EXTINCTION CALCULATORS
NED's own
Galactic Reddening and Extinction Calculator is incorporated
in the coordinate transformation and precession calculator. To use it,
enter a position in one of the accepted coordinate systems, choose the
input and output equinoxes, and click "Calculate".
In addition, a query of NED
By Name
or By
Position automatically gives Galactic extinctions
for fourteen popular bandpasses (UBVRIugrizJHKL') in the Basic Data section for each
object returned. This service uses the
Schlafly & Finkbeiner 2011 (ApJ 737, 103, 2011) recalibration of the
Schlegel, Finkbeiner & Davis 1998 (ApJ 500, 525, 1998; SFD98) extinction map.
The original SFD98 extinction values are also returned for comparison purposes.
NED's Basic Data additionally gives a value of AB using
the prescription given by
Burstein and Heiles 1982 (1982, AJ, 87, 1165) for direct comparison with the
SFD98 value given that there are some systematic differences between the two estimators.
Please read the caveats for using these extinction calculators.
NED is providing the following links to outside sites at the specific request
of users and as an additional service to extragalactic researchers in
general. The NED Team has not fully validated any of these
calculators, and questions concerning the algorithms used, their range
of application and the precision of the returned results should be
directed to the original Web site creators.
IRSA: Galactic
Reddening and Extinction Calculator
IRSA, Infrared Processing and Analysis Center
This service uses the Schlegel, Finkbeiner and Davis (1998, ApJ, 500, 525) Galactic reddening maps
to determine the total Galactic line-of-sight absorption for about 40
popular photometric systems including Landolt (UBVRI), Stromgren (uvby),
Sloan (u'g'r'i'z') and WFPC-2.
The calculator accepts an object name or an RA/DEC
position. The IRAS 100-micron map of the surrounding region is
returned and a detailed listing of extinctions can be obtained by
clicking the highlighted link "Reddening and Extinction by Bandpass" in
the upper-right panel, entitled "E(B-V) Reddening"
Interstellar
Extinction Calculator
Doug Welch, McMaster University
This calculator determines the total absorption for wavelengths
between 0.10 and 3.33 um using the algorithm published by Cardelli,
Clayton, and Mathis
(1989, ApJ, 345, 245).
Required input parameters are:
- RV the ratio of total to selective absorption at V
- AV the total absorption in magnitudes at V
- Wmicron the target wavelength in microns
Curator's email address:
[email protected]
Galactic HI Line-of-Sight Column-Density Calculator
P.M.W. Kalberia, Bonn University
HI column density and the complete spectrum
for any position on the sky from the Leiden/Argentine/Bonn (LAB)
Survey. Users can specify the desired position in either Equatorial or
Galactic coordinates.
York Extinction Solver (YES)
Marshall McCall, York University
The York Extinction Solver (YES) is a facility
for evaluating the Galactic or localized extinction of any celestial
body in any filter from any index of reddening. Its development was
motivated by a need to free extinction estimates from errors arising
from shifts in effective wavelengths, which permeate astronomy. For
example, it has been common practice to estimate the extinction of a
disk galaxy from an estimate of reddening derived from elliptical
galaxies and a reddening law derived from broad-band photometry of O
and B stars without any accommodation whatsoever for the differences
between the spectral energy distributions. YES facilitates the
determination of the ratio of total-to-selective extinction for a
target without concern as to the shape of the spectrum of the
reddening probe. Further background is given by M. L. McCall
2004, AJ, 128, 2144.
Curator's email address: [email protected]
