CrowdMag vs Polar Scope Align Pro
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- 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
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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 .
Polar Scope Align Pro
This app assists astronomers with precise polar alignment for telescopes, offering tools for various reticles and low-latitude accuracy. It also includes a comprehensive suite of astro tools, from object databases to calculators and weather reports.
- Accurate polar alignment calculation
- Support for numerous polar scope reticles
- Daytime/no polarscope alignment tool
- Deep Space Object database
- Astrophotography calculators
- World astro-weather report
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Polar Scope Align Pro is a complete toolkit for amateur astronomers: accurate polar alignment, deep-sky observing, astro weather, push-to/manual GoTo, iOptron mount WiFi control, widgets and more. All features and updates are free forever. Optional in-app purchases are just tips to support development. POLAR ALIGNMENT • Calculates Polaris or σ Octantis position for 30+ reticle types: iOptron, Astro-Physics, Takahashi, Skywatcher, Vixen, Celestron, Orion, Astrotrac and others* • Atmospheric refraction correction for accuracy at any latitude • Works with or without a polar scope ALIGNMENT WITHOUT A POLAR SCOPE • Daytime / No Polar Scope Alignment: works day and night with just your phone's gyro • Camera Azimuth Calibration: use sun/moon/stars to calibrate gyro and align accurately without a compass, immune to magnetic interference • Laser / Hop Align: nighttime alignment for maximum accuracy with a laser or a scope with no view of Polaris • Live sky map guides you to the celestial pole in real time • Sun Finder helps you point your filtered telescope/telephoto to the Sun PUSH TO (MANUAL GOTO) • Attach your phone to any scope and convert it to manual/push GoTo • Select from a large database and use direct push or more accurate hop-to mode DEEP SKY OBJECT DATABASE • 22,000+ objects with altitude graphs, rise/set times and more info • Save and manage curated observing lists • Filter, search, sort and push to any target XASTERIA ASTRO WEATHER • Hourly astronomy forecasts from 7Timer, OpenWeather, MET Norway and Apple Weather, plus a configurable Multi-source forecast • Animated satellite Cloud Map with recent EUMETSAT and NASA infrared imagery • Aurora forecasts • ISS and bright satellite passes with an All Sky night chart, individual sky charts, live map tracking, and Tiangong and Hubble views • Solar eclipse tool with past and future eclipses, live mode with audio cues • Experimental eclipse camera for automated photoshoots of partial phase, diamond ring, Baily's beads, totality bracketing • Interactive light pollution map using World Atlas and recent VIIRS data CALCULATORS & TOOLS • 30+ calculators for observing and astrophotography • Moon phase calendar with altitude graphs • Solar eclipse calculator and simulator • Bubble level & Compass IOPTRON WIFI MOUNT CONTROL • Connect to WiFi-enabled iOptron mounts (HAE, HAZ, HEM, CEM, GEM and more) • Automatic date/time/location setup • Switch between Equatorial and Alt-Az on mounts that support both • Move & Sync: directional control with a live sky map • Point GoTo: aim your phone at a patch of sky and send the mount there • Current Point Query: find out what the mount is pointing at • GoTo any object from the DSO Database NIGHT-FRIENDLY • Red, green or white night mode with dimmer WIDGETS • Configurable Tonight and Multi astronomy weather forecasts • Upcoming bright satellite passes • Aurora probability, activity forecast and NOAA aurora map * Full list of supported reticles: Astro-Physics RAPAS & PASILL, iOptron, the latest Orion / Skywatcher, the Classic Skywatcher / Orion / Celestron / Meade / EXOS2 / Bresser / MSM, various versions of Takahashi EM-10/11/200/400/500, NJP, PM-1, P2-Z, the Telrad, Rigel QuikFinder, a couple for Astrotrac / Losmandy / Kenko / Avalon, the Vixen PF-L/Atlux/SX/SXD/SXP/AXD/GP/GP-DX/Polarie Polar Axis Scopes, a Konus and several Polar Finders: Tuthill, Explore Scientific 8x50, Meade 9x60, Vixen Polaris, Celestron 7x50, Carton Optical. PoleMaster help view for South Hemisphere users.
Screenshots
Verdict
The clearest difference is price: CrowdMag at Free against Polar Scope Align Pro's $3.99. CrowdMag also leads on in-app purchases (none vs 3). Polar Scope Align Pro's advantage is review sentiment (97% vs 53%) and rating (4.9 vs 4.3). 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
CrowdMag is free to download; Polar Scope Align Pro costs $3.99 up front. Polar Scope Align Pro sells 3 one-off in-app purchases. CrowdMag asks for nothing beyond the download.
Polar Scope Align Pro holds the better App Store score, 4.9 against 4.3. That said, the two scores are not equally well evidenced: Polar Scope Align Pro has 305 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 97% of Polar Scope Align Pro's.
Both ship on a similar rhythm, roughly every 2 months. Both last shipped on September 22, 2026.
| Parameter | CrowdMag | Polar Scope Align Pro |
|---|---|---|
| Price | Free — better | $3.99 |
| Rating | 4.3 (24 ratings) | 4.9 (305 ratings) — better |
| Positive reviews | 52.9% of reviews | 97.0% of reviews — better |
| Number of ratings | 24 | 305 — better |
| Update frequency | Every 2 months | Every 2 months |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Best chart rank | — | #71 — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 13.0 — better |
| Further details — not scored | ||
| Size | 18 MB | 32 MB |
| Age rating | 4+ | 4+ |
| Developer | University of Colorado Boulder | Dimitrios Kechagias |
Customer experience
CrowdMag
Polar Scope Align Pro
Bugs and requests
CrowdMag
Not enough reviews yet to summarise bugs or requests.
Polar Scope Align Pro
Reported bugs
2 issues- Weather Updates Not Working
- Compass Deflected by Mount
Requested features
2 requests- Add Observation Recording Feature
- Add Push To Option for DSO Objects
In-app purchases
CrowdMag
No in-app purchases
Polar Scope Align Pro
- Tip 1x$0.99
- Tip 4x$3.99
- Tip 10x$9.99
Questions
Is CrowdMag free?
Is Polar Scope Align Pro free?
Which has better reviews, CrowdMag or Polar Scope Align Pro?
Do CrowdMag or Polar Scope Align Pro have ads?
Which is updated more often, CrowdMag or Polar Scope Align Pro?
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