{"id":306,"date":"2006-12-03T00:40:19","date_gmt":"2006-12-03T00:40:19","guid":{"rendered":"http:\/\/perezmedia.net\/beltofvenus\/2006\/12\/03\/xi_ursae_majori\/"},"modified":"2006-12-03T00:40:19","modified_gmt":"2006-12-03T00:40:19","slug":"xi_ursae_majori","status":"publish","type":"post","link":"https:\/\/perezmedia.net\/beltofvenus\/2006\/12\/03\/xi_ursae_majori\/","title":{"rendered":"Xi Ursae Majoris (Struve 1523)"},"content":{"rendered":"<p style=\"text-align: center\"><img decoding=\"async\" src=\"http:\/\/www.perezmedia.net\/beltofvenus\/archives\/images\/2006\/img2006102205_XiUMA.jpg\" border=\"1\" color=\"ffffff\"><\/p>\n<p><b>Observation Notes:<\/b><\/p>\n<p>This close double consisted of two yellow-orange stars very close in brightness. The northeast component was brightest, and both stars were close to riding each other&#8217;s first diffraction rings. That would put their separation somewhere between one and two arcseconds. PA was about 235 degrees. Roughly extrapolating from the orbital predictions listed in Burnham&#8217;s Celestial Handbook, the PA should be about 240 degrees with a separation of about 1.9 arcseconds.<\/p>\n<p>According to Burnham, this double was found by Sir William Herschel in May 1780. In 1804, it was announced as a physically associated pair  after a PA change of 59 degrees was noted. It was the first double to have its orbit computed by M. Savary in 1828. According to T. Rakowiecki, it&#8217;s period was computed in 1938 to be 59.74 years, with periastron in 1935. This is also one of the nearest binaries to the Solar System, at 26 light years distant. <\/p>\n<table width=\"470\" border=\"0\" cellspacing=\"2\" cellpadding=\"4\" style=\"line-height: 150%\">\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Subject<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">Xi Ursae Majoris (STF 1523)<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Classification<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">Double Star<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Position (J2000)<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">[RA: 11:18:11 \/ Dec: +31:31:46]*<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Position Angle*<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">40.3\u00c2\u00b0 (1991)<br \/>292.1\u00c2\u00b0 (1997)<br \/>~240\u00c2\u00b0 (2006)<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Separation*<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">.99&#8243; (1991)<br \/>1.68&#8243; (1997)<br \/>~1.9&#8243; (2006)<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Magnitudes*<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">A = 4.4; B = 4.9<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Spectral Types*<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">A = G0; B = G0<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Date\/Time<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">OCT 22, 2006 &#8211; 04:45 AM MST (OCT 22, 2006 &#8211; 11:45 UT)<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Observing Loc.<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">Cinder Hills Overlook, Sunset Crater National Monument, AZ<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Instrument<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">Orion SVP 6LT Reflector (150 mm dia.\/1200 mm F\/L)<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Eyepieces\/Mag.<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">10 mm + 2X Barlow (240X)<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Conditions<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">Clear, calm<\/p>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Seeing<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">5\/10<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>Transparency<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">NELM Mag 6.8+<\/td>\n<\/tr>\n<tr>\n<td bgcolor=\"#3f4d6d\"><b>References<\/b><\/td>\n<td bgcolor=\"#3f4d6d\">The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996), Tycho Double Star Catalogue (TDSC) (Fabricius+ 2002), Double stars measurements (Alzner 1998) via <a href=\"http:\/\/vizier.u-strasbg.fr\/viz-bin\/VizieR\" target=\"_blank\" rel=\"noopener\">VizieR<\/a>, and <i>Burnham&#8217;s Celestial Handbook<\/i> (Vol. 3)<\/td>\n<\/tr>\n<\/table>\n<p>*Based on published data.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Xi Ursae 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