sukye

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IOError: [Errno 28] No space left on device

ValueError: 21142170 requested and 8516880 written

multidrizzle and tweakshifts

0. help twe
Tweakshifts provides an automated interface for computing residual
shifts between input exposures being combined using MultiDrizzle or
PyDrizzle. The shifts computed by Tweakshifts correspond to
pointing differences after applying the WCS information from the
input image’s headers. Such errors would, for example, be due to
errors in guide-star positions when combining observations from
different observing visits or from slight offsets introduced upon
re-acquiring the guide stars in a slightly different position.

This task was written using Python and relies on the Python
interface to the IRAF environment, PyRAF, for its operation. As a
result, this task can only be run under PyRAF.

The primary implementation of ‘tweakshifts’ involves using existing
IRAF tasks such as DAOFIND, GEOMAP, and CROSSDRIZ to compute the
shifts. Tweakshifts automates the operation of these tasks to
produce a shiftfile and reference WCS file which can serve as input
to MultiDrizzle. The shiftfile will contain the residual shifts
for each input image, while the reference WCS file consists of a
FITS header with all the WCS keywords appropriate for the reference
image without any image data. The reference WCS will then be used
by MultiDrizzle to properly interpret the shifts from the shiftfile
for the final alignment of the images.

Tweakshifts supports multiple methods for determining the residual
shifts between images: primarily, catalog matching and
cross-correlation. Each mode of operation has its own requirements
for input file formats in order to properly compute the shifts
between the images.

1. http://forums.stsci.edu/phpbb/viewtopic.php?p=172

I have a slightly different approach to registering images than the above, utilizing tweakshifts. I also have MultiDrizzle generate the *single_sci.fits files (distortion-corrected, and in the final output space), and measure shifts using them. These files are generated by the first drizzle step in MultiDrizzle (can turn off all subsequent steps, since we are just generating input for tweakshifts).

Now, tweakshifts only works for data which are already reasonably well-registered (small rotation angles, and within 1 pixel of each other). This is generally true for data taken within the same visit, or otherwise with the same guide stars. But I am often combining data from different visits, and/or mosaic data where there are small overlaps between some frames (not many stars to use for registration).

So I first measure (with imexam and possibly geomap) crude shifts and rotations using just 3-5 stars, get them into a shiftfile, and apply them to generate the single_sci above. Then my single_sci images are ready for tweakshifts, where every available star (possibly hundreds) can be used to refine the shifts. I run tweakshifts with the following parameters:

tweakshifts.input = ‘@list_single_i’
tweakshifts.shiftfile = ‘’
tweakshifts.reference = ‘m82_i_21_wcs.fits’
tweakshifts.output = ‘m82_i_shifts.txt’
tweakshifts.findmode = ‘catalog’
tweakshifts.gencatalog = ‘daofind’
tweakshifts.sextractpars = ‘’
tweakshifts.undistort = no
tweakshifts.computesig = no
tweakshifts.idckey = ‘idctab’
tweakshifts.clean = no
tweakshifts.verbose = no
tweakshifts.catfile = ‘’
tweakshifts.xcol = 1
tweakshifts.ycol = 2
tweakshifts.fluxcol = 3
tweakshifts.fluxmax = INDEF
tweakshifts.fluxmin = INDEF
tweakshifts.fluxunits = ‘counts’
tweakshifts.nbright = INDEF
tweakshifts.refcat = ‘’
tweakshifts.refxcol = 1
tweakshifts.refycol = 2
tweakshifts.rfluxcol = 3
tweakshifts.rfluxmax = INDEF
tweakshifts.rfluxmin = INDEF
tweakshifts.rfluxunits = ‘cps’
tweakshifts.refnbright = INDEF
tweakshifts.minobj = 5
tweakshifts.nmatch = 30
tweakshifts.matching = ‘tolerance’
tweakshifts.tolerance = 0.7
tweakshifts.fwhmpsf = 2.5
tweakshifts.sigma = 0.1
tweakshifts.datamin = INDEF
tweakshifts.datamax = INDEF
tweakshifts.threshold = 6.0
tweakshifts.nsigma = 1.0
tweakshifts.fitgeometry = ’shift’
tweakshifts.function = ‘polynomial’
tweakshifts.maxiter = 5
tweakshifts.reject = 3.0
tweakshifts.crossref = ‘’
tweakshifts.margin = 50
tweakshifts.tapersz = 50
tweakshifts.pad = no
tweakshifts.fwhm = 7.0
tweakshifts.ellip = 0.05
tweakshifts.pa = 45.0
tweakshifts.fitbox = 7
tweakshifts.mode = ‘al’

The first image in the input list above (list_single_i) becomes the reference image, and tweakshifts automatically generates the reference WCS file from it (m82_i_21_wcs.fits). I often change the natural sequence of the listed files, to make a particular frame the reference image (e.g. a central frame, rather than a corner frame).

Note that the shiftfile tweakshifts generates is really a delta-delta shiftfile, i.e. it must be summed with the original crude shiftfile to get the shifts you want to provide for the final MultiDrizzle combination.

Also, since we gave single_sci files as input, the shiftfile that tweakshifts generates will list those single_sci files. But the shiftfile we give to MultiDrizzle must list the original flt images, so either edit the shiftfile, or sum the delta-delta values into your first shiftfile, which already lists the flt images.

I then repeat the process above, generating new single_sci using the refined shifts, and running tweakshifts again, to verify only small residual shifts are left (less than 0.1 WFC pixel or 5 mas). Then I’m ready to use my shiftfile to combine the dataset with MultiDrizzle.
_________________
Max

sukye: i dont know why it does not work for me but
tweakshifts try4_asn.fits undistort=yes mode=h
gives me shifts.txt as the shiftfile for multidrizzle

———————-
‘undistort=yes’ when and only when an *asn.fits file and the associated *flt.fits files as input.
‘undistort=no’ when *single_sci.fits files are provided directly as input.
———————-
Warren

2.
www.stsci.edu/hst/HST_overview/documents/ calworkshop/workshop2005/papers/koekemoer-multidrizzle.pdf

unix

cp file /data/…

copy

cd ..

up

ls ../data

list other directory

cp ../data/file .

copy from other directory

ls -al

more info

tar cvf data.tar *

package

gzip data.tar

zip

Tab

hint

Ctrl+k

delete following

sftp concorde.pha.jhu.edu
put file
get file

trans files

rm directory -r

delete directory

df

space usage

mkdir

new directory

oowriter

openoffice

!scp -r udf3.stsci.edu:/data/raid4/Jian/sextractor/ /belfast/sc1/sex/

pyraf

http://stsdas.stsci.edu/cgi-bin/gethelp.cgi

0. epar mul
workinplace no
updatewcs no
clean yes/no

1. imcopy
imcopy 020921_drz.fits[1][2785:4385,2122:3722] svea.fits

2. imexam
a
r
e
output=si2.fits
t
gawk ‘{if (NF==4){print $1,$2;}}’ tt.txt

3. qphot
annulus 7.0
dannulus 2.0
apertures 5.0

4. ds9 &
file->display fits header
scale->zscale
zoom->zoom to fit frame

5. starview/HSTsearch
searches->hst->general search
//instrument acs
radius 0.03
//config acs/wfc
apertures wfcenter
filters/gratings f850lp*
best reference files+flt

6.
hedit “*flt.fits[1]” targname .

v-dropouts

myb=SB_ACS_D10Z_ASCII
myi=SI_ACS_D10Z_ASCII
myv=SV_ACS_D10Z_ASCII
myz=SZ_ACS_D10Z_ASCII

radb=myb.field024
radi=myi.field024
radv=myv.field024
radz=myz.field024

clsz=myz.field028
clsv=myv.field028
clsi=myi.field028
clsb=myb.field028

flagz=myz.field030
flagv=myv.field030
flagi=myi.field030
flagb=myb.field030

b=myb.field042
i=myi.field042
v=myv.field042
z=myz.field042

sz=myz.field036
sv=myv.field036
si=myi.field036
sb=myb.field036

nb=myb.field037
ni=myi.field037
nv=myv.field037
nz=myz.field037

.run
openw,lun,’s_v_drop.txt’,/get_lun,width=105
For j=0u,33954u Do Begin
if (v[j]-i[j] gt 2.0 or v[j]-i[j]-0.890*(i[j]-z[j]) gt 1.470) $
and v[j]-i[j] gt 1.20 and i[j]-z[j] lt 1.30 $
and si[j]/ni[j] gt 5.0 and sb[j]/nb[j] lt 3.0 $
and (sb[j]/nb[j] lt 3.0 or b[j]-i[j]-v[j]+i[j] gt 1.0) $
and radi[j] lt 3.40 $
and flagi[j] le 8.0 $
and clsi[j] ge 0.90 $
and i[j] le 26.5 $
then printf,lun,myi.field001[j],myi.field004[j],myi.field005[j],myi.field006[j],myi.field034[j],myv.field034[j],myi.field042[j],j
Endfor
free_lun, lun
End