Sky Calendar - download

Download the installation file:
Operating system Program version Dated File Name Size
Windows Windows 8.1 or 10 - 32 bit 4.9
October 6, 2020
nk4a.exe 10,2 MB Download
Windows Windows 8.1 or 10 - 64 bit 4.9
October 6, 2020
nk4b.exe 11,5 MB Download
Apple MacOS 10.13 to 10.15 - 64 bit 4.9
December 2, 2020
NK4Mac.zip 16,10 MB Download

Program installation:
  • Windows: Run the downloaded file and follow the instructions of the installer. If you experience problems, check out the page FAQ.
  • Mac: Be sure to read the Recommended Installation Procedure!
The program manual
is part of the installation, but you can also download it separately (1,83 MB).



Alternatively, you can download the program just as a ZIP file to save Sky Calendar without installation (Windows only):
Operating system Program version Dated File Name Size
Windows Windows 8.1 or 10 - 32 bit 4.9
October 6, 2020
nk4a.zip 13,0 MB Download
Windows Windows 8.1 or 10 - 64 bit 4.9
October 6, 2020
nk4b .zip 15,2 MB Download

Save and run program:
Download the program, unpack it to any empty folder and run NK4.exe.


Unregistered version restrictions:
  • All work can be done only for period of 2000 to 2030 years (for 1 to 3000 years in registered version).
  • There are no other restrictions in unregistered version of Sky Calendar!