glenn@zeus.ocs.com (Glenn Ford) (06/12/91)
I am looking for a program (or algorithm, to write my own if need be) that, given current time of day, latitude and longitude, will calculate the suns current position. Any program or existing algorithm for this?? If there is a more proper news group, please let me know.. -- Glenn Ford glenn@zeus.ocs.com .uunet!zeus!glenn
userDHAL@mts.ucs.UAlberta.CA (David Halliwell) (06/13/91)
In article <1238@ocsmd.com>, glenn@zeus.ocs.com (Glenn Ford) writes: >I am looking for a program (or algorithm, to write my own if need be) >that, given current time of day, latitude and longitude, will calculate >the suns current position. Any program or existing algorithm for this?? >If there is a more proper news group, please let me know.. > > >-- Joseph J. Michalsky (1988) "The Astronomical Almanac's Algorithm for Approximate Solar Position (1950-2050)", SOLAR ENERGY 40, 227-235. There was an errata published for the article, mentioning that the formulae in the appendix have errors (although they appear correctly in the body of the text). Any decent climatolgy text provides a number of the formulae that you want. Two that might be easily found are Sellers, W.D. (1965) PHYSICAL CLIMATOLOGY and Oke, T. R. (1987) BOUNDARY LAYER CLIMATES (*second edition*) I have written a couple of Pascal programs to do some of this stuff: contact me at userdhal@mts.ucs.ualberta.ca if you want them. ... and finally, direct followups to sci.geo.meteorology! Dave Halliwell Dept. of Geography University of Alberta
ddavidso@gara.une.oz.au (Dean Davidson) (06/13/91)
In article <1238@ocsmd.com> glenn@zeus.ocs.com (Glenn Ford) writes: >I am looking for a program (or algorithm, to write my own if need be) >that, given current time of day, latitude and longitude, will calculate >the suns current position. Any program or existing algorithm for this?? I wrote (for Turbo Pascal) a unit which included calculation of rise and set times. In doing this it calculated the suns position but does not explicitly return the values. I have extracted this into a stand-alone unit and have placed it (to save net bandwidth) for anonymous ftp on suna.mqcc.mq.oz.au 137.111.161.1 in the directory pub/PC/Turbopas as sununit.pas Here is the header for the unit: Note the references I have included. These may be of some use if you are not into TP and also may give algorithms to calculate the position! ---------------------------------------------------------------------------- Unit sununit; {given latitude, longitude, current date & time difference W of Grenwich returns sunrise,sunset, first light, last light} { Refs and acknowledgements - Various Almanacs & Ephemiris "Practical Astronomy with your Calculator" P. Duffett-Smith Cambridge University Press 2nd Edition 1981 "United States Naval Observatory Almanac for Computers" (No more details known) "Astronomy" 12(4):75-7, Apr 1984 Original Basic Program written by W C Bell Adapted by Ken Shea 1988 in Brisbane Rewritten and modified for Turbo Pascal by Dean Davidson May 1988 Developed for Army War Game Centre, Mosman NSW Australia Copyright, Commonwealth of Australia 1988,1991 } -- Dean Davidson ddavidso@gara.une.oz.au Dept Psychology Phone 61 67 73 2585 University of New England Fax 61 67 72 9816 Armidale NSW 2351 Australia VK2 ZID
rkaminsk@risky.ecs.umass.edu (Robert D. Kaminsky) (06/13/91)
In article <1238@ocsmd.com> glenn@zeus.ocs.com (Glenn Ford) writes: >I am looking for a program (or algorithm, to write my own if need be) >that, given current time of day, latitude and longitude, will calculate >the suns current position. Any program or existing algorithm for this?? >If there is a more proper news group, please let me know.. > I highly recommend the book "Practical Astronomy with Your Calculator" or "Practival Astronomy with Your Computer" by Peter Duffett-Smith. The books lay out very easy to follow methods to calculate a very wide variety of astronomy problems. -- Bob Kaminsky
coffey@fionn.enet.dec.com (Aedan Coffey) (06/13/91)
In article <1238@ocsmd.com>, glenn@zeus.ocs.com (Glenn Ford) writes... >I am looking for a program (or algorithm, to write my own if need be) >that, given current time of day, latitude and longitude, will calculate >the suns current position. Any program or existing algorithm for this?? >If there is a more proper news group, please let me know.. Try the COSMOS program that was posted to c.b.i.p recently, it will do what you want, so will the floppy almanack published yearly by some US department or other. Good luck, Aedan. -- Aedan Coffey Coffey@Fionn.enet.dec.com Digital Equipment Intl. ..or.. ...!decwrl!fionn.enet.dec.com!coffey Dublin, Ireland. ..or.. coffey%fionn.dec@decwrl.enet.dec.com
fisher@sc2a.unige.ch (06/14/91)
In article <1238@ocsmd.com>, glenn@zeus.ocs.com (Glenn Ford) writes: > I am looking for a program (or algorithm, to write my own if need be) > that, given current time of day, latitude and longitude, will calculate > the suns current position. Any program or existing algorithm for this?? > If there is a more proper news group, please let me know.. Want to build a sundial, eh? I have a program to draw a sundial on the screen and dump the coordinates needed to draw the sundial for any size (even for declining sundials). The problem is, of course, the equation of time. (That is, the apparent sun rotation is not constant over the year(s).) I have recently posted a request to sci.astro (the proper newsgroup, BTW, not "meteorology", as someone proposed). An astronomer was kind enough to send me the time equation. This I built into the program, but in the form of a simple table. I would like to draw that equation on the wall (taking for example the year 2000, it doesn't vary *that* much), but didn't yet manage to do it. If you would like to share info, just drop me a note. (i.e. I'm also interested in your info!) good luck, Markus G. Fischer fisher@sc2a.unige.ch