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Bug about dual image mode?

September 17, 2017, 3:30 am
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Dear All,

I met a problem with sextractor dual image mode.
I tried to use sextractor with dual image mode and single image mode to do photometry to same image:

sex -c default.sex a.fits -WEIGHT_IMAGE a.weight.fits -PARAMETERS_NAME dual.param

sex -c default.sex a.fits,a.fits -WEIGHT_IMAGE a.weight.fits,a.weight.fits -PARAMETERS_NAME dual.param

Theoretically speaking, I should get same results for same sources.
However, they are different. Sad
The SNR of the source in dual image mode is much lower than that in single image mode.
Is any one know what happened to my image? Bug?
Any help would be appreciated!

Here is the default.sex:
# Default configuration file for SExtractor 2.19.5
# EB 2016-04-12
#

#-------------------------------- Catalog ------------------------------------

CATALOG_NAME test.cat # name of the output catalog
CATALOG_TYPE ASCII_HEAD # NONE,ASCII,ASCII_HEAD, ASCII_SKYCAT,
# ASCII_VOTABLE, FITS_1.0 or FITS_LDAC
PARAMETERS_NAME default.param # name of the file containing catalog contents

#------------------------------- Extraction ----------------------------------

DETECT_TYPE CCD # CCD (linear) or PHOTO (with gamma correction)
DETECT_MINAREA 4 # min. # of pixels above threshold
DETECT_MAXAREA 0 # max. # of pixels above threshold (0=unlimited)
THRESH_TYPE RELATIVE # threshold type: RELATIVE (in sigmas)
# or ABSOLUTE (in ADUs)
DETECT_THRESH 1.2 # <sigmas> or <threshold>,<ZP> in mag.arcsec-2
ANALYSIS_THRESH 1.2 # <sigmas> or <threshold>,<ZP> in mag.arcsec-2

FILTER Y # apply filter for detection (Y or N)?
FILTER_NAME gauss_4.0_7x7.conv # name of the file containing the filter
FILTER_THRESH # Threshold[s] for retina filtering

DEBLEND_NTHRESH 32 # Number of deblending sub-thresholds
DEBLEND_MINCONT 0.005 # Minimum contrast parameter for deblending

CLEAN Y # Clean spurious detections? (Y or N)?
CLEAN_PARAM 1.0 # Cleaning efficiency

MASK_TYPE CORRECT # type of detection MASKing: can be one of
# NONE, BLANK or CORRECT

#-------------------------------- WEIGHTing ----------------------------------

WEIGHT_TYPE MAP_WEIGHT # type of WEIGHTing: NONE, BACKGROUND,
# MAP_RMS, MAP_VAR or MAP_WEIGHT
RESCALE_WEIGHTS Y # Rescale input weights/variances (Y/N)?
WEIGHT_IMAGE weight.fits # weight-map filename
WEIGHT_GAIN N # modulate gain (E/ADU) with weights? (Y/N)
WEIGHT_THRESH # weight threshold[s] for bad pixels

#-------------------------------- FLAGging -----------------------------------

FLAG_IMAGE flag.fits # filename for an input FLAG-image
FLAG_TYPE OR # flag pixel combination: OR, AND, MIN, MAX
# or MOST

#------------------------------ Photometry -----------------------------------

PHOT_APERTURES 7.5,5 # MAG_APER aperture diameter(s) in pixels
PHOT_AUTOPARAMS 2.5, 3.5 # MAG_AUTO parameters: <Kron_fact>,<min_radius>
PHOT_PETROPARAMS 2.0, 3.5 # MAG_PETRO parameters: <Petrosian_fact>,
# <min_radius>
PHOT_AUTOAPERS 0.0,0.0 # <estimation>,<measurement> minimum apertures
# for MAG_AUTO and MAG_PETRO
PHOT_FLUXFRAC 0.5 # flux fraction[s] used for FLUX_RADIUS

SATUR_LEVEL 50000.0 # level (in ADUs) at which arises saturation
SATUR_KEY SATURATE # keyword for saturation level (in ADUs)

MAG_ZEROPOINT 0.0 # magnitude zero-point
GAIN_KEY GAIN # keyword for detector gain in e-/ADU
PIXEL_SCALE 1.0 # size of pixel in arcsec (0=use FITS WCS info)

#------------------------- Star/Galaxy Separation ----------------------------

SEEING_FWHM 1.2 # stellar FWHM in arcsec
STARNNW_NAME default.nnw # Neural-Network_Weight table filename

#------------------------------ Background -----------------------------------

BACK_TYPE AUTO # AUTO or MANUAL
BACK_VALUE 0.0 # Default background value in MANUAL mode
BACK_SIZE 128 # Background mesh: <size> or <width>,<height>
BACK_FILTERSIZE 3 # Background filter: <size> or <width>,<height>

BACKPHOTO_TYPE LOCAL # can be GLOBAL or LOCAL
BACKPHOTO_THICK 24 # thickness of the background LOCAL annulus
BACK_FILTTHRESH 0.0 # Threshold above which the background-
# map filter operates

#------------------------------ Check Image ----------------------------------

CHECKIMAGE_TYPE NONE # can be NONE, BACKGROUND, BACKGROUND_RMS,
# MINIBACKGROUND, MINIBACK_RMS, -BACKGROUND,
# FILTERED, OBJECTS, -OBJECTS, SEGMENTATION,
# or APERTURES
CHECKIMAGE_NAME check.fits # Filename for the check-image

#--------------------- Memory (change with caution!) -------------------------

MEMORY_OBJSTACK 3000 # number of objects in stack
MEMORY_PIXSTACK 300000 # number of pixels in stack
MEMORY_BUFSIZE 1024 # number of lines in buffer

#------------------------------- ASSOCiation ---------------------------------

ASSOC_NAME sky.list # name of the ASCII file to ASSOCiate
ASSOC_DATA 2,3,4 # columns of the data to replicate (0=all)
ASSOC_PARAMS 2,3,4 # columns of xpos,ypos[,mag]
ASSOCCOORD_TYPE PIXEL # ASSOC coordinates: PIXEL or WORLD
ASSOC_RADIUS 2.0 # cross-matching radius (pixels)
ASSOC_TYPE NEAREST # ASSOCiation method: FIRST, NEAREST, MEAN,
# MAG_MEAN, SUM, MAG_SUM, MIN or MAX
ASSOCSELEC_TYPE MATCHED # ASSOC selection type: ALL, MATCHED or -MATCHED

#----------------------------- Miscellaneous ---------------------------------

VERBOSE_TYPE NORMAL # can be QUIET, NORMAL or FULL
HEADER_SUFFIX .head # Filename extension for additional headers
WRITE_XML N # Write XML file (Y/N)?
XML_NAME sex.xml # Filename for XML output
XSL_URL file:///usr/local/share/sextractor/sextractor.xsl
# Filename for XSL style-sheet
NTHREADS 1 # 1 single thread

FITS_UNSIGNED N # Treat FITS integer values as unsigned (Y/N)?
INTERP_MAXXLAG 16 # Max. lag along X for 0-weight interpolation
INTERP_MAXYLAG 16 # Max. lag along Y for 0-weight interpolation
INTERP_TYPE ALL # Interpolation type: NONE, VAR_ONLY or ALL

#--------------------------- Experimental Stuff -----------------------------

PSF_NAME default.psf # File containing the PSF model
PSF_NMAX 1 # Max.number of PSFs fitted simultaneously
PATTERN_TYPE RINGS-HARMONIC # can RINGS-QUADPOLE, RINGS-OCTOPOLE,
# RINGS-HARMONICS or GAUSS-LAGUERRE
SOM_NAME default.som # File containing Self-Organizing Map weights
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All AstrOmatic tools in OS Ubuntu Astronomy 16.04 (64-bit)

September 25, 2017, 3:47 pm
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astrometric uncertainties

October 25, 2017, 1:10 pm
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Hello,

Some explanation is likely warranted.

The observational minor planet community uses diverse tools to acquire astrometry on asteroids and comets. The Catalina Sky Survey (CSS) (https://catalina.lpl.arizona.edu) uses SExtractor to detect and centroid known and unknown (candidate) solar system objects against the background stars, and SCAMP to match against astrometric and photometric catalog(s). A variety of other tools completes the workflow to recognize motion against the stars and determine rates and angles.

Astrometry is submitted to a central clearing house, the Minor Planet Center at the Smithsonian Astrophysical Observatory. For several decades the astrometric format has been quite terse, containing not much more than RA, Dec, a UTC timestamp, and the magnitude and bandpass. The community is transitioning to a much richer format (http://www.minorplanetcenter.net/iau/info/ADES.html) which, in particular, includes positional uncertainties and cross-terms.

The CSS workflow runs SCAMP after SExtractor to attach WCS keywords to about a thousand images per night from each telescope. As a separate step, we currently extract our candidate moving object detections from the original per-pixel SExtractor lists cross-matched between four-exposure fields looking for linear motion. Final validation is done by human eye after highly tuned scoring is applied.

We have evaluated running SExtractor a second time after SCAMP to pick up on the various "world" columns, but the logistics of handling the arbitrarily interleaved fields from our queue manager makes it undesirable to have to wait until each 4 frame stack completes. The pixel coordinates for each candidate detection are converted to sky coordinates directly from the FITS WCS using WCSTOOLS.

The difficulty is in how to combine the per-pixel centroiding uncertainties and cross-terms from SExtractor with sky-fitting uncertainties from the SCAMP solution. And honestly I don't understand from the SCAMP manual how fit uncertainties are meant to be applied from catalog stars onto non-catalog sources even if done in world coordinates. If it matters we recently transitioned from UCAC4 to the Gaia DR1 catalogs.

Perhaps it's best to leave it here to start. I can answer any questions, and maybe I'll have more pointed questions of my own when I grok the zen of SCAMP a bit better. I should say that we also use SWARP to build deep images, but these are not used in the astrometric workflow per se, which relies solely on solving many hundreds of single epoch images to find the moving dots.

Many thanks for any illumination or suggestions!

Rob Seaman
Catalina Sky Survey
Lunar and Planetary Laboratory
University of Arizona
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How to fit a linear distortion ?

December 18, 2017, 8:21 am
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Hi

I was testing what happens when using a 1st order polynomial fit in Scamp (DISTORT_DEGREES=1), that is a linear model for the distortions.

The distortion model is then

x' = PV1_0 + PV1_1x + PV1_2y
y' = PV2_0 + PV2_1y + PV2_2x

However, that produced a distortion map which has a circular shape.
Furthermore, the distortion parameters (PV*) are not written in the '.head' file of the image.

I am using SCAMP version 2.0.4 on Centos.

cheers, Kimmo
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How do I create mosaic distortion plots?

January 25, 2018, 7:17 am
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Given a 4 CCD mosaic camera, if I treat CCDs separately in Sextractor and Scamp, is there any way to assembly the individual CCD distortion PNG maps into one single mosaic plot? Many thanks in advance!
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How to set Scamp VizieR catalog search radius?

February 2, 2018, 6:46 am
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I think I've read the SCAMP manual quite well, but I could not find if there is a way to tell/order Scamp to search stars in VizieR within a (safer larger) radius, there is such an option in Scamp? Because in THELI (running Scamp) there is one (Astrom/Photom - Radius). Thanks in advance!
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Inaccurate astrometry in SCAMP/SWarp workflow - A challenge?

December 21, 2018, 12:48 pm
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Hello to everyone who reads this. I have a problem that has plagued me for a little while and, honestly, am not sure whether it is with SCAMP or SWarp.

The work that I do is typically with largish fields of view (15x15 degrees) for meteor work at video(ish) rates. Normally I have no problems with using SCAMP on my EMCCD imagery which has a limit of about 11th or 12th magnitude. Some of the cameras that I'm working with now, however, are much wider field (~80x50 degrees) and not nearly as sensitive (6th magnitude limit). This complicates my choice of catalogue and presents my first problem.

1. I would like to use Tycho-2, but I'm always faced with a 'No source found in reference catalog(s) for group 1; wrong sky zone?' regardless of the fiddling that I do with my scamp.conf

In the end, I've been using NOMAD-1 as the other catalogs that I've tried don't have the brighter stuff that I need. I should also note my imagery has no pointing information to begin with, so I use astrometry.net installed locally to generate a first-pass solution before moving on to SCAMP. Astrometry.net projects my images in TAN-SIP so I first remap (WCStools) to TAN. Possibly this is one problem.

The next step in my workflow is then use SWarp to create a max pixel mosaic. This works incredibly well with my medium-field EMCCD imagery but not well at all for the wide-field data. So, problem two is,

2. Regardless of the SWarp projection and fiddling that I do with my swarp.conf, I always see the warning, 'Astrometric approximation too inaccurate for this re-projection' and 'Significant inaccuracy likely to occur in projection.' I presume that this means that I need to fix things with SCAMP before expecting SWarp to work its magic.

I'm pretty sure that a lot of it comes down to poor conf files, but I've been struggling on this one. Does anyone care to take a look and try to help me out? I've uploaded some files to Google Drive at,

https://drive.google.com/open?id=1nyL8WM...sxJxWJsM3w

There are a selection of raw (no WCS), WCS (astrometry.net solution), SCAMP (remapped and SCAMPed), conf, and coadd files. There's also an example PNG (from the EMCCD workflow) that shows what I'm trying to achieve.

Thanks in advance for any pointers that you can provide!

Mike
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Determining camera+lens distortions with Scamp

November 3, 2016, 7:39 am
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Hi

I am digitizing old astronomical photographic glass plates with a digital camera, and I want to determine the distortions caused by the camera+lens combination.
I have got the following recipe:

1) Plot an artificial star field on a paper (just small dots on paper)
2) Take images of the field at different orientations
3) Use Sextractor to find the stars and their positions
4) Use the obtained 'star' catalogues as input to Scamp, and setting the following parameters in Scamp:

MATCH N # Do pattern-matching (Y/N) ?
SOLVE_ASTROM Y # Compute astrometric solution (Y/N)
ASTREF_CATALOG NONE

Furthermore, I need to set
CROSSID_RADIUS 3000.0 # Cross-id initial radius
or otherwise I get
WARNING: Not enough matched detections in instrument A1

Scamp gives the following information about the catalogs:

Group 1: 5 fields at 4.37e+03 2.93e+03 with radius 5259
instruments epoch center coordinates radius scale
distort-1.cat A1 P1 +4.3675e+03 +2.9275e+03 5259. 1.000
distort-2.cat A1 P1 +4.3675e+03 +2.9275e+03 5259. 1.000

and the same for all the rest of the catalogs.
Obviously, all the values are in pixel units.

However, Scamp crashes in the following way:

> Making mosaic adjustments...
> Solving the global astrometry matrix...
> WARNING: Not a positive definite matrix in astrometry solver

----- Astrometric clipping:
> Computing astrometric stats for group 1
> out of memory, core-dump

Does anybody has a solution for this ?

cheers, Kimmo
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Delete all FITS keywords?

November 14, 2016, 6:16 am
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Is there any way to delete all the keywords from one FITS image header?
Otherwise, could I replace one existing long header of an existing image with another small set defined in ASCII format?
Many thanks in advance!
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Poor astrometric solution with UCAC-4

November 18, 2016, 2:18 am
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Hello all,

on several fields I came across poor astrometric solution when using UCAC-4. There was always much better solution with UCAC-3 on the same images. The most obvious difference was the unexpected low number of reference stars queried from Vizier database.

Now I had a closer look at the internally generated query url and found a likely source of the problem: I often use ASTREFMAG_LIMITS parameter to choose the brighter reference stars only and this is applied to R magnitudes by default. But the catalog contains regions where the majority of stars have no R data in UCAC-4 and are skipped as soon as you choose a magnitude limit (setting this to 20 mag does not help).

I believe that the choice of R band as default for ASTREF_BAND is not a good choice in case of UCAC-4. Better choices woud be V or even better f (UCAC fit model magnitude in 579-642nm). Unfortunately it is not possible to reference either one or the other by a custom ASTREF_BAND setting.

Currently, the only workaround is to not use ASTREFMAG_LIMITS with UCAC-4 which is not always appropriate (e.g. wide fields, crowded regions).


I'd much appreciate if this could be dealt with in a future version of scamp.
Thanks,

Thomas Lehmann

(P.S.: I have seen the same odd behaviour in both scamp versions 2.0.4 and 2.2.6)
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Bug: image offset by 1 column

November 23, 2016, 2:06 am
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I recently switched from stiff version 2.4.0 to 2.6.1. Unfortunately the new version suffers from a bug which causes the image to roll by 1 pixel to the left.

I'd much appreciate an updated program version which fixes this issue.

Thanks,
Thomas
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dwarf galaxies

December 12, 2016, 1:31 pm
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Hi,

any idea how to set Sextractor parameters to make it see a (nearby) dwarf galaxy as a single galaxy and not a bunch of stars? Anyone had an experience with dwarfs?
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STABILITY_TYPE =- PREDISTORTED mode?

March 9, 2017, 6:11 am
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Does anyone have more information about how the STABILITY_TYPE=PREDISTORTED mode works?

Does scamp expect a "scamp-type" distortion solution (i.e. PV keywords) in the header?

If I then ask scamp to e.g. calculate a third-order distortion polynomial, is that put "on top" of the existing solution, i.e. does it fit the residuals of the predistorted solution, or does it take the predistorted solution as a starting point, to e.g. minimize the distances between detected sources and reference sources?

Thank you,

mischa
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How can I save the astrometry error result as text file ?

March 29, 2017, 11:11 pm
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Hi,

As I know, I can check astrometry result from only PS images.

But, when I deal with a lot of data, checking images one by one is very hard work.

So, I want to know how result data can save to text file like tab-separated, votable or ipac table, etc if SCAMP can possible.

Thanks,

Kyeongyeon Ko
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Tricks to install scamp plplot/qhull in openSUSE Tumbleweed

April 17, 2017, 2:45 am
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Dear Folks,

I've noted that the installation of scamp in new LINUX boxes is an issue. For many LINUX distributions, default plplot libraries are version 5.11 or higher and the library libplplotd.so.11 is missed.
I've used a workaround, which can be used to get scamp running.
This recipe is for openSUSE Tumbleweed, but it should useful for openSUSE Leap or some other new LINUX distributions with archive repositories.

a) Install the "rpm" of scamp without deps check, as:

rpm -ivh --nodeps scamp-2.0.4-1.x86_64.rpm

b) Find plplot and plplot-devel "rpms" for your OpenSUSE, which contains the mentioned libplplotd.so.11 library. For example, I've downloaded the rpm-files from rpmfind.net:

plplot-5.9.9-16.1.5.x86_64.rpm
plplot-devel-5.9.9-16.1.5.x86_64.rpm

c) Now, move the rpm-files to a scratch directory and unpackage them, for example using:

rpm2cpio plplot-5.9.9-16.1.5.x86_64.rpm | cpio -idmv
rpm2cpio plplot-devel-5.9.9-16.1.5.x86_64.rpm | cpio -idmv

d) In the scratch directory, you can find the structure of directories and files packaged in the rpm-files. Copy the device libraries and the libplplotd.so.11.0.0 files to /usr/lib64. For example:

cp -r scratch/usr/lib64/plplot5.9.9 /usr/lib64/
cp scratch/usr/lib64/libplplotd.so.11.0.0 /usr/lib64/

e) Create the link:

ln -s /usr/lib64/libplplotd.so.11.0.0 /usr/lib64/libplplotd.so.11

f) The last issue is the qhull library. Again, find a useful version like:

qhull-2010.1-1.el5.x86_64.rpm

Unpack it, copy to /usr/lib64 and create the link:

ln -s libqhull.so.5.0.0 libqhull.so.5

After this, you have scamp running in a very new LINUX distro openSUSE Tumbleweed "like a charm" Toungue. As example, attached a plot.

Saludos from La Serena.

Rodolfo


[attachment=317]
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Segmentation map missing object

June 2, 2017, 2:08 pm
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I am using SExtractor 2.19.5 and have come across a bug that seems to have been reported back in 2008. In rare instances, we are seeing that a detected object is not present in the segmentation map, and its pixels seem to be assigned to a different, adjacent object. It looks like it is a result of depending, but only in rare instances.

We are using the pixels from the segmentation map to select pixel values from a corresponding monte carlo variance map whose values we use for an error computation, so we do need to know specifically which pixels are assigned to each object.

We also see that there are cases of individual pixels that belong to one object that are entirely embedded within another object, which I am not sure is correct either.

An example cutout from a segmentation map and the correspond aperture checkimage is shown. You can see the two apertures that are close together in the aperture image (objects 9 & 2) are a single object (9) in the segmentation map

Ap vs. seg image
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Segmentation fault

June 5, 2017, 4:20 am
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I am new to scamp. I have used sextractor on many occasions.. I got the segmentation fault with scamp. I believe I may not be running it properly. In short, first I run sextractor with:
sex -c scamp.sex test.fit
where I have put FITS_LDAC as suggested in .sex file to get cat.fits file as an output catalog with all the relevant fields:
# 1 XWIN_IMAGE
# 2 YWIN_IMAGE
# 3 AWIN_IMAGE
# 4 BWIN_IMAGE
# 5 THETAWIN_IMAGE
# 6 ERRAWIN_IMAGE
# 7 ERRBWIN_IMAGE
# 8 ERRTHETAWIN_IMAGE
# 9 FLUX_AUTO
# 10 FLUXERR_AUTO
# 11 MAG_AUTO
# 12 FWHM_IMAGE
# 13 FLUX_RADIUS
The values look quite reasonable. But when I run scam afterwards with:
scamp cat.fits -c default.scamp
where default.scamp I changed only FWHM_THRESHOLDS from 0.5 to 10 and MATCH_FLIPPED to YES, since in my case I believe the axes are flipped. Anyway, I got the message:
----- SCAMP 2.0.4 started on 2017-06-05 at 13:19:47 with 4 threads

----- 1 inputs:
>
> WARNING: precessing EQUINOX 0.00 to 2000.00


> WARNING: FLAGS parameter not found in catalog cat.fits

Segmentation fault: 11


Help!!!
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Background Subtraction issue when swarping

June 9, 2017, 1:57 pm
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Hi all,

I have a question related to the background subtraction of SWarp (v2.38.0). I was trying to combine a list of images into a single mosaic. Hence I would like to subtract the background of each of them then combine them together with average or median.

But what I noticed is that the background is only subtracted for the first image in the list, or at least that's what the output of Swarp indicated.


In the config file I have the following:


#--------------------------- Background subtraction ---------------------------

SUBTRACT_BACK Y # Subtraction sky background (Y/N)?
# (all or for each image)

BACK_TYPE AUTO # AUTO or MANUAL
# (all or for each image)
BACK_SIZE 128 # Background mesh size (pixels)
# (all or for each image)
BACK_FILTERSIZE 3 # Background map filter range (meshes)
# (all or for each image)
....



Below is the SWarp output of all these images, as you can see only the first one show a non-zero background value. Are there some flags that I need to add to enable background subtraction for all of the input images? Thanks in advance for your reply!


----- SWarp 2.38.0 started on 2017-06-09 at 13:10:47 with 8 threads

------- Output File coadd.fits:
"no ident" WEIGHTED no ext. header 37821x37804 32 bits (floats)
Center: 10:00:59.49 +02:13:53.0 106'x106' Scale: 0.168 ''/pixel
Gain: 0 e-/ADU Flux scaling (astrom/photom): 1 X / 1 X

-------------- File 9813-0_3_img.fits:
"no ident" WEIGHTED no ext. header 4100x4200 32 bits (floats)
Center: 10:03:58.24 +02:02:40.5 11.5'x11.8' Scale: 0.168 ''/pixel
Gain: 0 e-/ADU Flux scaling (astrom/photom): 0.9998 X / 1 X
Background: 0.00555533 RMS: 0.1051587 Weight scale: 1

-------------- File 9813-0_4_img.fits:
"no ident" WEIGHTED no ext. header 4100x4200 32 bits (floats)
Center: 10:03:58.26 +02:13:52.5 11.5'x11.8' Scale: 0.168 ''/pixel
Gain: 0 e-/ADU Flux scaling (astrom/photom): 0.9998 X / 1 X
Background: 0 RMS: 1 Weight scale: 1

-------------- File 9813-0_5_img.fits:
"no ident" WEIGHTED no ext. header 4100x4200 32 bits (floats)
Center: 10:03:58.29 +02:25:04.4 11.5'x11.8' Scale: 0.168 ''/pixel
Gain: 0 e-/ADU Flux scaling (astrom/photom): 0.9998 X / 1 X
Background: 0 RMS: 1 Weight scale: 1

-------------- File 9813-0_6_img.fits:
"no ident" WEIGHTED no ext. header 4100x4200 32 bits (floats)
Center: 10:03:58.31 +02:36:16.3 11.5'x11.8' Scale: 0.168 ''/pixel
Gain: 0 e-/ADU Flux scaling (astrom/photom): 0.9998 X / 1 X
Background: 0 RMS: 1 Weight scale: 1

-------------- File 813-0_7_img.fits:
"no ident" WEIGHTED no ext. header 4100x4200 32 bits (floats)
Center: 10:03:58.33 +02:47:28.2 11.5'x11.8' Scale: 0.168 ''/pixel
Gain: 0 e-/ADU Flux scaling (astrom/photom): 0.9998 X / 1 X
Background: 0 RMS: 1 Weight scale: 1

....
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A pattern in simulated image.

June 12, 2017, 7:44 am
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Hi all,

I'm trying to simulate HST/ACS F606W and F814W band images.
After using Stuff to create a mock catalogs for both bands, on simulated images the pattern is clearly visible (see image: left panel - V band; right panel - I band). Values within this patterns are of the soutrrnading background and actually it don not have a big impact on what I want to do with the simulation but I'm wonder if this is a settings or Skymake version (3.10.5) issue?

img: https://drive.google.com/file/d/0BxVys35...sp=sharing

[Image: view?usp=sharing]
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Scamp fails to run

July 20, 2017, 9:04 pm
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Hi,

I successfully installed scamp-2.0.4, however, when I try to test if it works correctly following the install by typing 'scamp' in the command line, I get the following error message:

dyld: Library not loaded: /usr/local/gfortran/lib/gcc/x86_64-apple-darwin10/4.6.2/libgfortran.3.dylib
Referenced from: /usr/local/atlas-3.9.32/lib/liblapack.dylib
Reason: image not found
Trace/BPT trap: 5


I also have source extractor and SWarp installed and they work just fine. I'm not sure how to proceed. I've verified that I do have libgcc installed via macports.
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