3.1. Example 1 - Datasets descriptions

3.1.1. Star field with dithers

This is a GMOS-N imaging observation of a field of stars with dithers obtained in the i-band.

The calibratons we use in this example are:

  • BPM. The bad pixel masks are now found in the Gemini Science Archive instead of being packaged with the software. They are associated like the other calibrations. Here we need the 2x2 binning GMOS-N Hamamatsu BPM valid for data taken in 2017. (The date in the name is the “valid from” date.)

  • Biases for the science frames and the twilight flats. Note that the twilight flats were obtained just the day after the science observations. We can use the same master bias. If the twilights had been taken several days before or after the science observations, it would be preferable to use biases contemporary to the twilights.

  • Twilight flats.


The Bad Pixel Masks (BPMs) are now found in the archive rather than packaged with the software. You must get the static BPM from the archive. See Getting Bad Pixel Masks from the archive in Tips and Tricks.


10 s, i-band



Twilight Flats

40 to 16 s, i-band