It's been awhile since this series had an entry...but what goes around comes back around, non-periodic comets notwithstanding.
It's a fact of computocyberlife that every time you turn around, someone's updated your favorite piece of software. Sometimes the changes are not visible -- a rewritten algorithm, more compact code, a different dynamic for number crunching. Most of the time, though, and especially in the astronomy world, the changes are not only visual, they're staggering as well -- to the point of requiring a new graphics card 'cause the old one emitted a querulous 'queep' and all the magic smoke, and passed over into the realm of 286's and 9600 baud modems...
There is a market for such programs (if there wasn't, would people be selling them?). The stunning graphics in any of StarryNight's software makes for excellent teaching tools. TheSky is a bit less graphic but still image-intense. But for those of us who simply want something to be on the screen so we can find an object, there are numerous programs out there that fill the bill without popping the processor.
Let's start simple (all these website links have their own 'screen captures', so you'll have to go to the websites for images).
The hoo-hah in the world of binocular astronomy (where yr obdt svt is an enthusiastic resident) for the last two weeks of June 2005 is the upcoming conjunction of Mercury, Venus, and Saturn, with Jupiter about halfway back on the ecliptic. But if no one told you about it, what would you use to determine of several (or even one particular) planet was visible at any particular time? Enter Alcyone's Planetary/Lunar/Stellar Visibility 3.0. This program is FREEWARE (as in, go get it, it don't cost nothing!). An update of the old Planet's Visibility, the new version also calculates the visibility of major stars (in addition to listing their constellations, Bayer and Flamsteed numbers, and magnitudes). The user can add their favorite stars to the database also. Various locations around the world are listed, and the user can plug in their location if it's not already there. While this program doesn't give a picture of the sky, it does give a quick and easy-to-understand graphic representaion of whether or not the object in question is visible. Alcyone's website gives full details, documentation, and downloading.
Why spend all that time whipping together some sort of graphics engine when it's already been done for you? If you're willing to settle for a bit less than Star Wars-grade graphics, how about a little downloadable Java applet that gives a quick'n'dirty look at the sky above? Dirk Matussek's AstroViewer does just that. A Java planisphere, it has all its functions button selectable -- the sky now, and time change forward/backward in min/hour/day/month/year steps. There's a calendar popup that lets you select a date and go directly to it. Conveniently, the buttons select in one- or ten-unit steps. There's a fairly complete selection of locations, and a crosshair-targeted map settable in latitude/longitude for those out in the boonies. Various giudes can be set in the sky, and there's a searchable celestial object catalog that will either highlight the object if it's visible, or alert you if it's not. There's a Solar System planisphere, with the same time adjustments available, and it's scalable to show just the level of Solar System detail you need. Check out the AstroViewer home page for the manual, the online version, and a downloadable version. Dirk lists his program as "...This software is licensed, not bought. The licensee obtains the non-exclusive, non-transferable right, to use the software under the conditions given below. The license remains valid for an unlimited period of time...", so as long as you go by the rules, it doesn't cost.
For those who concentrate their efforts on the Moon, there is a program out there by Dr. Monzur Ahmed that satsifies the desires of the lunar astronomer and the needs of certain religious sects. Moon Calculator 6.0 is a DOS-style program that runs on newer Windows platforms (this writer has run this program on both Windows 2000 and Windows XP -- it should run no problem on just about anything Windows, as it calls for at least a 386 processor and a VGA graphics card). There are star charts with both horizon and the more common circular views, a pictorial of the Moon with craters and physical data, young moon visibility maps with your choice of 13 different sighting criteria, lunar libration graphs, and data for the Hijri (the Islamic calendar based on lunar months). (Click here for an explanation of the Islamic calendar Hijri, and then click here for a Gregorian-Hijri date converter.) The user can put their location in the database. The ReadMe file is comprehensive, and it's recommended that the user read the file closely (it's in both .txt and .pdf formats), as it covers many aspects of astronomy and lunar positions as they relate to one of the world's great religions. If for no other reason than to gain an understanding of the astronomy of an early scientific culture, this program is of great value to the casual Lunar gazer. The program is available for download here.
For those looking for a quick sky picture, Alex Zavalishin's StarCalc should fill the bill quite nicely. Available for both PC's and PocketPC's, the program has "plug-in modules" for various star catalogs, asteroids and comets, solar and lunar eclipses, deep sky objects, and the Milky Way. Numerous parameters can be set -- location, time, the various parameters affecting all the plug-ins, constellation boundaries and names, display of M and NGC objects, displayed star magnitude, just labeled stars' magnitude, the size of objects' labels, and the objects' relative size based on brightness. The image can be zoomed (fainter stars appear the more you zoom), and more. Az/El and RA/Dec readouts of the cursor are simultaneously available. Object paths can be laid it for a selected time range (shows the path of retrograde motion). The home page is a Russian site, but this URL leads you to the English version, with links to the image sample page and the download page.
Finally, for those who know what they're looking for, and where to look for it, but just need to know when to look for it, Stig's Sky Calendar is the program that feeds the need. The program can be run online, or downloaded to run offline (NOTE -- while the online version is currently suffering a small glitch, the HELP pages and the Download Page are working OK.) The program's main display shows daylight and dark for a month at a time, with the rise/transit/set times for the Solar System objects. There are icons on the toolbar to update the events noted from the website; to allow the user to set their location; to bring up a planet finder that works with the main display, in showing a planet's visibility and relative altitude above the ecliptic; a Solar System display settable for orientation and time; a planisphere settable for compass points and time, and more. For a basic quickie 'where is it and when will it be there',
Stig's Sky Calendar and all its various features could be just what you're looking for.
(OBLIGATORY DISCLAIMER: the author has no connection to any of the mentioned websites or program developers, other than that of a satisfied reader and customer. The author has neither asked for nor received any remuneration of any kind from anyone. This review was written and submitted in the interest of public information only, and is solely the opinion of the author.)
The preceding article is published simultaneously (except as noted) in the following places:
Phil Plait's Bad Astronomy Bulletin Board
http://www.badastronomy.com for the site in general
http://www.badastronomy.com/phpBB/index.php for the Board (see the General Astronomy forum)
The James Randi Educational Foundation Bulletin Board
http://www.randi.org for the site in general
http://www.randi.org/vbulletin/ for the Board (see the Science, Mathematics, Medicine, and Technology forum)
The Miami Valley Astronomical Society message board
http://www.mvas.org for the Society's site in general
http://www.mvas.org/discus/messages/board-topics.html for the Board (the General Astronomy forum)
on several message board groups that the author is a member of; the groups are associated with astronomy in general, and several aspects of astronomy in general
and depending on space limitations, will also be printed in the MVAS's monthly newsletter The Amateur Astronomer
http://www.mvas.org/aa.html (past issues available on the MVAS site in Adobe .pdf format).