App Overview

iMariner Celestial Navigation icon

iMariner Celestial Navigation

DFR Editions · Navigation

iMariner Celestial Navigation is a complete toolbox : sight, fix, meridian, starfinder, solar compass

$26.99 · In-app purchases

PRICE
$26.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.4
10 ratings · Top 30%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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A product spec, screen plans, and build steps for your coding agent.

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What's included15 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for iMariner Celestial Navigation: map the core Navigation workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Implement offline downloads for charts.

Assumption to check: Limited offline functionality for celestial charts

Validate with people who use this workflow before building.

Hypothesis 2

Offer a freemium model with basic features.

Assumption to check: High price point may deter users

Validate with people who use this workflow before building.

Hypothesis 3

Create a more guided onboarding experience.

Assumption to check: User interface can be confusing

Validate with people who use this workflow before building.

Hypothesis 4

Introduce social sharing or user-contributed content.

Assumption to check: Lack of community features

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

iMariner Celestial Navigation is a complete toolbox : sight, fix, meridian, starfinder, solar compass Also embedded : nautical almanac (sun, moon, planets, starts) and astronomical computation (no more need for HO-249/HO-229 tables) - displays almanac informations : Sun, Moon, Venus, Mars, Jupiter, Saturn and 92 brightest stars. At this step, you can use these almanac data with HO.249 tables, if you want to reduce manually. - reduces a sight : getting your observed altitude and the precise time, it calculate Intercept and Azimut. You don't need any calculation ! Simply report Intercept and Azimut to your navigational chart. - You can save your observations by passages and send them by email in CSV format - take a fix : with two sights, iMariner is able to calculate your position (latitude/longitude) - meridian passage : iMariner helps you to take observations mandatory to know your position (latitude/longitude) - sight preparation : iMariner proposes you the best objects, here position (azimut and elevation), and the approximate time of the day the observation can take (nautical_twilight or nautical dawn). iMariner is a standalone application. It doesn't require internet connection. It is light and calculations are optimized to save energy on your boat. Includes a solar compass (and moon compass too). REFERENCES : iMariner has been inspirated by astronomical works of the following people. Brightest Stars Catalog Extraction of 92 stars >= 2.5 Mag from the vizier catalog, completed with some stars and star names. V/53A Catalogue of the Brightest Stars (Ochsenbein+ 1988) This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France vizier.u-strasbg.fr ============================= Le catalogue des etoiles les plus brillantes Catalogue of the brightest stars Ochsenbein F., Halbwachs J.L. =1987BICDS..32...83O Ochsenbein F., Acker A., Legrand E., Poncelet J.M., Thuet-Fleck E. ============================= AlgorithmsFrom the reference book Astronomical Algorithms by Jean Meeus Planets : VSOP87D theoryTables extracted from ftp://ftp.imcce.fr/pub/ephem/planets/vsop87/ and adapted to Objective-C. Bretagnon P., Francou G., : 1988, Astron. Astrophys., 202, 309. Pierre Bretagnon, Gerard Francou Bureau des Longitudes 77, Avenue Denfert-Rochereau F75014, Paris, France Moon : ELP2000 theory The lunar ephemeris ELP2000 M. Chapront-Touze and J. Chapront Service de Mecanique Celeste du Bureau des Longitudes 77, Avenue Denfert-Rochereau F75014, Paris, France Sky Maps Free maps from the IAU site : http://www.iau.org/public/constellations/ DeltaT value maia.usno.navy.mil

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

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BUILD KIT DIFFICULTY
Advanced

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.