Astrophotography System Comparsion Tool

March 24, 2026

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This builder is usable on smaller screens, but the full layout is easiest to view and work with on a desktop or laptop display.

Table of Contents Show (Click on lines to navigate)

Introduction

Planning an astrophotography upgrade?

Wondering whether a new camera or filter set will actually make a difference?

This often comes down to guesswork. This tool replaces that guesswork with physics. Enter two imaging systems (cameras, filters, focal ratio, sky conditions), and it computes a quantitative signal ratio: how many hours on System B are equivalent to one hour on System A, accounting for quantum efficiency, read noise, sky background, and optical throughput. Both broadband (LRGB/OSC) and narrowband (Ha/OIII/SII, dual-band) modes are supported. The underlying model and all assumptions are documented in the Technical Appendix tab.

Astro efficiency model v2.7

Astrophotography System-to-System Comparison Tool

Set up two imaging systems and compare them at equal total exposure time. See which combination of camera, optics, sky, and filter strategy is doing the most work.

Equal-time comparison Broadband & narrowband Mode-aware appendix Validation & audit tools

1

Mode

2

Systems

3

Time & mix

Step 1 — imaging mode

Imaging typeBroadbandNarrowband

Target classBroadband continuumGalaxy / star fieldEmission nebulaMixed nebula

Active model

Step 2 — define systems

System APrimary

A

System name

Camera

Gain

Focal ratio

Sky brightness

Capture model

System BComparison

B

System name

Camera

Gain

Focal ratio

Sky brightness

Capture model

3

Shared comparison basis

Equal time and channel weighting applied to both systems

Total exposure time (hours)

System A mix

System B mix

Load broadband example Load narrowband example Reset

▲ Hide Setup

VS

—

—

Factor breakdown — what drives the result B advantageA advantage

Channel breakdown

A

B

How the result is built

View ▼ select a tab to change the analysis view below

Spectra Scenario Audit Appendix

The main result is always shown above. Use the other tabs to explore spectra, scenarios, audit data, and the technical appendix.

Camera quantum efficiency

System A (solid) vs System B (dashed) across the visible spectrum. Filter passbands overlaid as shaded regions. Dashed verticals mark Hα, OIII, and SII emission lines.

Active filter transmission curves

All filters in the selected capture model for both systems. X-axis auto-zooms to the active passband range.

Camera specifications

Methods & model limits

Scenario heatmap — hours B needs to match A

Rows = sky darkness of System B (Bortle 1–9). Columns = A/B system speed ratio. Highlighted cell = current selection. Cool blue = B needs fewer hours (B wins at that sky). Warm red = B needs more hours (A wins).

B needs fewer hours

B needs more hours

Narrowband filter audit

Line-by-line audit of active narrowband filter curves and modeled response terms.

Channel / filter contribution table

Validation lab

Catalog matrices and automated sanity checks for cameras, filters, and common comparison cases.

Data provenance & import audit

Product family identification, curve provenance, and import validation guidance.

Advanced debug

Condensed instrumentation for tracing the current detector and comparison pipeline.

Technical appendix loads here automatically after the tool above computes a result.

How to use the tool

1. Choose a mode. Select Broadband for LRGB or OSC galaxy and nebula work, or Narrowband for emission-line imaging with Ha, OIII, and SII filters. The tool adjusts its model, available filter sets, and output panels accordingly.

2. Configure System A and System B. Each system has a camera, focal ratio, Bortle-scale sky darkness, and a filter set. System A is typically your current or reference setup; System B is the one you're evaluating. Use the example buttons to load a representative starting configuration.

3. Read the result. The headline number is the equivalent hours figure — how many hours on System B yield the same collected signal as your chosen total on System A. A value below 10 h (when System A is set to 10 h) means System B is less efficient; above 10 h means it's more efficient. The signal ratio, sky factor, and optics factor panels break down exactly where the difference comes from.

4. Dig into the details. The QE chart overlays sensor quantum efficiency curves for both cameras. The Filter response chart shows passband transmission. The Channel heatmap compares per-channel contributions. In narrowband mode, the Narrowband audit panel adds FWHM, peak transmission, and per-line SNR terms for each filter.

5. Check the Technical Appendix. The Appendix tab contains the full mathematical derivation, all model assumptions, and the data provenance for every camera and filter set. If a result looks surprising, the appendix is the right place to audit it.

6. Validation Lab. The Audit tab runs a built-in test suite — curated sanity cases and a generated comparison matrix across all cameras — and flags any result that falls outside expected bounds. This is primarily a data-integrity check, but it's also a useful way to explore how different equipment combinations rank against each other.

Feedback and Suggestions

Any feedback or suggestions you might have for improving the tool can be sent here: Contact@CosgrovesCosmos.com

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