StarCalc

V2.0.0 WARNING!!! IF YOU USED PREVIOUS VERSION PLEASE REMOVE APP FROM WATCH AND REDOWNLOAD This is a calculator aimed at astronomers and navigators, however I think that anyone interested in night sky would benefit from it. It has base of 59 stars from Nautical Almanac (TheNauticalAlmanac.com) plus Sun, Moon and the rest of planets up to Neptune. It presents their actual equatorial coordinates (RA/SHA & Declination), plus based od you location and time - horizontal coordinates (Azimuth & Altitude). Additionally there are rise/set times and azimuths, and transit/anti-transit time and altitude Sun has special additional page with informations on start/end of geometric sunrise/sunset, beginning and ending of golden/blue hour plus beginnings and endings of civil, nautical and astronomical twilight (azimuth of sun at these very points can also be checked). For planets and Moon we can see their angular separation (elongation) from sun (+Moon illumination %), the stars have three-letter acronym of their constellations. Sun also has its actual constellation acronym. All celestial bodies within solar system have their apparent diameter listed. All celestial bodies within the almanac have their apparent magnitude listed. Magnitudes are calculated for planets, but hardcoded for Sun, Moon (when full moon) and stars. There is a manual mode, where you can input equatorial coordinates: SHA (so RA too, as RA = (360 - SHA)/15) and Declination of any point on celestial sphere to have all of its rise/set/transit/anti-transit data presented, as well as their horizontal coordinates (Azimuth & Altitude). There is also a reverse mode, where you input azimuth and altitude and get SHA, RA and declination of given point. It also includes many "basic" astronomical informations like Julian Day, Local/Greenwich Time, UTC offset, Local/Greenwich Sidereal Time, Equation of Time, Latitude, Longitude, Longitude Correction (which is UTC offset minus longitude / 15). In Sun Advanced Menu there is a Air Mass (AM) and Sun Intensity (γ). AM1.00 and γ100% is sun directly above your head (zenith) and you are at sea level. If sun elevation lowers, AM grows up to ~AM38 at sunset and γ goes to 0. However if you are in mountains and sun is in zenith, you get AM lower than 1 and γ greater 100%. Program calculates for your last gps location and by default for "now". You can add/subtract days/hours/minutes to arrive to desired time moment, but there is no option to "input" any data. Calcualtor is free and always will be. It is Garmin Instinct exclusive and probably always will be, as I am not interested in dealing with "frontend". Biggest flaw of apps on Garmin Instinct is that you can't use apps when doing activity. You might want to check "StarCalc Live" which is a widget showing data for Sun and Moon (also on glance). Settings: -"Manual Mode (MM)" enters input mode where you input equatorial coordinates for celestial body and get all the data -"MM Hor/Eq" changes the input mode to opposite, where you intput horizontal position of celestial body and get all the data -"Automatic Refresh" everytime you change one of coordinate the app refreshes. This works slower but allows you to see how changing particular coordinate affects all the other data for celestial body -"LHA, *T format" changes format of local hour angle of celestial body, and sidereal time format for our position If you liked the app, you might be interested in my other app "Sextant" which uses watch position as input, so you don't need to input any data by hand, but just move hand and point watch to a star. Cloudless nights! 3igen3ggy

v2.5.0 -new SDK/fixes v2.3.0 -added Air Mass separate card (in sun advanced info) -fixed calculation of current day/night percentage -removed automatic refreshing mode -small quality updates -removed saving location in between restarting the watch Because garmin damaged something (on some models, for example 3 solar), when you restart watch and use custom app that relies on last location, the app wouldn't work unless you used your gps to get current location. Just remember to use GPS once after restarting watch! v2.2.2 -fixed location resetting after reboot v2.2.1 -fixed local time not being calculated correctly when switching date/location between different changed daysaving timezone v2.2.0 -fixed Waning Crescent being presented as Waxing Crescent -added air mass (AM) and Sun intensity(γ) to Sun Advanced Menu. To learn about them, read description v2.1.2 -fixed Moon Age sometimes being negative v2.1.1 -fixed changing date/hour -tidying the code v2.1.0 -added visibility feature -added leading zeros for coordinates to be always output v.2.0.3 -added Moon Phase information panel -added new watches v2.0.2 -fixed underlining in 2s -fixed bug when setting position in manual mode v2.0.1 -added Instinct 2s resolutions support v2.0.0 -Massive refactor, changing many aspects of the app -New interactive menu -Possibility to change postition -Possibility to change position / date / hour within every view -Can save up to 3 positions (Save option appears in menu when "modifying" position) v1.0.6 -fixed day/night ratios incorrectly recognizing polar night as polar day -Added information on how much of day/night have passed at the moment ("D: 25.0%" means that a quarter of daylight time from sunrise to sunset have passed. "N: 50.0%" would mean its solar midnight - exactly between sunset and sunrise. If it is polar day/night it would say "D: Polar"/"N: Polar") -fixed changing hours/minutes forward/backward doubling sometimes the intended amount v1.0.5 -input mode (INM) now remembers coordinates v1.0.4 -fixed data sometimes not refreshing v1.0.3 -fixed doubling of days forward / backward when changing date v1.0.2 -fixed data not refreshing when going back to "now" (days +0, hours +0, minutes +0) v1.0.1 -updated DMS location to show seconds with 2dp (to match StarCalc Live widget - newly added to ConnectIQ) v1.0.0 -fixed Equation Of Time being wrong by one day on leap years after 29.02 -fixed one part of calculations that would stop working after 2100 year (yay) -small quality changes -decreased accuracy of variables throughout calculations (doubles to floats) to increase speed and optimize memory. This didn't change visible output as we are rounding most of presented data to 1dp and time to hours and minutes -added many many tests to ensure accuracy and quality