4
votes
Fits file re-alignment
I ended up making my own small code that you can find here:
https://github.com/crhea93/AstronomyTools/blob/master/Astrometry/Correction.py
Essentially, after inputting at least 3 matching ...
- 81
3
votes
Accepted
CoRoT FITS files read error
These are FITS binary tables not FITS images so the normal FITS image tools very likely won't read them. You have a couple of options to examine and manipulate them:
Use the 'fv' tool which works on ...
- 8,732
3
votes
How to invert fits headers order (primary/secondary)?
EDIT: I moved the last paragraph to the beginning because it's really a Python question, but I left my "manual" method answer in case it helps, too.
Forgot to add this link to Python code ...
- 612
2
votes
Cannot plot Kepler FITS files with topcat in Windows
FFI means "full frame image". It does not contain any tables, so the unhelpful error message is almost certainly due to that.
Chapter 2 of the Kepler Archive Manual is essential reading.
Light curve ...
- 159k
2
votes
Accepted
Align multiple fits images without WCS for future aperture photometry analysis
You can use astrometry.net to get the exact WCS of your image.
From the website:
If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then ...
- 17.7k
2
votes
How to use Astropy to edit a keyword (not value) in batches of FITS file headers to be used in AstroimageJ (AIJ)? (summer undergrad research project)
This code snippet should do what you want for an individual fits file. It searches for the HDU containing 'DATE-BEG' and then writes a header 'DATE-OBS' containing the value of 'DATE-BEG'. You can use ...
- 121
2
votes
Frequency coverage for first spectral channel of .fits cube?
After digging a little, I found the key sentence at the start of section 2.1.4 of Greisen et al (2002), which reads:
"Note that integer pixel numbers refer to the center of the pixel in
each ...
- 257
1
vote
Accepted
How can I replicate AstroImageJ's pixel to RA/Dec algorithm in my own code?
You don’t say what language your code is in, but there are Python functions to do this in the WCS module in astropy.
In particular, look at the pixel_to_world ...
- 4,914
1
vote
align an image to celestial North
Because you cut the image and rotated it, the old reference is no longer there.
Try this and it works perfectly for me:
After fixing the cutout center on original image ...
- 11
1
vote
Problems with FITS headers
Using Fits Fits View (FV)View (FV), you can either modify the header by terminal commands, or using the GUI which makes you visualize all the keywords and values.
- 1,975
1
vote
Accepted
In sky surveys, what does inverse variation really mean? How do we use inverse variation to remove noise?
It is inverse variance. A larger inverse variance means the value in that pixel is less uncertain (in a relative sense).
The inverse variance can be used as a weighting factor - it directly gives you ...
- 159k
1
vote
Accepted
Python: Find brightest pixel in fits-file and ignore brighter artefacts
Following Mick's comment, I found an astropy-function - DAOStarFinder - that does what I was looking for. It scans an image for light-sources and one can set threshhold for a detection, e.g. the "...
- 333
1
vote
Converting FITS (NuSTAR) coordinates to WCS
I did this exercise with IRAF by the functions geomap and geotran. There is PYRAF version of the IRAF, but I have never tried the python version. Using these routines, you can find the tranformation ...
- 1,434
1
vote
Converting FITS (NuSTAR) coordinates to WCS
You can upload your FITS files to astrometry.net (or use an API) and get the coordinates. You can optionally get new FITS files back with the coordinates included in the metadata. From there you will ...
- 1,420
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