"Astro Info" displays some basic information useful to star gazers, such as Sun Rise and Set, Moon Rise & Set and % Full, and the rising and setting of each of the 8 planets. (Yes, eight. You didn't expect me to include the Earth, did you?) In addition, Astro Info 2.0 and later features support for catalogs of deep space objects, such as clusters and galaxies.
òRequirements
"Astro Info" requires at least PalmOS 2.x, and it requires that "Mathlib.prc" be installed before it will run. You will also need a doc reader, such as AportisDoc, if you wish to read the "location.pdb" file.
òIncluded in this Version
Required to Run Astro Info:
Astro.prc: The Astro Info program
MathLib.prc: The Mathlib library (you should not install this if you use a Visor.)
Caldwell.pdb: The Caldwell Catalog - A list of 109 celestial objects designed for amateur astronomers. Objects are identified by their Caldwell and NGC numbers.
Messier.pdb: The Messier Catalog - The classic list of famous stellar objects.
Northernstars.pdb: A catalog of bright stars visible in the northern hemisphere. Stars are identified by their constellation, Beyer letter, and SAO number.
Southernstars.pdb: A catalog of bright stars visible in the southern hemisphere. Stars are identified by their constellation, Beyer letter, and SAO number.
Optional Documents
(You don't have to install these unless you want to):
Astro.pdb: This document.
Location.pdb: A list of cities and their latitude and longitude, in DOC format.
License.pdb: The Gnu Public License - This license governs the copying and distribution of Astro Info.
Additional Information:
Astro.txt: This document.
License.txt: The Gnu Public License - This license governs the copying and distribution of Astro Info.
Location.txt: A list of cities and their latitude and longitude, in TXT format.
òConfiguring Astro Info
To use "Astro Info", you need to first tell it your position and your time zone. To do this, start "Astro Info", and select "Options" from the menu. Enter your Time Zone (TZ) as how many hours off of GMT you are. Remeber to use the check box to specify a western time zone vs. an eastern time zone. For example, some one in Berlin would use a TZ of "1" while someone in California would use "8W". Remember to adjust the TZ for day light savings time. (For example, EST = 5W, EDT = 4W).
Next, set your latitude and longitude, in degrees and minutes. Remember to check the boxes for the southern and western hemispheres as needed.
And that's all there is to it! If you don't know your latitude and longitude, check out the "location.txt" or "location.pdb" file and find the city that's closest to you.
Color Support
If you install Astro Info on a color Palm, you will have an extra check box in the options page. This check box, called "Red Light" allows you to toggle the color scheme of the entire Palm from full-color to red-on-black: just the thing for using your Palm at your telescope!
Because of the way the Palm manages color, checking (or unchecking) the Red Light setting will not immediately change the screen. Instead, the next time you exit Astro Info, the Palm will reload it's color table, causing the change to take affect. This change will affect all applications, and lasts until you uncheck the Red Light option again.
WARNING:
If you turn on red light mode, then delete astro info, you will not be able to restore the default colors without doing a hard reset!!!
òUsing Astro Info
Setting the Date and Time:
Astro Info does not use the current date and time for it's calculations. All Astro Info displays have buttons to set the date and time at the top. To get the current date and time, press the "Now" button. To quickly see tomorrow or yesterday, use the arrow buttons. To set the time or date, press the appropriate button and the standard date or time dialog box will appear.
Using the Various Pages:
All Astro Info pages are similar, except the Catalog (see below). Each has the time controls, and a Help button, at the top. Most of the page is filled with information about one or more astronomical objects.
The Moon page shows the current age (phase) of the moon and how full it is. It also shows the next moon rise and moon set, and the Moon's current position in both equatorial and alt/az coordinates.
The Planet page shows the next rise and set for each of the other 8 planets. You can also click on the name of a planet, which will pop-up a dialog box showing the planet's current coordinates.
The Siderial Time page converts the time and date to various other astronomical time systems.
The Sun page is similar to the Moon page, showing sunrise and sunset, and the Sun's current position.
The Catalog page is new to Astro Info 2.0. This page displays a list of astronomical objects, such as the Messier List or the Caldwell Catalog. Clicking on the name of an object will pop-up a dialog box showing the object's magnitude, size, rise and set times and it's current position in both equatorial and alt/az coordinates. To select a new catalog, click on the Change Catalog button.
Creating New Catalogs
The good news is, yes, you can. The bad news is that (a) the program for doing this is not yet ready and (b) you need to be able to use Java applications. If you have a special interest in creating your own catalogs, drop me a note at michaelheinz@att.net
òReading the Numbers
When looking at rising and setting times, you should remember that they are always in the context of the current 24 hour day. That means that the setting time for a planet can be less than it's rising time. You should interpret this to mean that at the start of the day the planet was visible, then it set and then it rose.
There is an exception to this rule, however. Occasionally you may see a time that ends in "++". This means that the time occurs THE FOLLOWING DAY. In other words, if I see that Pluto rises at 12:15 and sets at 1:16++, that means that Pluto will rise a little after noon and will set again at 1:16 AM the FOLLOWING MORNING. This is an artifact of time zone adjustments.
And a quick note - some of you have noticed that when you push the "Now" button, the time gets rounded down to the nearest five minutes. The reason for this is that the 'time selection' dialog only lets you set the time to 5 minute intervals. For consistency I decided to place the same restriction on the "Now" button.
òNotes on Accuracy
I've tried my best to make these figures accurate. For the most part, I've succeeded - "Astro Info" results are generally within a few minutes of the results of commercial astronomy software like "SkyMap". The largest loss in accuracy in "Astro Info" comes from simply estimating the positional errors introduced by atmospheric distortion and from assuming that the observer is standing at sea level. Smaller losses in accuracy come from failing to compensate for perturbations in planetary orbits (caused by the other planets). None of these problems cause more than a very small shift in position. The is, however, one glaring exception. Calculating the position of the moon is much more difficult than tcalculating the positions of other celestial objects. As a result, Moon calculations are both slower and more prone to error than other calculations.
òFurther Reading
"Practical Astronomy With Your Calculator" by Peter Duffett-Smith.( IBSN 0-521-35600-7)
òVersion History
2.11 beta
Added a new feature! Now, when looking at the planetary information screen,
planets that are above the horizon for the current time will be shown in
bold.
2.10 beta
This version corrects a major bug in 2.00. Basically, if you delete the catalog that Astro Info currently has open, it would crash the Palm every time you start it, until you deleted and re-installed Astro Info. This has been corrected.
In addition, I've made a major change in how Sun Rise/Set and Moon Rise/Set are calculated. In previous versions, both these functions used an interpolation step to improve accuracy. Unfortunately, this step could also cause weird behaviour. To correct this, Sun Rise/Set now calculates the celestial position of the sun at local noon, and then uses that to estimate the position of the sun at rise and set time.
Because the moon's motion varies so much, this approach does not work for it. Instead, the initial estimate of the moon's position is used to approximate the rise and set times. At that point, each time is used in an iterative loop: (A) Where was the moon at time X? (B) At what time would the moon rise (or set)? Set X to the rise (or set) time and go back to (A). This loop repeats until X stops changing, typically three or four times, and the loop is done for both rising and setting. This means that Moon Rise/Set now takes about eight times as long to calculate as it did in 2.00. But the good news is that I think this completely eliminates all the bug reports about weird values for Moon Rise and Moon Set.
2.00 gold
No feature changes over the beta version. Additional catalogs were added.
2.00 beta
Catalog Support!
1.20
Color Support!
Now, when installing a new version of Astro it deletes the old preferences. Because of a quirk in the way form ID's are handed out, every time I add a new dialog box or page to AstroInfo, the old preferences cause problems. So, now I just whack 'em.
1.10
Added positional information to the Lunar and Solar information panels.
Switched from using an interpolation step in calculating Moon Rise/Moon Set to directly calculating the Moon's position both times. This seems to have improved the Moon Set time somewhat, although the error is still unacceptably large.
A lot of internal changes were made to the code to improve "Astro Info"'s coding style and to make it a better behaved PalmPilot application.
1.05
Significantly increased the accuracy of Planetary Position information by switching to using an iterative approximation of Kepler's equation instead of using a simple first order approximation. The downside is that this causes a slight decrease in performance. Still looking for the source of the discrepancy in the Moon Set time.
Also added an Alt/Az information display for the planets. To see the current position of a planet, click on the name of that planet.
Astro Info now remembers what it was displaying the last time you ran it and returns to that display automatically.
A number of minor code glitches have been corrected. For the most part they were harmless, but they could cause you to run out of memory if you ran Astro Info for a very long time without ever exiting the application. (PalmOS did clean up the leaking memory on exit, so there was no problem with Astro Info 1.02 trashing memory - as long as you exited the application every now and then.)
1.02a
Same code as 1.02; includes expanded documentation and location files.
1.02
Users instantly discovered that the Latitude and Longitude fields could not be set to negative values. (This is because PalmOS does not recognize that '-' is a legitimate numeric character.) I fixed this by adding a check box next to each option. Select the check box when entering a negative time zone (West of GMT), a negative latitude (below the equator) or a negative longitude (West of Greenwich, England).
1.01
Initial Release
ò Copyright
"Astro Info" is copyright 1998-2000, Michael Heinz. All rights reserved. However, both the "Astro Info" and the source code for "Astro Info" have been released under the Gnu Public License. Please see license.txt for more information.
All the formula used in "Astro Info" are derived from the book "Practical Astronomy With Your Calculator" by Peter Duffett-Smith.
òBug Reports
So, you think I'm likely to care, eh? Well, yeah - if you have a problem or a suggestion for an improvement, drop me a note at: Michael "Porkchop" Heinz <michaelheinz@att.net>;
Note: We're actively recruiting volunteers to help improve Astro Info. If you'd like to help, drop us a line!
