PRO DOL_TEMPLATE

 
; NAME:
;       DOL_template
;
; PURPOSE: 
;       Provide a simple starting point for running an IDL
;       procedure to solve the Problem set 1 of the course 'Detection
;       of Light'.  In addition it provides important information and
;       lists the most relevant procedures and functions that may be
;       helpful.
;
; CALLING SEQUENCE:
;       no calling sequence - this is a self standing procedure to be 
;       compiled (.run DOL_template) and run.
;
; MODIFICATION HISTORY:
;       WRITTEN BY BERNHARD BRANDL 20/10/2007
;
; ----------------------------------------------------------

; ****************** NOTE **********************
; IDL indices always start counting at zero
; an array of 128 pixels has indices from 0 - 127
; ***********************************************
 
; =========== SPECIFICALLY USEFUL IDL PROCEDURES ================
;             (in alphabetical order)
; ---------
; FLTARR
; The FLTARR function returns a single-precision, floating-point vector array.
; Example:  im = FLTARR(128,128)  creates a 128x128 array
; Example:  im = FLTARR(128,128,3)  creates a 128x128x3 cube
; ---------
; FOR-loop  [FOR ... DO BEGIN ... ENDFOR]
; Simple way to reformat arrays (although not very elegant)
; Example:  we reformat a square 10x10 pixel array into a string of 100x1
; pixels
;       FOR j=0,9 DO BEGIN
;           FOR i=0,9 DO BEGIN
;		imlong[i+j*10]= imsquare[i,j]
;	    ENDFOR
;       ENDFOR
; ---------
; INDGEN
; returns an integer array with the specified dimensions.
; Example:  vec = INDGEN(5) returns [0,1,2,3,4]
; ---------
; MEDARR
; This is a very useful procedure from the ASTROLIB
; It can be used to calculate the median across a set of image planes
; Calling sequence:  MEDARR, im_in, im_out
; where im_in is a data cube of x*y*n with n>1, 
; and im_out is the median computed, flattened image of size x*y
; ---------
; MEDIAN 
; returns the median value of an array 
; Example: x = MEDIAN(im[*,5]) computes the median of all pixel values
; of array im along the 5th column
; ---------
; PRINT
; prints output to the standard output device
; Example: PRINT, 'The median value is:', x
; ---------
; SHIFT
; shifts elements of vectors or arrays along any dimension by any
; number of elements. 
; Example: imshifted = SHIFT(im,50,-10)  shifts array `im' 
; by +50 pixels in x and by -10 pixels in y
; ---------
; TOTAL
; returns the sum of the elements of an array.
; Example: x = TOTAL(INDGEN(5)) sums up the vector [0,1,2,3,4] = 10
; Example: im = TOTAL(imcube,3) adds up all images in a cube together
; --------- 
; WRITEFITS
; another useful ASTROLIB procedure that writes an array in FITS
; format to disk
; Example:  WRITEFITS, 'im_out.fits', im
; -------------------------------------------------------------- 





; ============ START YOUR COMPUTATIONS HERE =====================

;  **********************************************************
;  Problem set 1:  Jailbar images
;  **********************************************************

im1 = READFITS('image1.fits')



;  -----------------------------------------------------------
;  Answer 1a)	I must subtract ???, ???, ???, and ???
;  		counts from channels 1 through 4, respectively
;  -----------------------------------------------------------


;  ---------------------------------------------------------------
;  Answer 1b)	Provide the FITS file of the adjusted image
;  		There is a faint source near pixel position [??,??]
;  ---------------------------------------------------------------




;  **********************************************************
;  Problem set 2:  50Hz humming
;  **********************************************************

im2 = READFITS('image2.fits')





;  ---------------------------------------------------------------
;  Answer 2)    Provide the FITS file of the 50 Hz free image
;               There is a faint source near pixel position [??,??]
;  ---------------------------------------------------------------






;  **********************************************************
;  Problem set 3:  Series of Observations in Space
;  **********************************************************
;
;  IMPORTANT NOTE:  In the following reduction it is strongly recommended 
;                   to write out the intermediate data products and check 
;                   the result to see if it worked.
;
;  Read the set of 3 x 5 data cubes
im3a = READFITS('image3a.fits')
im3b = READFITS('image3b.fits')
im3c = READFITS('image3c.fits')


;  ---------------------------------------------------------------
;  Answer 3a)	There are two dominant components:
;		(i)  ???
;		(ii) ???
;		Is the faint galaxy visible?
;  ---------------------------------------------------------------




;  ---------------------------------------------------------------
;  Answer 3b)  Provide the FITS file of the filtered "sky"
;  ---------------------------------------------------------------





;  ---------------------------------------------------------------
;  Answer 3c)  Provide the FITS file of the final image
;              The faint sooure is approximately at position [??,??]
;  ---------------------------------------------------------------




RETURN
END