IR Compendium: Background: Resolution

|| SPITZER HOME || SPITZER SCIENCE || COMPENDIUM HOME || EXAMPLES INDEX ||

This is the page on Resolution; also see Diffraction, Confusion, and (IR) Background

Resolution (Jump to Spitzer-specific section)

When comparing images at different wavelengths, check that the spatial resolution is comparable! This matters, particularly for mid- and far-IR observations (see 'diffraction' below).


Original visible light image of M33.	The same visible light image, smoothed to a resolution typical of far-IR observations.	Especially in IR images, intensities are often translated to colors ("false color"). Image colors are often selected to emphasize different details than are discernable in a black-and-white image.

Here is a table comparing pixel sizes and resolutions of several different instruments; see also the plot below:

Instrument/Data Set	Wavelength(s) (microns)	Pixel Size (arcsec)	Resolution (arcsec)	Array Field of View	Reference
DSS/POSS-I	0.4, 0.65	1.7	typically ˜2	6.5° x 6.5°	MAST DSS FAQ, Skyview survey summaries
DSS/POSS-II	0.45, 0.65, 0.8	1.0	typically better than 2	6.5° x 6.5°	MAST DSS FAQ, Skyview survey summaries
2MASS	1.25, 1.65, 2.17	˜2.0	1	8.5' x 8.5'	2MASS Explanatory Supplement, Skyview survey summaries
ISO-CAM SW5	4.0	1.5	˜ 1.66	45" x 45"	ISO Handbook, Version 1.2, ISO PSF Report (Okumura, 1998)
ISO-CAM LW1	4.5	1.5	˜ 2.30	45" x 45"	ISO Handbook, Version 1.2, ISO PSF Report (Okumura, 1998)
ISO-CAM LW5	6.8	1.5	˜ 2.40	45" x 45"	ISO Handbook, Version 1.2, ISO PSF Report (Okumura, 1998)
ISO-CAM LW7	9.6	1.5	˜ 3.19	45" x 45"	ISO Handbook, Version 1.2, ISO PSF Report (Okumura, 1998)
ISO-CAM LW10	12	1.5	˜ 3.70	45" x 45"	ISO Handbook, Version 1.2, ISO PSF Report (Okumura, 1998)
ISO-CAM LW9	14.9	1.5	˜ 5.11	45" x 45"	ISO Handbook, Version 1.2, ISO PSF Report (Okumura, 1998)
IRAS	12	30	˜20	4.45' x 0.76'	IRAS Explanatory Supplement, Skyview survey summaries
IRAS	25	30	˜20	4.65' x 0.76'	IRAS Explanatory Supplement, Skyview survey summaries
IRAS	60	60	˜60	4.75' x 1.51'	IRAS Explanatory Supplement, Skyview survey summaries
ISO-PHT C70	80	43.5	˜ 59.0	2.3' x 2.3'	ISO Handbook Volume 2.0
IRAS	100	120	˜120	5.05' x 3.03'	IRAS Explanatory Supplement, Skyview survey summaries
ISO-PHT C160	170	89.4	˜ 134.0	3.0' x 3.0'	ISO Handbook Volume 2.0

Resolution and Spitzer

Spitzer's resolution is a strong function of wavelength; see this overview page.

Also see the simulations on the page on confusion noise.

The following plot comes from the SOFIA website.

Part of this page was adapted from Marcia Rieke's talk at the Seattle AAS, January 2003

|| SPITZER HOME || SPITZER SCIENCE || COMPENDIUM HOME || EXAMPLES INDEX ||

help@spitzer.caltech.edu

http://ssc.spitzer.caltech.edu/documents/compendium/resolution/
This file was last modified on Tue Oct 3 15:56:05 2006.