Questions tagged [fits]
The fits tag has no usage guidance.
26
questions
5
votes
1
answer
90
views
What do the negative values in FITS images mean?
I am using FITS images, and noticed negative values in value matrix. What they mean? For example, for one of the images, the minimum value is -0.34472656 and the maximum = 552.0. The data type(format) ...
- 51
0
votes
0
answers
17
views
How to reproject a fits file using MontagePy
I am fairly new to image reprojection so I am trying to use MontagePy to go from a bigger fits file to its smaller subsection (which is in a different observation, therefore header) but the output ...
- 1
2
votes
1
answer
70
views
Making RGB image using FITS files with different dimensions
I want to make an RGB image using 3 FITS files: one IR image from Spitzer and the other two from UVIT. I tried to make them using make_lupton_rgb in Astropy, but it doesn't work in the case of FITS ...
- 174
2
votes
1
answer
74
views
How to slice WCS in a FITS file?
I have three WCS axes in a FITS image. I want to slice the axes and use only the first one. Note that though there are three axes, the WCS is superimposable. So there is no worry about a shift in WCS ...
- 174
3
votes
1
answer
35
views
Frequency coverage for first spectral channel of .fits cube?
A .fits cube has 3 dimensions, where the 1st axis is RA, 2nd axis is Declination and 3rd axis is frequency.
My question is rather simple, but causing pain none-the-less. Given a .fits cube, what is ...
- 257
1
vote
0
answers
60
views
What do negative values on bright sources in TIRSPEC mean?
I opened a FITs image data from TIRSPEC (NIR imaging) (an HgCdTe infrared imaging sensor) on DS9 and I saw that some of the bright stars have black patches at the center (negative values).
Can you ...
- 473
2
votes
0
answers
44
views
Where does FireCapture save FITS photos during recording?
I made a lot of FITS photos yesterday and accidentally the laptop battery was discharged and it was turned off before I pressed the stop button. Now, I don't see that last session in folder with other ...
- 246
2
votes
1
answer
81
views
Why does the same file differ so much in size between FITS / CSV / ECSV formats?
Maybe this is obvious for some people but I'm a newbie when it comes to working with astronomical data. I have the same catalogue in different formats and am a bit surprised as to how sizes change. ...
3
votes
1
answer
84
views
How can I use the "stiff"(the library from this site; astromatic.net). I can not escape from the error[*Error*: no 2D FITS data in <MY FITS FILE>]
I try to use "stiff" library now.
This library is from astromatic.net
I follow the tutorial's example1(page 18), but It is not worked.
...
- 335
1
vote
1
answer
35
views
Can't read documentation in pow, launched form fv: Error: can't read "env(POW_HELPDIR)": no such variable
I'm launching the pow tool from fv version 5.5, installed via apt on Ubuntu 20.04.
It is part of HEASoft's FITS software suite.
...
- 402
3
votes
1
answer
80
views
What's mean of the "FITS BLOCK"?
I am studying FITS file, through this: Definition of FITS
They said Fits block is like below(page3).
A sequence of 2880 eight-bit bytes aligned on
2880-byte boundaries in the FITS file, most commonly ...
- 335
1
vote
0
answers
31
views
uvotdetect sometimes doesn't make valid .fits files for DS9 to read (Swift UVOT, Heasoft)
I have downloaded galactic center sky images from the Swift database (https://www.swift.ac.uk/swift_live/index.php#doSimpleSearch.php?catname=swiftmastr&searchpos=galactic+center&searchrad=10&...
- 11
1
vote
0
answers
22
views
How to choose numeric precision when creating a file with STILTS?
I am using the STILTS command-line tools, popular in astronomical data processing, to merge many (~330k) .fits astronomic tables into 1 large table. I am doing this with the STILTS command in the ...
- 313
1
vote
0
answers
447
views
How to quickly loop through many small fits files for data analysis?
I need to extract information from a few columns in ~20k different fits files with python. Each file is relatively small, ~0.2MB. I have been doing this so far with a loop and ...
- 313
1
vote
0
answers
48
views
How to superimpose an optical image upon a radio contour image using AIPS?
I am using AIPS by NRAO. I am trying to overlay a radio contour image with an optical image in the r-band. From the cookbook I could not find the suitable command for it. Both are fits files pf course....
- 11
2
votes
0
answers
75
views
Frame used for RGB cube in SAOImage
I have RGB FITS images with NAXIS=3 so I read them into SAOImage (ds9 8.2.1). I use this command line:
$ ds9 -rgbcube myimage.fits
Doing so, the window is split in ...
- 121
2
votes
0
answers
66
views
healpix: creating isometric tiles for flat map of survey
I am currently tasked with creating a visual of a recently completed survey which is in HEALPix1 format. I am also required to use the DSS and Planck skymaps also in HEALPix, and would like to flatten ...
- 153
0
votes
0
answers
55
views
.fits Files for Exoplanets
I am learning to use AstroImageJ software. And using this software to plot transit graph for Exoplanet orbiting the star. I want to know from where can we find the .fits file of target star ? I tried ...
3
votes
1
answer
176
views
Finding galaxy spectra in SDSS Catalog by object name
I am looking to find galaxy spectra of early type elliptical galaxies in the SDSS catalog by the objects name. See: https://dr12.sdss.org/advancedSearch. I dont know how to find out the PLATEID of my ...
- 711
1
vote
1
answer
2k
views
working with stellar spectra in fits format in python
Hey I am new to working with astronomical data in Python. I wanted to start working with stellar spectra and I am having trouble with the data. To get a first look I just wanted to plot a spectra (...
- 711
4
votes
1
answer
368
views
Algorithm to fit galaxies
Do you know of any other data analysis algorithm that fits 2-D analytic functions to galaxies and point sources directly to digital images, other than GALFIT? Especially to subtract lens light from ...
- 43
3
votes
0
answers
461
views
Issues in dimensions and slicing while plotting contours over a FITS Image in Astronomical Plotting Library in python (APLpy)
I have been trying to plot the contours of a FITS image over itself in APLpy. The image was created in AIPS, and has dimensions (1024,1024,1,1), viz., right ascension (RA--SIN), declination (DEC--SIN),...
- 409
2
votes
0
answers
26
views
superimpose borders of several FITS on the sky map
I have several FITS files with correct WCS info (as far as I know) and want to project them or preferably their borders only in the same sky projection, so it will be easy to understand an actual ...
- 21
1
vote
0
answers
175
views
How can I create a mask for a fits image?
I need to create a mask of a fits image.
By this I mean that I want to create the image that covers all secondary objects from the original image except the one is in the center.
I have some routines ...
2
votes
2
answers
129
views
How to invert fits headers order (primary/secondary)?
I have an image from Hubble telescope with two headers and this creates a problem because my program expects the NAXIS, NAXIS1, NAXIS2 in the first header, but in this image case, this info is in the ...
1
vote
2
answers
1k
views
How can I crop a fits file and get correct WCS header info without a new plate solve and WITHOUT USING PYTHON?
While my question is similar to this one, the suggestions offered there won't work for my specific situation. For over a month I've been trying to find software capable of this but it's been an ...
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