* * StarPilot * *
2 Celestial Bodies...
3 Sight Reduction
4 Celestial Fix...
5 Update DR
|This is called the INDEX, the main menu of menus. Start by defining the Settings which will be used for repeated work. Then plan your sights with Celestial Bodies, take the sights, do the Sight Reduction, then compute a Fix. Update the Dead Reckoning (DR), execute the Rhumbline utility to find your new course to destination, and you are done. The Utilities are various related or special computations, some of which (such as Lunar distance for time, find best sights, and sights analyzer) are unique to the StarPilot program.|
* * Settings 1 * *
1 More settings...
3 DR Lat/Lon
4 Dest Lat/Lon
6 View Settings
* * Settings 2 * *
* * Settings 3 * *
* * Settings 4 * *
For convenience you enter here values which are common to many sights.
The active DR position, Course, and Speed are the ones valid at the Time stored — alternatively you can do DR by log reading instead of time (DR mode). We use careful DR coordination since all fixes with StarPilot are running fixes which correct all sights for your motion during each sight session and between subsequent sessions. The DR is integrated into the celestial reckoning to minimize keyboard input and possible error — not to mention that it makes your day's work a breeze. With Destination Lat/Lon also stored, we again save keystrokes in figuring new course after each fix.
Most of the settings are standard, others are unique to StarPilot. Temp and Press are for special sextant sight corrections, Dip Mode = true horizon or dip short. In the dip-short mode, users can practice sextant sights using a shoreline without a true sea horizon. Hc min/max and #cutoff limits the computed heights and number of stars displayed with the Sight Planner.
SR mode selects between doing Sight Reduction with the stored settings (SR mode = Sequential) or entering all new data for each sight (SR mode = Random). The former would be used for actual sights underway or on shore, the latter is best for working practice problems from a book or the odd sight reduction not in any particular sequence.
PC (precompute) mode lets you choose between quick computations for planning purposes or our regular High precision output. For sight planning, body ID and data analysis, the quick computations are more than adequate and twice as fast. See discussion of StarPilot almanac precision.
With Units settings you can choose between metric and US, Celsius and Fahrenheit, millibars and inches, etc.
"Set Defaults" returns the calculator to the shipped status, essentially zeroing out all the various optional settings in the calculator. When working the practice exercises, it is easiest to first Set Defaults.
* * Celestial Bodies * *
2 Sight Planner...
3 Sight Analyzer...
5 Star/Planet ID
* * Sight Planner * *
* * Sight Analyzer * *
Sight Planner is a premier feature of StarPilot. It computes and then plots out graphically a radar-like view of the sky showing all celestial bodies available for sights. Select the bodies you want, and click them with a cursor to read their altitudes and bearings.
You can use this to plan sights, or just to identify what you see in the sky — at sea or after a walk at home. An alternative for the latter is Star-Planet ID, where you enter the observed altitude and bearing and StarPilot tells you who it is.
The Best Sights function goes through the computed sky to select out the best triads of bodies for the optimum fix. You can step through them showing them marked on the sky plot, or do List sights to present the data as text.
Sight Analyzer is another unique feature of StarPilot. It lets you select out from the set of stored sights a series of sights of one body and then it computes the appropriate shape of the curve of data points taking into account the motion of the vessel during the sight session. This feature can be used to discover the best sights of a sequence, or it can be used to very precisely analyze a series of LAN sights to determine the true peak height needed for an LAN Lat.
* * Sight Reduction * *
5 Delete a Sight
6 Celestial Fix...
Choose the body, and you are off. StarPilot reads the SR mode to decide what it needs to ask you. In sequential mode, it needs only the sight time and the sextant reading, everything else is stored in Settings. In random mode, it will prompt you step-by-step for all input needed for that sight.
All the sights you take will be saved and used for the next fix. If you have recently completed a fix, then you will want to empty the sight list which is done on the Celestial fix page. You will be reminded of this when you start any sight reduction because the current sight number is clearly displayed.
The output display of each sight reduction also reviews for you the complete set of input you used so you can check for input errors. This is a unique feature of StarPilot. Other hand-held devices require stepping though the entire input sequence a second time to check for errors.
* * Celestial Fix * *
1 Review Sights
2 Fix by Computation
3 Fix by Plotting
4 Sight Archive
5 Delete s Sight
6 New Seq (Del All)
StarPilot uses three methods of determining a fix from your set of sextant sights. There is a basic Plot method and a pure computational procedure. The Computation method is the running fix computation described in the Nautical Almanac. It is interesting to compare this computed solution with what we would choose from the plot of the LOPs. The plot can be zoomed for precise fix selection. No other calculator — or even PC program — offers this valuable option.
If the plot — or your numerical review of the sights — shows that one or more sights are clearly in error, just remove them from the list and recompute the fix. Since all fixes are running fixes, corrected for your course and speed and adjusted to the fix time you selected, you can use the relative size of the a-values themselves to evaluate the sights. Just discard any that deviate significantly from the average.
StarPilot even has a feature that lets you know how much each LOP has been adjusted for your course and speed, you can view the list of a-values with and without the DR corrections.
* * Utilities * *
2 True wind
3 Route Sailings...
4 Current Sailings...
5 Celestial Utilities...
|There are so many special and utility computations included in StarPilot that it would be distracting to go through all of them here. So we just mention the major tools used in typical ocean navigation here, and we will then slowly add more specific descriptions as links from the menu items here as time goes by.|
* * Route Sailings * *
2 Great Circle
5 Compute Magnetic Variation
6 Set DR params
* * Current Sailings * *
* * Cel Utilities * *
* * Piloting * *
From your present position to your destination, StarPilot will compute the Rhumb line and Great Circle courses and distances — and itemize the GC route if you want to use that. A very convenient speed, time, and distance function is also included on this menu.
The new (Nov, 2002) magvar function now computes accurate magnetic variation for any date and location on earth. Just enter date and position to get present variation along with annual change.
Plus all "current sailings" starting from the simplest of knowing course and speed, set and drift, to find course and speed made good and others, including input of GPS values of SOG and COG along with knotmeter speed and compass heading to compute set and drift of current.
A very convenient DR function lets you update your DR by just typing in your log book entries. You can keep track of DR position by log readings or by times and speeds (DR mode). Or use Traverse Table function to determine equivalent route through various waypoints or legs.
And so on... We will add more discussion of the Celestial and Piloting utilities descriptions as time goes by... in the meantime, see full discussions in the User's Guide Link below
For those interested in details, here is a note on How we do Lunars.