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Catalog Guide

Browse, search, and filter over 22,000 astronomical objects across multiple catalogs.

Overview

The Astronomical Catalog is a searchable database of deep-sky objects, bright stars, and solar system bodies. Use the filters on the left to narrow results by catalog, object type, constellation, or magnitude. Select objects to view them on the Star Map, add them to observation plans or lists, or export them as PDF or CSV.

Available Catalogs

Messier (110 objects)

Charles Messier's classic list of bright nebulae, clusters, and galaxies. The best starting point for visual observers.

NGC (~7,800 objects)

New General Catalogue — the most widely used deep-sky catalog, covering galaxies, nebulae, and star clusters.

IC (~5,400 objects)

Index Catalogue — supplements to the NGC with additional fainter deep-sky objects.

Caldwell (109 objects)

Sir Patrick Moore's curated list of interesting objects not in the Messier catalog, spanning both hemispheres.

Bright Stars (~9,100 objects)

Stars visible to the naked eye (mag ≤ 6.5), including single, double, and variable stars with detailed stellar data.

Solar System (25 objects)

Planets, moons, dwarf planets, and major asteroids with real-time ephemeris positions.

Search

Type in the search box to find objects by name or catalog designation.

By common name: Orion Nebula, Andromeda Galaxy, Sirius
By catalog number: M42, NGC 7000, IC 1396, C49
By star designation: Alpha Orionis, Betelgeuse, BS 2061

Click Apply Filters or press Enter to search. Use the button to clear the search field.

Filters

The filter panel on the left has four sections. Combine them freely to refine your results.

Catalogs

Check one or more catalogs to include. Each checkbox shows the total object count in parentheses. Use the button to clear all catalog selections.

Object Types

Filter by astronomical object type. Types are grouped into three categories:

  • Stars — Star, Double Star, Variable Star
  • Deep Sky — Open Cluster, Globular Cluster, Diffuse Nebula, Planetary Nebula, Galaxy, Emission Nebula, Reflection Nebula, Dark Nebula, Supernova Remnant, Quasar
  • Solar System — Sun, Planet, Dwarf Planet, Moon, Asteroid

Constellations

Select one or more constellations to show only objects in those regions. Quick filter buttons narrow the list:

Northern Equatorial Southern Visible Tonight Select All Show All

Visible Tonight uses your default observation location to calculate which constellations are above the horizon tonight. Selected constellations appear as colored chips above the list.

Magnitude

Set a minimum and maximum magnitude to filter by brightness. Lower numbers are brighter. Use the presets for common equipment:

Naked Eye (−5 to 4.5) Binoculars (0 to 9) Telescope (0 to 12)

Click Apply Filters to update results, or Clear to reset all filters. Active filter counts appear as badges next to each section header.

Results Table

Matching objects appear in a sortable table with the following columns:

Checkbox — Select objects for batch operations
Name — Object name and catalog designation
Type — Astronomical object type (Galaxy, Nebula, etc.)
Const. — Constellation abbreviation
Mag — Visual magnitude (brightness)
Info — Observing rating (star icons) and difficulty level

Click any column header to sort by that column. Click again to reverse the sort order. Results are paginated — use the page buttons at the bottom to navigate.

Batch Actions

Select one or more objects using the checkboxes (or the header checkbox to select all on the current page). A blue action bar appears at the top of the results with these options:

Star Map — Open the selected objects on the Star Map for visual exploration.
Add to Plan — Add objects to an existing observation plan for a future session.
Add to List — Add objects to a custom list for organizing your targets.
PDF — Export the selected objects as a formatted PDF document.
CSV — Export the selected objects as a CSV file for use in spreadsheets.

Object Details Page

Click any object name in the results to open its detail page. The details page shows:

Mini Star Map — A small sky chart showing the object's position and surrounding stars (top right).
Observing Rating — A star rating (1–5) indicating how rewarding the object is to observe visually, from Modest to Showpiece.
Difficulty Level — A color-coded level (1–6) showing how challenging the object is to find and observe.
Coordinates — Right Ascension and Declination in standard notation.
Physical Data — Magnitude, angular size, distance, and type-specific properties (spectral type, star colors, separation for doubles, galaxy type, etc.).

From the details page you can jump to the Star Map, Add to List, or Add to Plan. The Back to Catalog button returns to your previous search results with all filters preserved.

Observing Ratings

Objects are automatically rated based on their properties to help you prioritize targets:

Showpiece — Outstanding, must-see objects
Excellent — Very rewarding to observe
Good — Worth seeking out
Fair — Interesting with the right equipment
Modest — For completionists and experienced observers

Ratings are computed from object properties like magnitude, angular size, separation (doubles), and magnitude range (variables). They are specific to each object type — double stars, variable stars, open clusters, globular clusters, galaxies, and planetary nebulae each have their own rating formula.

Difficulty Levels

Each object has a difficulty level indicating how challenging it is to locate and observe:

Level 1 Naked-eye objects — easy to find without any optical aid
Level 2 Binocular objects — visible in binoculars or a small finder
Level 3 Small telescope — requires a telescope to see clearly
Level 4 Moderate telescope — needs good conditions and moderate aperture
Level 5 Large telescope — faint objects requiring dark skies and larger aperture
Level 6 Expert — extremely challenging, often requiring photography or large instruments

Tips

  • Start with the Messier catalog if you're new to deep-sky observing — these are the brightest and most rewarding objects.
  • Use Visible Tonight in the constellation filter to focus on what you can actually see from your location.
  • Combine catalog and magnitude filters: e.g. select NGC + Naked Eye to find the brightest NGC objects.
  • Sort by Info to bring the highest-rated objects to the top of your results.
  • Use batch selection to add an entire filtered set to an observation plan for your next session.
  • The Caldwell catalog is great for observers who have finished the Messier list and want the next challenge.
  • Export to CSV for your own analysis, or PDF for a printable observing list to take to the field.
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