Comparison

tcSpeeds vs Celestial Nav

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

tcSpeeds

This app provides advanced sailing performance metrics using your device's GPS and sensors. It offers detailed speed, wind, and directional measurements, along with a proprietary performance index. Easily track your progress and compare it with others, with zero setup required.

Highlights
  • Advanced speed and velocity measurements
  • Proprietary Pilot Performance Index (PPI)
  • Wind measurement with optional sensor
  • Waypoint navigation and tracking
  • Apple Watch extension
  • Real-time performance alerts
Features
Read full description

tcSpeeds provides advanced knowledge of your current speed, average speeds, maximum speed, directional speeds, velocity made good, wind measurements, and much more. You will be able to measure your performance on a straight course with our proprietary Pilot Performance Index (PPI) computation. Compare how good you are at the controls with your friends or against your autopilot. tcSpeeds stands on its own and does not require external hardware or connections to operate. tcSpeeds uses your device's own internal GPS, accelerometers, and compass. For Wind measurement, you will need to acquire the Calypso Ultrasonic Wind sensor. More sensors will be supported in the future. Easy to use and conceived to minimize operational burden on the user, because we know you have other things to do. Zero setup required: install, launch and tap the start button. Designed for iPhones, and GPS-equipped iPads. CAPABILITIES - Add waypoints on the map - Apple watch extension - auto-VMG Velocity Made Good automatic detection - Add, move, or edit you waypoint location on the map - Cross track to waypoint indicator - Record and save your track - Start Line guide for speed and heading when you race - VMG automatic maximum VMG to waypoint - VMG visual assistant: guides you to the best course to the waypoint on the current tack - Maximum VMG indicator relative to waypoint - Audio alert for Acceleration and maximum speed: get instant feedback for you and your team when you are doing it right - Apple Watch Extension: Speed, Course, VMG, Cross-Track, Display remote control and more - Arrival Time: smart computation using filtered VMG averages - Barometer indicator on supported devices - Pilot Performance Index (PPI) calculation improvement - Speed indicator with color-scaled plot - Directional speed vectors panel with automatic polar graph - Maximum speed keeping - Maximum speed audio and visual alarms - Trip distance recording - Add, move, edit Waypoints - Accurate sub-second timer - GPS status with location accuracy indication - Boxed average speed by timed interval: 10-sec 1-min 10-min 1-hour - Pilot Performance Index (PPI) calculation, measurement, and guide - Target course indicator with automatic and manual fine tuning - Headings, bearings and directional indicators (magnetic/true) - Precise real-time cross track reporting - Course, Compass and proprietary C-Course heading selector - Rapid units selection: metric, nautical and imperial - Situational (non-navigational) map with color-coded speed track - Map display with target course and Look-Ahead-Vector (LAV) - Time and distance to autoscaled LAV endpoint - Velocity Made Good (VMG) relative to Waypoint - Magnetic compass and Course Over Ground (COG) integrated panel - Crab angle and local magnetic declination

About

Celestial Nav

This app provides tools for celestial navigation, offering computations for celestial bodies and sight reductions. It includes an offline perpetual almanac and allows for quick capture of observation data for accurate course adjustments.

Highlights
  • Celestial navigational computations
  • Offline perpetual almanac
  • Quick celestial observation data capture
  • High accuracy sight reductions
  • Sight planning and reduction tools
  • Celestial fix computations
Features
Read full description

We believe celestial navigation is an amazing skill and develop Celestial Nav to offer a simple, yet powerful and all encompassing app for our users. Celestial Nav is an easy to use, all-in-one tool which offers: • Celestial navigational computations for your device • Simple toolbar menu for quick access • Internally stored perpetual Almanac • Offline ready and functional without the need for other external tools • Quick and easy capture celestial observation data • High accuracy sight reductions • Star reference tables SIGHT PLANNING • Local Hour Angle (LHA) for Aries • Star tables sorted by name, magnitude, declination, and SHA • Sunrise, sunset, twilight, and location reference • Moon phase reference SIGHT REDUCTION • High accuracy sight reduction algorithm • Perpetual Almanac offering accurate data for years 1600 - 3000 • Almanac data for Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn • Detailed Almanac data for 58 navigational stars • Assumed Position (AP) for any user defined position • Line of Position (LOP) intercept data for accurate course and speed adjustments • Computational variables displayed for accuracy and validation CELESTIAL FIX • Computations by USNO algorithm in the Nautical Almanac • Save all your LOP in an easy reference table BASIC VERSION Free daytime celestial navigation tools using the sun: • Unlimited sextant sight reduction calculations • Sight reduction to a line of position using the sun • Perpetual almanac for the sun • Advanced sight corrections for index error, eye height, temperature, and pressure • Support for upper and lower limb reference • Star Table with navigational references • Detailed Sun references • Limited Moon references PRO FEATURES (IN-APP PURCHASE) Advanced Day & Night Celestial Navigation includes all BASIC features plus: • Almanac data for 65 navigational bodies for years 1600 through 3000 • Map display for saved LOPs • View intercepts with course and speed corrections • Metric and imperial unit support with automatic conversions • Support for coordinate entries in different formats (H° M’ S” or Decimals) • Save all your LOP calculations for future reference • Save user preferences and settings • Unrestricted moon references • Almanac and algorithmic models for 65 navigational bodies: • Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn • 58 navigational stars Supported stars: Acamar, Achernar, Acrux, Adhara, Aldebaran, Alioth, Alkaid, Alnair, Alnilam, Alphard, Alphecca, Alpheratz, Altair, Ankaa, Antares, Arcturus, Atria, Avior, Bellatrix, Betelgeuse, Canopus, Capella, Deneb, Denebola, Diphda, Dubhe, Elnath, Eltanin, Enif, Fomalhaut, Gacrux, Gienah, Hadar, Hamal, Kaus Australis, Kochab, Markab, Menkar, Menkent, Miaplacidus, Mirfak, Nunki, Peacock, Polaris, Pollux, Procyon, Rasalhague, Regulus, Rigel, Rigil Kent., Sabik, Schedar, Shaula, Sirius, Spica, Suhail, Vega, Zubengenubi REFERENCES Sight reductions and celestial calculations use various internationally accepted references for the most accurate results: • Jean Meeus - Astronomical Algorithms • US Naval Observatory (USNO) Almanac and Algorithms • Hipparcos New Astrometric Catalog, Published 2007 • ELP2000-85 SUBSCRIPTION TERMS Celestial Nav is free to download and the basic features free to use. A paid upgrade to the PRO version provides access to premium features and additional tools. We may offer trial subscriptions that give limited time access to all PRO features and premium content for the duration of the trial period. Trial subscriptions automatically expire and the app will revert back to the Basic version thereafter. No data is lost but access and use of premium features will no longer be available.

Screenshots

tcSpeeds4 screens
Celestial Nav4 screens

Verdict

The call

The clearest difference is rating: tcSpeeds at 4.9 against Celestial Nav's 4.3. tcSpeeds also leads on review sentiment (100% vs 64%) and monetization model (free vs free with in-app purchases). Celestial Nav's advantage is update cadence (every 3 weeks vs every 7 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. tcSpeeds sells 1 one-off in-app purchase and Celestial Nav sells 6 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

tcSpeeds holds the better App Store score, 4.9 against 4.3. Both are backed by a comparable volume of ratings — 10 and 10 respectively. Written reviews point the same way: 100% of tcSpeeds's written reviews are positive against 64% of Celestial Nav's.

UpkeepUpdate frequency

tcSpeeds ships an update every 7 months, Celestial Nav every 3 weeks. The most recent releases landed on September 30, 2026 and October 17, 2026 respectively.

Scorecard4 real differences · 6 level
tcSpeeds versus Celestial Nav: the parameters behind the verdict, then further details
ParametertcSpeedsCelestial Nav
PriceFreeFree
Rating4.9 (10 ratings) — better4.3 (10 ratings)
Positive reviews100.0% of reviews — better64.3% of reviews
Number of ratings1010
Update frequencyEvery 7 monthsEvery 3 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, Apple WatchiPhone, iPad, iPod
Requires iOS16.615.0 — better
Further details — not scored
Size18 MB20 MB
Age rating4+4+
Developertransitional continuumSkytip LLC

Customer experience

tcSpeeds

All ratings10 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Celestial Nav

All ratings10 ratings
Positive80.0%
Neutral10.0%
Negative10.0%
Written reviews14 reviews
Positive64.3%
Neutral7.1%
Negative28.6%

In-app purchases

1 purchases

tcSpeeds

One-time1
  • Advanced Performance Features$2.99
6 purchases

Celestial Nav

Subscriptions3
  • PRO Version$1.991 Month
  • PRO Version$7.996 Months
  • PRO Version$9.991 Year
One-time3
  • 7 Day Trial License$0.99
  • 30 Day Trial License$2.99
  • PRO Version Lifetime$24.99

Questions

Is tcSpeeds free?
tcSpeeds is free to download, with in-app purchases available.
Is Celestial Nav free?
Celestial Nav is free to download, with in-app purchases available.
Which has better reviews, tcSpeeds or Celestial Nav?
tcSpeeds is rated higher. tcSpeeds averages 4.9 out of 5 from 10 ratings, while Celestial Nav averages 4.3 from 10 ratings.
Do tcSpeeds or Celestial Nav have ads?
Neither tcSpeeds nor Celestial Nav shows ads.
Which is updated more often, tcSpeeds or Celestial Nav?
tcSpeeds ships an update every 7 months, and Celestial Nav every 3 weeks. Most recently, tcSpeeds was updated on September 30, 2026 and Celestial Nav on October 17, 2026.

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