Selection Screen

Under Files, on the menu, you can save or load a parameter file. A parameter file is essentially a memorized snapshot of all selection criteria at any given time. If you repeatedly use the same selection criteria, set everything on all tabs and pull down the file menu and select Parameter/Save. All parameters as well as their active/inactive status are saved and can be recalled at any time.

For example, in the above screen shot the parameter file "visibles.prm" was loaded and satellites will be selected if:

While the following values are also set from the "visibles.prm" file, they were marked inactive in that file and so won't be used in picking out satellites.

The Argument of Perigee selection can be used to find satellites that reach their perigee over your hemisphere. Generally, the argument of perigee is the position in degrees where the satellite reaches perigee. This argument starts at zero when the satellite passes the equator on its ascending node. It reaches 180 degrees as it passes the equator on its descending node. So, if you live in the Northern Hemisphere you can set this to pick out satellites with an Arg of Perigee of between 0 degrees and 180 degrees. 

These values were also set by "visdibles.prm" however, they are marked inactive and won't be used in the selection process.

perigee > 200 km and < 300 km 
apogee > 400 km and < 500 km 

On the Visibility tab, selections can be made on the Standard Magnitude from the visibles.prm file. Radar Cross Sections can be selected too.

Clicking on "Yes" in the Select Satellites Above Local Horizon will force the program to include only those satellites (along with any other selection options) when you Run Selections.

On the miscellaneous tab, the International Designator for the launch piece can be selected by Piece "number" (letter),  Launch Number of the year and the year of the launch. For instance, you could find all primary payloads launched in the 50's by entering minimum and maximum launch piece as "A", as above, leaving the launch number inactive and setting the launch year to 57 to 59. The program is semi Y2K compliant in that it will take all years < 56 and convert them to 20xx and all years > = 56 as 19xx.  

Also on this screen, the Age of Element Sets can be selected for any satellites newer than the indicated date. 

You can select out all satellites with particular classifications (most elements are classified U for unclassified, but some folks make their own element sets and distribute them with different classifications).

And you can select satellites by name. Selecting (default) partial match will turn up satellites where that text appears anywhere within the first 15 characters. For instance, searching on "ir" will turn up Mir, all the iridium sats as well as some others (depending naturally on what satellites are in your file). Selecting on an exact match on "Mir" would turn up only Mir. If you have duplicates all of those would also appear.

Using the Exclude parameter for the Common Name search will remove satellites where the excluded terms are present in their name. For instance, enter "r/b" and any element set that contains those three characters will be removed (rocket bodies). Enter in "deb" and any satellite whose name contains those three characters will be removed. Be careful with this. If there is a satellite named DEBORAH, it will be removed along with the other "deb"s (debris). You can string multiple exclude terms together with commas separating them, and you can include leading or trailing spaces to further help reduce the inadvertent removal of some good satellite, for instance, "r/b, deb" would not remove the satellite Deborah, if the satellite name began with that word (no leading space). Case is not considered when comparing for exclusions so, r/b and R/b are the same.

On the Files Tab, you can open a parameter file or select file. Double clicking on the fields for the filenames will display an open file dialog box. You can also use the File Menu available at the top of the screen. 

If you have loaded a selection file they you can use that file in one of two modes. The button that is labeled Select Satellites is a toggle. When you see Select Satellites and the selection file is active, EM will only display satellites that match entries in the select file that also match any other selection criteria you've set on previous screens. However, you can click on this button and it changes to Remove Satellites. In this mode all the selection criteria must be met, then any satellites that are contained in the select file are removed. 

On the File Menu of this screen there are two options:

Because of the multi-page nature of this form, you need to be careful which selections are active. As an indicator something below the top tab might be active, the "Deactivate ALL ??" button is highlighted in bold when any selection is active.

You can "Deactivate All"  selection parameters by pressing that button. The values set will be retained, but their active status will be changed to inactive. Each field can be set to either active or inactive status in any combination. Only the satellites that match ALL parameters of the ACTIVE selections will be selected .

If you are getting strange search results, come to the selection screen and click "Deactivate All" and then go through the pages and reactivate each term you wish to search on. 

If you wish to zero out the entire form, click on "Clear All Selections" and everything will be reset to default values and all search terms will be set to InActive.

note: View files opens the text editor, and points the open file dialog box to the folder where you've indicated you store these files. Select a file and it is displayed in plain text. I don't recommend editing these files, especially the Parameter files, in the text editor. The parameter files are structured for easy import into Element Manager. But, this option may come in handy as a way to delete satellites from Select files.

Once you've designed a query you find useful, you can save those parameters in a *.prm file for later recall. Select the Parameter Files Option and a sub menu opens allowing you to Open or Save a Parameter file.

Select File Usage

You can also select or ignore satellites by using a Select file. A select file can be created in a text editor or from within Element Manager. It looks like this:

The Norad Id number comes first, then a colon then the satellite name. When this file is used for the selection process, only the catalog number is used. Previously the names in the file were included only for reference. However, now that you can use a select file to rename satellites, the name isn't as extraneous as it used to be.

To use a Select file, open the File menu, then the Select Files then Open Selection file. Pick the file you wish to use.

Once the Select file is loaded, you need to decide how you wish to use it. There are two options. You can use the file to select only elements in the active display that match entries in the select file, or you can use the file to remove any element sets on the active display that match entries in the select file. Do this by clicking on the "Select Satellites"/"Remove Satellites" button. The caption of that button changes to indicate the current method being used. Once you've made these selections you must click on the Activate button to use the select file.

If you've made lots of selections using parameters and perhaps a Select file and wish to view the original full element file, click on the "Clear All Selections" button and the program will return you to the main screen with all satellites once again active. If you return to the main screen and want to remove all the selections, click on the "Main Screen" menu bar Select/Remove All Selection Criteria option and the original file will be restored.

Once you have entered selection parameters and wish to see the subset of satellites these selections have generated, click the OK button. You'll return to the main screen. But, you will notice a diminution in the number of Active Satellites indicating that some number of elements did not meet your selection criteria.

A good way to check this out is to sort the active elements and examine the results. If you've set mean motion to select only satellites with Mean Motions between 15 and 16 revs/day, you can sort the file by mean motion, and quickly see that the first element set matches one criteria, and the last element set the other end of that selection criteria.