| |
 |
| Paper: |
Calibration of SOT Dopplergrams |
| Volume: |
369, New Solar Physics with Solar-B Mission |
| Page: |
43 |
| Authors: |
Katsukawa, Y.; Ichimoto, K.; Sekii, T.; Suematsu, Y.; Tsuneta, S.; Shine, R.A.; Tarbell, T.D. |
| Abstract: |
Narrow-band Filter Imager on SOT provides Dopplergrams (DGs) which are images of Doppler (line- of-sight) velocities. Observations with DGs are critically important in studies of photospheric dynamics and helioseismology. The primary photospheric line used for DGs is Fe I 5576 Å which is a line insensitive to Zeeman effect. We made a calibration function for the 5576 Å DGs to get actual Doppler velocities from velocity indexes using an atlas spectrum and simulated transmission profiles for the tunable filter (TF) on SOT. Using data sets taken in the natural sun-light test, we quantitatively evaluated accuracy of the DGs by comparing the rotational speed of the Sun measured with DGs with the expected one. There was a little systematic error in the velocity obtained by SOT, but the error was less than 20 % of the predicted velocities. |
|
|
|
|
|
