Sight Calc vs VesselFinder

Sight Calc is a specialized calculator for calculating sight reductions via the "Law of Cosines" method. It does not use Nautical Almanac data, so you must first compute LHA (Local Hour Angle) and declination, and determine your approximate latitude. It is designed particularly for students learning celestial navigation, such as the Celestial Navigation courses taught by the United States Power Squadrons®. If you are unfamiliar with how to do sight reductions, some good resources are available from the United States Power Squadrons® at www.usps.org. In particular, this calculator is useful in conjunction with Form SR96a, www.usps.org/eddept/n/files/sr96a.pdf Inputs may be entered as two numbers: Degrees - left column Minutes - right column Or enter as decimal degrees (e.g., 44.48833). Sight Calc will prompt you to enter six number in sequence: LHA (degrees) LHA (minutes) Lat (degrees) Lat (minutes) Dec (degrees) Dec (minutes) In v 2.0 you may enter values in any sequence. Hc, Z and Zn are continuously computed and displayed. Be sure to enter North Latitude as a positive number and South Latitude as a NEGATIVE number. Sight Calc will take the absolute value of Latitude in the law of cosines formula, but needs the hemisphere to calculate azimuth (Zn). Similarly, enter Declination as positive if North and negative if South. (Note: this differs from version 1.x of Sight Calc.) If you want to do repeated calculations with some of the same numbers, just enter the changed numbers. To start over fresh at any time, press "C" to clear everything. "CE" key clears the Current Entry. Optionally, use the "o" key to convert minutes to decimal degrees, add that to the degrees field, and clear the minutes field. This has no effect on the calculation. Please report any bugs or suggestions to: sightcalc@nuvocom.com

VesselFinder is the world’s most popular and trusted vessel tracking and marine traffic app, delivering real-time information on ship positions and movements worldwide. Using a powerful network of satellites, roaming and terrestrial AIS receivers, VesselFinder provides accurate and up-to-date insight into global maritime activity. Designed for maritime professionals, shipping enthusiasts, and anyone interested in live ship tracking, VesselFinder offers a fast, intuitive, and reliable way to explore vessel traffic across the globe. VesselFinder key features: • Real-time tracking of over 300,000 vessels daily using global AIS data • Vessel movement history with track visualization • Predicted routes and ETAs to next port • Comprehensive vessel particulars, including technical specifications, and cargo capacity information • Contact details for the owning company, manager, ISM manager, and more • Port Calls per vessel, showing arrival times and duration of stay • Port Calls per port, with detailed lists of expected vessels, arrivals, departures, and ships currently in port • My Fleet – save and monitor favorite vessels, synchronized with your VesselFinder account • My Views – save preferred map views for fast and easy navigation • Ship Photos contributed by the VesselFinder user community • Multiple map styles: Simple, Detailed, Dark, Satellite, and Nautical • Weather overlays, including wind, waves, and temperature • See your location feature for instant orientation • Distance measurement tool for route and range estimation Vessel visibility depends on AIS signal availability, with near-shore coverage consistent with the data provided on VesselFinder.com. If a vessel is outside our terrestrial AIS coverage area, its last reported position will be displayed and updated as soon as new data is received. Extended real-time coverage via satellite and roaming AIS sources is available through a subscription. While we make every effort to ensure accuracy, the completeness of the information cannot be guaranteed. Connect with VesselFinder • Facebook: http://www.facebook.com/vesselfinder • Twitter: http://www.twitter.com/vesselfinder