FITS2HV
From Helioviewer Wiki
This page describes solar FITS files keywords and their meaning in relation to the Helioviewer Project. A description of the FITS format can be found here and here.
Contents |
SDO
| FITS | HV Default value FITS default value | hv |
|---|---|---|
| BITPIX | 32 32 | bits per pixel |
| NAXIS1 | 4096 4096 | number of pixels in the x direction |
| NAXIS2 | 4096 4096 | number of pixels in the y direction |
| DATE_OBS or DATE__OBS | n/a | yyyy-mm-ddThh:mm:ss.mmZ, date and time of observation CCSDS format |
| TELESCOP | SDO SDO/AIA | Observatory |
| INSTRUME | AIA AIA | Instrument |
| INSTRUME | AIA AIA | Detector |
| WAVELNTH | one of the choices below 4500, 1700, 304, 1600, 171, 193, 211, 335, 94, 131 | Measurement |
| n/a | AIA | Obs-Ins-Det Nickname (see note 'a') |
| CRPIX1 or X0_LF or X0_MP | 2048 2048 or NAN (see note 'c') | x position, Center of the sun in image pixels |
| CRPIX2 or Y0_LF or Y0_MP | 2048 2048 or NAN | y position, Center of the sun in image pixels |
| CDELT1 | 0.599900 0.599900 | x direction, arcseconds per pixel |
| CDELT2 | 0.599900 0.599900 | y direction, arcseconds per pixel |
| R_SUN or RSUN_LF | 1577.67 or NAN | solar radius in image pixels |
For more details on AIA FITS keywords go to ???
SOHO
| FITS | Default value | hv |
|---|---|---|
| NAXIS1 | 1024 | number of pixels in the x direction |
| NAXIS2 | 1024 | number of pixels in the y direction |
| DATE_OBS | n/a | yyyy-mm-ddThh:mm:ss.mmmZ, date and time of observation CCSDS format |
| TELESCOP | SOHO | Observatory |
| INSTRUME | EIT | Instrument |
| INSTRUME | EIT | Detector |
| WAVELNTH | one of 171, 195, 284, 304 | Measurement |
| n/a | EIT | Obs-Ins-Det Nickname (see note 'a') |
| CRPIX1 | 512 | x position, Center of the sun in image pixels |
| CRPIX2 | 512 | y position, Center of the sun in image pixels |
| CDELT1 | 2.63 | x direction, arcseconds per pixel |
| CDELT2 | 2.63 | y direction, arcseconds per pixel |
| SOLAR_R | 369.88 | solar radius in image pixels |
For more details on EIT FITS keywords go to http://umbra.nascom.nasa.gov/eit/eit_guide/
| FITS | Default value | hv |
|---|---|---|
| NAXIS1 | 1024 | number of pixels in the x direction |
| NAXIS2 | 1024 | number of pixels in the y direction |
| DATE_OBS | n/a | yyyy-mm-dd |
| TIME_OBS | n/a | hh:mm:ss.mmm |
| TELESCOP | SOHO | Observatory |
| INSTRUME | LASCO | Instrument |
| DETECTOR | C2 | Detector |
| n/a | LASCO C2 | Obs-Ins-Det Nickname |
| FILTER + POLAR | Orange + Clear | Measurement |
| n/a | white light | Measurement Nickname |
| CRPIX1 | 512 | x position, Center of the sun in image pixels |
| CRPIX2 | 512 | y position, Center of the sun in image pixels |
| CDELT1 | 11.9 | x direction, arcseconds per pixel |
| CDELT2 | 11.9 | y direction, arcseconds per pixel |
| RSUN | 80.814221 | solar radius in image pixels |
For more details on LASCO C2 FITS keywords at http://lasco-www.nrl.navy.mil/keywords.html
| FITS | Default value | hv |
|---|---|---|
| NAXIS1 | 1024 | number of pixels in the x direction |
| NAXIS2 | 1024 | number of pixels in the y direction |
| DATE_OBS | n/a | yyyy-mm-dd |
| TIME_OBS | n/a | hh:mm:ss.mmm |
| TELESCOP | SOHO | Observatory |
| INSTRUME | LASCO | Instrument |
| DETECTOR | C3 | Detector |
| n/a | LASCO C3 | Obs-Ins-Det Nickname [a] |
| FILTER + POLAR | Clear + Clear | Measurement |
| n/a | white light | Measurement Nickname |
| CRPIX1 | 512 | x position, Center of the sun in image pixels |
| CRPIX2 | 512 | y position, Center of the sun in image pixels |
| CDELT1 | 56.0 | x direction, arcseconds per pixel |
| CDELT2 | 56.0 | y direction, arcseconds per pixel |
| RSUN | 17.173021 | solar radius in image pixels |
For more details on LASCO C3 FITS keywords go to http://lasco-www.nrl.navy.mil/keywords.html
| FITS | Default value | hv |
|---|---|---|
| NAXIS1 | 1024 | number of pixels in the x direction |
| NAXIS2 | 1024 | number of pixels in the y direction |
| DATE_OBS | n/a | yyyy-mm-ddThh:mm:ss.mmmZ, date and time of observation CCSDS format |
| TELESCOP | SOHO | Observatory |
| INSTRUME | MDI | Instrument |
| INSTRUME | MDI | Detector |
| n/a | MDI | Obs-Ins-Det Nickname |
| DPC_OBSR | n/a | Measurement |
| n/a | "magnetogram" or "continuum" | Measurement Nickname - if DPC_OBSR contains alternatively "Magnetogram" or "Continuum" |
| CRPIX1 | 512 | x position, Center of the sun in image pixels |
| CRPIX2 | 512 | y position, Center of the sun in image pixels |
| CDELT1 | 1.9840299 | x direction, arcseconds per pixel |
| CDELT2 | 1.9840299 | y direction, arcseconds per pixel |
| R_SUN | 488.48498 | solar radius in image pixels |
For more detail on MDI keywords go to http://soi.stanford.edu/sssc/doc/keywords.html
STEREO
| FITS | Default value | hv |
|---|---|---|
| NAXIS1 | 1024 | number of pixels in the x direction |
| NAXIS2 | 1024 | number of pixels in the y direction |
| DATE-OBS | n/a | yyyy-mm-ddThh:mm:ss.mmmZ, date and time of observation CCSDS format |
| OBSRVTRY | STEREO_A or STEREO_B | Observatory |
| n/a | SECCHI | Instrument |
| DETECTOR | EUVI | Detector |
| WAVELNTH | n/a | Measurement |
| n/a | EUVI-A or EUVI-B | Obs-Ins-Det Nickname |
| CRPIX1 | 1024 | x position, Center of the sun in image pixels |
| CRPIX2 | 1024 | y position, Center of the sun in image pixels |
| CDELT1 | n/a | x direction, arcseconds per pixel |
| CDELT2 | n/a | y direction, arcseconds per pixel |
| RSUN | n/a | solar radius in image pixels |
For more details on EUVI FITS keywords go to http://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf
| FITS | Default value | hv |
|---|---|---|
| NAXIS1 | 1024 | number of pixels in the x direction |
| NAXIS2 | 1024 | number of pixels in the y direction |
| DATE-OBS | n/a | yyyy-mm-ddThh:mm:ss.mmmZ, date and time of observation CCSDS format |
| OBSRVTRY | STEREO_A or STEREO_B | Observatory |
| n/a | SECCHI | Instrument |
| DETECTOR | COR1 or COR2 | Detector |
| WAVELNTH | n/a | Measurement |
| n/a | COR1-A or COR2-A COR1-B or COR2-B | Obs-Ins-Det Nickname (note the dependence on OBSRVTRY |
| CRPIX1 | 1024 | x position, Center of the sun in image pixels |
| CRPIX2 | 1024 | y position, Center of the sun in image pixels |
| CDELT1 | n/a | x direction, arcseconds per pixel |
| CDELT2 | n/a | y direction, arcseconds per pixel |
| RSUN | n/a | solar radius in image pixels |
For more details on COR1/COR2 FITS keywords go to http://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf
Notes
(a): Obs-Ins-Det Nickname refers to what a solar physicist commonly calls the particular experimental apparatus that we have classified via its parent Observatory, parent Instrument and Detector. It's the common name used in conversation. The nickname should probably be the name used in the user interfaces of HV and JHV.
(b): Measurement Nickname refers to what a solar physicist commonly calls a well-known type of measurement made by a given Observatory-Instrument-Detector apparatus. The nickname should be used where it is indicated.
(c): NAN means "not a number".
Where to place a JP2 file given the positioning information above
- Radius of the Sun in metres: r0= 695500000
- Meters per pixel: k = r0/(solar radius in image pixels)
- If we assume the center of the Sun is (0,0), then the bottom left hand corner in metres is k*(-CRPIX1, -CRPIX2).
- Offset between Sun center and image center in metres is k*( CRPIX1-NAXIS1/2, CRPIX2-NAXIS2/2 )
- More detailed information on solar co-ordinates and pointing on the solar disk can be found at http://gong.nso.edu/data/DMAC_documentation/Vmbical/Solar_coord_defined.html
