Finder Chart: Overview

Finder Chart is a searching and visualization tool that allows cross-comparison of images from various surveys of different wavelengths and different epochs. Data can be downloaded in any of a variety of formats, either singly or in bulk. Catalogs from any of a variety of sources are also available.

This tool provides access to data sets from the Two Micron All Sky Survey (2MASS), the Wide-field Infrared Explorer (WISE) AllWISE all-sky survey, the InfraRed Astronomy Satellite (IRAS) all-sky survey, AKARI Far Infrared Surveyor (FIS), the Digitized Sky Surveys (DSS) (both First and Second Generation), and the Sloan Digital Sky Survey (SDSS). Please note that the DSS and SDSS data do not reside at IRSA, so the successful retrieval of DSS and SDSS data depends on the operation of the DSS and SDSS services, located at other institutions.

Besides this online help (also available as a PDF), there are also Finder Chart video tutorials, available at the IRSA YouTube channel . There is a playlist that collects together all of the Finder Chart videos. Also see the list of "micro-tutorials" relevant for more than one tool, and the list of tutorials using more than one tool.

This service makes use of components of Montage, funded by the National Aeronautics and Space Administration's Earth Science Technology Office, Computational Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology.

Contents of page/chapter:
+Surveys, Wavelengths, and Sky Coverage
+Terminology
+Side Menu and Adding to the Tabs Menu
+Side Menu and Appearance
+User Login Overview
+Getting More Help

Surveys, Wavelengths, and Sky Coverage

DSS

The Digitized Sky Survey (DSS) is a digitization of the photographic sky survey plates from the Palomar and UK Schmidt telescopes. DSS images have pixels between 1 and 1.7 arcsec and use three broad-band filters covering roughly 3950 Angstroms to 9000 Angstroms. None of the underlying datasets are all-sky; the DSS "surveys" are actually composites of multiple image sets taken at different times using different instruments. The date for the specific retrieved image appears with the image in Finder Chart. For more detailed information on filters, dates, and coverage, see the DSS webpage at STScI

image	band	approx. wavelength range
DSS1B	Bj	3950 - 5400 Angstroms
DSS1R	R	6125 - 6475 Angstroms
DSS2B	Bj	3950 - 5400 Angstroms
DSS2R	R	6300 - 6900 Angstroms
DSS2IR	I	6950 - 9000 Angstroms

SDSS

The Sloan Digital Sky Survey (SDSS) is not an all-sky survey, but covers more than a quarter of the sky in five optical filters, at about 1.5 arcsecond resolution. The date that the image was obtained is included in Finder Chart. For more detailed information on filters, dates, and coverage, see the SDSS webpage

. The version of SDSS image data that is being used here is DR7.

Band	Approximate central wavelength
u	2910 Angstroms
g	4810 Angstroms
r	6230 Angstroms
i	7640 Angstroms
z	9060 Angstroms

2MASS

The Two-Micron All-Sky Survey (2MASS) is an all-sky survey. 2MASS images have about 1 arcsecond resolution and were obtained in three broadband filters: J, H, and K_s (K-short). The date that the image was obtained is included in Finder Chart. For more detailed information about filters, dates, and coverage, see the 2MASS web page at IRSA

(and references linked therein) or the 2MASS webpage

Band	Approximate central wavelength
J	1.235 microns
H	1.662 microns
Ks	2.159 microns

WISE

Widefield Infrared Survey Explorer (WISE) is a spacecraft that conducted an all-sky survey. WISE mapped the sky in four bands (3.4, 4.6, 12, and 22 microns) with an angular resolution of about 6.1, 6.4, 6.5, and 12.0 arcseconds in the four bands, respectively. For more detailed information about filters, dates, and coverage, see the WISE webpage at IRSA

and references linked therein. IMPORTANT NOTES: The dates for these images as shown in Finder Chart are the average date of the coadded frames from the AllWISE data release. Remember that these images are coadds from individual frames taken at different times. Near the ecliptic poles, these images may span several months. The average date is also included in the FITS header. Note also that there are rather a lot of WISE-1 and -2 data taken after the AllWISE data release that are not included in the AllWISE data products.

Band	Approximate central wavelength
W1	3.4 microns
W2	4.6 microns
W3	12 microns
W4	22 microns

SEIP

The Spitzer Space Telescope was a spacecraft that was a pointed mission, not an all-sky survey. However, much of the most popular regions of the sky have Spitzer data. The Spitzer Enhanced Imaging Products (SEIP

) combined all of the data taken during the cryogenic era, made mosaics, and extracted a source list. There are SEIP products for IRAC (3.6, 4.5, 5.8, 8 microns) and MIPS-24 (24 microns). For more detailed information about filters, dates, and coverage, see the Spitzer webpage at IRSA

and references linked therein. IMPORTANT NOTES: The dates for these images are not shown in Finder Chart; these images are coadds from individual frames taken at different times, possibly over years. The average date is included in the FITS header. Also, please note that the post-cryo mission was more than twice as long as the cryo-era mission, so there are rather a lot of IRAC-1 and -2 data that are not part of SEIP.

Band	Approximate central wavelength
IRAC-1	3.6 microns
IRAC-2	4.5 microns
IRAC-3	5.8 microns
IRAC-4	8 microns
MIPS-1	24 microns

AKARI

AKARI was a Japanese satellite that conducted an all-sky survey at several bands between 1.8 and 180 microns. FIS was the long wavelength instrument, with bands between 65 and 180 microns. For more detailed information about filters, dates, and coverage, see the AKARI webpage at IRSA

and references linked therein. IMPORTANT NOTE: The dates for these images are not shown in Finder Chart because these images are coadds from individual frames taken at different times. Near the ecliptic poles, these images may span several months. The average date is included in the FITS header.

Band	Approximate central wavelength
N60, or flux65	60 microns
WIDE-S, or flux90	90 microns
WIDE-L, or flux140	140 microns
N160, or flux160	160 microns

IRAS

The InfraRed Astronomy Satellite (IRAS) was a satellite that flew in 1983 and conducted an all-sky survey in 12, 25, 60, and 100 microns. The angular resolution of the instrument varied between about 0.5 arcmin at 12 microns to about 2 arcmin at 100 microns. The original images have been reprocessed into the IRAS Sky Survey Atlas (ISSA) and IRIS (Improved Reprocessing of the IRAS Survey). For more detailed information about filters and coverage, see the IRAS webpage at IRSA

or the IRAS documentation

. For specific information on IRIS, see the IRIS webpage at IRSA

Band	Approximate central wavelength
IRAS-1	12 microns
IRAS-2	25 microns
IRAS-3	60 microns
IRAS-4	100 microns

Terminology

The words in blue rectangles at the top are 'tabs.'

This icon in the upper left pulls open a "drawer" from the left hand side which enables you to add or remove tabs from this top level (see below). It also can allow you to change the appearance (dark or light mode) (see below).

When you have results loaded into Finder Chart, your browser window is divided into "panes", like "window panes." The contents of the panes depends on what you are doing with the tool, but could include an image pane, at least one table pane, and/or a plot pane. You can expand any of the window panes by clicking on the expand icon:

Each of the three main kinds of 'panes' in the display has its own toolbox in its upper right corner which operates on things in that pane, and the basic functionality for each of these panes is covered elsewhere in this document:

The Tables section covers (among other things) the tables toolbox
The Plots section covers (among other things) the plots toolbox
The Visualization section covers (among other things) the images toolbox

The only mechanism for searching in Finder Chart is searching by position. One can submit a single target ("single position") or a list of targets ("multiple positions"). (More on searching.)

Side Menu and Adding to the Tabs Menu

This icon

in the upper left pulls open a "drawer" from the left hand side; the top of it looks like this:

The highlighted bar ("Results" in this example) is the tab you have in the foreground on your main window.

You can use this side menu to add (or remove) blue tabs from the top of your Finder Chart interface. By default, Results, Single Position (a searching option), and Multiple Position (another searching option) are shown, along with the Job Monitor.

Under "IRSA search tabs," Catalogs and VO TAP search IRSA holdings.

Under "External archive search tabs," NED Objects and Multi-archive VO TAP (that is, a general TAP search) search other (non-IRSA) archives.

Click on the "Hide Tab" button to remove that corresponding tab.

Side Menu and Appearance

This icon

in the upper left pulls open a "drawer" from the left hand side; the bottom of it looks like this:

This controls the appearance of the tool in your browser -- do you want it to run as light mode, dark mode, or respect whatever preferences you have set on your system? Try out the different modes; you may have a preference!

User Login

In the far upper right, there is a link to log in. Finder Chart can remember you when you return. See the user registration section for more information.

Getting More Help

The "Help" icon

leads you into this online help. There are also context-sensitive help markers throughout the tools (

). You can also download a PDF version of this manual; look at the top left of the help window. (The PDF may be easier to search than the web pages; use your PDF reader's search function.)

You can submit questions to the IRSA Help Desk .

A set of frequently asked questions (FAQs) about Finder Chart is here.

The IRSA YouTube channel has lots of short videos about IRSA tools.

Found a bug? The known bugs and issues in this version of the Finder Chart are listed here . If you think you have found a bug, before reporting it, please check this list, and read this online Finder Chart help. It may be a "feature" we already know about. If you have found a new, real bug, then please do contact us via the IRSA Help Desk . Please include your operating system version and your browser software and version. If you can, please also include any specific error message you may have gotten. (NB: In our testing, copying shortcuts worked on Windows and Linux; the command-C did not always work on Macs, but selecting and clicking the right mouse button often did when command-C did not.)