Comparison

Sight Calc vs Compass

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

Head to head
About

Sight Calc

This app is a specialized calculator for sight reductions using the Law of Cosines method. It's designed for students learning celestial navigation and requires manual input of LHA, declination, and approximate latitude.

Highlights
  • Law of Cosines sight reduction
  • Manual LHA, declination, and latitude input
  • Input as degrees/minutes or decimal degrees
  • Continuous computation of Hc, Z, and Zn
  • Supports North/South latitude and declination conventions
  • Clear and clear entry functions
  • Convert minutes to decimal degrees
Features
Read full description

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

About

Compass

This navigation tool uses your device's gyroscope for enhanced accuracy. Simply point your device at an object and tap the screen to freeze the compass bearing. It's useful for travel and outdoor activities.

Highlights
  • Gyroscope enhanced accuracy
  • HD Retina display
  • Universal App support
  • Tap to freeze compass
  • Read compass bearing
Read full description

Compass-PRO Features - Gyroscope enhanced - HD Retina display - Universal App How to use: - Use your iPhone/iPad side to aim at any object. - Tap anywhere on screen to freeze compass. - Read compass bearing. You can also use it while traveling or at your favorites sports.

Screenshots

Sight Calc4 screens
Compass1 screens

Verdict

The call

The clearest difference is review sentiment: Sight Calc at 82% against Compass's 33%. Sight Calc also leads on rating (5.0 vs 2.0) and in-app purchases (none vs 1). Compass's advantage is price (Free vs $1.99) and iOS requirement (10.0 vs 16.0). On update cadence, ads and device support 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

Compass is free to download; Sight Calc costs $1.99 up front. Compass sells 1 one-off in-app purchase. Sight Calc asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Sight Calc holds the better App Store score, 5.0 against 2.0. That said, the two scores are not equally well evidenced: Sight Calc has 7 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 82% of Sight Calc's written reviews are positive against 33% of Compass's.

UpkeepUpdate frequency

Sight Calc ships an update every 11 months, Compass every 8 months. The most recent releases landed on September 10, 2026 and September 19, 2026 respectively.

Scorecard7 real differences · 3 level
Sight Calc versus Compass: the parameters behind the verdict, then further details
ParameterSight CalcCompass
Price$1.99Free — better
Rating5.0 (7 ratings) — better2.0 (1 ratings)
Positive reviews82.4% of reviews — better33.3% of reviews
Number of ratings7 — better1
Update frequencyEvery 11 monthsEvery 8 months — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS16.010.0 — better
Further details — not scored
Size1 MB9 MB
Age rating4+4+
DeveloperNUVOCOM INCORPORATEDSavvas Petrou

Customer experience

Sight Calc

All ratings7 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews17 reviews
Positive82.4%
Neutral0.0%
Negative17.6%

Compass

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews3 reviews
Positive33.3%
Neutral0.0%
Negative66.7%

In-app purchases

None

Sight Calc

No in-app purchases

1 purchases

Compass

One-time1
  • Remove Ads$0.99

Questions

Is Sight Calc free?
Sight Calc costs $1.99, with no in-app purchases.
Is Compass free?
Compass is free to download, with in-app purchases available.
Which has better reviews, Sight Calc or Compass?
Sight Calc is rated higher. Sight Calc averages 5.0 out of 5 from 7 ratings, while Compass averages 2.0 from 1 ratings.
Do Sight Calc or Compass have ads?
Neither Sight Calc nor Compass shows ads.
Which is updated more often, Sight Calc or Compass?
Sight Calc ships an update every 11 months, and Compass every 8 months. Most recently, Sight Calc was updated on September 10, 2026 and Compass on September 19, 2026.

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