Difference between revisions of "SHIPsData"
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==Flexible Image Transport System== | ==Flexible Image Transport System== | ||
| − | + | A file format used by astronomers to store images, spectra, tables and lots of other things that are data-like in nature (i.e. no one writes a document in FITS format, although this is possible). | |
| − | + | ||
| − | + | References | |
| − | + | * [http://heasarc.nasa.gov/docs/heasarc/fits.html What is FITS?] | |
| − | + | * [http://fits.gsfc.nasa.gov FITS support office] | |
| − | + | * [http://fits.gsfc.nasa.gov/fits_viewer.html List of FITS image viewers and converters?] | |
| − | + | Primary components of FITS images for our purposes | |
| − | + | * We are talking about '''images''' here. FITS can also store spectrum, tables, anything else really. | |
| − | + | * '''Header'''. Contains 'meta' information about the data. At minimum it should simply describe the form factor of the data (2D, 1D, etc.). It has no maximum limits, but practical limits truncate it to what is useful. For our purposes, we need to particular pay attention to a subsection of the header known as the World Coordinate System (WCS, for short, see next item). Header also should tell you when, where the data were taken. What filter was used? And, anything else that the astronomer, observatory thought you ought to know for your science. Look at the NGC 28 image headers to get some idea of what is stored. | |
| + | * '''WCS'''. A subsection of the FITS header. This relates the image coordinates in pixels to a different coordinate system. In Astronomy, the most commonly used coordinate system is the Equatorial one (Right Ascension and Declination). But, any coordinate system (just about) is possible. Another commonly used astronomy system is the Galactic coordinate system. | ||
| + | * Data | ||
Revision as of 21:20, 14 March 2013
This wiki area is a dedicated workspace for the NITARP 2013 team SHIPs.
Flexible Image Transport System
A file format used by astronomers to store images, spectra, tables and lots of other things that are data-like in nature (i.e. no one writes a document in FITS format, although this is possible).
References
Primary components of FITS images for our purposes
- We are talking about images here. FITS can also store spectrum, tables, anything else really.
- Header. Contains 'meta' information about the data. At minimum it should simply describe the form factor of the data (2D, 1D, etc.). It has no maximum limits, but practical limits truncate it to what is useful. For our purposes, we need to particular pay attention to a subsection of the header known as the World Coordinate System (WCS, for short, see next item). Header also should tell you when, where the data were taken. What filter was used? And, anything else that the astronomer, observatory thought you ought to know for your science. Look at the NGC 28 image headers to get some idea of what is stored.
- WCS. A subsection of the FITS header. This relates the image coordinates in pixels to a different coordinate system. In Astronomy, the most commonly used coordinate system is the Equatorial one (Right Ascension and Declination). But, any coordinate system (just about) is possible. Another commonly used astronomy system is the Galactic coordinate system.
- Data
Tools
- ds9
- ds9 exercises
- Load an image.
- Change the stretch between log, linear
- Change color table
- Change scale between displaying all values to zscale.
- Change scale between two fixed values.
- Zoom/pan to different parts of the image, isolate a single protester
- Mark a region, save a region.
- Load a region
- Display two images side by side
- Align the two side-by-side displayed images using their astrometry.
- Display two images by blinking between the two.
- Use 'fixed cursor' to locate the same star on two side-by-side displayed images.
- Find a particular position (ra,dec) on the image.
