![[EMspectrum_collective.png|align:center]] ![[EMspectrum_wavelengths.png|align:center]] ![[EMspectrum_instruments.png|align:center]] ## Radiation Classes For observational practices and public usage, the electromagnetic spectrum has been divided into an assortment of sub-classes based on frequency and wavelength. The following terminology is used in the different sub-fields of astronomy, but there are other classification systems and more detailed sub-types as well. (For example, radio has three systems on [Wikipedia](https://en.wikipedia.org/wiki/Radio_spectrum)) | <nobr>EM Spectrum</nobr> | <nobr>Abbrev.</nobr> | <nobr>Radiation Class</nobr> | <nobr>Median Wavelength (m)</nobr> | <nobr>Frequency (Hz)</nobr> | <nobr>Energy per Photon (eV)</nobr> | | :-------------------------------------------------------------------------------------------: | :------------------: | ------------------------------------------------------- | :----------------------------------: | :---------------------------------: | :-------------------------------------: | | <mark class="hltr-gammaray-purple">Gamma</mark> | $\gamma$ | Gamma Rays | $10 \; {\rm pm}$ | $30 \; {\rm EHz}$ | $124 \; {\rm keV}$ | | <mark class="hltr-xray-purple">X-Ray</mark> | HX | Hard X-rays | $100 \; {\rm pm}$ | $3 \; {\rm EHz}$ | $12.4 \; {\rm keV}$ | | <mark class="hltr-xray-purple">X-Ray</mark> | SX | Soft X-rays | $10 \; {\rm nm}$ | $30 \; {\rm PHz}$ | $124 \; {\rm eV}$ | | <mark class="hltr-uv-purple">Ultraviolet</mark> | EUV | Extreme Ultraviolet | $121 \; {\rm nm}$ | $3 \; {\rm PHz}$ | $10.2 \; {\rm eV}$ | | <mark class="hltr-uv-purple">Ultraviolet</mark> | NUV | Near Ultraviolet | $400 \; {\rm nm}$ | $750 \; {\rm THz}$ | | | <mark class="hltr-purple">Visible</mark> | Vis-V | <mark class="hltr-purple">Visible Light (Violet)</mark> | $380 - 450 \; {\rm nm}$ | $670-790 \; {\rm THz}$ | $2.75 - 3.26 \; {\rm eV}$ | | <mark class="hltr-blue">Visible</mark> | Vis-I | <mark class="hltr-blue">Visible Light (Indigo)</mark> | $450 - 485 \; {\rm nm}$ | $620-670 \; {\rm THz}$ | $2.56 - 2.75 \; {\rm eV}$ | | <mark class="hltr-cyan">Visible</mark> | Vis-B | <mark class="hltr-cyan">Visible Light (Blue)</mark> | $485 - 500 \; {\rm nm}$ | $600-620 \; {\rm THz}$ | $2.48 - 2.56 \; {\rm eV}$ | | <mark class="hltr-green">Visible</mark> | Vis-G | <mark class="hltr-green">Visible Light (Green)</mark> | $500 - 565 \; {\rm nm}$ | $530-600 \; {\rm THz}$ | $2.19 - 2.48 \; {\rm eV}$ | | <mark class="hltr-yellow">Visible</mark> | Vis-Y | <mark class="hltr-yellow">Visible Light (Yellow)</mark> | $565 - 590 \; {\rm nm}$ | $510-530 \; {\rm THz}$ | $2.10 - 2.19 \; {\rm eV}$ | | <mark class="hltr-orange">Visible</mark> | Vis-O | <mark class="hltr-orange">Visible Light (Orange)</mark> | $590 - 625 \; {\rm nm}$ | $480-510 \; {\rm THz}$ | $1.98 - 2.10 \; {\rm eV}$ | | <mark class="hltr-red">Visible</mark> | Vis-R | <mark class="hltr-red">Visible Light (Red)</mark> | $625 - 750 \; {\rm nm}$ | $400-480 \; {\rm THz}$ | $1.65 - 1.98 \; {\rm eV}$ | | <mark class="hltr-ir-red">Infrared</mark> | NIR | Near Infrared | $1 \; {\rm \mu m}$ | $300 \; {\rm THz}$ | $1.24 \; {\rm eV}$ | | <mark class="hltr-ir-red">Infrared</mark> | MIR | Mid Infrared | $10 \; {\rm \mu m}$ | $30 \; {\rm THz}$ | $124 \; {\rm meV}$ | | <mark class="hltr-ir-red">Infrared</mark> | FIR | Far Infrared | $100 \; {\rm \mu m}$ | $3 \; {\rm THz}$ | $12.4 \; {\rm meV}$ | | <mark class="hltr-microwave-red">Microwave</mark> / <mark class="hltr-radio-red">Radio</mark> | THF | Tetrahertz Frequency | $1 \; {\rm mm} - 100 \; {\rm \mu m}$ | $300 \; {\rm GHz} - 3 \; {\rm THz}$ | $1.24 \; {\rm meV} = 12.4 \; {\rm meV}$ | | <mark class="hltr-microwave-red">Microwave</mark> / <mark class="hltr-radio-red">Radio</mark> | EHF | <nobr>Extremely High Frequency</nobr> | $1 \; {\rm mm}$ | $300 \; {\rm GHz}$ | $1.24 \; {\rm meV}$ | | <mark class="hltr-microwave-red">Microwave</mark> / <mark class="hltr-radio-red">Radio</mark> | EHF/SHF | --- | $10 \; {\rm mm}$ | $30 \; {\rm GHz}$ | $124 \; {\rm \mu eV}$ | | <mark class="hltr-microwave-red">Microwave</mark> / <mark class="hltr-radio-red">Radio</mark> | SHF | Super High Frequency | $100 \; {\rm mm}$ | $3 \; {\rm GHz}$ | $12.4 \; {\rm \mu eV}$ | | <mark class="hltr-microwave-red">Microwave</mark> / <mark class="hltr-radio-red">Radio</mark> | UHF | Ultra High Frequency | $1 \; {\rm m}$ | $300 \; {\rm MHz}$ | $1.24 \; {\rm \mu eV}$ | | <mark class="hltr-radio-red">Radio</mark> | VHF | Very High Frequency | $10 \; {\rm m}$ | $30 \; {\rm MHz}$ | $124 \; {\rm neV}$ | | <mark class="hltr-radio-red">Radio</mark> | HF | High Frequency | $100 \; {\rm m}$ | $3 \; {\rm MHz}$ | $12.4 \; {\rm neV}$ | | <mark class="hltr-radio-red">Radio</mark> | MF | Medium Frequency | $1 \; {\rm km}$ | $300 \; {\rm kHz}$ | $1.24 \; {\rm neV}$ | | <mark class="hltr-radio-red">Radio</mark> | LF | Low Frequency | $10 \; {\rm km}$ | $30 \; {\rm kHz}$ | $124 \; {\rm peV}$ | | <mark class="hltr-radio-red">Radio</mark> | VLF | Very Low Frequency | $100 \; {\rm km}$ | $3 \; {\rm kHz}$ | $12.4 \; {\rm peV}$ | | <mark class="hltr-radio-red">Radio</mark> | ULF | Ultra Low Frequency | $1 \; {\rm Mm}$ | $300 \; {\rm Hz}$ | $1.24 \; {\rm peV}$ | | <mark class="hltr-radio-red">Radio</mark> | SLF | Super Low Frequency | $10 \; {\rm Mm}$ | $30 \; {\rm Hz}$ | $124 \; {\rm feV}$ | | <mark class="hltr-radio-red">Radio</mark> | ELF | Extremely Low Frequency | $100 \; {\rm Mm}$ | $3 \; {\rm Hz}$ | $12.4 \; {\rm feV}$ | > [!image] Different Radio Band Conventions: > ![[radio_band_classifcations.png]]