Pipeline Questions

From Tauwiki

[edit] Coordinate Issues

The RA and Dec are rounded off to 1 decimal place in the telemetry in create_level0_data. Is this what will really happen?

I know that the coordinates are only good to 0.1° but how many decimal places are given. Also note that a precision of 0.1° at the pole can translate into a huge uncertainty in the RA.

Will there be jitter in the coordinates?

[edit] W,S,Z data

-Suggested by Elhanan

It turns out that there is no escape from defining a separate magnification for X and Y in the image, in contrast to what I wrote earlier. After computing the initial x and y from the W, S and Z values (x = 2048 * W/(W+S+Z) and the same for y) one uses magnification and shift to get the correct values (not including distortion).

X= x*xscale - xshift

Y= y*yscale - yshift

[edit] Order of distortion and flat-field

-Suggested by Elhanan

In the pipeline, the distortion should come before the flat-fielding. The flat field data will be distortion-corrected a-priori, so data will be treated in the right way.