iNA computes all ephemeris data available in the daily pages of the USNO Nautical Almanac. This information is required when doing astronomical computations for celestial navigation, local noon, sunrise, and others. The program computes GHA, Dec, SHA, SD, HP, magnitudes, sunrise, sunset, LAN, twilight times, moonrise, moonset, moon age and phase for sun, moon, 5 planets, and 173 stars; all at GMT which is longitude 0. INA also computes addition useful information not included in the Nautical Almanac such as ephemeris for Mercury, Hc at LAN, bearing of sunrise and sunset (amplitudes), and the GHA of Aries midway between civil and nautical twilights for star planning.
INA's internal celestial almanac is valid for the years 1582 through 2800 AD.
iNA requires no external resources to complete its computations. Internet access is not required to use this program or to access any of its help files.
iNA returns results at GMT which is longitude 0. Interpolation for your specific location and/or times other than on the hour, must be computed manually. We recommend using StarPilot which has a built-in Nautical Almanac and will perform all the complex calculations for you.
Ratings and Reviews
Don't Waste Your Money
Sunrise/Sunset calculations ARE incorrect... so the question is what else is calculated incorrectly. I tried to make their support aware of the problem but they pretty much blamed me for entering data wrong and blew me off. I may not have a Phd in astrophysics, but I was a Quartermaster in the US Navy for 20 years, so I believe I know how to calculate SR/SS. Kinda hard to go wrong making sure the date is correct, GMT is correct and then entering latitude, click on SUN and click on GO. This program doesn't even deserve the 1 Star.
Developer Response ,
I am very sorry to hear of your experience with StarPilot support. The StarPilot programs including iNA are under new management as of July 1, 2018, and we can promise that all support inquires will be treated with respect and answered promptly and thoroughly. We do not know the details of this inquiry, but we can assure users that the iNA app does compute the times of sunrise, sunset, and twilight times properly. To see various examples worked out, please refer to the app support link, which redirects to a list of specific topics including this one. Or contact us directly for more individual help.
Lots of ephemeris data, accuracy could be improved.
Used primarily to determine sunrise and sunset. Found results to be consistently 5-10 minutes off compared to both NOAA and calculation by hand. It's nice to have ballpark figures for the navigable stars, but I can't rely on this app alone for sunrise and sunset when precision is required.
Developer Response ,
Please see our response to a related comment above. We would be happy to help you track down the discrepancies noted. The iNav computes these values as used in the official USNO Nautical Almanac. Procedures used on a generic NOAA website may be referenced to a longitude different than you intended—I am not sure of these details till we learn more. Please contact us and we will help resolve this. In principle, the iNA should give more accurate rise, set, and twilight times than obtained from a source that is making assumptions about your longitude.
use caution! up to 0.5' diff from naut. al. also, no SD for moon!
With Family Sharing set up, up to six family members can use this app.