Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ftp/software/tables/testdata/restore/sims/pn/README Дата изменения: Wed Jul 21 18:32:51 1993 Дата индексирования: Mon Dec 24 00:57:51 2007 Кодировка: Поисковые слова: aurora

[Note: This data set was updated on Wed 21 July 1993 at 10:28 am, EDT.
Previous versions of the data set should be ignored.]

Planetary nebula data is for object Sp1 (see Bond and Livio 1990, ApJ 355, 568).
Original data is from CTIO with RCA CCD, gain = 8.3 e-/DN, read-noise = 52 e-.
The original data frame is `sp1'.

Image `pn' is 256x256 image subset centered on the PN central star. A mean
background level of 15 DN has been subtracted, and CR's have been removed
using two passes of the cosmicray task in noao.imred.ccdred.

Image `psf' is a PSF for the original CCD data, extracted from the original
frame (bright star at upper left).

Image `f656n' is an HST PC PSF for the N656N filter (H-alpha). `f656n_ss3'
is another PSF, but subsampled by a factor of 3 (to make diffraction rings
of similar radius to ring of PN).

Since the seeing in the original data is rather poor (with off-center peaks in
stellar images), a lucy restoration has been run using the extracted psf, and
this forms the basis of subsequent tests. The "truth image" is `pn_true_ss3'
(at full resolution) and `pn_true' (block summed by 3 in x and y to correspond
to the PC PSF without subsampling).

The truth image is convolved with the subsampled PSF to form `pn_pc6_ss3'.
This image is block-summed by 3 in x and y to yield `pn_pc6'. Noise is added
to `pn_pc6' to produce the final test image, `pn_pc6n'. Noise parameters are
7.5 e-/DN and read-out noise 13 e-, with Poisson noise also.

A Lucy restoration has been done using the STSDAS `lucy' task (100 iterations)
to yield image `pn_pc6l'.

All files are in FITS format (16-bit integers) and have the extension "fit".

Summary:
-------
standard resolution 3x3 subsampling
------------------- ---------------
original data sp1
preprocessed data pn
ground-based PSF psf
PC PSF, F656N (H-alpha) f656n f656n_ss3
PC truth image pn_true pn_true_ss3
PC truth conv. w/PSF pn_pc6 pn_pc6_ss3
PC simulation pn_pc6n
PC restoration pn_pc6l

PN.tar.Z All of the above files in compressed tar format.