Comparison

CatalogueMessier vs Rock Identifier

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

Head to head
About

CatalogueMessier

Explore the Messier, NGC, and Caldwell astronomical catalogs. Log your observations with photos, filter celestial objects by type, and track your progress with detailed statistics. Export your data for further analysis.

Highlights
  • View Messier, NGC, and Caldwell catalogs
  • Add observation photos
  • Filter objects by category
  • Track observation progress
  • Export observation data
  • Multi-language support
Read full description

The application allows you to view the 110 objects in the Messier catalog, the 812 main objects in the New General Catalog (NGC), and the 109 objects in the Caldwell catalog. You can add photos taken during your observations for each object. You can filter objects by category (galaxies, nebulae, clusters) and view the observation order for the annual Messier Marathon. Statistics allow you to track the progress of your observations. Export your photos to a spreadsheet summarizing your observations. Statistics allow you to track the progress of your observations. 
Privacy: - No ads. - No data collection. - No registration (neither by email nor locally). - No tracking. - No location tracking. - No connection to a server to collect information. Languages: French, English, Italian, German, Dutch, Chinese, Japanese, Spanish, Portuguese, Dutch.

About

Rock Identifier

Features
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Point your camera at a rock or mineral and Rocco tells you what it is — then helps you confirm it with the same tests geologists actually use. Identify from multiple angles - Guided capture: the whole specimen, a close-up of the surface, and a fresh break or cut face - Rock class or mineral group, chemical formula, and crystal system - Hardness on the Mohs scale, luster, streak color, and common colors - Formation, common locations, and typical uses - Estimated value range and hazard notes where relevant Confirm it yourself with guided field tests - A step-by-step Mohs hardness test using a fingernail, a copper coin, glass, and steel - A guided streak test to read a mineral's true powder color - Identification tips specific to what you found Build a real collecting record - Mark find sites on a map so you remember exactly where each specimen came from - Save specimens to your collection or a wishlist, with a full scan history - Ask Rocco's AI companion follow-up questions about any rock or mineral Identification is based on visual AI analysis and may be inaccurate, especially for specimens that look similar but differ in composition. Hardness and streak tests can mark or damage a specimen — test on an inconspicuous spot, and skip testing anything you'd rather keep pristine. Terms of Use (EULA): https://drive.google.com/file/d/1tKMiMuHcAe4zS6HUwAiIvkX0l8ruLYzz/view?usp=sharing Privacy Policy: https://drive.google.com/file/d/1tKMiMuHcAe4zS6HUwAiIvkX0l8ruLYzz/view?usp=sharing

Screenshots

CatalogueMessier4 screens
Rock Identifier4 screens

Verdict

The call

The clearest difference is price: Rock Identifier at Free against CatalogueMessier's $0.99. Rock Identifier also leads on update cadence (every 8 days vs every 3 weeks). CatalogueMessier's advantage is in-app purchases (none vs 3). On ads, device support and iOS requirement 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

Rock Identifier is free to download; CatalogueMessier costs $0.99 up front. Rock Identifier sells 3 in-app purchases, starting at $4.99 per 7 days. CatalogueMessier asks for nothing beyond the download.

UpkeepUpdate frequency

CatalogueMessier ships an update every 3 weeks, Rock Identifier every 8 days. The most recent releases landed on November 5, 2026 and November 11, 2026 respectively.

Scorecard3 real differences · 5 level
CatalogueMessier versus Rock Identifier: the parameters behind the verdict, then further details
ParameterCatalogueMessierRock Identifier
Price$0.99Free — better
Positive reviews0.0% of reviews—
Update frequencyEvery 3 weeksEvery 8 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaid—
DevicesiPhone, iPad — betteriPhone
Requires iOS17.017.0
Further details — not scored
Size9 MB27 MB
Age rating4+4+
DeveloperLaurent DURLIATEbubekir Sezer

In-app purchases

None

CatalogueMessier

No in-app purchases

3 purchases

Rock Identifier

Subscriptions3
  • Weekly$4.997 Days
  • Monthly$9.991 Month
  • Yearly3 Days trial$39.991 Year

Questions

Is CatalogueMessier free?
CatalogueMessier costs $0.99, with no in-app purchases.
Is Rock Identifier free?
Rock Identifier is free to download, with in-app purchases available.
Do CatalogueMessier or Rock Identifier have ads?
Neither CatalogueMessier nor Rock Identifier shows ads.
Which is updated more often, CatalogueMessier or Rock Identifier?
CatalogueMessier ships an update every 3 weeks, and Rock Identifier every 8 days. Most recently, CatalogueMessier was updated on November 5, 2026 and Rock Identifier on November 11, 2026.

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