Guidelines for writing astronomical papers
for students writing their first paper (and others)
Rev. December, 2007
Here are a few generally accepted practices for science writing,
with some of my own biases. I'm sure I've forgotten a lot
of things that could be here. Suggestions are welcome. This is an evolving document.
The Big Picture
- 1. The whole point of an article is to tell a story. What is the
story you want to tell? Your pictures and graphs help in telling the
story, but each one needs to be thoroughly introduced as if you were
giving a lecture to a group of students. Revisit the abstract after
you think you are done. Does it sum up the story and communicate the
big picture of what this means to science (or to humanity) as a whole?
- 2. Figures:
- A. Each figure needs a descriptive caption that not only
introduces the axes and symbols used, but summarizes what the
figure is intended to communicate.
- B. When preparing for publication, use a line weight of 2 or
greater to make thick, dark, bold lines and symbols.
- C. Every figure needs a legend to explain symbols and lines or
other annotations, even if these are also explained in the caption.
It makes your figures much easier to digest for newcomers.
- D. Figures are always introduced in the text in order. I.e.,
never talk about Figure 3 before Figure 2.
- E. Always use different line types and point types in figures so that
you don't rely on color. Most people will read your figure in B&W so make
it legible that way.
- 3. Tables
- A. Use proper number of significant figures.
- B. Include uncertainties on all measurements
- C. Use table footnotes to explain your table headings
General proofreading advice
- 1. Active/Passive voice
- Use the active voice wherever possible, Subject followed by verb.
I.e., "Figure 4 shows the correlation between amplitude and mass" is
superior to "A correlation between amplitude and mass can be seen in
Figure 4". Reserve use of the passive voice for things which are not your
fault, i.e., "The night was not photometric so the data were not flux
- Other examples of active/passive preference: Say "Table 1 lists the
magnitudes of each star" rather than "The magnitudes of each star can
be found in Table 1."
- Active sentences are punchier and more fun to read than passive
- "Figure 1 reveals the differences between Population 1 and Population II".
- "Figure 2 displays the 8.0 and 10.0 micron images of the cluster."
- "Figure 3 reveals that stars without disks are preferentially more blue than
stars with disks."
- "Figure 4 shows a greyscale V-band image of NGC 4565." etc...
- 2. Use of We/I.
- It is increasingly acceptable to use the second person, or (less
commonly) even first person pronouns to describe the activity of the
- "We obtained data on the night of 2004 February 30."
- "We cross correlated the Hubble Guide Star catalog objects with the 2MASS catalog."
- Limited, appropriate use of we/I is encouraged.
- 3. Sentence structure
- A. Eschew gerund phrases that open a sentence. E.g., "Looking at
Figure 1, the star lies on the periphery of the cloud". This is
poor syntax because it means something colloquial like "When I look
at Figure 1 I see that ....". Replace it with, "Figure 1 shows
that the star lies on the periphery of the cloud".
- B. Avoid leading prepositional phrases. They are often
colloquial and informal. "To flux calibrate the photometry, we
observed five standard stars." Instead use, "We observed five
standard stars to flux calibrate the photometry."
- C. Make good use of simple sentences. They are punchy and lively
and easy to read. Where possible, combine related ideas in
adjacent sentences to save space and form a single sentence.
- D. Commas always follow the "and" or "but" which joins independent
clauses in a compound sentence. "Galaxies with active central
black holes often exhibit jets, but galaxies without active nuclei
should not show them."
Commas do not join trailing dependent clauses to an independent
clause. WRONG: Stars with disks have infrared excesses, and have
submillimeter excesses. OK: Stars with disks have infrared excesses,
and they have submillimeter excesses.
- E. Commas always follow leading prepositional phrases.
"Although the weather was partly cloudy, we obtained several short
exposures of Beta Pictoris."
When completing a paper, spend 6-8 hours (over several days) carefully going through
a paper. The temptation when writing is often to throw down a bunch of
somewhat-related ideas with a few citation to show that you're
aware there's a literature out there on your topic. Your goal should be
a masterful synthesis (especially for intros to theses and some papers) that
demonstrates your mastery of your subfield. Writing is supposed to be
educational...yea, even entertaining!
- 1. Read, sentence by sentence, looking for
- A. Is each sentence grammatically correct? Is there
singular/plural agreement between the subject and the verb? (Note:
"spectrum" is the singular of the plural "spectra". "Data" is the
plural of the singular "datum".)
- B. Is the sentence unnecessarily long and complex? Can it be
shortened into two simpler, punchier sentences? Make a revision through
your text, replacing boring words with exciting words, where possible.
- C. Can two simple ideas be synthesized into a single sentence to
- D. Is every term or concept introduced with a sufficient level of detail for your audience, especially words that carry technical meanings?
- 2. Read, paragraph by paragraph, looking for
- A. Does the lead sentence of the paragraph clearly convey the main
idea of the paragraph?
- B. Are the topics covered in a paragraph
sufficiently united to warrant being one paragraph, or should the
paragraph be split up?
- C. Are neighboring paragraphs (especially
short ones) sufficiently related that they can be joined into a
- 3. Read, section by section, looking for
- A. Is the flow of ideas continuous and logical? Is there a more
logical ordering of the sections of the paper which would
facilitate reading by a novice in the field?
- B. Can long blocks of text be broken into logically titled subsections
to facilitate reading and organization?
- 1. Avoid overuse of the possessive pronouns: It's ok to say "our
data" or "our models" or "our sample" but inappropriate to say "our
galaxies" or "our stars" since they really don't belong to us.
- 2. Avoid overuse of distracting and qualifying words. E.g.,
"Figure 5 appears to show that ...." -> "Figure 5 shows that ..."
"Thus, the data are inconsistent with the model" -> "The data are
inconsistent with the model." Reserve words like "Thus" or "Therefore"
only for rare situations where a real logical conclusion is being
imposed by the preceding sentences.
- 3. Adverbs that end in "ly" are not hyphenated. E.g., "photometrically
calibrated" NOT "photometrically-calibrated".
- 4. e.g., and i.e., are always followed by commas because they are abbreviations
for "for example" and "in other words".
- 5. Avoid acronyms because they can make reading a real slog. Only use
"very famous" acronyms that everyone will immediately know, e.g. CMB
- 6. Enclose all variable names in $ $ in TeX. E.g., "The factor, $X$, denotes
the conversion factor of $CO$ to $H_2$."
- 7. Capitalize "Figure 1", "Table 3", etc.
- 8. In Tex and LeTeX (and to a printer) there is an important difference between "-" and "--" and "---".
The first is called a hyphen and is used to separate compound works like "ever-lasting".
The second is called an n-dash
and is used to illustrate ranges: "The range of possible stellar masses is 3--4 solar masses."
The last is called an m-dash and is used when indicates a sudden break in
thought--- parenthetical statement like this one---or an open range (such as "John Doe, 1987---").
- 10. Use a spell checker!
- 11. Read ApJ & AJ instructions for authors.
- 12. Read and study Online writing style guides
- 13. Read and study read about
the use of hyphens and dashes