"Hallo northern sky" software page  

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Welcome to the free planetarium program HNSKY for Windows. It is complete with the SAO, PPM, Tycho-2 star databases, up to date deepsky database containing 30000 objects , Realsky (r) images and access to the external GSC and USNO UCAC4 star catalogs. Telescope control using the universal ASCOM interface package. Provides with menu's in 21 languages.


  1. Jump to the HNSKY program
  2. Screen shots of HNSKY.
  3. History, list of changes and latest ß version HNSKY.
  4. Answers to problems with HNSKY
  5. The public HNSKY discussion group at:
  7. Source code of some HNSKY units and other interesting astronomy programs/routines
  8. Some background information from Bill Anderson, Raymond Bruton, Giuseppe Matarazzo and Han Kleijn.
  9. Han Kleijn's astronomy home page.

The next program: "Hallo northern sky" or HNSKY is a planetarium program for windows. Have a try. It is free with 30000 deepsky objects and all stars to magnitude 12 and with the original GSC CD's, GSC-ACT or the USNO UCAC4 to magnitude 16. It displays all planets, the Moon, Sun, moons of Saturn, Jupiter, Mars, Uranus and Neptune and a few hundred asteroids and comets. It comes with 255 small DSS deepsky images which will blend in at the right size and orientation. To install the program you start with the basic package or just put all the files in one directory and just run the main file HNSKY.EXE.

Download the program: (Your are invited to spread/upload free copies on the web. Please do, no permission required !)

Small basic package                     

Small basic package HNSKY241.EXE (7 MB v2.4.1, version 2014-7-14)

Complete with the SAO star database (magn. 9.5), comet, asteroid deep sky databases, several supplements and images of the Moon, Mars Jupiter, M31,  M42, M81 and M82.

For telescope control you have to download and install the ASCOM  interface program.

2015-1-30  Release of beta version 2.5.0ß11 , extract and overwrite these files in the HNSKY directory.

  • New lock-on popup menu

  • Moon covers stars, optional in settings menu.

  • Persistent feature of the window's canvas. So if a program is in the front of HNSKY window and moved away again, repainting will be almost instantly.

  • Database complete updated using Wolfgang Steinicke 2014 NGC/IC database and SAC81.

  • Deepsky database reading works now correctly for 3 names. (supplements only 2)

  • Search shortcut is now CTRL-F and ALT-S

  • Dark night forecast display for Moon updated.

  • Night vision improved.

  • Supplement plotting speed improved

  • Added brightness estimate for deepsky objects

  • Ascom telescope interface moved to popup menu, azimuth indication in altitude grid changed in N, NE, E, SE, S, SW, W, NW . Outstanding language modules and interfacing to be updated.

  • Ascom connection can be saved in settings.

  • Program can guide the telescope to follow solar objects.

  • Measuring frame routine erase improved.

  • Telescope cursor improved.

  • HyperLeda_980000_galaxies supplement Dated 2015-1-5 (10 MB)  Slow but nice to identify al those small fuzzy objects on your CCD images.  Here a  demo image using a 65 mm telescope CCD image.

  • Made HNSKY compatible with Maxim DL images (uncompressed).


Large program package

Large basic package HNSKY241_large.EXE (56 MB v2.4.1, version 2014-7-14)

Complete with SAO (up to magnitude 9.5, 258.000 stars), PPM (up to magnitude 10, 470.000 stars) and large TYCHO2+  (2.5 million star) database, deepsky help file, non-English menus, planetary and 255 deepsky images.

For telescope control you have to download and install the ASCOM  interface program.

1) Downloading DSS images via internet is more integrated. Just hit one of the DSS servers in the popup menu and after a few second the DSS image will pop in HNSKY. HNSKY will store up to 9 images in the FITS directory as download1.fits, download2.fits.... After 9 files it overrides the first to prevent creating too many files. The size of the DSS can be defined by the rubber square.

2) Secondly in this  version the comet or asteroid database can be updated with a button click from the settings menu. The  update is then downloaded from Furthermore the editor can read and convert "mpcorb.dat" and "astorb.dat" asteroid files. Asteroid have now a size based on the absolute magnitude and standard albedo (0.15).  Conversion of 30.000 object takes 5 minutes or so. Note that the complete database of 353.000 named objects will take hours!! . So first reduce "Mpcorb.dat" in a tekst editor below 10 MB or. You can  read any *.dat file but it will assume "mpcorb.dat"  unless the filename is "astorb.dat" or "AsteroidElements.dat" from Occult. 

3) Introduced a mouse popup menu. Note that you can also pull a rubber square with the right mouse button to size a DSS download or define a Simbad area search.

4) Numerical integration for asteroids to achieve highest accuracy positions years in the future or past. Select in editor a number of lines and push right mouse button to select numerical integration. From version 2.4.0ß2, the error is less then 1" after 10 years !!!  So a asteroid file from 10 years ago will after numerical integration be within 1" accurate!!

5) Small changes such as reverse mouse wheel action, time stamp markers, improved drawing lines, online request to Simbad and other sites.

6) Better FITS images based mainly on DSS2


Asteroids/Comets updates Download  and  import the huge MPCORB.DAT file. For more asteroids you have to download and import this original Minor Planet Center file containing orbital element  of about 360.000 numbered asteroids.
Additional stars databases UCAC4:  You can download the 113 milion stars, 8.5 Gbytes large USNO UCAC4 from   HNSKY can access this catalog directly. Download Z001 to Z900 from  the U4b  directory and add to the same directory file u4index.unf from U4i. This is the only catalog where HNSKY will use proper motion for maximum accuracy. See HNSKY UCAC screenshots.
GSC:  The GSC 1.2 (catalog 254)  of 15 million stars to about magnitude 15 is available at CDS in the compact binary format (303 MB).

Alternatively download the older uncompressed GSC 1.1 (catalog 220) or the calibrated GSC_ACT (catalog 255) in FITS format (2 full CD's !)

The uncompressed GSC 1.1 or GSC_ACT can compressed by the the EXPORT  program to the same compact binary format (total 303 MB) as used for the GSC 1.2.

Hipparcus star database, Hipparcos 118.000 stars file for reference purposes only. One zip file 1.2 MB containing one DAT file. Version 2000-8-9.
Obsolete TYCHO-1 star databases, more then 1 million stars, total size 10 MB, 4 Zip files containing 32 x D32 files, version 2000-8-10.
Obsolete, for historical and scientific purposes, the complete Bonner, Southern and Cordoba Durchmusterung of the 19 century in a HNSKY database:  Size 10 MB containing more then 1.000.000 stars.
Additional supplements

Problems solver supplements

Constellations in form of a supplement, Bright Quasars and BL Lacertae Objects.sup, Coordinates from 110 extra solar Planets.sup
HyperLeda_980000_galaxies supplement Dated 2015-1-5 (10 MB) demo image using 65 mm telescope  or  71000 Galaxies supplement based on Leda data  Dated 2002-6-11 (15 MB)
World map supplement: World map supplement version 3.0 dated 2000-10-22. World map and 2700 cities with there location and relative brightness. Scale 1 : 5.000.000. See screen shot of version 2.0. Included a conversion program to convert coastlines to a supplement.
GCVS 4.1 variable star supplement. Complete 37382 star version. In this supplement the GCVS is displayed as labels so you can easily cross check with Tycho or UCAC2. To get Tycho star info switch off the supplement. (The smaller 7800 star version is included to the basic package)
Obsolete using the Tycho 2+ database: Star supplement Tycho-2: Supplement (star) version 00-3-24 containing the 6395 in Tycho-2 omitted stars as taken from TYCHO-1-main and Tycho reference. Contains HNS_TYC2.SUP. These stars are already included in the tycho2+ star database.
Additional FITS images Extra  large Mars map (Color 1000x500 pixels)large Mercury maps (1440x720 pixels) based on Mariner 10, SVTS and large Jupiter map (Color 600x300 pixels) . Use the large maps only if you have a fast computer or some patience. The planetary FITS files should be placed in your FITS directory.

45 hand made drawings/sketches (880 Kbytes) of  Bill Ferris, Todd Nowlan and Rainer Töpler as FITS files. These can blended inside the map. They should be put in an other directory as the Realsky images otherwise they are blend with the Realsky images.

Other languages non-English help files and language  modules. If you  want create a new language module start modifying the English one .
CD covers Some designs by volunteers: or or or or
Conversion tools Conversion programs/tools Tools for converting GSC 1.1 star database from FITS format to the compact binary format as GSC 1.2. (EXPORT.EXE program)  This will compress GSC 1.1 or GSC ACT from 2 CD's to 303 MB only !! EXPORT.EXE (v 2001) will also export the HNSKY databases to text files (ASCII). Utilities to export GSC 1.1/ACT and USNO A2 to TXT/ASCII files. And finally for experts some DOS programs to create new star databases for the HNSKY program. Conversion program and source code for Hyperleda catalog.



Realsky and DSS image viewer using HNSKY DDE link (HNS_REAL)  Manual or DDE controlled Realsky image viewer. Click on an object and get the realsky image (you have to own the Realsky or DSS CD's). Click on the Realsky image and to center to get cross at HNSKY at the same place. Version 2.0.0b,  Dated 2015-1-9. Here are the instructions and screen shot demo's If your FITS directory in HNSKY is set to the HNS_REAL directory, you will get every result blended in the next screen refresh. HNS_REAL can also be used in batch programs to create several images. Complete with Delphi and C source. Can also batch wise convert FITS to BMP. An other possibility is to control HNS_REAL from the provided Excel table. Contains GETDSS source code version 1.1plus dated 11 june 2013. See also
HNS_FITS version 1.4.0 dated 2003-9-19. Utility program to create FITS files from BMP files with the correct WCS header by entering the position of two reference stars. Screen shot and describtion. This is a great tools to blend your own pictures inside the HNSKY sky map. With three added example files.
Miscellaneous Deepsky help file in CHM format as standalone file. HNSKY can call only the HNS_DEEP.HLP  format file  

Sky commander DDE program for HNSKY and source by Jack Patterson. 

A supplement  of guide stars made by a Sky commander user.

The deep sky database contains 26000 deep sky objects based on SAC 7.2, Wolfgang Steinicke revised NGC & IC, Kent Wallace SEC (PN) database and many galaxies from LEDA. They are in the standard CSV format with a comma as separator, so they can be read/imported by many programs such as Excel. They contain the latest modern data and many corrections of the last years from sources such as

If you have problems with the program or supplementary files read this: Answers to problems HNSKY version 2.0 for win95/98/NT/XP

Questions, suggestions regarding the HNSKY program you could email directly to me han kleijn's email address(in English, Dutch or German) or better post them in the Yahoo group HNSKY:

To post a  message and to get an answer send back by e-mail you have to join this yahoo group. To prevent too much spam/junk mail there is approval which can take a day or so. This is just there to detect that your are an human being and not a stupid spam producing robot program filling our email boxes.

If you afraid to ask a trivial question at such a place, please do not hesitate and send it to my email address directly.

In this group I will send newsletters as special notice:  Newsletters of the "Hallo northern sky" planetarium program

You also welcome to fill my GUESTBOOK

Some stuff to read:

The HNSKY program has printing facilities and the status can be saved/loaded. Here are some screen shot's of the HNSKY program:

Orion constellation using the GSC CD-rom database and provided FITS images:


hns_move.gif ===> Many more screen shot's of HNSKY<===hns_move.gif

The following Excel 4.0 spreadsheet calculates the required photographic exposure time for all the planets, Sun, Moon, stars and deepsky objects. See comments on main index page:

The following Windows program ORB_DEB is a simple windows program which calculates the orbital elements of a minor planet based on three observations/positions using the Gauss method:

Here the standard ASCII input file for my HNSKY help file (version 2013) including the programs to compile it such as the free RTFGEN program . If you can correct my English or the Help file, send a correction to .

Here are some Pascal routines as used inside the HNSKY program. If you have any suggestion to improve them, please let me know:

Here are some links and source codes for ephemerides calculation and some other interesting astronomy programs:

Other astronomy pages:

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