The story of HNSKY:
Dated: 2000-8-8
Today it is almost 2 1/2 years ago that I started writing this program. First I started with a simple program with not much intentions and somehow it reached the current state of one of the best free ware programs available. This was never planned but somehow there where always improvements to make. My first computer ever owned was a ZX80 and I own a PC since 1987. I made many DOS programs in the past. That was a good learning tool.
I rediscovered astronomy in December 96, about a half year after moving from (bright) Rotterdam in the Netherlands to our new house here in Bruehl, Germany. I still own my very simple toy telescope since a was a kid long time ago. I was born in 1959. Rediscovering astronomy, I slowly collected a lot of astronomical knowledge from books, magazines and the internet. In December 97, I was thinking of making a program to simulate of rotable star map showing the bright stars and the constellations.
The Borland Pascal compiler 7.0 for Windows contains a demo of a rotating globe and the first idea was to create 12 gifs for each month. Quickly I changed my mind and used the bright Yale catalog as found on Compuserve astronomy forum to build a vector based map. A good exercise was a simple dynamic map created with a spreadsheet. The very first HNSKY version did not use the spherical projection and was only showing a kind of spider projection of the northern hemisphere. There was no menu and version 1.0 could switch between northern and southern hemisphere. File size only 80 kbytes or so. Somehow the name "Hallo Northern Sky" occurred during the Beta versions in January/February 97 and is still in use today. "Hallo" is the Dutch version of "Hello".
Somewhere in April 1997, I mastered (after weeks of thinking and experimenting), the mathematics for creating a spherical projection just using my school mathematics books. The planets where introduced using a basic code as found on the astronomy forum of CompuServe. Next step was the introduction of a more accurate planet calculation including disturbances due to interactions between the planets. There I had to rely on others. At a much later state, the books of Meeus and others where discovered in the library local astronomy club and are now part of my well appreciated book collection. At the same time the SAO catalog and later the PPM and finally the GSC and USNO A2 where introduced. It was all very time consuming , but the program became better and better. At the same time, my first son came to world and was starting in the beginning of 98 to crawl around. He pretty soon called the program "the Ball".
The final windows 3.1 version 1.62 was ready in mid 99. At the same time I bought the Pascal compiler Delphi 4.0 with the idea to compile the program to a Window 95 application in only a few month maximum. Somehow it grow out of control. It became much easier using Delphi to introduce new menus and Windows features. Contacts with some member of the SAC club and others initiated the creation of the Tycho-2 catalog. Additional the SAC club came with their deepsky database SAC 7.0.
So at this moment of looking back, I put an tremendous amount of time in making this program. (three or four evenings or more a week) It was lot of fun and kept me out of the pub as my wife called it. My second boy is now almost 5 month's old. It becomes now more difficult to make time available for this program. I can still do a lot in the free time of my regular business trips, but at this moment, I think the program has reached a state where it is more or less completed.
I just ordered a computerized scope and it is time to spend more time looking to the sky then to the screen. However the screen is and will stay a great help and tool for me and other astronomers.
Just for curiosity, the HNSKY program was programmed on my old Pentium 100 and a very good 14 inch monitor. I could afford to buy a better/faster PC, but this one is fine for the job.
Clear skies to all, Han Kleijn
