ASTROCLK Astronomical Clock and Celestial Tracking Program Page 1 Program Revision History ASTROCLK REVISION HISTORY Each released version of ASTROCLK uses a four digit revision code such as 9117. The first two digits indicate the year and the second two digits indicate the week of the year. In some cases, an additional letter suffix is added to distinguish changes occuring within the same week. A partial week at the beginning or end of the year is counted as a full week. Using this method, a year will typically have 53 weeks although it is possible to have 54 weeks in a leap year (1972 is an example). The current year-week revision code is shown on the Julian Date display, Display Mode 7, in ASTROCLK. This file records the recent revision history of program ASTROCLK through all of the minor twists and turns that usually accompany the evolution of such a program. (Early revision notes have been deleted from this file but are available on request.) It illustrates the tortuous process of maintaining and refining a program as ideas and problems are reported from every quarter. It may also be helpful to users who are upgrading from one version to another to find out what has changed. This file may also describe recent changes not included in the main documentation; compare the version numbers below with the main documentation. David H. Ransom, Jr. 9117 04/22/91 ----------------- -This release is a MAJOR UPGRADE from Version 9050. NOTE: ASTROCLK now requires binary external star catalogs which have a filetype of ".CC1". ASTROCLK's external catalog star searches (Function Key F5) will NOT operate correctly with prior versions of the external star catalogs! See below. -Added a sixth mode to the Precision Data Displays (Display Mode 8) to show the local times for sunrise, sunset, and Civil, Nautical, and Astronomical twilight. Thanks to Matt Merrill for writing and debugging the original code which I then then adapted for use in ASTROCLK. -Changed external star catalog from ASCII to binary format, identified by the filetype ".CC1".. The new supplied catalog names are ASTROCLK.CC1 and MESSIER.CC1. Catalog searches now require approximately one half the search time and the binary catalogs are less than half the size of the previous ASCII versions. Binary catalogs are created by my program STARCAT which will be available on my BBS. Other star catalogs may be available in a binary format for use with ASTROCLK. -Edited ASTROCLK.CC1 and MESSIER.CC1 to delete the all-zero "place holder" which occupied the record for the non-existent Messier object M40. This caused an incorrect match on star searches near RA=0 and DEC=0. However, this means that the catalog number (when searching MESSIER.CC1 by catalog number ASTROCLK Astronomical Clock and Celestial Tracking Program Page 2 Program Revision History rather than by object name) for Messier objects greater than 40 will be one less than the Messier number. -Corrected an error in angular separations during star searches if right ascension were set to zero. -Added AUTO mode to DAYLIGHT FLAG, set using ALT-F10+F1. After pressing ALT-F10, press F1 repeatedly until the desired DAYLIGHT FLAG mode is displayed: "[OFF]", "[ON]", or "[AUTO ON]"/"AUTO OFF]". Note that when the AUTO mode is selected, the state of the DAYLIGHT FLAG ("ON" or "OFF") is selected based upon the current DOS date and time. Do not select the AUTO mode if your location does not use daylight time! -When set to the AUTO mode, the DAYLIGHT FLAG will be set or reset automatically and the local time zone clock display title (Display Mode 1) will change from standard to daylight time or vice versa. Daylight time is ENABLED as of 02:00 on the first Sunday in April; daylight time is DISABLED as of 02:00 on the last Sunday in October. These dates are valid ONLY for the United States and Canada; all other users should set the DAYLIGHT FLAG to ON or OFF manually to correspond to daylight or summer time conventions in their location. NOTE: Systems with an 80286 processor or higher AND using DOS Version 3.3 or higher will also change the hardware clock when using the AUTO mode. For these systems, including ASTROCLK in the AUTOEXEC.BAT file and setting the DAYLIGHT FLAG to the AUTO mode will automatically adjust the computer hardware and software clocks for daylight time changes at boot-up. -Changing the DAYLIGHT FLAG using ALT-F10+F1 or allowing the DAYLIGHT FLAG to be changed in the AUTO mode now automatically adjusts the UTC OFFSET to reflect the time change. In prior versions, the UTC OFFSET had to be manually changed using F10+F10 every time the DAYLIGHT FLAG was changed. -Repaired minor bug with INTERVAL TIMER. If the DAYLIGHT FLAG was changed while the timer was on, the timer was in error by one hour. The timer start time is now automatically adjusted if the DAYLIGHT FLAG is changed either manually or automatically. -Modified Perpetual Calendar, Display Mode 6. When the calendar is displayed, pressing the digit 6 will toggle between the calendar display and a list of the holidays in that month. Several additional holidays plus the beginning and end of Daylight Savings time added. Corrected taxes due date so that it does not occur on Saturday or Sunday but on the following Monday. -Adjusted DD/MM/YYYY date input error checking using F3 to properly check the day for each month (beginning with day 1) but to allow January 0 and December 32 to correspond with common usage and the Astronomical Almanac. Prior versions allowed the 0th of any month and disallowed December 32. -Corrected date input using F3 to agree with documentation such that using the form "+nnn" adds nnn days to the current Julian Date. Prior versions assumed absolute Julian Date if nnn was greater than 50 even if the "+" was included. Absolute Julian Date is now assumed only if nnn is greater than 400 AND the "+" sign is omitted. -Corrected bug in external star catalog searches. If one of the nearby stars were selected instead of the nearest star, the program aborted with a "Bad file name or number" error. This was ASTROCLK Astronomical Clock and Celestial Tracking Program Page 3 Program Revision History still another (but never reported) file handle error introduced at Version 9016! -Corrected cosmetic problem with city file searches using F6. When the SPACE BAR was pressed to search for the next match, the prior city name was not cleared before next name was displayed. If the next city name was shorter than the previous city name, excess characters were "left over" on the display. -Corrected minor bug in city file searches: if no city was accepted, elevation for the current location was reset to zero. -Updated ASTROCLK.MPC to use the first 250 minor planets from file ELEM911.MPC (as of February 1991). -File ASTROCLK.CTY corrected. "West Covina" was mispelled as "West Corina", and the coordinates for Sunnyvale, CA have been updated (per Mike Gardner). Added Greenwich Obs, England for easier checking of Greenwich-based data along with several other cities whose coordinates were sent in by users. -Moved some code to new ASTROSB4.BAS SUB and FUNCTION source file to fix compiler memory overflow for main module. Added source file ASTROCLK.INC, an include file with DIM, COMMON and CONST statements used by all other source files. 9050 12/14/90 ----------------- -Added UTC Day-of-Year to Display Mode 7 for years > 1949. This is the format used by NORAD with 2-line orbital elements, i.e. 90247.451472. The first two digits are the year, then the day of the year, and the time is the fractional part of the day. This is the time/date format required by satellite tracking programs such as STSORBIT and TRAKSAT. -Adjusted Delta-T and Delta-AT in accordance with revised data in the 1991 Astronomical Almanac and to take into account the Leap Second at the end of 1990. The change in Delta-T amounts to about 0.2 seconds for 1989, 1990 and subsequent years. -Changed .CTY file format to include elevation in meters. Do NOT use OLD .CTY files without editing each line to add ",0" (without the quotation marks) at the end for elevation. Or substitute the elevation in meters if known. -Added feature to append new local coordinates entered with F6 to the current CITYFILE. -Extensive revisions to the documentation to bring it up to date from Version 8947. This was such a chore that I will resume updating the documentation at every revision. It is likely that I've missed some corrections in this process; if in doubt, consult these notes. 9027 07/06/90 ----------------- -This is a maintenance release to correct an error and change several time zone abbreviations and names. -Corrected major error in reduction of star sights. If less than 7 sights were entered, an array was not cleared and spurious data were included in the calculations. OOOPS! Except for minor differences in the fourth and following decimal places, the calculation results now agree with Version 8947 documentation again! Thanks to Ward Harman for finding and reporting this ASTROCLK Astronomical Clock and Celestial Tracking Program Page 4 Program Revision History problem! -Changed UK time zones to GMT (Standard) and BST (Daylight, British Summer Time) to conform to standard usage. Added CET for CENTRAL EUROPEAN TIME @ UT+1 (no Daylight). -The main documentation remains unchanged from Version 8947. The next major release of ASTROCLK, planned to occur about mid-Summer 1990, will include revised documentation incorporating all changes since Version 8947. 9019 05/08/90 ----------------- -Corrected problem which caused ASTROCLK to abort when certain external star catalog searches were requested (F5+F4 and F5+F5). Program reported Bad File Name or Number, Error #52 and returned to DOS. Problem was introduced at Version 9016 when all file handles were changed to variables in order to accomodate new F2 enhancement, writing ephemeris to a file. [Missed one ... OOPS!] -F2 ephemeris generation to a file now APPENDS data to existing file. If the specified file does not exist, it is created. Data for multiple targets may thus be written to a single file. To record data from the start of the output file, either give a new file name or erase the old file from DOS (use F9 to exit to DOS). -Corrected a bug ("QuickBASIC Error, Overflow) which caused ASTROCLK to abort and return to DOS when orbit data was requested for Halley's Comet ("9"). Thanks to Steve Brewster for reporting this problem! -When in Navigation Mode and speed is zero, the local coordinates window is no longer labeled "Calculated Position" but remains the original place name. Similarly, when speed is zero the Navigation Display ("N" key) will now show data relative to the current place name rather than "LAST NAVIGATION FIX" in the top portion of the window. Both changes reflect the fact that the user is stationary at a specified location; position calculations and navigation fixes are therefore not appropriate. -Corrected minor cosmetic errors which erased right side of main window when entering degree information. -Updated F2 help screen to include printer and file output. -Updated F8 prompt screen to include day-of-year date format. -The main documentation remains unchanged from Version 8947. The next major release of ASTROCLK, planned to occur about mid-Summer 1990, will include revised documentation incorporating all changes since Version 8947. 9016 04/15/90 ----------------- -Changed ephemeris format to UTC date and time rather than local. -Added ephemeris epoch/equinox selection: Equinox of Date OR the current internal Standard Epoch (set using F8). -Added PRINT OPTION to F2 Ephemeris Generation. Printer output is sent to the DOS device "PRN". Be sure printer is ready BEFORE selecting it for output. Titles plus 55 lines of data are sent per page with auto formfeeds between pages and at the end. Note that "graphics characters" are included in the data lines; if these characters are not wanted, use FILE OPTION and edit out the unwanted characters. ASTROCLK Astronomical Clock and Celestial Tracking Program Page 5 Program Revision History -Added FILE OPTION to F2 Ephemeris Generation. Data are identical to PRINT OPTION above except are sent to file. Enter complete file name when requested; default file is ASTROCLK.EPH located in ASTROCLK path. -Corrected time calculations for Minor Planets to avoid adding the correction for UTC to TDT/ET twice. -Updated file ASTROCLK.MPC with osculating elements as of 1989 OCT 1.0. Data taken from file ELEM892.MPC. -Since Minor Planet elements are often published [in Sky and Telescope, for example] with T (Time of Perihelion) rather than M (Mean Anomaly), manual data entry now requests the user to select M or T and enter the desired value. For T, use the format: DD[.DDD],MM,YYYY When the input data are displayed for acceptance, only M is displayed; if T was entered, it has been converted to M. If T is input, then the program requests q (Perihelion Distance) instead of a (Semi-Major Axis). -Calculation of minor planet perihelion changed to date nearest the date of the osculating elements. Thus for reasonably current elements and if the minor planet is more than half way around in its orbit, the perihelion date may be in the future. -Reworked manual data reentry ("Z") for Minor Planets to show prior data of osculating elements if present (from previous manual entry or from "X" catalog entry). -Minor cosmetic changes to Precession screens for clarity. -The main documentation remains unchanged from Version 8947. 9014 04/02/90 ----------------- -Corrected a significant error in Minor Planet positions when data are read from Minor Planet Catalog ELEM891.MPC (Epoch B1950.0). For example, Mean Anomaly might be in error by as much as 0.5 degrees. The error was less serious when current data were used. Using ELEM891.MPC, ASTROCLK's J2000.0 calculated positions now agree with AA 1989 to typically less than five seconds or arcseconds. Thanks to Ward Harman for many hours of patient analysis which enabled us to pin down the problem. -Changed minor planet calculations to make sure all calculations performed regardless of display mode. Under certain circumstances the equatorial coordinates (RA/DEC) were incorrect in Mode 0. -Added "prior value" code to manual orbital data input ("Z" after "P" Planet Selection). Input routines modified to accept the usual formats for angles: DDD[.DDD] DDD,MM[.MMM] DDD,MM,SS[.SSS] Once data are entered, the values are retained and displayed on subsequent "Z" inputs. Press RETURN to leave an entry unchanged. The manually entered data are discarded when you exit ASTROCLK. -Added "/" as a valid separator for date inputs. Dates may now be input as "dd/mm/yyyy" or "dd,mm,yyyy". -Minor cosmetic changes in Minor Planet displays. -The main documentation remains unchanged from Version 8947. ASTROCLK Astronomical Clock and Celestial Tracking Program Page 6 Program Revision History 9012 03/21/90 ----------------- -Versions 9007 and 9010 were limited beta releases. This is the first public release since Version 8951. The main documentation, files ASTROCLK.DC1 and ASTROCLK.DC2, remains unchanged from Version 8947. All subsequent changes are described in these notes ONLY! -Corrected color error on large digit navigation position. 9010 03/08/90 ----------------- -Added "Zone x", where "x" represents the standard international time zone letter, to the local clock title (Display Mode 1). Zone Z is Greenwich, Zones A thru M are East Longitudes, and Zones N thru X are West Longitudes. -Repaired error which could cause program to hang if navigation is active and the key sequence F10+F2+F10 is entered to cancel navigation. -Corrected nautical mile conversion factor to 6080.2 feet. 9007 02/12/90 ----------------- -Version 9007 is a MAINTENANCE UPDATE in order to improve various navigation features and to correct several minor errors. The changes are described below and NOT in the main documentation which is unchanged from Version 8947. -Special thanks to Captain Helge Brudvik of the Royal Viking Sky for the freedom of the bridge, and to Chief Officer Magnus Bakken for his practical demonstrations of navigation at sea (as well as many hours of pleasant conversation). The changes in this version have been made during a cruise around South America and reflect what I have learned and observed during that ten week period. -Added large digit display for calculated position in navigation mode; press "N" to toggle navigation displays. -Number of star sights which may be entered for navigation fix increased from three to seven maximum to conform with Air Almanac. When last star sight entered, press RETURN to stop data entry. -Added DRIFT and DIRECTION to navigation to permit correction for combined wind and current effects. Enter using F10+F2. -Corrected UT Time entry in F10+F2 Navigation Fix entry so that RETURN leaves time unchanged rather than resetting it to zero. -Conversion factor for nautical miles corrected to 6082 feet. -Suppressed "Federal/State Taxes Due" message on calendar for Easter Sunday on April 15th. -Minor cosmetic changes in navigation functions. 8951 12/21/89 ----------------- -Version 8951 is a MAINTENANCE UPDATE in order to correct various minor errors. The changes are described below and NOT in the main documentation. -By popular request, the documentation is UNCHANGED from Version 8947. The documentation will remain unchanged until the next major revision so the full documentation need not be reprinted ASTROCLK Astronomical Clock and Celestial Tracking Program Page 7 Program Revision History for minor upgrades in the program. All changes are documented in files ASTROCLK.HST and ASTROCLK.NEW only. -The default responses (pressing RETURN/ENTER only) when using F6 and SHIFT-F6 to enter new LOCAL or DESTINATION coordinates were incorrect and reset the new value instead of using the prior value. The prompts have been improved and the logic has been repaired. Note that the ELEVATION is now left UNCHANGED as the default response. Thanks to Bob Khron for the bug report! -SHIFT-F6 may now be used to review the DESTINATION coordinates and name. Press RETURN to leave all data unchanged. -When navigation is active and SPEED is non-zero, the calculated position window includes the date and time of the last navigation fix: "Fix @ 12-11-1989 15:30 UT" to remind the user when the last fix was entered or calculated. -Dead reckoning positions were calculated one second behind the current time when the clocks were ON. I sure hope nobody crashed on account of that one! -Added Leap Second at end of 1989 to Delta AT table. 8947 11/19/89 ----------------- -Improved Apparent Geocentric Equatorial Coordinates for internal database stars and catalog stars, mean to apparent position, to include effects of nutation and annual aberration. Parallax NOT included. Apparent coordinates are now accurate to within one second/arc-second. -Added navigation function F5 to show first 20 USNO stars in view and suitable for star sights. Uses current coordinates and time. -Revised external star catalog logic. Search times halved and direct access by catalog number is now immediate. -Expanded external star catalog searches F5+F4 and F5+F5 to show list of 10 stars nearest the coordinates input. -Repaired SUB Refract to give correct answer when converting apparent to real altitudes and adjusted the navigation example data accordingly. Real to apparent was OK. -Fixed horizon dip calculation (misplaced decimal point in a constant). -Added SHIFT-F6 for entry of DESTINATION data using external city file and updated HELP. -Added '/' prefix to F6 and SHIFT-F6 city name input to allow match within name. -Improved degree input routine for small negative angles; now processes both "-0,26" and "0,-26" correctly. A minus sign anywhere flags a negative angle. -Fixed "Division by Zero" error in navigation mode when speed was set to zero. -Corrected Planetary Heliocentric Longitude to remove multiples of 360 degrees. -Corrected USNO coordinates per AA 1989. -Corrected paging problem with ephemeris if more than 40 intervals requested. -ASTROCLK.INI now always written on exit. -Reformatted these notes to use a little less paper ... ASTROCLK Astronomical Clock and Celestial Tracking Program Page 8 Program Revision History --------------------------------------------------------------- 8806 thru 8943 NOTE: Intermediate revision notes have been deleted here to save file space. --------------------------------------------------------------- 8805 1/24/88 -Initial Release