST\INF
File contents
ASTRO is a general utility for converting between two sets of spherical polar coordinates (the kind used in normal lattitude and longitude). It is however presented by being put to a use that will be appreciated by all amateur astronomers - namely converting between three of the more commonly used methods of mapping the heavens. The answers given by this version for conversion between equatorial and galactic coordinates are correct to within a degree or so of the chart given in 'Nortons Star Atlas' but this program converts for the entire sky whereas Nortons only converts between galactic lattitudes +50 to -50. Inaccuracies are due to rounding and the accuracy of the conversion parameters (see below) rather than any inadequacy of the method. ASTRO works by taking one of the intersections between the equators of the two systems as a common point and calculating within the hemisphere with this point at its centre. Points in the other hemisphere are reflected onto the calculated hemisphere before conversion and then back again after. Multiple conversions may easily be strung together as is demonstrated by options 5 and 6 in this program. ASTRO requires three parameters for each conversion which are coded into the program: these are the longitudes of the common intersection referred to both equators (in degrees) and the dihedral angle between the planes of the two equators which must have the correct associated sign. This angle must be less than 90 degrees and both longitude measurements must increase from it which may mean that one or other system could need the sign of longitude measurements changed at input and output. This is demonstrated in altazimuth coordinates in this program. In the program the respective longitudes are RACORR and GACORR and the angle is RAGA.
00000000 41 53 54 52 4f 20 69 73 20 61 20 67 65 6e 65 72 |ASTRO is a gener| 00000010 61 6c 20 75 74 69 6c 69 74 79 20 66 6f 72 20 63 |al utility for c| 00000020 6f 6e 76 65 72 74 69 6e 67 20 62 65 74 77 65 65 |onverting betwee| 00000030 6e 20 74 77 6f 20 73 65 74 73 20 6f 66 20 73 70 |n two sets of sp| 00000040 68 65 72 69 63 61 6c 0d 70 6f 6c 61 72 20 63 6f |herical.polar co| 00000050 6f 72 64 69 6e 61 74 65 73 20 28 74 68 65 20 6b |ordinates (the k| 00000060 69 6e 64 20 75 73 65 64 20 69 6e 20 6e 6f 72 6d |ind used in norm| 00000070 61 6c 20 6c 61 74 74 69 74 75 64 65 20 61 6e 64 |al lattitude and| 00000080 20 6c 6f 6e 67 69 74 75 64 65 29 2e 20 49 74 20 | longitude). It | 00000090 69 73 0d 68 6f 77 65 76 65 72 20 70 72 65 73 65 |is.however prese| 000000a0 6e 74 65 64 20 62 79 20 62 65 69 6e 67 20 70 75 |nted by being pu| 000000b0 74 20 74 6f 20 61 20 75 73 65 20 74 68 61 74 20 |t to a use that | 000000c0 77 69 6c 6c 20 62 65 20 61 70 70 72 65 63 69 61 |will be apprecia| 000000d0 74 65 64 20 62 79 20 61 6c 6c 0d 61 6d 61 74 65 |ted by all.amate| 000000e0 75 72 20 61 73 74 72 6f 6e 6f 6d 65 72 73 20 2d |ur astronomers -| 000000f0 20 6e 61 6d 65 6c 79 20 63 6f 6e 76 65 72 74 69 | namely converti| 00000100 6e 67 20 62 65 74 77 65 65 6e 20 74 68 72 65 65 |ng between three| 00000110 20 6f 66 20 74 68 65 20 6d 6f 72 65 20 63 6f 6d | of the more com| 00000120 6d 6f 6e 6c 79 0d 75 73 65 64 20 6d 65 74 68 6f |monly.used metho| 00000130 64 73 20 6f 66 20 6d 61 70 70 69 6e 67 20 74 68 |ds of mapping th| 00000140 65 20 68 65 61 76 65 6e 73 2e 20 0d 0d 54 68 65 |e heavens. ..The| 00000150 20 61 6e 73 77 65 72 73 20 67 69 76 65 6e 20 62 | answers given b| 00000160 79 20 74 68 69 73 20 76 65 72 73 69 6f 6e 20 66 |y this version f| 00000170 6f 72 20 63 6f 6e 76 65 72 73 69 6f 6e 20 62 65 |or conversion be| 00000180 74 77 65 65 6e 20 65 71 75 61 74 6f 72 69 61 6c |tween equatorial| 00000190 20 61 6e 64 0d 67 61 6c 61 63 74 69 63 20 63 6f | and.galactic co| 000001a0 6f 72 64 69 6e 61 74 65 73 20 61 72 65 20 63 6f |ordinates are co| 000001b0 72 72 65 63 74 20 74 6f 20 77 69 74 68 69 6e 20 |rrect to within | 000001c0 61 20 64 65 67 72 65 65 20 6f 72 20 73 6f 20 6f |a degree or so o| 000001d0 66 20 74 68 65 20 63 68 61 72 74 0d 67 69 76 65 |f the chart.give| 000001e0 6e 20 69 6e 20 27 4e 6f 72 74 6f 6e 73 20 53 74 |n in 'Nortons St| 000001f0 61 72 20 41 74 6c 61 73 27 20 62 75 74 20 74 68 |ar Atlas' but th| 00000200 69 73 20 70 72 6f 67 72 61 6d 20 63 6f 6e 76 65 |is program conve| 00000210 72 74 73 20 66 6f 72 20 74 68 65 20 65 6e 74 69 |rts for the enti| 00000220 72 65 20 73 6b 79 0d 77 68 65 72 65 61 73 20 4e |re sky.whereas N| 00000230 6f 72 74 6f 6e 73 20 6f 6e 6c 79 20 63 6f 6e 76 |ortons only conv| 00000240 65 72 74 73 20 62 65 74 77 65 65 6e 20 67 61 6c |erts between gal| 00000250 61 63 74 69 63 20 6c 61 74 74 69 74 75 64 65 73 |actic lattitudes| 00000260 20 2b 35 30 20 74 6f 20 2d 35 30 2e 0d 49 6e 61 | +50 to -50..Ina| 00000270 63 63 75 72 61 63 69 65 73 20 61 72 65 20 64 75 |ccuracies are du| 00000280 65 20 74 6f 20 72 6f 75 6e 64 69 6e 67 20 61 6e |e to rounding an| 00000290 64 20 74 68 65 20 61 63 63 75 72 61 63 79 20 6f |d the accuracy o| 000002a0 66 20 74 68 65 20 63 6f 6e 76 65 72 73 69 6f 6e |f the conversion| 000002b0 0d 70 61 72 61 6d 65 74 65 72 73 20 28 73 65 65 |.parameters (see| 000002c0 20 62 65 6c 6f 77 29 20 72 61 74 68 65 72 20 74 | below) rather t| 000002d0 68 61 6e 20 61 6e 79 20 69 6e 61 64 65 71 75 61 |han any inadequa| 000002e0 63 79 20 6f 66 20 74 68 65 20 6d 65 74 68 6f 64 |cy of the method| 000002f0 2e 0d 0d 41 53 54 52 4f 20 77 6f 72 6b 73 20 62 |...ASTRO works b| 00000300 79 20 74 61 6b 69 6e 67 20 6f 6e 65 20 6f 66 20 |y taking one of | 00000310 74 68 65 20 69 6e 74 65 72 73 65 63 74 69 6f 6e |the intersection| 00000320 73 20 62 65 74 77 65 65 6e 20 74 68 65 20 65 71 |s between the eq| 00000330 75 61 74 6f 72 73 20 6f 66 20 74 68 65 0d 74 77 |uators of the.tw| 00000340 6f 20 73 79 73 74 65 6d 73 20 61 73 20 61 20 63 |o systems as a c| 00000350 6f 6d 6d 6f 6e 20 70 6f 69 6e 74 20 61 6e 64 20 |ommon point and | 00000360 63 61 6c 63 75 6c 61 74 69 6e 67 20 77 69 74 68 |calculating with| 00000370 69 6e 20 74 68 65 20 68 65 6d 69 73 70 68 65 72 |in the hemispher| 00000380 65 20 77 69 74 68 0d 74 68 69 73 20 70 6f 69 6e |e with.this poin| 00000390 74 20 61 74 20 69 74 73 20 63 65 6e 74 72 65 2e |t at its centre.| 000003a0 20 50 6f 69 6e 74 73 20 69 6e 20 74 68 65 20 6f | Points in the o| 000003b0 74 68 65 72 20 68 65 6d 69 73 70 68 65 72 65 20 |ther hemisphere | 000003c0 61 72 65 20 72 65 66 6c 65 63 74 65 64 0d 6f 6e |are reflected.on| 000003d0 74 6f 20 74 68 65 20 63 61 6c 63 75 6c 61 74 65 |to the calculate| 000003e0 64 20 68 65 6d 69 73 70 68 65 72 65 20 62 65 66 |d hemisphere bef| 000003f0 6f 72 65 20 63 6f 6e 76 65 72 73 69 6f 6e 20 61 |ore conversion a| 00000400 6e 64 20 74 68 65 6e 20 62 61 63 6b 20 61 67 61 |nd then back aga| 00000410 69 6e 0d 61 66 74 65 72 2e 0d 0d 4d 75 6c 74 69 |in.after...Multi| 00000420 70 6c 65 20 63 6f 6e 76 65 72 73 69 6f 6e 73 20 |ple conversions | 00000430 6d 61 79 20 65 61 73 69 6c 79 20 62 65 20 73 74 |may easily be st| 00000440 72 75 6e 67 20 74 6f 67 65 74 68 65 72 20 61 73 |rung together as| 00000450 20 69 73 20 64 65 6d 6f 6e 73 74 72 61 74 65 64 | is demonstrated| 00000460 20 62 79 0d 6f 70 74 69 6f 6e 73 20 35 20 61 6e | by.options 5 an| 00000470 64 20 36 20 69 6e 20 74 68 69 73 20 70 72 6f 67 |d 6 in this prog| 00000480 72 61 6d 2e 0d 0d 41 53 54 52 4f 20 72 65 71 75 |ram...ASTRO requ| 00000490 69 72 65 73 20 74 68 72 65 65 20 70 61 72 61 6d |ires three param| 000004a0 65 74 65 72 73 20 66 6f 72 20 65 61 63 68 20 63 |eters for each c| 000004b0 6f 6e 76 65 72 73 69 6f 6e 20 77 68 69 63 68 20 |onversion which | 000004c0 61 72 65 20 63 6f 64 65 64 20 69 6e 74 6f 0d 74 |are coded into.t| 000004d0 68 65 20 70 72 6f 67 72 61 6d 3a 20 74 68 65 73 |he program: thes| 000004e0 65 20 61 72 65 20 74 68 65 20 6c 6f 6e 67 69 74 |e are the longit| 000004f0 75 64 65 73 20 6f 66 20 74 68 65 20 63 6f 6d 6d |udes of the comm| 00000500 6f 6e 20 69 6e 74 65 72 73 65 63 74 69 6f 6e 20 |on intersection | 00000510 72 65 66 65 72 72 65 64 0d 74 6f 20 62 6f 74 68 |referred.to both| 00000520 20 65 71 75 61 74 6f 72 73 20 28 69 6e 20 64 65 | equators (in de| 00000530 67 72 65 65 73 29 20 61 6e 64 20 74 68 65 20 64 |grees) and the d| 00000540 69 68 65 64 72 61 6c 20 61 6e 67 6c 65 20 62 65 |ihedral angle be| 00000550 74 77 65 65 6e 20 74 68 65 20 70 6c 61 6e 65 73 |tween the planes| 00000560 20 6f 66 0d 74 68 65 20 74 77 6f 20 65 71 75 61 | of.the two equa| 00000570 74 6f 72 73 20 77 68 69 63 68 20 6d 75 73 74 20 |tors which must | 00000580 68 61 76 65 20 74 68 65 20 63 6f 72 72 65 63 74 |have the correct| 00000590 20 61 73 73 6f 63 69 61 74 65 64 20 73 69 67 6e | associated sign| 000005a0 2e 20 54 68 69 73 20 61 6e 67 6c 65 0d 6d 75 73 |. This angle.mus| 000005b0 74 20 62 65 20 6c 65 73 73 20 74 68 61 6e 20 39 |t be less than 9| 000005c0 30 20 64 65 67 72 65 65 73 20 61 6e 64 20 62 6f |0 degrees and bo| 000005d0 74 68 20 6c 6f 6e 67 69 74 75 64 65 20 6d 65 61 |th longitude mea| 000005e0 73 75 72 65 6d 65 6e 74 73 20 6d 75 73 74 20 69 |surements must i| 000005f0 6e 63 72 65 61 73 65 0d 66 72 6f 6d 20 69 74 20 |ncrease.from it | 00000600 77 68 69 63 68 20 6d 61 79 20 6d 65 61 6e 20 74 |which may mean t| 00000610 68 61 74 20 6f 6e 65 20 6f 72 20 6f 74 68 65 72 |hat one or other| 00000620 20 73 79 73 74 65 6d 20 63 6f 75 6c 64 20 6e 65 | system could ne| 00000630 65 64 20 74 68 65 20 73 69 67 6e 20 6f 66 0d 6c |ed the sign of.l| 00000640 6f 6e 67 69 74 75 64 65 20 6d 65 61 73 75 72 65 |ongitude measure| 00000650 6d 65 6e 74 73 20 63 68 61 6e 67 65 64 20 61 74 |ments changed at| 00000660 20 69 6e 70 75 74 20 61 6e 64 20 6f 75 74 70 75 | input and outpu| 00000670 74 2e 20 54 68 69 73 20 69 73 20 64 65 6d 6f 6e |t. This is demon| 00000680 73 74 72 61 74 65 64 0d 69 6e 20 61 6c 74 61 7a |strated.in altaz| 00000690 69 6d 75 74 68 20 63 6f 6f 72 64 69 6e 61 74 65 |imuth coordinate| 000006a0 73 20 69 6e 20 74 68 69 73 20 70 72 6f 67 72 61 |s in this progra| 000006b0 6d 2e 0d 0d 49 6e 20 74 68 65 20 70 72 6f 67 72 |m...In the progr| 000006c0 61 6d 20 74 68 65 20 72 65 73 70 65 63 74 69 76 |am the respectiv| 000006d0 65 20 6c 6f 6e 67 69 74 75 64 65 73 20 61 72 65 |e longitudes are| 000006e0 20 52 41 43 4f 52 52 20 61 6e 64 20 47 41 43 4f | RACORR and GACO| 000006f0 52 52 20 61 6e 64 20 74 68 65 0d 61 6e 67 6c 65 |RR and the.angle| 00000700 20 69 73 20 52 41 47 41 2e 0d | is RAGA..| 0000070a
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