hnsky_b.gif     "Hallo northern sky" software page    

Welcome to the semi professional free planetarium program HNSKY for MS Windows, intended for amateur astronomers. The program controls your telescope via the ASCOM interface, has a comprehensive up to date deep sky database with 30.000 objects and detailed descriptions, a star database with millions of stars and hundreds of Deep Sky Survey images which blends in accurately. Additional the program can access the online version of  the Deep Sky Survey,  allows online update of the asteroid and comet databases and can search online in professional astronomical databases. Is provided with menu's in 21 languages and it is totally free without any advertisement or restriction!!



 HELP file




Planetarium program HNSKY version 3.2.2c (63 MB, containing both 32 bit and native 64 bit version dated 2016-4-27)  with new powerful animation menu.
Hallo Northern Sky" or HNSKY is a full feature planetarium program for Windows. Free with 30.000 deep sky objects and the TYCHO2++  4.5 million star database up to magnitude 12.5. Online access to UCAC4 en NOMAD star catalog or download the complete GSC 1.2 up to magnitude 15 or the USNO UCAC4 up to magnitude 16. The Sun, Moon, the planets and their major moons are all displayed with surface features. Comet and asteroid databases and with hundreds of DSS deep sky images which will blend in at the correct size and orientation. It has an integrated deep sky observations help file with and 21 non-English menus.

In can control almost any telescope using the ASCOM  interface program. Works flawlessly together with programs like EQMOD and MaximDL.

Downloading of additional DSS images via the Internet is fully integrated. Just select an area and select download. After a few second the DSS image will pop in HNSKY at the correct size and orientation.

HNSKY popup menuHNSKY

The comet or asteroid database can be updated online with just one click

Online database search for objects in the selected area.

Numerical integration  for asteroids to achieve highest accuracy positions years in the future or past. The error is less then 1" after 10 years !!!  So a asteroid orbital  elements from 10 years ago will after numerical integration allow position calculation within 1" accurate!! So also 10 years in the future.

In version 3.02 a significant menu change was introduced. Note that you can remove menu buttons with the pop-up menu or hide the menu completely.

New horizon:

                  Earth view

New version 3.2.1, access to wide field Sky survey of Axel Mellinger via Skyview:

Update version

Version 3.2.2c executables and modified files only (version 2016-4-27) extract and overwrite these files in the existing HNSKY program directory. The 64 bit version file is hnsky64.exe. New users please install main version first. This is only an update of the executables. This version is allowing access to Axel Mellinger low resolution sky survey. From the pop-up menu select "Get DSS image from internet",  "Skyview" for downloading wide field FITS files.  If you select a field larger the 3.5 degrees height it will select the Mellinger survey. Default is the MELL-R (red) of the survey. For better quality add &sampler=Lanczos to the Skyview instruction in settings.

Last classic 32 bit version  HNSKY Planetarium program v3.0.0m1, 64 mbytes 2015-8-8.     Planetarium program HNSKY version 2.4.1  (56 MB, version 2014-7-14), 

More asteroids/minor planets 

For more asteroids you have to download and import the huge uncompressed MPCORB.DAT file from the Minor Planet Center. This file contains the orbital element contains about 710.000 numbered asteroids and size is uncompressed 140 mbytes. Save this file as MPCORB.DAT. Open this file in Wordpad or any editor and keep the first 30.000 asteroids or so and  remove the rest. Open the MPCORB.DAT file in the internal HNSKY asteroid editor. HNSKY will then convert format. To  make permanent save to HNS_AST1.AST. HNSKY will  only read the numbered asteroids. 

Alternatively conversion of MPCORB.DAT to supplement format can be done with this small DOS program

Additional stars databases UCAC4:  You can download the 113 million 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 UCAC4 and Nomad are the catalogues where HNSKY will use proper motion for maximum accuracy. See HNSKY UCAC screenshots.
If you only want the UCAC4 up to magnitude 13, download this UCAC4 converted version (64 mbytes) in the D32 format  (7 million stars) version 2015-6-7 and  extract  it  in the program directory. For conversion the tool D32conversiont is used.

GSC:  The GSC_ACT  or (catalog 255)  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  GSC 1.1  / GSC 1.1 (catalog 220) in the compact binary format (303 MB)

If you have an uncompressed GSC 1.1 or GSC_ACT, it can be compressed by the the EXPORT  program to the same compact binary format (total 303 MB) as used for the GSC 1.2.

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.
Additional supplements

HyperLeda_980.000_galaxies supplement Dated 2015-1-5 (10 MB) demo image using 65 mm telescope.  
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)
Additional FITS images Extra  large Mars map (Color 1000x500 pixels)large Mercury maps (1440x720 pixels) based on Mariner 10, SVTS and large Jupiter maps (Color 600x300 and 1200x450 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

Star catalog conversion tool with Delphi source  D32 conversion. (Dated 2015-6-7, v0.05)
SAO PPM conversion too with Delphi source,  DAT conversion.   (Version 2015-6-2 )
SKY_TOASTER, program for conversion to the TOAST projection,with Delphi source.  v0.0 2016-3-28



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 2.0.0c,  Dated 2015-8-11. 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 august 2015. 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 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: Download ORB_DET.ZIP version 1.01.

Here are some Pascal routines as used inside the HNSKY program. If you have any suggestion to improve them, please let me know: Pascal source code for some astronomical routines and constellation arrays as used in HNSKY program.

PDF map Example printed PDF map, format A2, 1200 DPI, azimuthal equidistant projection,  from declination +90 degrees to -50 degrees. Stars up to magnitude 8.5 and 253 deepsky objects. Zoom in to 1200% to see deepsky objects.. Text searchable.

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.

You also welcome to fill my GUESTBOOK


  2. Screen shots of HNSKY.
  3. History, list of changes and latest ß version HNSKY.

Some stuff to read:

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

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