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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 ...
Carter Rhea's user avatar
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 ...
astrosnapper's user avatar
  • 8,357
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 ...
AstroShannon's user avatar
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 ...
ProfRob's user avatar
  • 153k
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 ...
usernumber's user avatar
  • 17.5k
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 ...
antoine's user avatar
  • 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 ...
simonp2207's user avatar
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 ...
Eric Jensen's user avatar
  • 4,874
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 ...
Jerry Zhang's user avatar
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.
Py-ser's user avatar
  • 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 ...
ProfRob's user avatar
  • 153k
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 "...
NeStack's user avatar
  • 313
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 ...
Kornpob Bhirombhakdi's user avatar
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 ...
Mick's user avatar
  • 1,410

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