Normally the Editor (Mariya Lyubenova) solicits contributions to The Messenger. Unsolicited manuscripts are also welcome, but are subject to approval by the Editor before they can be published. All Messenger articles must have some connection to ESO. Submitted manuscripts are checked for obvious errors as far as possible. The Messenger articles are normally not refereed, although the Editor may in some cases solicit the advice of other ESO astronomers before finally accepting an article.

If you have received an invitation to submit an article to The Messenger, the editorial assistant will provide you with a MS Word template to help you prepare your article, as well as further instructions regarding the submission.

The Messenger and all articles are published open access under a Creative Commons Attribution 4.0 International License.

Authors that have used Large Language Models tools (e.g. GPT, BERT, etc.) should document this in the acknowledgements section of their articles. Furthermore, LLMs should not be listed as co-authors as attribution of authorship carries with it accountability for the work, which cannot be effectively applied to LLMs.

Submitted manuscripts are checked for obvious errors as far as possible, including language. Nevertheless, authors are encouraged to have colleagues go over manuscripts for advice on language, style and content before submission. Messenger articles are normally not refereed, although the Editor may in some cases solicit the advice of other ESO astronomers before finally accepting an article.

Authors will receive proofs of their articles as PDF files shortly before publication. These should be examined carefully, and any corrections (not revisions) should be sent back to the Editor as quickly as possible. On some occasions an article may have to be delayed to the next issue. The authors will be informed of this immediately, and will have the opportunity to revise the article, if so desired.

Because of the very broad readership, articles in The Messenger must be of wide general interest and reader-friendly - more like magazine articles than formal reviews in professional scientific/technical journals, hence not too narrow, detailed or technical. The beginning of an article must introduce the broad subject and its background to the general reader. Overall, the style should be readable while informative.

Articles, including figures, tables, etc. should not normally exceed four Messenger pages in total (see below for conversion factors). Of course, shorter contributions, down to a figure with an appropriate caption, are certainly welcome. An article should contain no more that 10 references, and no more than 6 figures. Equations should be avoided or kept to an absolute minimum.

Articles of this size should be able to convey the essence, relevance and most important aspects of the subject to the average reader. Longer articles containing many details, figures and references (typical of professional reviews) are normally not appropriate for The Messenger.

Specific style points:

• Each article should contain a short summary especially geared towards non-specialists.
• Full first and last names of all authors, and their affiliations, should be given.
• Do not number your sections. The section titles should be as concise as possible. Please avoid section titles such as “Introduction” and “Conclusion” (do not include a conclusion at the end which is only a summary of your article - the very short summary at the beginning of the article serves this purpose).
• The text should be written in British English. If you are unsure, please have your text checked by a native-English speaker. At the least, use a spelling checker. Numbers up to nine should be written in letters – i.e. do not write “this system comprises 2 windows” but rather “this system comprises two windows”. Use SI units, i.e. nm instead of angstroms. Explain all abbreviations.
• Avoid the use of upper case text throughout the document (including the summary and section titles).
• Avoid equations unless absolutely necessary.
• Figure captions should be kept fairly short. They should serve largely (or completely) to explain the figure itself. They should contain minimal (or no) discussion or conclusions, which belong in the main body of text which refers to the figure.
• The references (no more than 10) should be in the Astronomy & Astrophysics format.

• A text-only Messenger page contains about 1100 words or 6500 characters (with spaces). One should typically consider about two figures or tables per page of text. A typical four page article in The Messenger therefore comprises roughly 5 figures or tables and about 2000 words main body of text (excluding title, authors, affiliations, references, and figure captions).
• For the manuscript text, Word is preferred (template is available), otherwise plain text. In all cases, use as little formatting as possible.
• All figures that have line plots or text should be in vector format (EPS or PDF) so that they have sufficient resolution and can be brought into The Messenger format. Please also make sure that the labels on the figures are large enough that they can still be read when the figures are reduced in size. Typical sizes for figures in The Messenger are 5.9, 7.5, 9 and 12 cm wide.
• A printable version of the complete article, with all figures included in the document, should be sent.
• Please name the figures following this example: author_figx.format.
• The article text, the figures and the printable version should preferably be sent as a zip file with the name of the first author as filename.