NAME

wairmass -- Compute weighted airmass

USAGE

wairmas input

PARAMETERS

input

The name of the images to process. Any image template, image lists, including @ lists, may be used. may be used.

update = no

Update the airmass in the header ?. If set to yes the computed value of the airmass will replace the old one in the header. Otherwise it just will print the computed values, leaving the image untouched.

verify = yes

Verify the update operation ?. If set to yes the user is quieried before each update operation.

latitude = ).observatory.latitude

Observatory latitude in degrees.

DESCRIPTION

A weighted airmass value is computed for all images in the list and printed on the standard output. If update=yes the old value of the airmass in the header is replaced with the new computed value, or added if there is no value already. If verify=yes the user is quieried to whether perform the update operation or not. The user may answer yes , no , YES , and NO . The lowercase answers apply to the current image whereas the uppercase answers apply to all remaining images. The weighted value is computed by dividing the exposure time in intervals of five minutes and evaluating the airmass for each interval. The weigted value is determined by averaging all the partial values. If the dark time is different from the exposure time, the image is skipped with a warning message. The same applies for images with incomplete data for evaluating the airmass.

EXAMPLES

First list the airmass values in all the image headers and the computed airmass values, but do not update the image headers:

lo> wairmass *.imh update-
obj014.0001.imh: 1.40200 -> 1.40326
obj015.0001.imh: 1.40600 -> 1.40656
obj016.0001.imh: 1.40700 -> 1.40820
obj024.0001.imh: 1.20900 -> 1.21161
obj025.0001.imh: 1.21000 -> 1.21277
obj026.0001.imh: 1.21000 -> 1.21320
obj027.0001.imh: 1.21400 -> 1.21649
obj028.0001.imh: 1.21400 -> 1.21698
obj029.0001.imh: 1.21500 -> 1.21747

Now update the airmass values in the image headrs with the computed values. Verify the update operation only for the first three images and then proceed automaticaly:

lo> wairmass *.imh update+ verify+
obj014.0001.imh: 1.40200 -> 1.40326, update ? (yes):
obj015.0001.imh: 1.40600-> 1.40656, update ? (yes):
obj016.0001.imh: 1.40700 -> 1.40820, update ? (yes): YES  <- NO MORE !!
obj024.0001.imh: 1.20900 -> 1.21161, updated
obj025.0001.imh: 1.21000 -> 1.21277, updated
obj026.0001.imh: 1.21000 -> 1.21320, updated
obj027.0001.imh: 1.21400 -> 1.21649, updated
obj028.0001.imh: 1.21400 -> 1.21698, updated
obj029.0001.imh: 1.21500 -> 1.21747, updated

SEE ALSO

imred.observatory