Wikipedia:WikiProject Astronomy/Style advice

The following is WikiProject Astronomy's advice for writing and editing clear, encyclopedic, attractive, and interesting articles on astronomy. For matters of style not treated on this subpage, follow the main Manual of Style and its other subpages to achieve consistency of style throughout Wikipedia.

Naming conventions

See also: Wikipedia:Naming conventions (astronomical objects)

Articles about astronomical objects should use conventional astronomical naming conventions for the article title, particularly as specified by the International Astronomical Union.

For catalogue names, standard astronomy abbreviations can be used. Hence, BD instead of Bonner Durchmusterung and GJ rather than Gliese–Jahreiß. The exception is the Bayer designation of a star, which uses the fully Latinized greek letter followed by the genitive form of the constellation name. An example is Sigma Orionis, for σ Ori.

For components of multiple star system, the convention is to follow the system name by a capital letter. Thus, Alpha Centauri A and Alpha Centauri B. Exoplanets typically use a lower case letter, such as Epsilon Eridani b.

Capitalizing object names

The capitalization of specific astronomy objects is discussed at: MOS:CELESTIALBODIES. The universe, including the visible universe, uses lower case, except when discussing it in its entirety, such as in a multiverse context.

Images

An astronomical image is any image file concerning non-artificial objects or phenomena that originate outside the Earth's atmosphere. It can include photographs, diagrams, and illustrations. In addition to the usual standards of image selection outlined by the Wikipedia:Image use policy and Wikipedia:Manual of Style/Images, which cover image quality and pertinence, other considerations apply to articles about astronomy:

• Wherever possible, the lead image in an astronomical object article should:
  • Show the article object as viewed in natural light, without enhancements of specific spectral bands or frequency shifting. Usually this means an image taken in the V-band of the UBV photometric system. This may not be possible for heavily redshifted or dust-obscured objects, in which case an infrared image will serve. If the lead image has been modified or enhanced, it should state this in the caption.
  • Feature the entire object in full phase with no occultations or obstructions. Hence, planet, moon, and asteroid images should show the full disk. Hubble staircase images (with a lower-resolution background field image made by WFPC2) should be avoided when a full view image is available.
  • Avoid the use of computer 2D or 3D images when a photograph of the object is available.

• Restrictions on the use of artistic illustrations are discussed at WP:ASTROART. When choosing an artistic illustration, select an image with maximum potential to inform the reader and minimum potential for misinformation. Illustrations made by reliable sources should be preferred.

• Any diagrams should include a reliable source for the data used to create the diagram. In most cases, SVG format is preferred for this type of illustration.

Careful consideration should be made before adding any AI-generated illustrations. The accuracy of the image should be confirmed by an astronomy expert, and copyright use should follow the guidelines for other Wikipedia images.

Units

Main pages: MOS:UNITS and MOS:CONVERSIONS

Per the Manual of Style, the conventional units for astronomy science articles are the International System of Units (SI) and units accepted for use with SI; these should be used consistently throughout an article. Astronomy uses certain unit conventions for specific parameters, and these take primacy where appropriate for the scale. When converting to SI/SI-accepted units, it is usually only necessary supply one conversion (e.g. there's no need to convert to both g and kg).

• Light-years (ly), parsecs (pc), and astronomical units (au) have specific guidelines at MOS:CONVERSIONS. See MOS:UNITSYMBOLS for "au" vs. "AU" and other symbols.
• Density of a material is given directly in the SI units of g/cm³.
• The masses and radii of large astronomical objects are listed relative to the same quantity for the Sun (M_☉, R_☉), Jupiter (M_J, R_J), Earth (M_🜨, R_🜨), or the Moon (M_L, R_L). Mass conversions should be to SI kilograms.
• Luminosities are listed relative to the Sun (L_☉), converted to SI watts.
• Ages are in kyr, Myr, or Gyr (no need to convert to SI seconds).
• Spectral flux density can be given in Jansky, particularly in radio astronomy. This is converted to SI units with the treatment noted at MOS:CONVERSIONS.
• Units of energy can be given in electronvolts (eV) which are accepted for use with the SI, or in SI joules, as appropriate to scale.
• Surface gravity should be shown in both m/s² and standard gravity units, with the symbol g₀. For example:

  {{cvt|3.7|m/s2|g0|lk=out}} gives: 3.7 m/s² (0.38 g₀).

• In astronomical contexts, m/s or km/s (as appropriate depending on magnitude) is preferred for speed or velocity. For planetary weather conditions, km/h is preferred.

To reduce clutter, do not use United States customary units or imperial units in infoboxes. If a reference uses these units, to allow easy verification, convert value to SI (and if appropriate astronomical unit of measure) using the {{cvt}} template but only display the output. For example:

{{convert|140000000|mi|disp=out|au e6km|abbr=unit}} produces: 1.5 au; 230 million km

References

Database sources such as SIMBAD, NED, and Extrasolar Planets Encyclopaedia are invaluable sites for finding reliable sources. However, they are not stable data sources, being subject to change over time. The data comes from multiple overlapping sources, some of which can later be removed. Hence they should not be used directly, but as sources for more static references. But they are useful as a stable reference for the other designations listing.

In the case of the JPL Small-Body Database lookup, the data is not stable, but the report does not always provide an alternative source for static data. The reported data will change over time, particularly in the later decimal fields. Keeping only a few decimals of accuracy will reduce the need to make updates.

There are specific templates for citing catalogues. For example {{Cite EPE}} can be used to cite the Extrasolar Planets Encyclopaedia, {{Cite simbad}} can be used to cite SIMBAD, and {{Cite Gaia DR3}} can be used for citing Gaia DR3.

Infoboxes

All object-specific infobox data entries should have inline references specifying reliable sources.

Whenever the coordinates of an astronomical object is included, it should also list an epoch so the date context is clear. Typically this is J2000. For a minor planet, the epoch of the listed orbital elements is used.

Providing error ranges gives the reader a useful indication of the accuracy of the data. In most cases where an error range exists, there is little need to retain accuracy beyond the first two or three digits of the error margin. For example, 48.8047215840±1.9920 can be listed as 48.80±1.99.

In some instances, different reliable sources may give data values with error ranges that do not overlap. It may be of interest to provide two or more such data values in the infobox, if this is believed to be of interest to the reader. An example of this are diameter estimates for a minor planet that are derived through different methods. The values should be separated by a comma or a new line, and include the margins of error.

There is a set of standard infoboxes for astronomical objects and associations of different types:

• All galaxy types use {{Infobox galaxy}}. Groups and clusters of galaxies use {{Infobox galaxy cluster}}.
• Open clusters use {{Infobox open cluster}}, while globulars use {{Infobox globular cluster}}.
• Moving groups and stellar associations use {{Infobox stellar association}}.
• All nebulae use {{Infobox nebula}}.
• Planets, exoplanets, and minor planets use {{Infobox planet}}.
• Comets use {{Infobox comet}}.

Stellar objects

Stellar articles generally include an infobox consisting of templates from the starbox group. These start with the {{Starbox begin}} and continue to the {{Starbox end}}. Typically they will include the {{Starbox observe}}, {{Starbox character}}, {{Starbox astrometry}}, and {{Starbox catalogue}} templates. When a star has more detailed parameter information, {{Starbox detail}} can be included after the Starbox astrometry template. For multi-star systems, the {{Starbox orbit}} and {{Starbox relpos}} templates are available.

For stars that are visible to the naked eye, a location chart may be included at the top of the infobox using the {{Starbox image}} template. These generally use an appropriate constellation map, available from the Wikimedia Commons. The {{Location mark}} template is recommended for overlaying a marker identifying the star, as it provides consistent positioning accuracy. See the starbox image template documentation for further information.

The {{odlist}} template is strongly recommended for formatting the entries in the Starbox catalogue template. The 'name=' field can be used for a proper name. Positions in the equatorial coordinate system can be displayed in a consistent manner using the {{RA}} and {{DEC}} templates.

See also

• Wikipedia:Naming conventions (astronomical objects)
• Wikipedia:Notability (astronomical objects)