Editing Infrared (section)

=== Astronomy division scheme ===

Astronomers typically divide the infrared spectrum as follows:<ref>{{Cite web |title=Near, Mid and Far-Infrared |url=http://www.ipac.caltech.edu/Outreach/Edu/Regions/irregions.html |url-status=dead |archive-url=https://archive.today/20120529/http://www.ipac.caltech.edu/Outreach/Edu/Regions/irregions.html |archive-date=2012-05-29 |access-date=2007-04-04 |publisher=NASA IPAC}}</ref>

{| class="wikitable"
|-
! style="width:100pt; text-align:left;" | Designation
! style="width:100pt; text-align:center;" | Abbreviation
! style="width:150pt; text-align:center;" | Wavelength
|-
| align="left" | Near-infrared
| style="text-align:center;" | NIR
| style="text-align:center;" | {{val|0.7|–|2.5|u=μm}}
|-
| align="left" | Mid-infrared
| style="text-align:center;" | MIR
| style="text-align:center;" | {{val|3|–|25|u=μm}}
|-
| align="left" | Far-infrared
| style="text-align:center;" | FIR
| style="text-align:center;" | above {{val|25|u=μm}}
|}

These divisions are not precise and can vary depending on the publication. The three regions are used for observation of different temperature ranges,<ref>{{Cite web |title=Near, Mid and Far-Infrared |url=https://www.icc.dur.ac.uk/~tt/Lectures/Galaxies/Images/Infrared/Regions/irregions.html |url-status=live |archive-url=https://web.archive.org/web/20240328203215/https://www.icc.dur.ac.uk/~tt/Lectures/Galaxies/Images/Infrared/Regions/irregions.html |archive-date=2024-03-28 |access-date=2024-03-28 |website=www.icc.dur.ac.uk}}</ref> and hence different environments in space.

The most common photometric system used in astronomy allocates capital [[Jhk|letters to different spectral regions]] according to filters used; I, J, H, and K cover the near-infrared wavelengths; L, M, N, and Q refer to the mid-infrared region. These letters are commonly understood in reference to [[Infrared window|atmospheric windows]] and appear, for instance, in the titles of many [[Academic paper|papers]].<!--A Wikipedia search for JHK finds several examples-->