Comparison

CrowdMag vs Polar Scope Align

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

Head to head
About

CrowdMag

This app allows users to measure and contribute to scientific research on Earth's magnetic field using their smartphone. It offers features for recording magnetic data during various activities, including flights, and provides tools for data visualization and analysis.

Highlights
  • Measure magnetic field data
  • Contribute to scientific research
  • Record data during flights
  • Visualize data on maps and graphs
  • Magnetic calculator with WMM2020
  • Live magnetic compass
  • Export data via email/Google Drive
Features
Read full description

Introducing CrowdMag's newest feature: Flight Mode, which lets you contribute to scientific research by measuring the magnetic field as you fly around the world. To get started, simply provide your itinerary on the CrowdMag app, and you'll be able to turn your flight into a scientific expedition. Check out this step-by-step tutorial for measuring data while flying: https://geomag.colorado.edu/crowdmag-flight-mode-tutorial . CrowdMag is an app that lets you measure the local magnetic field using your smartphone. You can view the data as a graph or a map in nanotesla units. CrowdMag measures the Z (downward component), H (horizontal intensity), and F (total intensity) magnetic field components. You can use CrowdMag for measuring magnetic data during outdoor activities, while flying, or to conduct your own experiments. You can also share it with NOAA to help scientists better understand Earth's magnetic field. If you're going for a walk, run, or other outdoor activities, you can use CrowdMag to measure the magnetic data along your path and save it as a "magtivity." And, if you get a new phone, don't worry! You can export a backup of your CrowdMag data and save it on your computer. This way, if you have to reset your phone or switch to a new one, you can import your backup and continue using CrowdMag without losing your data or progress. CrowdMag also has a magnetic calculator that provides magvar (declination), the magnetic field's dip angle, total magnetic field, and other magnetic field components based on the latest World Magnetic Model (WMM2020). Some of the other features of CrowdMag include creating your own magtivities, customizing recording frequency and location accuracy, exporting your data via email or Google Drive, and seeing generalized crowdsourced magnetic data from other users. And, before we forget, CrowdMag also features a compass that distinctly shows both true and magnetic north. As an added feature, the compass also has a 3D display with an optional audio output - check it out! CrowdMag features: * Create your own magnetic activity (called a "magtivity") * Measure data while flying * Customize recording frequency and location accuracy to your preferences * View your magnetic data on an interactive Google Map * Graph your data as a time series line chart * Check the quality of your data by comparing it with the World Magnetic Model (WMM) * Export your data as a CSV file * Clear stored data on your phone when you want to start fresh * Choose to share your data with NOAA (optional) * See generalized crowdsourced magnetic data from other users * Use the live magnetic compass for 2D and 3D rendering * View information about the current solar magnetic disturbance * Use the most up-to-date magnetic field model (WMM2020) * Export your data via email, Google Drive, or other options * Export a CrowdMag backup to save your contributions' status and data * Import your CrowdMag backup (works across different phone platforms) Visit https://geomag.colorado.edu/crowdmag to see crowdsourced magnetic data .

About

Polar Scope Align

This app calculates the precise position of celestial poles in your telescope's polar scope reticle for accurate alignment. It supports a wide range of reticles and corrects for atmospheric refraction, offering precision even at lower latitudes. Features include night mode, moon phase, and astronomical databases.

Highlights
  • Polaris/Sigma Octantis position calculation
  • Atmospheric refraction correction
  • Reticle centering error correction
  • Supports numerous reticle types
  • Red-color night mode
  • Moon phase and astronomical databases
Features
Read full description

Polar Scope Align is a free, ad-supported polar alignment app for iPhone and iPad. It calculates the position of Polaris or σ Octantis in your polar scope reticle for your location, date and time, helping you get a quick and accurate polar alignment with an equatorial mount. POLAR SCOPE ALIGNMENT • Accurate Polaris and Sigma Octantis position for your date and location • Atmospheric refraction correction for better accuracy, especially at lower latitudes - readings may differ slightly from simpler apps that skip this correction, but will agree with precise sources (USNO, scientific software) • Automatic time and location • Manual location support • Reticle centering-error measurement and correction • Zero-position help for common Celestron / Sky-Watcher / Orion style reticles • Full red night-mode interface SUPPORTED RETICLES Polar Scope Align supports 35+ polar scope and finder reticle types, including: iOptron, Astro-Physics RAPAS & PASILL, Takahashi (EM-10/11/200/400/500, NJP, PM-1, P2-Z), Sky-Watcher / Orion (including EQ6/AZ-EQ and Star Adventurer), Celestron, Meade, EXOS2, Bresser, Vixen (Atlux/SX/SXD/SXP/AXD/GP/GP-DX, Polarie), Astrotrac, Losmandy, Kenko, Avalon, Konus, Telrad, Rigel QuikFinder, and several older polar finders (Tuthill, Explore Scientific, Meade 9x60, Vixen Polaris, Celestron 7x50, Carton Optical). OBSERVING TOOLS The free version also includes: • Moon phase • Messier, Caldwell and bright-star database • DSS image downloads for included database objects • Saved, editable and printable DSO lists • 8 astronomy calculators for observing and imaging • Sample Pro tools available from Settings, including aurora forecast • iOptron WiFi Connect - report mount status, set mount Time/Date/Location LOOKING FOR ALIGNMENT WITHOUT A POLAR SCOPE? Polar Scope Align Pro adds the advanced tools many users search for: • Daytime / No Polar Scope Alignment • Camera Azimuth Calibration using the Sun, Moon, planets or bright stars • Laser / Hop Align for night alignment when Polaris is blocked • Push To / manual GoTo for non-GoTo telescopes • Live sky maps for Daytime Alignment, Laser / Hop Align, Push To and Hop To • Full 22,000+ object DSO database • Xasteria astro weather, aurora, satellite passes and widgets • 30+ calculators • Bubble level, compass and iOptron WiFi mount control • Apple Watch companion app • No ads If you only need accurate polar-scope alignment, this free version is a capable tool. If you want alignment without a polar scope, observing planning, weather and field tools, Pro is the complete version.

Screenshots

CrowdMag4 screens
Polar Scope Align4 screens

Verdict

The call

The clearest difference is review sentiment: Polar Scope Align at 91% against CrowdMag's 53%. Polar Scope Align also leads on rating (4.7 vs 4.3) and ratings volume (171 vs 24). CrowdMag's advantage is in-app purchases (none vs 3) and ads (none vs shown). On price, update cadence 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

Both are free to download. Polar Scope Align sells 3 one-off in-app purchases. CrowdMag asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Polar Scope Align holds the better App Store score, 4.7 against 4.3. That said, the two scores are not equally well evidenced: Polar Scope Align has 171 ratings behind it against 24, so its average is the more settled of the two. Written reviews point the same way: 53% of CrowdMag's written reviews are positive against 91% of Polar Scope Align's.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on September 22, 2026 and September 8, 2026 respectively.

Scorecard7 real differences · 3 level
CrowdMag versus Polar Scope Align: the parameters behind the verdict, then further details
ParameterCrowdMagPolar Scope Align
PriceFreeFree
Rating4.3 (24 ratings)4.7 (171 ratings) — better
Positive reviews52.9% of reviews91.2% of reviews — better
Number of ratings24171 — better
Update frequencyEvery 2 monthsEvery 2 months
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.013.0 — better
Further details — not scored
Size18 MB23 MB
Age rating4+4+
DeveloperUniversity of Colorado BoulderDimitrios Kechagias

Customer experience

CrowdMag

All ratings24 ratings
Positive79.2%
Neutral8.3%
Negative12.5%
Written reviews17 reviews
Positive52.9%
Neutral17.6%
Negative29.4%

Polar Scope Align

All ratings171 ratings
Positive92.4%
Neutral0.6%
Negative7.0%
Written reviews170 reviews
Positive91.2%
Neutral1.8%
Negative7.1%

Bugs and requests

CrowdMag

Not enough reviews yet to summarise bugs or requests.

Polar Scope Align

Reported bugs

6 issues
  • Date and time dial do not match correctly
  • GMT and LST times appear to be switched
  • App crashes or fails to initialize for some users
  • Alignment accuracy varies inconsistently between sessions
  • Location detection issues with cell tower vs GPS
Show 1 more
  • Reticle display not rendering properly in some cases

Requested features

7 requests
  • Online video tutorials demonstrating all features
  • Remove or reduce center dot size in reticle
  • Larger, bolder font options for better readability
  • Brighter star options for southern hemisphere alignment
  • Smaller ad button or ad customization
Show 2 more
  • Better beginner onboarding and instructions
  • More robust alternative alignment methods for southern hemisphere

In-app purchases

None

CrowdMag

No in-app purchases

3 purchases

Polar Scope Align

One-time3
  • Tip 1x$0.99
  • Tip 4x$3.99
  • Tip 10x$9.99

Questions

Is CrowdMag free?
CrowdMag is free to download, with no in-app purchases.
Is Polar Scope Align free?
Polar Scope Align is free to download, with in-app purchases available.
Which has better reviews, CrowdMag or Polar Scope Align?
Polar Scope Align is rated higher. CrowdMag averages 4.3 out of 5 from 24 ratings, while Polar Scope Align averages 4.7 from 171 ratings.
Do CrowdMag or Polar Scope Align have ads?
Polar Scope Align shows ads; CrowdMag does not.
Which is updated more often, CrowdMag or Polar Scope Align?
CrowdMag ships an update every 2 months, and Polar Scope Align every 2 months. Most recently, CrowdMag was updated on September 22, 2026 and Polar Scope Align on September 8, 2026.

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