Scans of plates kept at Landessternwarte Heidelberg-Königstuhl. They
were obtained at location, at the German-Spanish Astronomical Center
(Calar Alto Observatory), Spain, and at La Silla, Chile. The plates
cover a time span between 1880 and 1999.
Specifically, HDAP is essentially complete for the plates taken with
the Bruce telescope, the Walz reflector, and Wolf's Doppelastrograph
at both the original location in Heidelberg and its later home on
Königstuhl.
GAVO's historical photographic plate archive (GHHPA) is a
collection of various digitized historical photographic
plates. It currently exposes:
* the scans of plates of selected Kapteyn special fields obtained
at Potsdam
* the Palomar-Leiden Trojan surveys, 1960-1977,
* a collection of plates obtained at Boyden Station, South Africa,
kept at various German observatories.
Other plate collections kept by GAVO include the Heidelberg
Digitized Astronomical Plates HDAP,
ivo://org.gavo.dc/lswscans/res/positions/siap, and the APPLAUSE
database from Potsdam.
This services provides 1D spectra from DR5 of LAMOST (Large Sky Area
Multi-Object Fiber Spectroscopic Telescope) through SSAP;
data is served both in VO-standard SDM and, via datalink, the original
SDSS-inspired FITS described in
http://dr5.lamost.org/doc/data-production-description .
In this data release from the ongoing LOw-Frequency ARray (LOFAR)
Two-metre Sky Survey (LoTSS) we present 120-168 MHz images covering
27% of the northern sky. Our coverage is split into two regions
centred at approximately 12h45m +44°30′ and 1h00m +28°00′ and spanning
4178 and 1457 square degrees respectively. The images were derived
from 3,451 hrs (7.6 PB) of LOFAR High Band Antenna data which were
corrected for the direction-independent instrumental properties as
well as direction-dependent ionospheric distortions during extensive,
but fully automated, data processing. A catalogue of 4,395,448 radio
sources is derived from our total intensity (Stokes I) maps, where the
majority of these have never been detected at radio wavelengths
before. At 6′′ resolution, our full bandwidth Stokes I continuum maps
with a central frequency of 144 MHz have: a median rms sensitivity of
83 μ Jy/beam; a flux density scale accuracy of approximately 10%; an
astrometric accuracy of 0.2′′; and we estimate the point-source
completeness to be 90% at a peak brightness of 0.8 mJy/beam. By
creating three 16 MHz bandwidth images across the band we are able to
measure the in-band spectral index of many sources, albeit the error
on the derived spectral index is > ±0.2 which is a consequence of our
flux-density scale accuracy and small fractional bandwidth. Our
circular polarisation (Stokes V) 20′′ resolution 120-168 MHz continuum
images have a median rms sensitivity of 95 μ Jy/beam, and we estimate
a Stokes I to Stokes V leakage of 0.056%. Our linear polarisation
(Stokes Q and Stokes U) image cubes consist of 480 97.6 kHz wide
planes and have a median rms sensitivity per plane of 10.8mJy/beam at
4′ and 2.2mJy/beam at 20′′; we estimate the Stokes I to Stokes Q/U
leakage to be approximately 0.2%. Here we characterise and publicly
release our Stokes I, Q, U and V images in addition to the calibrated
uv-data to facilitate the thorough scientific exploitation of this
unique dataset. This service queries the Stokes I continuum mosaic
images.
The LOFAR Two Meter Sky Survey LoTSS DR2
(:bibcode:`2022A&A...659A...1S`) obtained radio data from 27% of the
northern sky between 120 and 168 MHz in the year 2014 through 2020. This
service publishes polarization spectra of extragalactic radio sources
(radio galaxies and blazars) and the rotation measures derived from them.
We also give redshifts for all sources. The data has a spatial resolution
of 20 arcsec.
The LOFAR Two Meter Sky Survey LoTSS DR2
(:bibcode:`2022A&A...659A...1S`) obtained radio data from 27% of the
northern sky between 120 and 168 MHz in the year 2014 through 2020. This
service publishes polarization spectra of extragalactic radio sources
(radio galaxies and blazars) and the rotation measures derived from them.
We also give redshifts for all sources. The data has a spatial resolution
of 20 arcsec.