BayTech PS-4A Guía para resolver problemas descargar pdf (Pagina 14)

detail the use of both here.

The flmntools tasks fwcheck and fwscan take differences of images, and then run SExtractor on

the central 1250 × 1250 pixel region to determine the average FWHM; sources brighter than 10,000

ADU in the difference image are ignored and objects with FWHM < 1.3 pixels are rejected as cosmic ray

hits. To use these, first enter the flmntools package to get the following prompt:

cl> flmn

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Welcome to FLMNTOOLS - The FLAMINGOS Observing Tools

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Tasks included are:

fwcheck - Quickly check the fwhm and display the difference image

fwscan - Compute the fwhm for each frame in a set of observations

fwcheck fwscan

fl>

This package is used at more than one telescope, so on the off-chance that the parameters have been

unlearned, verify the telescope field is set to Mayall (the 4-m):

fl> epar fwscan

PACKAGE = flmntools

TASK = fwscan

root = ugc3371.j Root infile name?

First = 21 First image in set?

Last = 25 Last image in set?

(telesco= Mayall) Telescope(MMT,Mayall,KPNO2.1m)?

(mode = q)

fwscan takes a range of images as inputs, in the form

fwscan <image root name> <First image number> <Last image number>

It computes running difference images from which it computes the FWHM. You can use this to monitor

the seeing during a sequence of observations. To use this for focus runs, e.g.

4mguest@flmn-4m-1a{1} singleimage.pl

4mguest@flmn-4m-1a{2} relative.offset.kpno.pl 10 0

Ask the operator to increment the focus (e.g 50 – 100 units).

Repeat these three steps as necessary, offsetting the telescope back and forth between each image.

Once you've taken 2 or more images epar fwscan to make certain it is setup for the 4-m, then run

fwscan. Here's some sample output:

fl> fwscan p182e.j 1 9

#Main Bkgd 1st

#Frame Frame Average Median Quartile #stars

1 2 0.85'' 0.83'' 0.81'' 51

2 1 0.89'' 0.88'' 0.85'' 49

FLAMINGOS@4-m, Ver. 2.34, 2006 Apr 04 Page 14 of 44

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BayTech PS-4A Guía para resolver problemas Pagina 14