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data:data_analysis_manual [2023/11/10 09:19] Terje Fredvik [Data products] |
data:data_analysis_manual [2024/01/17 16:26] Peter Young [Units and uncertainties] |
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* ''EAR\_TDEL'': light travel time difference between Sun centre to Spacecraft and Sun centre to Earth (seconds) | * ''EAR\_TDEL'': light travel time difference between Sun centre to Spacecraft and Sun centre to Earth (seconds) | ||
- | The full list of keywords is given in the [[https://spice.ias.u-psud.fr/spice-data/documents/SPICE-UIO-DPDD-0002-1.4-Data_Product_Description_Document.pdf|DPDD]] - search for "Solar ephemeris keywords". | + | The full list of keywords is given in the [[https://spice-wiki.ias.u-psud.fr/lib/exe/fetch.php/public:spice-uio-dpdd-0002-1.8-data_product_description_document_spicefits_.pdf|DPDD]] - search for "Solar ephemeris keywords". |
Users should make sure to correct the SPICE observing times for EAR\_TDEL in order to compare with observations from Earth-orbiting spacecraft. This is especially important for highly-dynamic structures such as flares or CMEs. | Users should make sure to correct the SPICE observing times for EAR\_TDEL in order to compare with observations from Earth-orbiting spacecraft. This is especially important for highly-dynamic structures such as flares or CMEs. | ||
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==== Units and uncertainties ==== | ==== Units and uncertainties ==== | ||
- | The data cube (returned by the SSW object method ''get\_window\_data'' or by the Python ''astropy'' or ''sunraster'' libraries) of the SPICE level-2 files contains spectral radiances in units of W/m²/s/sr/nm. The wavelength vector has units of nm. To convert a radiance in W/m²/s/sr to erg/cm²/s/sr, it is necessary to multiply by 1000. | + | The data cube (returned by the SSW object method ''get\_window\_data'' or by the Python ''astropy'' or ''sunraster'' libraries) of the SPICE level-2 files contains spectral radiances in units of W/m²/sr/nm. The wavelength vector has units of nm. To convert a radiance in W/m²/sr to erg/cm²/s/sr, it is necessary to multiply by 1000. |
Uncertainties on the spectral radiances can be obtained with: | Uncertainties on the spectral radiances can be obtained with: |