ASTROCLK REVISION HISTORY Each released version of ASTROCLK uses a four digit revision code such as 0126. 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. 240 Bristlecone Pines Road Sedona, Arizona 86336 USA e-mail: rans7500@spacelink.nasa.gov Version 0126 -- June 2001 ------------------------- -This is a MINOR UPDATE to correct Delta-T values per data from the US Naval Observatory and the Astronomical Almanac 2001. -The program documentation is essentially unchanged from prior versions. Version 0014 -- March 2000 -------------------------- -This is a MINOR UPDATE to correct several problems. -Corrected Delta-AT and Delta-GPS to remove a spurious Leap Second added at the end of 1999 in error. Thanks to Peter Jones for reporting the problem. -Corrected Apparent Altitude for stellar objects to remove an incorrect parallax correction that was inadvertently applied. Thanks to Peter Jones for spotting the error. Version 9945 -- November 1999 ---------------------------- -This is the usual annual update to correct Delta-T per the Astronomical Almanac 2000. -The documentation is unchanged from prior versions. Version 9938 -- September 1999 ------------------------------ -This is a minor update to correct a sign error in calculatinmg GPS Time. ************************** * Year 2000 Compliance * ************************** ASTROCLK has been subjected to a final round of Y2K testing to ensure compliance with Year 2000. No Y2K problems are known as of Version 9848. Note that these tests only verified that ASTRPCLK executes correctly at and after the transition to Year 2000, not that a particular computer and/or its clock will make the transition correctly. Older computers may have BIOS or other systemic problems in hardware and/or software which may prevent proper operation at or after Year 2000 independent of the operation of ASTROCLK. -Corrected GPS Time so that it is AHEAD OF rather than behind UTC Time. Press "8" several times to view GPS Time on "Precision Time Display #1". Delta-GPS remains as a positive number, 13 seconds as of September, 1999. Thanks to Geoff Hitchcox for pointing out my careless error! -Removed references to my RPV Astronomy BBS. After 12 years of continuous service since it first went "on the air" on 1 November 1987, the BBS is scheduled to be shut down on 31 December 1999. Support for and calls to the BBS have fallen precipitously in recent years to the point where it is no longer worth the considerable personal effort to operate and maintain the system. From a high water mark of 400 calls per day in 1995, traffic is now only a few calls per day -- sometimes none at all. My thanks to everyone who supported the RPV Astronomy BBS. It was fun while it lasted ... Version 9848 -- November 1998 ----------------------------- -This is a minor update to add the Leap Second scheduled for 31 December 1998 to DeltaAT calculations. Version 9841 -- October 1998 ---------------------------- -This is the usual annual update for Delta-T and Delta-AT per the Astronomical Almanac 1999. (Delta-AT is unchanged from 1998.) -File WIN95.TXT has been included with an improved setup for Win95/98.