Python examples

Explore signal and saturation

The complete source is included below.

python -m nextastro_obs_client.examples.exposure_ladder --ra 12.5 --dec -30 --target "Student field" --filter V --seconds 1 2 5 10 --saturation 50000

Writes exposure_ladder.csv with requested/actual seconds, mean, median, population standard deviation and optional saturated-pixel counts. Statistics explicitly read raw images in student Python. The supplied saturation value is a student-chosen diagnostic, not a quality cutoff. Sky variation, stars and offsets can affect the response.

Student extension: Measure a fixed region, subtract a bias level and fit count rate against actual exposure.

Python source

"""Measure the signal response across explicitly chosen exposures."""
from nextastro_obs_client.examples._common import parser, target_arguments, point, execute, write_rows


def run(obs, camera, args):
    point(obs, args)
    rows = []
    for seconds in args.seconds:
        for image in camera.expose(seconds=seconds, filter=args.filter, target_name=args.target):
            stats = image.statistics(saturation=args.saturation)
            rows.append(dict(requested_seconds=seconds, actual_seconds=image.seconds, mean=stats.mean,
                median=stats.median, stddev=stats.stddev, saturated_pixels=stats.saturated_pixels, path=str(image.path)))
        write_rows(args.output, rows)
    return rows


def main(argv=None):
    p = parser("Exposure ladder")
    target_arguments(p)
    p.add_argument("--seconds", type=float, nargs="+", required=True)
    p.add_argument("--saturation", type=float, default=None, help="Optional diagnostic threshold in raw ADU")
    p.add_argument("--output", default="exposure_ladder.csv")
    return execute(p, run, argv)


if __name__ == "__main__":
    main()

Shared argument and session helpers: Example support code.