July 25, 2020

iPhemeris Now Covers 7700 Years (4700BC – 2995 AD)

iPhemeris has now been extended to cover a date range of 7700 years from 4700 AD to 2995 BC and also has gotten dramatically smaller in size on disk. We accomplished this by adopting the Swiss Ephemeris which has excellent data compression and which also makes it fairly easy to add additional asteroids and hypothetical bodies with minimal impact to the size of the App. iPhemeris formerly used our own version of the JPL Ephemeris (DE 431) but this was very large and additional asteroids only made it more so. We therefore considered that as the Swiss Ephemeris had the same underlying JPL DE 431 data quality but much, much better data compression we might as well switch. We decided we preferred to add features than to spend time working on data compression. By simply adopting Swiss Ephemeris we can now offer many more astronomical bodies and hypotheticals but with a substantial reduction in App sizes on device. This will have major benefits for the iOS versions of the App. Thank you Astrodienst for your work!