Satellites Form


Satellites Form The Satellites form is accessed from the Main form via the menu. This is where you examine the satellites that you have data for and choose which you wish to include in calculations. The form contains a table that consists of 4 columns:

bullet Selection checkbox. If checked, satellite will be included in calculations.
bullet Satellite name.
bullet Orbital inclination. If this number is less than your latitude, the satellite will probably not be visible from your location.
bullet Age (in days) of the satellite ephemeris data. As data gets older, predictions become less accurate.

There are two buttons on the form:

bullet Done. Returns you to the Main form.
bullet Details. Brings up a dialog showing detailed information about the selected satellite.

There are the following menu selections available from the Satellites form:

bullet Select All. Mark all satellites as selected.
bullet Select None. Unmark all satellites.
bullet Delete Selected. Remove all marked satellites from the list.
bullet Import From Memo. Brings up a form allowing you to import data from a memo.
bullet Import From DB. Brings up a form allowing you to import data from a PocketSat import database.

Satellites can be organized into categories, just like records in many Palm applications, and at the upper right of the screen is a pulldown menu that allows you to specify a category. As is the case in other applications, you can also edit the category list itself by choosing 'Edit Categories..." from the list. There are 3 special categories that cannot be deleted. If 'All' is selected, all satellites, in all categories, will be listed. The 'Unfiled' category contains satellites that have not been placed in a category yet. The 'Iridium' category currently doesn't serve any purpose... but it might in the future.

It should be noted that only selected satellites in the current category are used in pass calculations. In order to, for instance, perform calculations for all satellites in a 'Bright 50' category and an 'AMSAT' category, but no others, you would:

  1. Select the 'All' category
  2. Choose 'Deselect All' from the menu
  3. Select the 'Bright 50' category
  4. Choose 'Select All' from the menu
  5. Select the 'AMSAT' category
  6. Choose 'Select All' from the menu
  7. Select the 'All' category
You will now have a list of all of the satellites, but with only the 'Bright 50' and 'AMSAT' satellites selected. If you now return to the main form, only these satellites will be used in calculations.

For more information on the use of categories, see the "Importing Data" section below.

Satellite Details

Satellite Details Pressing the 'Details' button on the Satellites form brings up this dialog, which displays the following information about the currently selected satellite.

bullet Name. The satellite's common name. This is a user-editable field and is not overwritten by subsequent TLE data imports.
bullet Category. This pulldown can be used to change the satellite's category.
bullet NORAD ID. The satellite's NORAD catalog number.
bullet Int. Designation. The international designator consists of the year of the launch, the launch number for that year, and a letter describing which 'piece' of the launch the satellite was.
bullet Orbital inclination. How 'tilted', in degrees the orbit is from the equator.
bullet Orbital period. How many minutes it takes the satellite to travel once around the Earth.
bullet Semi-major axis. The 'mean radius' of the orbit.
bullet Eccentricity. How 'flattened' is the orbit? 0 is a perfect circle.
bullet Data age. The age in days of the ephemeris data.

There is also a button on this dialog allowing you to delete the satellite if you wish.

Importing Data

PocketSat keeps an internal database containing satellite orbital data. As the data ages, it is periodically necessary to replace it with new data. This is done by using the two 'Import' menu items from the Satellites form. If an imported dataset includes a satellite that is already in PocketSat's database, the old data will simply be overwritten, so there is no need to delete old data before performing an import. During the import process, if PocketSat detects that a satellite in the import dataset does not have a low-Earth orbit (an orbital period less than 225 minutes), it will reject it and bring up a dialog to let you know. PocketSat will then proceed to import the rest of the data.

Importing and Categories

There are some points worth noting regarding how the data import process deals with categories:

  • If a satellite is already in the database, importing new data for it will not change its category, regardless what category is current.
  • Any new satellites will be placed into whatever category is currently selected.
  • If the current category is 'All', any new satellites will be placed into the 'Unfiled' category.

Importing From a Memo

If you only have a small amount of data to import, one easy way to handle it is to copy the data into a memo in the 'Palm Desktop' application, add a descriptive first line as a title, and perform a HotSync to get the memo onto your Palm Pilot. The 'Import From Memo' menu item in the Satellites form will bring up a list of all of your memos, allowing you to import the data that you transferred. Be careful though: It is very important that you put a title line at the top of the memo. The satellite data must begin on the second line. Also, be sure not to inadvertently put any carriage returns in the data. The memo will be almost unreadable - don't worry about it. Importing from a memo can be a bit tricky, but once you get the hang of it, it can be the quickest way to update just a couple of satellites. Here is an example of a memo containing TLE data. You should be able to cut this text and paste in into a memo as a test:

Mir & ISS (memo title)
1 16609U 86017A   99076.54703436  .00037756  00000-0  27472-3 0  3152
2 16609  51.6611  93.6229 0011761 251.2320 108.7379 15.72860261746983
1 25544U 98067A   99076.53636457  .00024082  00000-0  31143-3 0  4042
2 25544  51.5919 299.3023 0004337 230.5013 129.5640 15.58783698 18298

Importing From a Database

When you want to import more data than will fit in a memo, you can use one of the tools from the PocketSat web site to create or download a 'PocketSat import database'. The database will be a .pdb file which you can then install and load using the 'Import From DB' menu item from the Satellites form. Note that when one of these databases is imported, the data is transferred into PocketSat's internal satellites database, and the import database can (and should) be deleted. It is not necessary to delete satellites before you import new data. When the import database contains new data for satellites already in the PocketSat satellites database, the data is just updated in place.

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