The text below is taken from the CALSPEC website
(https://www.stsci.edu/hst/instrumentation/reference-data-for-calibration-and-tools/astronomical-catalogs/calspec)
on April 17th 2024.

CALSPEC contains the composite stellar spectra that are flux standards on the HST system.
All files are in machine independent binary FITS table format. Information about the pedigree
of a given spectrum is in the header of the FITS file, which can be read with the IRAF hedit task,
by mrdfits.pro in IDL, or with the Python astropy.io.fits package. Table 1 below summarizes this
set of standard star spectra. Columns 2-4 give the spectral type, V, and B-V magnitudes of the stars.
Column 5 is the computer compatible file name with the plus and minus signs converted to underscores or omitted.
Thus, the actual CALSPEC file name is the prefix in column 5, plus one of the suffixes in columns 6 or 7,
plus ".fits". For example, a standard that has STIS data is "bd_28d4211_stis_005.fits".
The naming convention in column 7 includes STIS, NIC, and WFC to indicate some contribution from
any of the three HST spectrophotometers. Column 8 has the amount of variability found by Mullally et al. (2022),
including upper limits. More documentation on some of these stars, including coordinates, finding charts and
spectral types are in Turnshek et al. (1990), Bohlin, Colina & Finley (1995), and Colina & Bohlin (1997).

The BOSZ grid for main-sequence (MS) stars (Bohlin et al. 2017) provides models for each G-A type MS standard,
while a separate file includes the STIS and NICMOS fluxes concatenated with a BOSZ R=500 model for the
extrapolation to 32 microns (col. 7). In 2023, Szabolcs Meszaros updated his BOSZ models because of important
improvements of the model atmosphere spectral synthesis codes and linelists. The original models are now
replaced by updated calculations with the old R=300,000 model (col. 6) now replaced with R=200,000 resolution
models that extend to a shorter wavelength limit of 500A. Starting in 2022 April, the BOSZ LTE models are
replaced with R=5000 Hubeny NLTE models for stars hotter than 15,000K (Bohlin et al. 2022). Beginning in 2019,
WFC3 IR grism fluxes (Bohlin & Deustua 2019) supplement the NICMOS spectral energy distributions (SEDs).
Coordinates are in Table 2. The final two columns of Table 2 provide the complete long names needed for
a successful Simbad search.

High-fidelity, non-BOSZ models at resolutions of less than R=200,000 are available for a few of the WD stars.
The modeled IR fluxes for 13 stars are compared to Spitzer IRAC photometry in Bohlin et al. (2011).
NLTE models for the three fundamental primary WD standards GD71, GD153, and G191B2B are updated by
Bohlin, et al. (2020), where the pure H I models of Rauch (TMAP) are used for GD71 and GD153, while
G191B2B has a Hubeny (TLUSTY) metal line-blanketed model. Wavelength dependent changes are <1% from
0.167-10 microns, and there is also a wavelength independent increase of 0.87% for all SEDs. A driving
force for the 2020 update is greatly improved agreement to <1% at 0.15-30 microns between the TMAP
and TLUSTY models. As a result of the changes to the primary standards, the flux calibration is revised,
and all stars with STIS spectra and their models are updated as of 2020 March.

The observational spectra from column 7 can be compared with the column 6 models. The model calculations
cover the long wavelength limits of 2.5 microns for NICMOS, 1.7 microns for WFC3, one micron for STIS
and ACS, and ~30 microns for some JWST or Spitzer filters. The composite flux standard alpha_lyr_stis
consists of a special Kurucz 9550K model from 900-1152A (Kurucz 2003), IUE data from 1152-1675A, STIS CCD
fluxes from 1675-10200A (Bohlin & Gilliland 2004a), and the 9550K model longward of 10200A. The STIS and ACS
observations of the SDSS standard BD+17 4708 are documented in Bohlin & Gilliland (2004b) and are extended
to 2.5 microns with NICMOS data, while Bohlin & Landolt (2015) present the evidence for variability
of BD+17 4708. All observed wavelengths are corrected to the heliocentric vacuum reference frame.
Model wavelengths are corrected to the same vacuum heliocentric standard, if the radial velocity appears
in Simbad. In summary, the files of choice for calibration of photometry and low resolution spectra are
the *stis* files. For calibration of high resolution spectrometers, the R=200,000 *mod* files may be helpful.

CALSPEC also contains the ultraviolet to near-infrared absolute flux distribution of the Sun to 2.7 microns
(filename: sun_reference_stis_001.fits). The solar reference spectrum combines absolute flux measurements
from space and the ground with a model spectrum for the near-infrared (Colina, Bohlin, & Castelli 1996).
The absolute solar flux measurements of Thuillier (2003) from 1990-23975A, the composite of Rieke et al. (2009),
and the solar model from the website of R. Kurucz are additional choices for a solar reference spectrum.
The Kurucz model for the Sun (sun_mod_001.fits) at a spectral resolution of R=5000 is in column 6 of Table 1b,
where the model has been normalized to the SED of Thuillier (2003) at 6800-7700A.

Also in the CALSPEC data directory are a combined FUSE and STIS high resolution spectrum of G191B2B (Rauch et al. 2013)
 g191b2b_stisfuse_001.fits and the covariance matrix WDcovar_002.fits for the uncertainty of the HST flux
 system as a function of wavelength. As explained in more detail by Bohlin et al. (2014), the uncertainty
 is relative to the reference wavelength of 5556A (5557.5 in vacuum), where this relative uncertainty
 is zero and the absolute uncertainty is 0.5% (Bohlin 2014, Bohlin et al. 2020).

CAUTIONS:

Even though the column-7 flux distributions are the best observational SEDs, caution is still required,
because some SEDs flagged with an asterisk are not entirely from the gold-standard STIS, NICMOS, or WFC3 data.
Supplemental IUE, FOS, or Oke observations have lower signal-to-noise, wavelength precision,
and photometric accuracy, as discussed in BDC. Thus, the FITS headers of any SED used
for precision science applications should be checked to be sure that the wavelength region of
interest is identified as STIS, NICMOS, or WFC3. To aid in selecting the best SEDs,
Table 1 is divided into 1a and 1b, where the 1a stars in column 7 have all the possible STIS
coverage and 1b tabulates stars that are missing some STIS coverage. In case the UV is too
bright for the STIS MAMA detectors, IUE or FOS data may be used for 1a stars, but the asterisk
flag is retained to remind users of this deficiency. Stars cooler than A type are considered complete,
if the only missing coverage is in regions where the UV continuum flux is tiny and undetectable.
For the coolest M, L, and T stars, G750L provides complete STIS coverage.

Table 1a: Files of the Flux1 Standards with Complete STIS Coverage

Star name   Sp. T.      V       B-V   Name               Model      STIS**      Var (%)
[1]         [2]         [3]     [4]   [5]                [6]        [7]              [8]
109 VIR     A0III       3.73    -0.01 109vir             _mod_003   _stis_003        --
10 LAC      O9V         4.88    -0.21 10lac              _mod_005   _stis_007        <0.23
16 CYG B    G3V         6.20    0.66  16cygb             _mod_004   _stis_004        <0.21
18 SCO      G2V         5.50    0.65  18sco              _mod_005   _stis_005        --
1732526     A4V         12.53   0.12  1732526            _mod_005   _stisnic_007     1.40
17403462    A6V         12.48   0.20  1740346            --         _stisnic_005     --
1743045     A8III       13.52   0.28  1743045            _mod_005   _stisnic_007     <1.32
1757132     A3V         12.01   -0.10 1757132            _mod_005   _stiswfc_004     <0.37
1802271     A2V         11.53   0.02  1802271            _mod_005   _stiswfcnic_004  <0.82
1805292     A4V         12.28   0.14  1805292            _mod_004   _stisnic_006     <0.49
1808347     A3V         11.69   0.49  1808347            _mod_005   _stiswfc_004     1.65
1812095     A3V         12.01   -0.07 1812095            _mod_004   _stisnic_006     1.57
2M0036+18   L3.5        J=12.47 ...   2m003618           --         _stiswfcnic_006  --
2M0559-14   T4.5        J=13.80 ...   2m055914           --         _stiswfcnic_005  --
AGK+81 266  sdO         11.95   -0.36 agk_81d266         --         _stisnic_007*    --
ALPHA LYR   A0V         0.031   0.00  alpha_lyr          _mod_004   _stis_011*       --
BD+02 3375  A5          9.93    0.45  bd02d3375          _mod_003   _stis_006        --
BD-11 3759  M3.5V       11.32   1.60  bd11d3759          --         _stis_003        --
BD+21 0607  F2          9.22    0.44  bd21d0607          _mod_003   _stis_006        --
BD+26 2606  A5          9.73    0.39  bd26d2606          _mod_003   _stis_006        --
BD+29 2091  F5          10.22   0.50  bd29d2091          _mod_003   _stis_006        --
BD+54 1216  sdF6        9.71    0.48  bd54d1216          _mod_002   _stis_005        --
BD+60 1753  A1V         9.65    0.07  bd60d1753          _mod_005   _stiswfc_004     <0.17
BD+17 47083 sdF8        9.47    0.44  bd_17d4708         --         _stisnic_007     --
BD+75 325   sdO5        9.55    -0.33 bd_75d325          --         _stis_006*       --
C26202      F8IV        16.64   0.26  c26202             _mod_006   _stiswfcnic_005  --
DELTA UMI   A1V         4.34    0.03  delumi             _mod_004   _stis_004        0.04
ETA1 DOR    A0V         5.69    -0.01 eta1dor            _mod_004   _stis_004        0.18
ETA UMA     B3V         1.85    -0.10 etauma             _mod_004   _stis_007        --
FEIGE110    sdO         11.83   -0.30 feige110           --         _stisnic_008*    --
FEIGE34     sdO         11.14   -0.23 feige34            --         _stis_006*       --
G191B2B     DA.8        11.781  -0.33 g191b2b            _mod_012   _stiswfcnic_004* <0.74
GD153       DA1.2       13.349  -0.29 gd153              _mod_012   _stiswfcnic_004  <2.44
GD71        DA1.5       13.032  -0.25 gd71               _mod_012   _stiswfcnic_004  <1.90
GJ754.1A    DBQA5       12.29   0.05  gj7541a            _mod_001   _stis_004        --
GRW+70 5824 DA2.4       12.60   -0.06 grw_70d5824        _mod_001   _stiswfcnic_003  --
HD009051    G7III       8.92    0.81  hd009051           _mod_004   _stis_007        --
HD031128    F4V         9.14    0.41  hd031128           _mod_003   _stis_006        --
HD074000    sdF6        9.66    0.45  hd074000           _mod_003   _stis_006        --
HD101452    A2/3        8.20    -0.36 hd101452           _mod_003   _stis_003        <0.09
HD106252    G0          7.36    0.64  hd106252           _mod_006   _stis_008        --
HD111980    F7V         8.38    0.53  hd111980           _mod_003   _stis_006        --
HD115169    G3V         9.20    0.69  hd115169           _mod_003   _stis_003        <0.11
HD116405    A0V         8.34    -0.07 hd116405           _mod_004   _stis_006        <0.10
HD128998    A1V         5.83    0.00  hd128998           _mod_003   _stis_003        0.05
HD142331    G5V         8.75    0.64  hd142331           _mod_005   _stis_005        --
HD14943     A5V         5.91    0.19  hd14943            _mod_003   _stis_005        0.05
HD158485    A4V         6.50    0.13  hd158485           _mod_003   _stis_005        0.42
HD159222    G1V         6.56    0.65  hd159222           _mod_006   _stis_008        --
HD160617    F           8.73    0.45  hd160617           _mod_002   _stis_005        --
HD163466    A6V         6.85    0.19  hd163466           _mod_003   _stis_005        0.17
HD1654595   A4V         6.86    0.13  hd165459           _mod_004   _stisnic_006     --
HD167060    G3V         8.92    0.64  hd167060           _mod_005   _stis_005        <0.09
HD172728    A0V         5.74    -0.05 hd172728           _mod_002  _stis_002         --
HD180609    A0V         9.42    0.15  hd180609           _mod_004   _stis_006        <0.13
HD185975    G3V         8.10    0.68  hd185975           _mod_004   _stis_007        --
HD200654    G           9.11    0.63  hd200654           _mod_004   _stis_007        --
HD200775    B2Ve        7.43    0.33  hd200775                      _stis_001        --
HD205905    G2V         6.74    0.62  hd205905           _mod_007   _stis_009        0.26
HD2094586   G0V         7.65    0.59  hd209458           _mod_003   _stisnic_008     --
HD2811      A3V         7.50    0.17  hd2811             _mod_004   _stis_004        --
HD37725     A3V         8.31    -0.19 hd37725            _mod_005   _stiswfc_004     0.13
HD37962     G2V         7.85    0.65  hd37962            _mod_008   _stis_010        <0.09
HD38949     G1V         7.80    0.57  hd38949            _mod_005   _stis_007        1.17
HD55677     A4V         9.41    0.06  hd55677            _mod_004   _stis_004        0.24
HD607537    B3IV        6.68    -0.09 hd60753            --         _stis_004        --
HD93521     O9Vp        6.99    -0.27 hd93521            _mod_003   _stis_007*       --
HS2027+0651 DO          16.9    ...   hs2027             --         _stis_006        --
HZ21        DO2         14.69   -0.33 hz21               --         _stis_007        --
HZ438       DA          12.91   -0.31 hz43               --         _stis_005*       --
HZ43B8      M3Ve        14.30   ...   hz43b              --         _stis_005        --
HZ44        sdB         11.65   -0.23 hz44               --         _stis_006*       --
HZ4         DA3.4       14.51   0.09  hz4                --         _stis_008        --
KF06T2      K1.5III     13.80   1.30  kf06t2             _mod_006   _stiswfcnic_005  --
KF08T3      K0.5III     13.18   1.21  kf08t3             _mod_005   _stisnic_004     --
KSI2 CETI   B9III       4.28    -0.04 ksi2ceti           _mod_004   _stis_006        --
LAMBDA LEP  B0.5V       4.29    -0.25 lamlep             _mod_005   _stis_007        0.35
LDS749B     DBQ4        14.674  -0.04 lds749b            _mod_007   _stisnic_008     --
MU COL      O9.5V       5.18    -0.28 mucol              _mod_005   _stis_007        0.12
NGC2506-G31 G1V         17.9    0.7   ngc2506g31         _mod_003   _stis_003        --
NGC6681-1   ...         15.77   0.18  NGC6681_1          --         _stis_002        --
NGC6681-2   ...         16.20   0.05  NGC6681_2          --         _stis_002        --
NGC6681-3   ...         16.90   0.03  NGC6681_3          --         _stis_002        --
NGC6681-4   ...         16.14   0.04  NGC6681_4          --         _stis_002        --
NGC6681-5   ...         16.37   0.03  NGC6681_5          --         _stis_002        --
NGC6681-6   ...         16.20   0.04  NGC6681_6          --         _stis_002        --
NGC6681-7   ...         16.05   1.24  NGC6681_7          --         _stis_002        --
NGC6681-8   ...         17.01   -0.01 NGC6681_8          --         _stis_002        --
NGC6681-9   ...         15.80   0.18  NGC6681_9          --         _stis_002        --
NGC6681-10  ...         19.14   -0.14 NGC6681_10         --         _stis_002        --
NGC6681-11  ...         15.65   0.22  NGC6681_11         --         _stis_002        --
NGC6681-12  ...         17.62   -0.08 NGC6681_12         --         _stis_002        --
P041C9      GOV         12.16   0.68  p041c              _mod_004   _stisnic_009*    <0.44
P177D       G0V         13.49   0.60  p177d              _mod_005   _stisnic_010*    <1.00
P330E       G2V         12.92   0.64  p330e              _mod_007   _stiswfcnic_006* <0.76
SDSS132811  DA          g=17.01 ...   sdss132811         --         _stis_004        --
SDSSJ151421 DA1.8       16.5    0.89  sdss151421         _mod_004   _stis_005        --
SF1615+001A G           16.75   0.49  sf1615_001a        _mod_005   _stisnic_010     --
SIGMA ORI   O9.5V+B0.2V 3.79    -0.21 sigori             --         _stis_001        --
SIRIUS      A1V         -1.46   0.00  sirius             _mod_005   _stis_005*       --
SNAP-2      G0-5        16.23   0.86  snap2              _mod_006   _stiswfcnic_005  --
VB8         M7V         16.92   1.8   vb8                --         _stiswfcnic_004  --
WD0148+467  DA3.6       12.46   0.06  wd0148_467         --         _stiswfc_001     --
WD0227+050  DA2.5       12.80   -0.05 wd0227_050         --         _stiswfc_002     --
WD0308-565  sdB         14.07   -0.11 wd0308_565         _mod_007   _stis_009        --
WD0809+177  DA          13.46   --    wd0809_177         --         _stiswfc_002     --
WD1057+719  DA1.2       14.68   ...   wd1057_719         _mod_009   _stisnic_011     <6.05
WD1105-048  DA3         13.06   0.04  wd1105_048         --         _stiswfc_002     --
WD1105-340  DA3.6       13.63   0.16  wd1105_340         --         _stiswfc_002     --
WD1202-232  DA5.7       12.90   0.14  wd1202_232         --         _stiswfc_002     --
WD1327-083  DA3.5       12.34   0.06  wd1327_083         --         _stiswfc_004     --
WD1544-377  DA4.8       12.80   0.30  wd1544_377         --         _stiswfc_002     --
WD1657+343  DA.9        16.1    ...   wd1657_343         _mod_009   _stiswfcnic_006  <37.88
WD1713+695  DA3.2       13.20   ~0.2  wd1713_695         --         _stiswfc_002     --
WD1911+536  DA          13.26   ~-0.1 wd1911_536         --         _stiswfc_001     --
WD1919+145  DA3.3       13.01   0.06  wd1919_145         --         _stiswfc_001     --
WD2039-682  DA3.0       13.30   0.05  wd2039_682         --         _stiswfc_001     --
WD2117+539  DA3.4       12.81   --    wd2117_539         --         _stiswfc_002     --
WD2126+734  DA3.1       12.83   -0.03 wd2126_734         --         _stiswfc_002     --
WD2149+021  DA2.8       12.74   -0.01 wd2149_021         --         _stiswfc_001     --
WD2341+322  DA3.8       12.94   0.12  wd2341_322         --         _stiswfc_004     --


Table 1b: Files of the Flux1 Standards with Incomplete STIS Coverage

Star name   Sp. T.  V      B-V   Name          Model    STIS**
[1]         [2]     [3]    [4]   [5]           [6]      [7]
1812524     A4V     12.27  0.18  1812524       --       _nic_005
BD+28 42114 sdO     10.51  -0.34 bd_28d4211    --       _stis_005*
KF01T5      K1III   13.56  ...   kf01t5        --       _nic_004
KF06T1      K1.5III 13.52  0.98  kf06t1        --       _nic_004
SNAP-1      sdB     15.40  0.20  snap1         --       _stisnic_008
SUN         G2V     -26.75 0.63  sun_reference --       _stis_002*
SUN         G2V     -26.75 0.63  sun           _mod_001 --
WD0320-539  DA      14.9   ...   wd0320_539    _mod_001 _stis_005
WD0947+857  DA      16.4   ...   wd0947_857    _mod_003 _stis_006
WD1026+453  DA      16.13  -0.04 wd1026_453    _mod_003 _stis_006

* WARNING. Some wavelength coverage from sources of lower precision, such as IUE, FOS, or Oke.
** The STIS low resolution modes cover the 1140-10200A range, the NICMOS grism coverage is 0.8-2.5 micron,
and the two WFC3 grisms cover 0.8-1.7 micron. See the *.fits headers for the exact source ranges.

(1)  The unit of flux in all files is erg s-1 cm-2 A-1.
(2)  Dust ring (Bohlin et al, 2011). Variable at +/- 0.01 mag (Pancino et al. 2012).
(3)  BD+17 4708 is variable (Bohlin & Landolt 2015).
(4)  BD+28 4211 has a companion at 2.8arcsec (Landolt & Uomoto (2007).
(5)  Dust ring (Bohlin et al, 2011).
(6)  Transiting Planet.
(7)  No single model fits well in the sense that an unresolved cool companion would explain the problem.
(8)  HZ43 and HZ3B are separated by ~3arcsec (BDC).
(9)  P041C has an M companion 0.57arcsec away (Gilliland & Rajan 2011)
Access to the latest CALSPEC files



Table 2:  Coordinates, Radial Velocity (km/s), Proper Motion (PM), and Alternate Star Names

Star Name    R.A.        Decl.        Vr     PM (mas/yr)         Simbad Name                  Alt. Simbad Name
--          (2000)       (2000)       --     R.A.        Decl.   --                           --
10 LAC      22 39 15.679 +39 03 00.97 -10.0  -0.32       -5.46   --                           --
109 VIR     14 46 14.925 +01 53 34.38 -6.1   -114.03     -22.13  HD130109                     --
16 CYG B    19 41 51.973 +50 31 03.09 -27.7  -134.79     -162.49 HD186427                     --
18 SCO      16 15 37.270 -08 22 09.98 11.9   232.16      -495.37 HD146233                     --
1732526     17 32 52.630 +71 04 43.12 --     0.22        -2.71   2MASS J17325264+7104431      TYC 4424-1286-1
1740346     17 40 34.679 +65 27 14.77 --     -5.72       -3.44   2MASS J17403468+6527148      TYC 4207-219-1
1743045     17 43 04.486 +66 55 01.66 --     1.10        -2.79   2MASS J17430448+6655015      --
1757132     17 57 13.233 +67 03 40.77 --     0.41        -14.03  2MASS J17571324+6703409      TYC 4212-455-1
1802271     18 02 27.163 +60 43 35.54 --     5.40        2.17    2MASS J18022716+6043356      TYC 4201-1542-12
1805292     18 05 29.275 +64 27 52.13 --     -1.64       10.06   2MASS J18052927+6427520      TYC 4209-1396-1
1808347     18 08 34.736 +69 27 28.72 --     4.43        8.52    2MASS J18083474+6927286      TYC 4433-1800-1
1812095     18 12 09.567 +63 29 42.26 --     4.07        1.31    2MASS J18120957+6329423      TYC 4205-1677-1
1812524     18 12 52.381 +60 02 31.95 --     -3.03       -8.02   2MASS J18125240+6002319      TYC 4201-1717-1
2M0036+18   00 36 16.112 +18 21 10.29 19.0   901.56      124.02  2MASS J00361617+1821104      --
2M0559-14   05 59 19.188 -14 04 49.22 --     570.20      -337.59 2MASS J05591914-1404488      --
AGK+81 266  09 21 19.177 +81 43 27.63 --     -11.26      -51.26  --                           --
ALPHA LYR   18 36 56.336 +38 47 01.28 -21.0  200.94      286.23  Vega                         HD172167
BD+02 3375  17 39 45.595 +02 24 59.61 -398.0 -366.01     75.12   --                           --
BD-11 3759  14 34 16.812 -12 31 10.42 -1.0   -355.04     593.22  --                           --
BD+17 4708  22 11 31.375 +18 05 34.16 -291.0 506.37      60.49   --                           --
BD+21 0607  04 14 35.516 +22 21 04.25 340.0  425.99      -301.87 HD284248                     --
BD+26 2606  14 49 02.355 +25 42 09.14 33.0   -5.88       -347.60 --                           --
BD+28 4211  21 51 11.022 +28 51 50.37 --     -34.73      -56.85  WD2148+286                   --
BD+29 2091  10 47 23.163 +28 23 55.93 83.0   177.50      -824.83 --                           --
BD+54 1216  08 19 22.572 +54 05 09.63 66.0   -34.20      -628.56 HD233511                     --
BD+60 1753  17 24 52.275 +60 25 50.75 -27.3  4.89        3.76    --                           --
BD+75 325   08 10 49.490 +74 57 57.94 -50.0  7.17        10.30   --                           --
C26202      03 32 32.843 -27 51 48.58 --     --          --      2MASS J03323287-2751483      [B2010] C26202
DELTA UMI   17 32 12.997 +86 35 11.26 -7.6   10.17       53.97   HD166205                     --
ETA UMA     13 47 32.438 +49 18 47.76 -13.0  -121.17     -14.91  HD120315                     --
ETA1 DOR    06 06 09.382 -66 02 22.63 17.6   13.66       27.82   HD42525                      --
FEIGE110    23 19 58.400 -05 09 56.17 --     -10.68      0.31    --                           --
FEIGE34     10 39 36.738 +43 06 09.21 1.0    12.54       -25.41  WD1036+433                   --
G191B2B     05 05 30.618 +52 49 51.92 22.1   12.70       -93.42  BD+52 913                    EGGR 247 WD0501+527
GD153       12 57 02.322 +22 01 52.63 8.3    -38.40      -202.99 WD1254+223                   --
GD71        05 52 27.620 +15 53 13.23 30.0   76.73       -172.96 WD0549+158                   --
GJ754.1A    19 20 34.923 -07 40 00.07 --     -61.28      -161.77 LAWD74                       WD1917-077
GRW+70 5824 13 38 50.478 +70 17 07.64 26.0   -402.08     -24.56  LAWD52                       WD1337+705
HD2811      00 31 18.490 -43 36 23.00 --     -6.02       -4.18   --                           --
HD009051    01 28 46.503 -24 20 25.44 -72.0  53.56       -17.03  --                           --
HD14943     02 22 54.675 -51 05 31.66 5.0    22.33       66.38   HR 701                       --
HD031128    04 52 09.910 -27 03 50.94 112.0  164.76      -26.52  --                           --
HD37725     05 41 54.370 +29 17 50.96 --     15.05       -26.93  --                           --
HD37962     05 40 51.966 -31 21 03.99 3.0    -59.65      -365.23 --                           --
HD38949     05 48 20.059 -24 27 49.85 3.0    -30.44      -35.42  --                           --
HD55677     07 14 31.290 +13 51 36.79 -2.0   -2.66       -6.81   --                           --
HD60753     07 33 27.319 -50 35 03.31 20.0   -3.12       5.31    --                           --
HD074000    08 40 50.804 -16 20 42.51 206.0  350.82      -484.16 --                           --
HD93521     10 48 23.512 +37 34 13.09 -14.0  0.22        1.72    --                           --
HD101452    11 40 13.651 -39 08 47.67 --     -34.17      -20.98  --                           --
HD106252    12 13 29.510 +10 02 29.89 16.0   22.86       -280.01 --                           --
HD111980    12 53 15.053 -18 31 20.01 155.0  299.49      -796.09 --                           --
HD115169    13 15 47.388 -29 30 21.18 21.2   -110.57     -82.09  --                           --
HD116405    13 22 45.124 +44 42 53.91 -19.0  8.01        -10.29  --                           --
HD128998    14 38 15.222 +54 01 24.02 -3.0   17.28       -18.99  HR 5467                      --
HD142331    15 54 19.788 -08 34 49.37 -70.8  -105.98     -23.73  --                           --
HD158485    17 26 04.837 +58 39 06.83 -30.0  -9.10       14.67   HR 6514                      --
HD159222    17 32 00.992 +34 16 16.13 -52.0  -240.70     63.71   HR 6538                      --
HD160617    17 42 49.324 -40 19 15.51 100.0  -62.39      -393.23 --                           --
HD163466    17 52 25.376 +60 23 46.94 -16.0  -2.73       42.67   --                           --
HD165459    18 02 30.741 +58 37 38.16 -19.2  -13.06      24.61   --                           --
HD167060    18 17 44.143 -61 42 31.62 15.2   88.52       -145.15 --                           --
HD172728    18 37 33.517 +62 31 35.67 -10.5  -8.98       49.58   --                           --
HD180609    19 12 47.200 +64 10 37.17 --     -3.06       -7.79   --                           --
HD185975    20 28 18.740 -87 28 19.94 -19.0  169.76      -56.99  --                           --
HD200654    21 06 34.751 -49 57 50.28 -45.0  193.94      -273.89 --                           --
HD200775    21 01 36.921 +68 09 47.79 -3.4   7.60        -2.82   --                           --
HD205905    21 39 10.151 -27 18 23.67 -17.0  384.10      -83.96  --                           --
HD209458    22 03 10.773 +18 53 03.55 -15.0  29.58       -17.89  --                           --
HS2027+0651 20 29 32.506 +07 01 07.70 --     9.24        1.53    WD2027+0651                  --
HZ21        12 13 56.264 +32 56 31.36 --     -100.88     30.13   WD1211+332                   --
HZ4         03 55 21.988 +09 47 18.13 46.0   173.27      -5.51   WD0352+096                   --
HZ43        13 16 21.853 +29 05 55.38 54.0   -157.96     -110.23 WD1314+293                   --
HZ43B       13 16 21.495 +29 05 53.07 --     --          --      --                           --
HZ44        13 23 35.263 +36 07 59.55 --     -66.27      -4.52   WD1321+364                   --
KF01T5      18 04 03.894 +66 55 43.81 -22.0  -0.40       0.47    2MASS J18040388+6655437      [RMC2005] KF01T5
KF06T1      17 57 58.486 +66 52 29.41 -41.0  -2.13       -8.70   2MASS J17575849+6652293      [RMC2005] KF06T1
KF06T2      17 58 37.995 +66 46 52.11 --     0.62        -4.42   2MASS J17583798+6646522      [RMC2005] KF06T2
KF08T3      17 55 16.216 +66 10 11.61 -50.0  2.09        -6.39   2MASS J17551622+6610116      [RMC2005] KF08T3
KSI2 CETI   02 28 09.557 +08 27 36.22 12.0   23.71       -4.79   --                           --
LAMBDA LEP  05 19 34.524 -13 10 36.44 20.0   -3.30       -4.91   --                           --
LDS749B     21 32 16.233 +00 15 14.40 -81.0  413.23      27.27   LAWD87                       WD2129+000
MU COL      05 45 59.895 -32 18 23.16 109.0  2.99        -22.03  --                           --
NGC2506G31  08 00 14.212 -10 47 29.47 --     --          --      --                           --
NGC6681-1   18 43 13.319 -32 17 25.36 218.7  --          --      --                           --
NGC6681-2   18 43 13.165 -32 17 25.82 218.7  --          --      --                           --
NGC6681-3   18 43 13.041 -32 17 25.41 218.7  --          --      --                           --
NGC6681-4   18 43 12.893 -32 17 26.43 218.7  --          --      --                           --
NGC6681-5   18 43 12.872 -32 17 26.56 218.7  --          --      --                           --
NGC6681-6   18 43 12.755 -32 17 25.69 218.7  --          --      --                           --
NGC6681-7   18 43 12.639 -32 17 27.09 218.7  --          --      --                           --
NGC6681-8   18 43 12.278 -32 17 27.51 218.7  --          --      --                           --
NGC6681-9   18 43 12.199 -32 17 27.11 218.7  --          --      --                           --
NGC6681-10  18 43 12.146 -32 17 26.58 218.7  --          --      --                           --
NGC6681-11  18 43 12.049 -32 17 27.52 218.7  --          --      --                           --
NGC6681-12  18 43 11.902 -32 17 27.91 218.7  --          --      --                           --
P041C       14 51 57.980 +71 43 17.39 -22.0  -49.32      19.58   2MASS J14515797+7143173      GSPC P 41-C
P177D       15 59 13.579 +47 36 41.91 --     -7.90       1.57    2MASS J15591357+4736419      GSPC P177-D
P330E       16 31 33.813 +30 08 46.40 -53.0  -8.99       -38.77  2MASS J16313382+3008465      GSPC P330-E
SDSS132811  13 28 11.498 +46 30 50.94 --     -130.86     -30.80  SDSS J132811.45+463050.8     WD1326+467
SDSSJ151421 15 14 21.273 +00 47 52.81 12.0   4.4         -27.04  SDSS J151421.27+004752.8     LB769 WD1511+009
SF1615+001A 16 18 14.240 +00 00 08.61 --     2.40        -10.94  2MASS J16181422+0000086      [B2010] SF1615+001A
SIGMA ORI   05 38 44.765 -02 36 00.28 29.9   4.6         -0.4    --                           --
SIRIUS      06 45 08.917 -16 42 58.02 -6.0   -546.01     -1223.1 --                           --
SNAP-1      16 29 35.747 +52 55 53.61 --     -3.16       -20.80  2MASS J16293576+5255532      --
SNAP-2      16 19 46.103 +55 34 17.86 --     -2.91       -10.95  2MASS J16194609+5534178      --
VB8         16 55 35.256 -08 23 40.75 15.0   -813.42     -870.61 --                           --
WD0148+467  01 52 02.962 +47 00 06.65 64.0   4.64        122.02  --                           --
WD0227+050  02 30 16.628 +05 15 50.70 16.5   76.96       -24.50  --                           --
WD0809+177  08 12 37.809 +17 37 01.43 --     73.48       -87.17  --                           --
WD1105-048  11 07 59.950 -05 09 26.03 47.9   -55.55      -442.63 --                           --
WD1105-340  11 07 47.897 -34 20 51.49 --     39.89       -263.43 --                           --
WD1202-232  12 05 26.674 -23 33 12.14 23.3   41.82       226.56  --                           --
WD1544-377  15 47 30.021 -37 55 08.46 21.1   -423.69     -209.11 --                           --
WD1713+695  17 13 06.091 +69 31 25.51 --     -55.51      -343.04 --                           --
WD1911+536  19 12 48.566 +53 43 13.45 --     144.45      136.06  --                           --
WD1919+145  19 21 40.418 +14 40 41.40 49.5   -33.02      -75.93  --                           --
WD2039-682  20 44 21.459 -68 05 21.36 57.0   182.10      -228.17 --                           --
WD2117+539  21 18 56.264 +54 12 41.24 --     -85.45      193.19  --                           --
WD2126+734  21 26 57.656 +73 38 44.67 8.0    55.34       -314.20 --                           --
WD2149+021  21 52 25.379 +02 23 19.58 28.2   15.32       -300.53 --                           --
WD0308-565  03 09 47.918 -56 23 49.41 -68.0  149.24      66.92   --                           --
WD0320-539  03 22 14.820 -53 45 16.47 57.8   6.56        -59.93  --                           --
WD0947+857  09 57 54.296 +85 29 40.88 --     -28.13      -27.27  --                           --
WD1026+453  10 29 45.295 +45 07 04.93 --     -90.46      1.68    --                           --
WD1057+719  11 00 34.243 +71 38 02.92 76.0   -43.64      -21.75  --                           --
WD1327-083  13 30 13.637 -08 34 29.47 36.0   -1111.1     -472.38 Gaia DR2 3630035787972473600 --
WD1657+343  16 58 51.113 +34 18 53.32 --     8.77        -31.23  Gaia DR2 1337946019956816256 --
WD2341+322  23 43 50.721 +32 32 46.73 -16.0  -215.82     -59.74  Gaia DR2 2871730307948650368 LAWD93

History

2023 September Update
In addition to Ks photometry for nine G-stars from a G. Rieke draft (Absolute Calibration IV:
Use of G-Type Stars as Primary Calibrators), the available Spitzer IRAC photometry of Bohlin et al. (2022)
is now a constraint to the model fits for nine G-stars: 16cygb, 18sco, hd106252, hd142331, hd159222,
hd167060, hd205905, hd37962, and p330e. HD142331 is not included in Bohlin et al. (2022). The E(B-V)=0.02
prior on 18 Sco is removed, even though the best fit of E(B-V)=0.06 seems a bit high.
2023 April Update
George Rieke provided precision Ks photometry that improved the constraints on fitting BOSZ LTE models
for seven stars (18sco, hd106252, hd205905, hd37962, ngc2506g31, p177d, and snap2.) Because of instabilities
of the fits due to partial degeneracy of effective temperature and reddening, two stars required priors
of E(B-V)=0.02 for 18sco and E(B-V)=0.08 for ngc2506g31. The Rieke Ks values for 16CygB, HD159222, and P330E
are consistent to better than 1% with existing fits to their HST spectrophotometry.

2023 February Update
Karl Gordon provided a new extinction curve for 912A to 32 microns and R(V)=A(V)/E(B-V)=3.1 (Gordon et al. 2023).
Szabolcs Meszaros updated his BOSZ models for the G-A type stars; and those *mod* files that were originally
at R=300,000 are now R=200,000. GD153 and GD71 have revised radial velocities. Of the total of 126 *stis* SEDs,
there are now 71 revised stellar spectra files. There are revised *mod* files for 59 of the 76 stars with models.
Only those SEDs with substantial change of >0.3% are updated.

2022 October Update
The CTE correction for the STIS CCD data is updated (Bohlin & Lockwood 2022); and there are 18 new stars of
which only two have models. There are a total of 69 new and revised stellar spectra files (*stis*), plus new
or revised model files (*mod*) for 30 of the 69 stars. An existing SED is revised if there are substantial
changes of >0.5% in the stellar flux. With the new formulation for the STIS CTE correction the STIS, ACS,
and WFC3 flux measures are in accord at the 1% level, not only for the primary standards and other stars in
the neighborhood of V=13 and brighter, but also now for fainter stars in the V=16 range.

2022 April Update
A column 8 is added to Table 1a for the amount of variability found by Mullally et al. (2022). Eleven revised
observational and 10 revised model SEDs are in CALSPEC. Three of these have improved model fits with a change
that exceeds 0.5% (1732526, 1743045, HD37962); four faint WDs have significant additional STIS observations
(SDSSJ151421, WD0308-565, WD1057+719, WD1657+343); and four hot stars are now modeled with a new NLTE grid to
replace the previous LTE models (10LAC, ETAUMA, LAMLEP, MUCOL). The model for the He star WD0308-565 is unchanged.
Compare the Narayan et al. (2019) model to the CALSPEC model for SDSSJ151421.

2021 March Update
There are new pure helium Koester models for LDS749B and WD0308-565; both the model and the observational
SEDs are new for these two stars. The 19 SEDs with WFC3 IR grism data are updated. The columns for FOS+Oke
and IUE+Oke are deleted, and those SEDs are removed from current_calspec, because of lower precision than
the robust set of modern HST data. Those demoted SEDs remain in the full CALSPEC directory.

2020 April Update
Three stars with more STIS observations and 12 new stars in the NGC6681 globular cluster are delivered.
WD1057+719 now has full STIS coverage and is promoted from Table 1b to 1a. A preferred faint standard,
WD1657+343 has a robust set of STIS observations along with WFC3 and NICMOS spectra, while WD1057+719 is
deficient in G750L with only one exposure. The faint WD0308-565 has only two repeat verification observations,
except for G230L with the desired minimum of three observations. The 12 faint NGC6681 stars are in a crowded
field, and some have a few percent long-wavelength contamination from neighbors. These 12 stars appear in the
finding chart of Proffitt, et al, (2003), Avila et al. (2019) and correspond to those labels a-m with the
omission of star d. The Table 1a B and V values are actually HST/WFC3 F438W and F606W photometry from here.

2020 March Update
The most recent SEDs calculated by the TLUSTY and TMAP NLTE model atmosphere codes for the primary
WDs G191B2B, GD153, and GD71 show improved agreement to 1% from 0.15 to 30 microns, in comparison to the
previous 1% consistency only from 0.2 to 5 microns. These new NLTE models of hot WDs now provide the flux
standards from the FUV to the mid-IR (Bohlin, Hubeny, and Rauch 2020, AJ, in press). The wavelength dependent
change in the HST flux scale exceeds 1% only shortward of 0.167 and longward of 10 microns but does reach 2%
at the short wavelength limit of STIS at 0.115 micron. In addition, there is a gray increase of 0.87% in all
fluxes due to the increase of the 5556A (air) flux of Vega from 3.44 to 3.47 e-9 erg s-1 cm-2 A-1.

2019 September Update
To improve the photometric precision, the standard extraction height is increased for the STIS G230LB and
G430L gratings, making the default height 11 pixels for all five CCD modes. New STIS observations of Table
1b stars in Cycle 26 have promoted eta UMa, Feige 110, Feige 34, HD93521, HZ21, HZ4, and HZ44 from Table 1b
to Table 1a. New stars for JWST calibration are 109 Vir, 16 CygB, 18 Sco, delta UMi, eta1 Dor, HD101452,
HD115169, HD128998, HD142331, HD167060, HD2811, and HD55677. Models for 12 low-metallicity, Southern stars
from program 12813 now have R=300,000 BOSZ models. There is one new WD, while Vega and Sirius change by 1-2%,
because the correction for these highly saturated data is found to change with time (Bohlin, et al. 2019).

2019 January Update
New WFC3 IR grism SEDs are incorporated in revised SEDs for 17 stars and in two new WDs WD1327_083 and
WD2341_322 (Bohlin & Deustua 2019 subm.) Two new stars with only STIS data are added: BD_11D3759
(Maíz Apellániz & Weiler 2018) and a faint WD SDSS132811 for ACS/SBC calibration.

2017 November Update
The R=5000 resolution solar model from the Kurucz website is added as sun_mod_001.fits.

2017 August Update
The STIS G430L region of GRW+70 5824 is upgraded from the poor single observation to an average of
multiple visits. Because of the multitude of UV observation for monitoring the changing STIS sensitivity,
GRW+70 5824 is now among the best choices of standard stars. The sparse sample of cool stars in CALSPEC
motivated new STIS observations of KF08T3 (K1.5III) for combining with the existing NICMOS SED to make
the new kf08t3_stisnic_001. The models for the JWST calibration are updated to include the computed model continuum.

2017 February Update
Thirty-two main sequence stars for JWST calibration are re-delivered after fitting BOSZ models to the
STIS & NICMOS SEDs (Bohlin et al. 2017). The R=500 model provides the extrapolation of the data to 32 microns,
while the pure R=300,000 model is also available here; both models are normalized to the STIS flux
distribution at 6000-9000A.

2015 April Update
The wavelength coverage of P330E is extended to 2000A, and Table 2 is updated.

2015 January Update
The G750L STIS spectra require a wider extraction width of 11 pixels, resulting in flux changes
of up to ~2% (Bohlin & Proffitt 2015).

2014 March Update
A STIS flux distribution for the primary IR standard Sirius (Bohlin 2014) is added to CALSPEC with
an IUE extension to shorter wavelengths and with a special Kurucz model beyond 1 micron. The specially
tailored Kurucz models for both Sirius and Vega, as normalized to STIS, are also now included.
Bohlin (2014) reconciled the absolute visible and IR flux measures, resulting in a 5556A flux reduction
from 3.46 to 3.44 e-9 erg s-1 cm-2 A-1. Thus, all of the STIS and NICMOS SEDs are reduced by 0.6% at all wavelengths.

2013 December Update
Added coordinates for Reach et al. (2005) stars to Table 2.

2013 November Update
The low dispersion (R~500) CALSPEC database is expanded from 60 to 93 members with 19 new SEDs for
JWST flux calibration (programs 12428 and 12682), 13 new southern standards (12813), and one partial
flux distribution from the MAST HST archive. The new stars are measured with STIS and have preliminary
extensions to 40 microns from model atmosphere fits. The basis for the wavelength dependence of the
fluxes is switched from Hubeny pure hydrogen to Rauch model atmosphere calculations, and all dependence
on ground based V magnitudes is removed (Bohlin, Gordon, & Tremblay 2014). This delivery encompasses
an update for 48 stars with STIS or NICMOS spectrophotometry, the 32 new standards with complete STIS
coverage, and eta UMa with archival STIS G230LB data. In addition, 8 high fidelity stellar models are
new or updated. For the first time, high dispersion observations of G191B2B and an uncertainty
covariance matrix are included.

2011 December Update
Calibration standard WD0308-565 derived from STIS data was added to the list of CALSPEC data.

2010 February Update
The 2010 February CALSPEC delivery included six revised models, 22 revised standard star flux distributions,
and four new SEDs from STIS observations. HZ43 was demoted from its primary standard category some years
ago because of its bright cool companion. The revisions to the flux distributions are all generally
less than 1%. The main change was driven by the discovery of a small error of ~0.57% in the gain 4 to
gain 1 ratio for the STIS CCD (Goudfroiij, et al. 2009). The weighting for the STIS sensitivity is changed
from the total counts for each observation to equal weight for each of the three primary standard WDs,
regardless of the number of observations. A few stars have additional STIS observations included in their
observed average SED. The NICMOS dispersion relations have been updated (Pirzkal, Bohlin, & Thatte 2009).
For seven G stars (Bohlin 2010), the observed flux distributions have been extended from the NICMOS
long wavelength limit of ~2.5 microns to 40 microns, using the best fitting Castelli & Kurucz (2004) model SED.

2009 January Update
The 2009 January CALSPEC delivery encompassed six new models and 22 standard star flux distributions.
The switch to TLUSTY203 caused a small change in the continuum fluxes with a 0.3% increase in the
1300A/10000A flux ratio. In a narrow region around 4000A between H-delta and H-epsilon, the new models
are up to ~0.9% fainter. The correction of a V bandpass error made all stars fainter by a constant 0.35%,
independent of wavelength. Pure hydrogen NLTE models are provided for the first time for the faint stars
WD1057+719 and WD1657+343; and these models include a small amount of interstellar reddening (Bohlin 2007).
There is one new standard, HD209458, delivered to CALSPEC for the first time. The G230LB STIS spectra of
G191B2B have replaced the FOS fluxes at 1700-3850A, and new NICMOS observations are included for many stars.

UPDATES: 1996Feb22, 1999Jul19, 2001Jun5, 2004Feb27, 2006Sep1, 2007Oct LDS749B (Bohlin & Koester 2008),
2008Jul Bohlin & Cohen (2008), 2009Jan, 2010Feb, 2011Dec WD0308-565, 2013Nov, 2013Dec, 2014Mar, 2015Jan,
2015Apr, 2017Feb, 2017Aug, 2017Nov, 2019Jan, 2019Sep, 2020Mar, 2020Apr, 2021Mar, 2022Apr, 2022Oct,
2023Feb, 2023Apr, 2023Sep..

PLEASE report errors or send comments to bohlin@stsci.edu.

Thanks to Pierre Maxted for a set of corrections.

This page made use of the SIMBAD database, operated at CDS, Strasbourg, France.

References
Avila, R. J., et al. 2019, Instrument Science Report, ACS 2019-05, (Baltimore:STScI)
Bohlin, R. C., & Lockwood, S. 2022, Instrument Science Report, STIS 2022-07, (Baltimore:STScI)
Bohlin, R. C., Krick, J. E., Gordon, K. D., and Hubeny, I. 2022, AJ, 164, 10
Bohlin, R. C., Hubeny, I., & Rauch, T. 2020, AJ, 160, 21
Bohlin. R. C., & Deustua, S. E. 2019, AJ, 157, 229.
Bohlin, R. C., Deustua, S. E., and de Rosa 2019, AJ, 158, 211
Bohlin, R. C., Meszaros, Sz., Fleming, S., Gordon, K. D., Koekemoer, A. M., & Kovacs, J. 2017, AJ, 153, 234
Bohlin, R. C., & Landolt, A. U. 2015, AJ, 149, 122
Bohlin, R. C., & Proffitt, C. R. 2015, Instrument Science Report, STIS 2015-01, (Baltimore:STScI)
Bohlin, R. C. 2014, AJ, 147, 127
Bohlin, R. C., Gordon, K. D., & Tremblay, P.-E. 2014, PASP, 126, 711
Bohlin, R. C., et al. 2011, AJ, 141, 173
Bohlin, R. C. 2010, AJ, 139, 1515
Bohlin, R. C., & Cohen, M. 2008, AJ, 136, 1171
Bohlin, R. C., & Koester, D. 2008, AJ, 135, 1092
Bohlin, R. C. 2007, in The Future of Photometric, Spectrophotometric, and Polarimetric Standardization, ASP Conf. Series,
    Vol. 364, p. 315 ed. C. Sterken
Bohlin, R. C., & Gilliland, R. L. 2004a, AJ, 127, 3508
Bohlin, R. C., & Gilliland, R. L. 2004b, AJ, 128, 3053
Bohlin, R. C., Dickinson, M. E., & Calzetti, D. 2001, AJ, 122, 2118 (BDC)
Bohlin, R.C. 2000, AJ, 120, 437
Bohlin, R.C. 1996, AJ, 111, 1743
Bohlin, R.C., Colina, L., & Finley, D.S. 1995, AJ, 110, 1316
Castelli, F., & Kurucz, R. 2004, IAU Symp. No. 210, Modeling of Stellar Atmospheres, eds. N. Piskunov, W. Weiss,
    & D. Gray 2003, poster A20; also arXiv:0405.087 [astro-ph]
Cohen, M., Megeath, S.~T., Hammersley, P.~L., Martin-Luis, F., & Stauffer, J. 2003, AJ, 125, 2645
Colina, L., & Bohlin, R. 1994, AJ, 108, 1931
Colina, L., & Bohlin, R. 1997, AJ, 113, 1138
Colina, L., Bohlin, R.C., & Castelli, F. 1996, AJ, 112, 307
Gilliland, R., & Rajan, A. 2011, Instrument Science Report, WFC3 2011-03, (Baltimore:STScI)
Gordon, K. D., et al. 2023, ApJ, 950, 86
Goudfrooij, P., Wolfe, M. A., Bohlin, R. C., Proffitt, C. R., & Lennon, D. J. 2009, Instrument Science Report,
    STIS 2009-02, (Baltimore:STScI)
Kurucz, R. 2003, and all references to Kurucz website, http://kurucz.harvard.edu/
Landolt, A., & Uomoto, A. 2007, AJ, 133, 768
Maíz Apellániz, J., & Weiler, M. 2018, A&A, 619, 180
Megessier, C. 1995, A&A, 296, 771
Mullally, S. E., et al. 2022, AJ, 163, 136
Narayan, G., et al. 2019, ApJS, 241, 20
Oke, J.B. 1990, AJ, 99, 1621
Pancino, E., et al. 2012, MNRAS, 426, 1767
Pirzkal, N., Bohlin, R.,  & Thatte D. 2009, Instrument Science Report, NICMOS 2009-006, (Baltimore:STScI)
Proffitt, C. R., Brown, T. M., Mobasher, B., & Davies, J. 2003, Instrument Science Report, STIS 2003-01,
    (Baltimore:STScI)
Rauch, T., Werner, K., Bohlin, R., & Kruk, J. 2013, A&A, 560, A106
Reach, W. T., et al. 2005, PASP, 117, 978
Rieke, G. H., et al. 2008, AJ, 135, 2245
Thuillier, G., Herse, M., Labs, D., Foujols, T., Peetermans, W., Gillotay, D., Simon, P., & Mandel, H. 2003,
    Sol. Phys., 214, 1
Turnshek, D.A., Bohlin, R.C., Williamson, R., Lupie, O., Koornneef, J., & Morgan D. 1990, AJ, 99, 1243