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The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
|
A Close Encounter Of The Ste
…
| Title |
A Close Encounter Of The Stellar Kind |
| Explanation |
The unassuming star centered in this sky view [ http://skyview.gsfc.nasa.gov ] will one day be our next door [ http://antwrp.gsfc.nasa.gov/apod/ap010318.html ] stellar neighbor. The faint 9th magnitude red dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap991120.html ], currently 63 light-years away in the constellation Ophiucus [ http://www.seds.org/Maps/Stars_en/Fig/ophiuchus.html ], was recently discovered to be approaching our Solar System. Known in catalogs of nearby stars [ http://cdsweb.u-strasbg.fr/htbin/myqcat3?V/70A/ ] as Gliese (Gl) 710 it is predicted to come within nearly 1 light-year of the Sun ... about 1.5 million years from now. At that distance this star, presently much too faint to be seen [ http://liftoff.msfc.nasa.gov/academy/universe/MAG.HTML ] by the naked eye, will blaze at 0.6 magnitude - rivaling the apparent brightness of the mighty red giant Antares [ http://antwrp.gsfc.nasa.gov/apod/ap970624.html ]. Ultimately Gliese 710 poses no direct collision danger itself although its gravitational influence will likely scatter comets out of the Solar System's reservoir, the Oort cloud [ http://www.windows.umich.edu/cgi-bin/tour_def/comets/ Oort_cloud.html ], sending some inbound. This future stellar encounter [ http://adsabs.harvard.edu/cgi-bin/ nph-bib_query?bibcode=1999AJ....117.1042G&db_key=AST&high=3af6c03e8102908 ] was discovered by researchers Joan Garcia-Sanchez and Robert Preston (JPL [ http://www.jpl.nasa.gov ]), and collaborators while studying stars in the solar neighborhood [ http://www.clockwk.com/stars/ ] using data from the Hipparcos Astrometry Satellite [ http://astro.estec.esa.nl/SA-general/Projects/Hipparcos/ hipparcos.html ]. The star field shown is based on the Palomar Digitized Sky Survey [ http://www-gsss.stsci.edu/Dss/dss_home.HTM ] and is 1/4 degree wide (about half the diameter of the full moon). |
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Saturn and Vesta in Taurus
| Title |
Saturn and Vesta in Taurus |
| Explanation |
Last November, while skygazing [ http://pages.prodigy.net/pam.orman/ JoeGallery.html ] toward the constellation Taurus [ http://hou.lbl.gov/~vhoette/Explorations/StarHop/ ], astrophotographer Joe Orman arranged this time exposure to include the lovely Hyades and Pleiades star clusters in the field of his telephoto lens. A distance of 400 light-years [ http://school.discovery.com/ schooladventures/universe/itsawesome/lightyears/ ] for the close-knit Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap010506.html ] and 150 light-years for the V-shaped [ http://www.aspsky.org/mercury/mercury/9803/hyades.html ] Hyades [ http://astro.estec.esa.nl/Hipparcos/hyades.html ] puts these clusters in the general galactic neighborhood [ http://www.anzwers.org/free/universe/ 250lys.html ] of the Sun. Punctuating the Hyades' appearance, bright yellow Aldebaran [ http://www.astro.uiuc.edu/~kaler/sow/aldebaran.html ], 60 light-years away, is not actually a member of the cluster, but it is Taurus' brightest star. Above Aldebaran a yellower, even brighter Saturn [ http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=6& vbody=3&month=11&day=17¢ury=20&decade=0&year=1&hour=00& minute=0&rfov=30&fovmul=-1&bfov=30 ] is is seen about 1.2 light-hours [ http://casswww.ucsd.edu/public/tutorial/Intro.html ] from our fair planet. Last and least massive [ http://aa.usno.navy.mil/hilton/asteroid_masses.htm ], one of the faint specks below Aldebaran is main-belt asteroid [ http://www.seds.org/nineplanets/nineplanets/ asteroids.html ] Vesta, a mere 13 light-minutes [ http://www.unmuseum.org/speed.htm ] away. Still cruising through Taurus, Vesta [ http://oposite.stsci.edu/pubinfo/PR/95/20.html ] is steadily approaching a close alignment or conjunction [ http://scienceworld.wolfram.com/astronomy/ Conjunction.html ] with Saturn on March 19. Need a program [ http://pages.prodigy.net/pam.orman/ JoeAlmanac2002.html ] to follow the players? Click on the image for a labeled version. |
|
A Close Encounter of the Ste
…
| Title |
A Close Encounter of the Stellar Kind |
| Explanation |
The unassuming star centered in this sky view [ http://skyview.gsfc.nasa.gov ] will one day be our next door [ http://www.bigear.org/vol1no2/kraus.htm ] stellar neighbor [ http://www.astro.wisc.edu/~dolan/constellations/extra/nearest.html ]. The faint 9th magnitude red dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap970605.html ] currently 63 light-years away [ http://zebu.uoregon.edu/~soper/Stars/parallax_ly.html ] in the constellation Ophiucus [ http://www.astro.wisc.edu/~dolan/constellations/extra/nearest.html ] was recently discovered to be on a course toward our Solar System. Known in catalogs of nearby stars [ http://proxima.astro.virginia.edu/~pai/Recons/index.html ] as Gliese 710 it is predicted to come within 1 light-year of the Sun ... a million years from now. At that distance this star, presently much too faint to be seen [ http://liftoff.msfc.nasa.gov/academy/universe/MAG.HTML ] by the naked eye, will blaze at 0.6 magnitude - rivaling the apparent brightness of the mighty red giant Antares [ http://antwrp.gsfc.nasa.gov/apod/ap970624.html ]. Gliese 710 poses no direct collision danger [ http://ccf.arc.nasa.gov/sst/main.html ] itself although its gravitational influence will likely scatter comets out of the Solar System's reservoir, the Oort cloud, sending some inbound [ http://antwrp.gsfc.nasa.gov/apod/ap961219.html ]. This future stellar encounter was discovered by researchers Joan Garcia-Sanchez and Robert Preston (JPL [ http://www.jpl.nasa.gov ]), and collaborators while studying stars in the solar neighborhood [ http://www.clockwk.com/stars/ ] using data from the Hipparcos Astrometry Satellite [ http://astro.estec.esa.nl/SA-general/Projects/Hipparcos/ hipparcos.html ]. The star field shown is based on the Palomar Digitized Sky Survey [ http://www-gsss.stsci.edu/dss/dss.html ] and is 1/4 degree wide (about half the diameter of the full moon). |
|
The Magellanic Stream
| Title |
The Magellanic Stream |
| Explanation |
Spanning the sky behind the majestic Clouds of Magellan [ http://antwrp.gsfc.nasa.gov/apod/ap980203.html ] is an unusual stream of gas: the Magellanic Stream [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995ApJ...439..652L&db_key=AST&high=34f6e1de7f03390 ]. The origin of this gas might hold a clue to origin and fate of our Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap971229.html ]'s most famous satellite galaxies: the LMC [ http://antwrp.gsfc.nasa.gov/apod/ap980124.html ] and the SMC [ http://antwrp.gsfc.nasa.gov/apod/ap980125.html ]. Two leading genesis hypotheses have surfaced: that the stream was created by gas stripped off [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994MNRAS.270..209M&db_key=AST&high=34f6e1de7f03390 ] these galaxies as they passed through the halo of our Milky Way, or that the stream was created by the differential gravitational tug [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998IAUS..190E.170W&db_key=AST&high=34f6e1de7f03390 ] of the Milky Way. Measurements of slight angular motions by the Hipparcos satellite [ http://astro.estec.esa.nl/SA-general/Projects/Hipparcos/ ] have indicated that the Clouds are leading the Stream. Now, recent radio measurements [ http://www.csiro.au/news/lmc.html ] have located fresh gas emerging from the Clouds, bolstering the later, tidal explanation. Most probably, in a few hundred million years, the Magellanic Clouds [ http://www.seds.org/messier/xtra/ngc/lmc.html ] themselves will fall victim to this same tidal force. |
|
A Close Encounter Of The Ste
…
| Title |
A Close Encounter Of The Stellar Kind |
| Explanation |
The unassuming star centered in this sky view [ http://skyview.gsfc.nasa.gov ] will one day be our next door [ http://www.bigear.org/vol1no2/kraus.htm ] stellar neighbor [ http://www.astro.wisc.edu/~dolan/constellations/extra/nearest.html ]. The faint 9th magnitude red dwarf [ http://antwrp.gsfc.nasa.gov/apod/ap991120.html ], currently 63 light-years away [ http://zebu.uoregon.edu/~soper/Stars/parallax_ly.html ] in the constellation Ophiucus [ http://www.astro.wisc.edu/~dolan/constellations/constellations/ Ophiuchus.html ], was recently discovered to be approaching our Solar System. Known in catalogs of nearby stars [ http://tarkus.pha.jhu.edu/~thenry/RECONS.html ] as Gliese 710 it is predicted to come within 1 light-year of the Sun ... a million years from now. At that distance this star, presently much too faint to be seen [ http://liftoff.msfc.nasa.gov/academy/universe/MAG.HTML ] by the naked eye, will blaze at 0.6 magnitude - rivaling the apparent brightness of the mighty red giant Antares [ http://antwrp.gsfc.nasa.gov/apod/ap970624.html ]. Ultimately Gliese 710 poses no direct collision danger itself although its gravitational influence will likely scatter comets out of the Solar System's reservoir, the Oort cloud [ http://www.windows.umich.edu/cgi-bin/tour_def/comets/ Oort_cloud.html ], sending some inbound. This future stellar encounter [ http://cass.jsc.nasa.gov/meetings/dps97/html/H2501/H2501.html ] was discovered by researchers [ http://www.newscientist.com/ns/970524/doomstar.html ] Joan Garcia-Sanchez and Robert Preston (JPL [ http://www.jpl.nasa.gov ]), and collaborators while studying stars in the solar neighborhood [ http://www.clockwk.com/stars/ ] using data from the Hipparcos Astrometry Satellite [ http://astro.estec.esa.nl/SA-general/Projects/Hipparcos/ hipparcos.html ]. The star field shown is based on the Palomar Digitized Sky Survey [ http://www-gsss.stsci.edu/dss/dss.html ] and is 1/4 degree wide (about half the diameter of the full moon). |
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