Solar Fire’s “Other Bodies” report lists the positions of various astronomical bodies for the time of any chart. The list of bodies that appear in this report may be edited by the user, so that it is possible to add new bodies to the report, or to remove existing ones.

 

>> To see the “Other Bodies” report

1.Select the Current Chart option from the Reports menu

2.In the Reports tab select Extra Bodies.

When Solar Fire is first installed, the bodies included are The Dark Moon (elements according to Waltemath), and all of Charles Jayne’s hypothetical planets (Sigma, Pan, Isis etc.)

The orbital elements for these bodies are contained in editable text files called “extras.dat” and “jayne.dat”, in Solar Fire’s USERDATA folder. You can create any number of similar files and select them from within Solar Fire, provided that you put them in this same subfolder.

It is possible for the user to add orbital elements for any other geocentrically or heliocentrically elliptically orbiting bodies. For example, you could add the elements of recently discovered body QB1992. However it is not possible to add elements for parabolic orbits, so you cannot add the Hale-Bopp comet, for example.

These files are comma-quote delimited (CQD), which means that they are text files in which character strings are enclosed in quotes, and each item on a line is separated by a comma from the next entry.

The data for a each body takes 8 lines of text, and must follow the prescribed format exactly. Following is an example of how the data must be entered for a single body (Sigma).

 

Example of Format

"***Name Abbr Symbol", "Sigma", "Sig", "S"

"BaseYr/Epoch/Geo/Prec.", 19350107.0, 0, 0, 1

"Semimajor Axis", 5.789593, 0, 0, 0

"Eccentricity", 0.26, 0, 0, 0

"Inclination (Degs)", 5.0, 0, 0, 0

"Perihelion (Degs)", 2.0, 0, 0, 0

"Node (Degs)", 161.0, 0, 0, 0

"Mean Anomaly (Degs)", 137.5489, 2584.1766225, 0, 0

 

A description of each of the 8 lines follows.

Line 1 - Comment, Name, Abbr, Symbol

Comment - (Text) This is for reference only, and contains a reminder of the items on this line.

Name - (Text) This is the name of the body which will appear in reports in Solar Fire, containing up to 20 characters.

Abbr - (Text) This is a 3 or 4 letter abbreviation of the name of the body.

Symbol - (Text) This is a single character representing the body.

Line 2 - Comment, BaseYr, EpochYr, Geo/Helio Flag, Precession Flag

Comment - (Text) This is for reference only, and contains a reminder of the items on this line.

BaseYr - (Numeric) The date (expressed either as a decimal year number YYYY.yyyyyyyy or as a decimal year date YYYYMMDD.ddddd) for which the following orbital elements were calculated..

EpochYr - (Numeric) The date (expressed either as a decimal year number YYYY.yyyyyyyy or as a decimal year date YYYYMMDD.ddddd) of the standard ecliptic for which these orbital elements were calculated. If this is set to 0 (zero), then the EpochYr is taken to be the same as the BaseYr.

Geo/Helio Flag - (Numeric) Set to 0 (zero) if the orbit is a heliocentric one, or to 1 (one) if it is a geocentric one.

Precession Flag - (Numeric) Set to 0 (zero) if the orbital elements apply to the Tropical (precessing) zodiac, or to 1 (one) if the elements apply to the fixed zodiac of the EpochYr date. When set to 1, the orbital elements are precessed to the date of the calculation, whereas when set to 0, no precession is performed.

Lines 3 to 8 - Comment, Orbital Elements

Comment - (Text) This is for reference only, and contains a reminder of the items on this line.

Elements - Each line has 4 numeric items. These items are used to calculate the elements for a specific date in the following manner.

X = Item1 + Item2 * t + Item3 * t² + Item4 * t³

where t is time since the BaseYr date, expressed in decimal centuries (if the EpochYr date is prior to yr 2000) or in decimal millennia (if the EpochYr date is yr 2000 or later).

In many cases where the elements are approximate, items 2, 3 and 4 may be zero. However, they must still appear on the line as zeros, in this case.

Line 3 – Semi-Major Axis

This must be in astronomical units (1 = average earth/sun distance). This item is ignored for bodies which have a geocentric orbit.

Line 4 - Eccentricity

This must be in units of eccentricity (0 = circular orbit).

Line 5 - Inclination

This must be the inclination of the orbit to the ecliptic, in degrees.

Line 6 - Perigee/Perihelion

This must be the position of perigee or perihelion in degrees. (Note that this is not the same as the “argument of the perihelion”, which is equal to the position of the perihelion minus the position of the north node.).

Line 7 - Node

This must be the position of the north node in degrees.

Line 8 - Mean Anomaly

This must be the mean anomaly in degrees. If the second item on this line is set to 0 (zero), then the rate of change of mean anomaly is automatically calculated from the semi-major axis instead, according to the formula:

Daily Motion = 0.9856076686 / (Semi-Major Axis)1.5