StarPilot Celestial Navigation FAQs


A good idea about batteries

This simple idea applies to all devices that use batteries.

When you replace the batteries, use a fine point sharpie pen and write the date on the battery. Then the next time you change them, you will know a bit more than you would have otherwise.

Not a bad idea for light bulbs either.

Thanks John P. for this good idea.

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To copy StarPilot from ROM to RAM

If you have removed StarPilot from RAM for any reason and need to replace it, then do the following:

[mode] [f3]
scroll down to 'apps desktop' and turn OFF the desktop
[2nd] [varlink]
scroll down to spsetup so it is highlighted using the blue arrow keys
press [enter]
press [)] so the small bar then reads "spsetup()"
press [enter]
and you will see the various programs in ROM unarchiving themselves into RAM.

Once done, press enter again until your CODE is showing and the program asks for your KEY.

Your KEY is on the back of the calculator cover; or, if a new installation, you can register online using your StarPilot serial number to get the KEY by email.

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Removing SP-89 battery while program running

In the StarPilot-89 calculator, the program is stored in ROM, so if you remove any one of the main batteries the program will be safe. The state of the calculator when you remove the batteries, however, will affect how you proceed after the battery is replaced.

If you remove a battery when the calculator is OFF (Recommended), then nothing special occurs. Battery out, battery in, and all is as before.

But, if you remove a battery while the StarPilot program is running (Not Recommended) and insert the new battery immediately, the program appears to lock up (i.e. the keys do not do anything)

The solution is to take the new battery out and leave it out for 5 minutes. Put the new battery back in and the calculator will reboot itself. You will have lost StarPilot from RAM, but it will still be in ROM.

To move from ROM to RAM, follow instructions To copy StarPilot from ROM to RAM

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Do you have the latest version?

Registered StarPilotPC and calculator users can always download the latest version from the downloads page. Users of StarPilot for iOS can get the latest version from the iTunes store.

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Trouble with TI-Connect "Restore" Function

Some users have experienced difficulty while reinstalling StarPilot onto their TI calculator because TI-Connect "Restore" function is not recognizing the StarPilot file. If this happens to you, go to where the unpacked files are stored on your PC (usually c:\myTIConnect\Backup). Select the file that looks similar to 'bld23082.89g'. Right click on that file and "Send To" your TI Device (be sure your calculator is plugged into your computer). Once loaded into your calculator, follow the initializing instructions in the manual.

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Finding Best Sights

When asking the PC or especially your calculator to find the best sights from the entire sky, keep in mind that it might take a long time to compute if you have the magnitude limit set to dim stars. This is true even on older PCs, since in some skies with many stars and planets, the program does many many thousands of computations to come up with the best triads of sights. The best bet is to limit the magnitude to 2.0 to start with, or even 1.5 for a quick look. As a rule, you will get all you need with 2.0, and only very rarely will you need to extend to 2.3 or so. If, on the other hand, you choose magnitude 4 (barely visible) then be prepared for a long computation. The location and elevation of the stars can end up contributing more to the "best choice" than the magnitude does, which accounts for the extra computations. Another solution is to go into the best sights settings and change the goodness criteria to add more weight to the brightness, but we would not recommend that. We think we have this set about right for practical use at sea.

A symptom of the above issue (i.e. magnitude set too high), is that the program appears to quit or lock up during Best sights computation. It has not, it is just crunching away as described above.

This is a powerful feature of the StarPilot program; we must just keep in mind what it is doing. There is no celestial navigation program on the market except StarPilot that can actually figure out what the best sights are for any complete sky. The only comparison would be Pub 249, vol 1, for selected stars only.

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Math functions with SP-89

The TI-89 and later versions have very small numbers in the display for doing conventional math operations with the calculators. To overcome this we have built a custom math function display that you access with the custom keys. From anywhere within StarPilot, press [F5] [F5] to enter this mode. You can do all conventional math functions, including trig, etc, with large displays. When done press [ESC].

Note that in all TI-calculators, they give back what they call exact answers. If you do 15/4 you will get back 15/4 as an answer, since that is in some sense technically the correct exact answer. If you want (as we usually do) a decimal answer, enter a decimal point in any of the numbers, i.e. 15/4. and you will get 3.75. In short, we must learn to enter a decimal point at least once, anywhere, when doing math functions in these calculators.

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Magnetic variation computation

For SP-89, 92+, V200 and SP-PC in all versions newer than Nov 20, 2002, StarPilot will compute magnetic variation for a given date and location. This feature is not available in the SP-86; use the free update option if you wish to add this functionality. StarPilot PC computes all aspects of the magnetic field; the calculator versions compute only the variation and its annual rate of change. Current StarPilot versions will compute magnetic variations from January 1, 2010 through December 31, 2015. As new magnetic declination information is published by the US National Geophysical Data Center it will be incorporated into StarPilot. The next update is scheduled for January 01, 2016.

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IMAC, PC laptops without serial ports, and with USB

Today, most IMAC and PC laptop computers have only a USB connector to communicate with a TI calculator for installing or updating software. The cables and special software are available from www.education.ti.com or authorized outlets. These computers also require the use of the TI-connect program.

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Great Circle Waypoints

In versions dated prior to 1705 (17 May 2000), great circle waypoints were computed every 180 nmi. This was changed on May 20, 2000 so that users have the option to enter a longitude interval and StarPilot will then compute the corresponding latitudes at these longitudes that mark off the Great Circle route. This method is more convenient for plotting and more in keeping with standard Bowditch solutions.

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Viewing DR and Destination positions

Since these are the two settings we are likely to want to check often (i.e. they are used for all routing and DR computations) we have changed the order of the View Settings display. Now View settings shows these data first, then you can [Exit] if you like and stay where you were without viewing the rest of the settings. Likewise [Custom] [View] in the SP-86 will display DR and Destination immediately from anywhere within the program, as will [F2] [F2] [1] in the SP-89.

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Using plot, zoom, and pan options

Use of StarPilot's various LOP plot options including zooming is in the manuals which can be downloaded from the Documentation page. Plot options also apply to star map plots and to the sight analyzer plots. In the PC version, they also apply to the 3-body fix plots.

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For PalmPilot and Pocket PC sync users

The TI GraphLink program for connecting your calculator to the PC may not function properly if you have recently used PalmPilot Hotsync or Windows Active Sync. When users install either of these, the sync function installs a resident program that grabs COM1 for the sync'ing process, therefore TI-Link cannot access the port. If this occurs, you will need to disable or exit the Sync program prior to running the TI-Link. Thanks to Capt. David O. for reminding us of this. It is also an issue to those using a com port for your GPS.

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DR across midnight

The Update DR function does not read the date stored in the calculator (date is for cel nav functions only). When you must DR across midnight in the Speed and Time mode, then take one leg up to 2400, then start another at 0000. In the Log mode this is not an issue. Note, however, that you can indeed do running fixes that span midnight in any time zone since the date is read in all cel nav functions.

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Comparing a-values

If you wish to compare a-values (intercepts) computed from tables by hand with those obtained from StarPilot (or any calculator or software) then you must use the Assumed Position for the DR position in StarPilot. If you do not, you will still get the same LOPs once plotted, but the a-values themselves will be different since you use different reference points. Hence if you want to see the same a-values, simply enter the AP used in the tables approach as the DR in the calculator and you should get the same values out.

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Contrast adjustments

To increase the screen contrast on TI-86 StarPilot calculators, do [2nd] [up arrow] and to decrease it do [2nd] [down arrow]. A number will briefly appear in top right of the screen. It varies from 1 to 9. With new batteries the screen will be solid black at about 4 or 5, and you will typically start with a setting of 1 or 2. When this gets to about 7 or 8, i.e. the screen is faint enough that you adjust it that high to see clearly, then you will start getting notices to change the 4 AAA batteries.... but you will still have weeks of normal usage after that.

For contrast adjustments in the TI-89 StarPilot calculators, do [green diamond] then [+] or [-] keys. Note that the 89 does not show a numeric contrast level as the 86 does.

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DR Update at 090 and 270

First some background: The StarPilot DR Update function takes the stored DR position and updates it with your input of either a new DR Time (and Speed) or a new DR Log reading, depending on the DR mode setting. After it computes the new position (by mid-latitude sailings) it does a double-check on the results by computing from scratch the range and bearing from the old position to the new position using the Rhumbline function (mercator sailing using meridional parts).
Consequently, when you view the range and bearing reported back in the StarPilot with the new position coordinates, you may see results that differ very slightly (few hundredths) from what you entered... you have, however, still computed the best position you can when applying a given distance and course to a particular position... short of an iterative procedure that is not included in any products we know of, nor is it covered in Bowditch.

Issue at hand: Rhumbline computations do not work for courses of precisely 090 and 270 (this is parallel sailing, not mercator sailing). In versions of StarPilot dated 06/06/00 and earlier, we compensated for this by simply changing the double-check routine to a great-circle computation whenever the course was within 0.03 of 090 or 270. In retrospect, this was not a good approach since in some cases the discrepancy reported for even rather short runs due east or west was several tenths of a mile. Consequently, for all versions dated later than 06/06/00, we now abandon the double-check, and simply repeat back to you what you entered for course and distance whenever the course lies within 0.03 of 090 or 270. The updated position is still the same, as it always has been, it is just that the reported range and bearing you see will be exactly what you put in, you are not getting any "double check" for this parallel route. Thanks to Dr. G.P. in Germany for bringing this to our attention.

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Note on deleting sights

This is not a change in any version, just a clarification. It is even in the manual, but should be stressed more. The easiest way to delete a sight (or several sights) from a sequence of stored sights is to simply execute Review Sights from the Cel Fix menu and when the one you want to remove is showing, press Delete key (Del). This way you do not need to know the sight number. The alternative is to use the Delete a Sight function and enter the sight number to delete it. This works well for just one or two sights, but after deleting one sight, the rest get renumbered from that one on, so you have to recheck the numbering with Review Sights or keep track of the sight numbers.

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Installing SP into TI-Voyage 200

Unlike the TI-89, the Voyage comes LOADED with software; at least 10 applications. The applications are loaded into ROM but the data for the programs is loaded into RAM. There is not enough memory in the Voyage to accommodate all the TI programs and the StarPilot. Note that all the TI programs are included on the resource CD and/or can be downloaded from the TI web site. Users purchasing Voyage 200 will need to remove the TI applications from memory before they can load the StarPilot. Once StarPilot is loaded, it can be uninstalled with the SP ROM image left in ROM. Then the TI programs can be reloaded. The Data for the TI programs must be erased or moved to ROM before StarPilot is unarchived and used. The easiest way to install the SP on a stock Voyage 200 is to do a memory reset first [2nd][MEM][F1][3]. There is no need to backup the TI programs since they are all included on the resource CD.

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Plot of LOPs does not make sense

The plot will appear wrong, or insensitive or erratic to your commands if you have not set the DR position correctly. The DR position is always in the center of the plot when first displayed, so if this has not been set, the graphic will center on 0, 0 (the default position) which can highly compress the scales used, unless you happen to be in that neighborhood. Check the User's Guide on how the settings are used or not used depending on your choice... or just note that before each plot you are asked for the DR position, course and speed, and set them at that time. As a general rule for most convenient usage, it is best to take advantage of the Settings options.

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DR Update in Speed/Time mode

After a running fix, StarPilot asks if you wish to update the stored DR position with the new fix position. In DR mode = Speed/Time, this operation will store the new position and also update the DR Time with the Watch time of the fix. This last step, however, was not working right in that it applied the ZD to the WT and changed the DR time into GMT. This was not our intention, just an oversight, and this has now been fixed. In all versions Aug 19, 2000 or newer, when you update DR after a running fix, the WT of the sight will be recorded as the new DR Time regardless of what is stored in the ZD. Our intention is that this stored ZD only be used for actual sight reductions, and now it does work that way. This use of WT and DR time is the most convenient for actual navigation underway. (If you had been running in DR mode = Log or Off this would not have been noticed, and if you used only GMT, i.e. ZD = 0, it also would not have shown up.) Thanks to Don F. for finding this glitch.

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Twilight times at high latitudes

At the start of morning nautical twilight the sun has risen to a point that is some 12 below the horizon. At the start of morning civil twilight it has reached the point of being some 6 below the horizon. At high latitudes in some seasons, however, the sun might not ever get far enough below the horizon to cross one of these defining times. In these cases there are no beginnings of twilight. If your computation coincides with these circumstances, we present this fact in the calculator versions of StarPilot by setting the corresponding "twilight time" answer to the same as the rise or set time. (We are forced to this convention because we can only enter numbers in the calculator output fields and we believe that 00:00:00 is not as good a choice since this is an unlikely but still possible correct answer, whereas the convention we use is unambiguous.) Hence if you get the answer: nautical/civil/rise = 04:15:23, 03:44:12, 04:15:23, it means there is no nautical twilight (sun did not descend more than 12 below the horizon), civil twilight is 03:44:12 (sun did go at least 6 below), and then it rose at 04:15:23 in whatever time zone you had set in the StarPilot. Likewise, 04:15:23,04:15:23,04:15:23, has the corresponding meaning that there was no nautical nor civil twilight.

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Rise and set times

Computed rise or set times can end up negative or greater than 24hr. This happens whenever the rise and set phenomena take place on different days from the perspective of the time zone you selected in the UT offsets option. If one of the answers is greater than 24 hr, it means the event has been calculated for the next day, whereas if one is negative it means that one was calculated for the previous day.

If the output is simply being used for planning, you can correct with a +/- 24h and get a result that will likely be right to within a minute or two. If you want more precise values, then adjust the date by 1 and then when you make the 24hr correction you will end up with the value on the date of interest. Note that StarPilot sunrise and sunset times should be a bit more accurate than those in the Nautical Almanac since we use a temperature and pressure sensitive correction for Refraction whereas the Almanac uses a fixed value and we also use a computed SD instead of the fixed value used in the NA. If you want to compare StarPilot values with official Almanac computations you can use the Sun/Moon data from the Naval Observatory.

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Getting in and out of StarPilot-89

To get out of StarPilot-89 in order to use the math functions of the TI-89 calculator, you can do [2nd] [ESC] and then [2nd] [CUSTOM]. The first step gets you out of StarPilot, the second changes the menu bar to the TI version.

To get back into StarPilot, do [2nd] [ESC] then [green Diamond] [1]. Then you are back in StarPilot from just about anywhere you might be. If there is any chance that you have changed stored constants during your math work, then do Set Defaults Settings [4] [2] to reload StarPilot data.

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Printing problems with StarPilot-PC

We have run across several cases where the print function does not seem to work. One way to make a quick test is to look to the print preview option. If the plot or list of data shows there then it will most likely print fine. If not there, then it will not print.

We do not know what causes some systems to not work properly. We have found that in most of these cases, if you add a new printer (use any generic one that windows has a driver for), then set it to default, then set the default back to your original printer that seems to shake loose the communication between starpilot and the printer and it will work.

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Reminder about upgrades

Please remember that all registered users, whether they purchased StarPilot as hardware or as software, have free upgrades to the latest version.

The latest version for PC and for calculators is always available on our Downloads page.

When there is a new version available you may download it and install it onto your calculator or pc. If you are not familiar with the calculator process, you can call or e-mail us to arrange for us to do it for you.

No new registration KEYs are required. Simply download the program and then install it. Instructions come with each download. To transfer the program onto the calculator you will need a PC-TI Link cable and the free TI-Connect or similar program. Please note that we do not provide tech support on calculator software installation. There are instructions that come with the download and alternatively, you may contact us to arrange for sending us the calculator for updating.

Users of StarPilot for iPhone and iPad will receive update notifications via the iTunes store.

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This page contains answers to common questions handled by our support staff, along with some tips and tricks that we have found useful and which are presented here as questions.

If you have discovered a favorite tip or trick using any StarPilot product, please pass it along on our feedback page.