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IAU and Sky & Telescope charts (Roger Sinnott, Rick Fienberg), J2000

Objects of the sky · how to read them, and sources

Star Variable star Galaxy Open cluster Globular cluster Planetary nebula Nebula
Navigation, names and cards

Click the background of a chart to travel to its constellation: the view switches to the sky, moves across and frames it automatically. The constellation list and the search box trigger the same move. Dragging or zooming interrupts the animation. Clicking an object symbol keeps its card open.

Hover a symbol to read its name and data. Click or tap to keep the card. The search box accepts names, stellar designations and references such as M31 or NGC 7000. The “Names” button adds lettering to the chart; zooming in reveals more of it. Names are drawn whole, and hidden whole where they would overlap.

Hover a symbol to show its card. Click or tap to keep it open. The search box also accepts star names and references such as M31 or NGC 7000. Esc closes a card.

Brightness, positions and distances

A lower magnitude means a brighter object. V is the visual band, B the blue band. The total magnitude of an extended object does not on its own describe how visible it is. Variable stars change in brightness.

Distances are approximate and rounded; missing values read “Not available”. Stellar distances come from HYG. Every deep-sky distance available carries its own source. Reference data retrieved on 10 October 2026.

The lower the magnitude, the brighter the object. V is the visual band, B the blue band: the two are not interchangeable. For an extended object, the total magnitude does not on its own describe how visible it is. A variable star can change in brightness.

“ly” means light-year: the distance light travels in one year. Distances are rounded estimates, sometimes given as a range. Stars use HYG; for galaxies, clusters and nebulae, a “Distance” link gives the source of each value available. These estimates vary from one publication to another.

Some symbols remain unidentified. Associations are made by proximity and symbol type; catalogue positions are kept separate from the drawings. Missing values are still reported as not available.

Catalogues, credits and provenance

Card coordinates are the catalogue ones, in J2000. The circular marker surrounds the printed symbol, whose position may differ from the catalogue centre. Some symbols are not identified; the associations carried over from the reference were made by proximity and symbol category.

Stars: HYG v4.1, David Nash / Astronomy Nexus. Deep sky: OpenNGC, Mattia Verga and contributors. Catalogue extracts and adaptations: CC BY-SA 4.0.

Further distance sources: NASA/Hubble (Messier and Caldwell), NASA/APOD, Chandra, JPL, ESO and Cantat-Gaudin et al. (2020), A&A 640, A1 via VizieR/CDS. The credits and links for each value are kept in the cards. The data is embedded in the HTML and stays readable offline.

Stars: HYG v4.1, David Nash / Astronomy Nexus.
Deep sky: OpenNGC, Mattia Verga and contributors.

Extracts and adaptations of these catalogues are distributed under CC BY-SA 4.0. Positions are J2000. The data is embedded in the file: no connection is needed to read it.

Deep-sky distance sources: NASA/Hubble (Messier), NASA/Hubble (Caldwell), NASA/APOD, Chandra, JPL and ESO. Further clusters: Cantat-Gaudin et al., A&A 640, A1 (2020), via VizieR/CDS; distances in parsecs converted to light-years (1 pc ≈ 3.26156 ly), rounded to at most three significant figures.

Charts: IAU and Sky & Telescope, Roger Sinnott and Rick Fienberg, CC BY 4.0.

Accuracy and the IAU charts

Apogee · current display

The charts, the catalogue coordinates and Apogee's own registration are preserved. The corrected lettering stays independent of the boundaries. The checks below come from Sphère céleste UAI; they describe the source file, not a new registration of Apogee.

Checks from Sphère céleste UAI

All 89 PDFs were re-read and re-registered from their original data. The charts use an equidistant conic projection, polar for some regions. The computation recovers the J2000 right ascension and declination at every pixel on screen.

No title is cut by a boundary. Each constellation name, with all of its lines, is a single piece of lettering. A title is shown whole or hidden whole when it leaves the window or overlaps another title. Zooming in reveals the smaller lettering. The vector lettering that was kept uses the glyphs from the PDFs.

The Auriga and Caelum PDFs are 300 dpi images. Their registration is fitted to the graticule lines; their sharpness stays limited by the pixels. The printed symbols and positions remain those of the documents, with their own accuracy. This file is a J2000 atlas; it does not compute apparent positions for the date of observation. The optional horizon is drawn for Marseille (43.2965° N, 5.3698° E) at the machine's own time: mean sidereal time and IAU 1976 precession, without nutation, aberration or refraction — a fraction of an arcminute of difference.

The joins use Delporte's B1875 boundaries, via the CDS VI/49 and Roman (1987) catalogues, checked against the J2000 vertices published by the IAU.

Show the checks for all 89 charts
ChartFull titleRegistration RMS

Reconstruction carried out on 11 October 2026. The source files are not modified. The display resources are embedded; the provenance links are optional and need the internet.