Anyone think they know what the tilt of the EIS slit is?

Ken Dere

--129.174.112.201, 25-Apr-2007

And how linear is it (and where, if at all)?

--David R Williams, 03-May-2007

The slit tilt is not fully understood and some further calibration studies need to be run. Preliminary work has been done, so for example Peter Young has produced a short document on this. TiltFiles

--Louise Harra, 14-May-2007

I find the tilt of the SW slit to be 1.6 x 10^-6 Angstroms / pixel

Peters number correspond to a value of 1.2 x 10^-6 Angstroms / pixel

--Ken Dere, 15-May-2007

I've made another attempt at measuring the slit tilt. For the SW band I get a number close to Peter's value. I've written a routine called eis_slit_tilt that calculates the offset as a function of position along the slit. I'm sending the routine to be included in SSW. Some details on my calculations are given in the attached pdf. There is still a lot of scatter in the data and more analysis is needed. TiltFiles

--Harry Warren, 06-JUL-2007

The slit tilt is different for the 2" slit. Maria Madjarska has measured a tilt of 1.14 x 10^-4 Angstroms/pixel for the SW band. Further work should be performed to check this value.

--Peter Young, 10-AUG-2007

Harry also has a routine which is preliminary called eis_wave_corr - this corrects for the tilt for the 1" slit and the orbital variation.

I've measured the tilt for the 2 arcsec slit for the SW band. I used a quiet Sun raster made on 20th April 2007. This raster uses the full 512 arcsec slit height and is 120 arcseconds in the x-direction. I measure a tilt of 1.12 x 10^-4 Angstroms/pixel. This seems to be in reasonably good agreement with the value determined by Maria Madjarska of 1.14 x10^-4 Angstroms/pixel, although I do not know which raster(s) Maria used.

--Gemma Attrill, 05-Oct-2007