{"id":328,"date":"2007-04-30T23:05:00","date_gmt":"2007-04-30T23:05:00","guid":{"rendered":"http:\/\/perezmedia.net\/beltofvenus\/2007\/04\/30\/gamma_velorum_d\/"},"modified":"2007-04-30T23:05:00","modified_gmt":"2007-04-30T23:05:00","slug":"gamma_velorum_d","status":"publish","type":"post","link":"https:\/\/perezmedia.net\/beltofvenus\/2007\/04\/30\/gamma_velorum_d\/","title":{"rendered":"Gamma Velorum (Dunlop 65)"},"content":{"rendered":"

Binocular Observation – February 26, 2007:<\/b><\/p>\n

<\/a>
\nClick above image for larger version (20K).<\/i><\/p>\n

I made this binocular observation from my front doorstep with moonlight strongly lighting up the field. The primary of Gamma Velorum was the brightest star in the murky view near the horizon, and gave off a blue light. The secondary snuggled close to the glare of its buddy and at times seemed to appear orange in contrast. I tried for about 15 minutes to pick out the combined light of the third and fourth components, and couldn’t convince myself I had seen them.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Subject<\/b><\/td>\nGamma Velorum (DUN 65)<\/b><\/td>\n<\/tr>\n
Classification<\/b><\/td>\nMultiple Star<\/td>\n<\/tr>\n
Position (J2000)<\/b><\/td>\n[RA: 08:09:31.9 \/ Dec: -47:20:11]*<\/td>\n<\/tr>\n
Position Angle*<\/b><\/td>\nA-B: 220\u00c2\u00b0 (1826)
A-C: 151\u00c2\u00b0 (1835)
A-D: 141\u00c2\u00b0 (1846)<\/td>\n<\/tr>\n
Separation*<\/b><\/td>\nA-B: 41.3″ (1826)
A-C: 62.3″ (1835)
A-D: 93.5″ (1846)<\/td>\n<\/tr>\n
Magnitudes*<\/b><\/td>\nA = 2.2; B = 4.5; C = 8.5; D = 9.4<\/td>\n<\/tr>\n
Spectral Types*<\/b><\/td>\nA = O9+W; B = B3; C = A0; D = A0<\/td>\n<\/tr>\n
Date\/Time<\/b><\/td>\nFEB 26, 2007 – 09:20 AM MST (FEB 27, 2007 – 04:20 UT)<\/td>\n<\/tr>\n
Observing Loc.<\/b><\/td>\nFlagstaff, AZ – Home<\/td>\n<\/tr>\n
Instrument<\/b><\/td>\n10 x 50 Binoculars<\/td>\n<\/tr>\n
Conditions<\/b><\/td>\nClear, breezy, waxing gibbous moon<\/td>\n<\/tr>\n
Seeing<\/b><\/td>\n–<\/td>\n<\/tr>\n
Transparency<\/b><\/td>\nNELM ~ Mag 4<\/td>\n<\/tr>\n
References<\/b><\/td>\nThe Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996), Visual Double Stars in Hipparcos (Dommanget+, 2000) via VizieR<\/a>, and Burnham’s Celestial Handbook<\/i>.<\/td>\n<\/tr>\n<\/table>\n
\n

<\/p>\n

Observation Notes:<\/b><\/p>\n

This is my most southern observation yet. At a declination of -47 degrees, it was about 8 degrees above my southern horizon–add some low hills, and I was only barely able to catch it. As you can imagine, the seeing was horrible, but despite this, Gamma Velorum was a brilliant and worthwhile multiple star to view. Due to the fluttering atmosphere, and strong spreading of the spectrum, estimating color was a bit difficult. Still, I was able to pick out a blue-white color for the primary and bluish coloration to the next two brightest stars. <\/p>\n

I estimated the PAs as AB=215\u00c2\u00b0, AC=160\u00c2\u00b0, and AD=150\u00c2\u00b0. Actual values are 220\u00c2\u00b0, 151\u00c2\u00b0, and 141\u00c2\u00b0. I sketched separations as AB=65″, AC=80″, and AD=106″. Those are a bit stretched, with the actual values being 41.3″, 62.3″, and 93.5″. I was surprised not to find a Struve number attached to this one. Rather it was listed as Dunlop 65. I guess I hadn’t considered the southern limit for Struve’s catalog.<\/p>\n

According to Burnham, the primary star of this multiple is actually a spectroscopic binary composed of an O9 blue giant and a Wolf-Rayet giant that orbit with a period of 78.5 days. <\/p>\n\n\n\n\n\n\n\n\n
Date\/Time<\/b><\/td>\nOCT 22, 2006 – 05:00 AM MST (OCT 22, 2006 – 12:00 UT)<\/td>\n<\/tr>\n
Observing Loc.<\/b><\/td>\nCinder Hills Overlook, Sunset Crater National Monument, AZ<\/td>\n<\/tr>\n
Instrument<\/b><\/td>\nOrion SVP 6LT Reflector (150 mm dia.\/1200 mm F\/L)<\/td>\n<\/tr>\n
Eyepieces\/Mag.<\/b><\/td>\n10 mm + 2X Barlow (240X)<\/td>\n<\/tr>\n
Conditions<\/b><\/td>\nClear, calm<\/p>\n
Seeing<\/b><\/td>\n1-2\/10<\/td>\n<\/tr>\n
Transparency<\/b><\/td>\nNELM Mag 6.8+<\/td>\n<\/tr>\n<\/table>\n

*Based on published data.<\/p>\n","protected":false},"excerpt":{"rendered":"

Gamma Velorum<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[56,57,104,15],"tags":[],"class_list":["post-328","post","type-post","status-publish","format-standard","hentry","category-double-star","category-sg-double-star","category-sgc-vela","category-sketch-gallery"],"jetpack_featured_media_url":"","jetpack-related-posts":[{"id":430,"url":"https:\/\/perezmedia.net\/beltofvenus\/2004\/08\/01\/binocular_sketc\/","url_meta":{"origin":328,"position":0},"title":"Binocular Sketches","author":"jperez1690","date":"August 1, 2004","format":false,"excerpt":"Binocular Sketches","rel":"","context":"In "Gallery"","block_context":{"text":"Gallery","link":"https:\/\/perezmedia.net\/beltofvenus\/category\/gallery\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":14,"url":"https:\/\/perezmedia.net\/beltofvenus\/2004\/08\/01\/double_star_ske\/","url_meta":{"origin":328,"position":1},"title":"Double Star Sketches","author":"jperez1690","date":"August 1, 2004","format":false,"excerpt":"Double Star Sketches","rel":"","context":"In "General"","block_context":{"text":"General","link":"https:\/\/perezmedia.net\/beltofvenus\/category\/general\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":21,"url":"https:\/\/perezmedia.net\/beltofvenus\/2004\/08\/01\/published_mater\/","url_meta":{"origin":328,"position":2},"title":"Published Material","author":"jperez1690","date":"August 1, 2004","format":false,"excerpt":"Updated December 25, 2010 Books Astronomical Sketching: A Step-by-Step Introduction (Patrick Moore's Practical Astronomy Series) By Richard Handy, David B. Moody, Jeremy Perez, Erika Rix, Sol Robbins.Published by Springer, 2007. Contributed three chapters: Comets, Star Clusters, and Nebulae. Stargazing with Binoculars Firefly book by Robin Scagell and David Frydman -\u2026","rel":"","context":"In "General"","block_context":{"text":"General","link":"https:\/\/perezmedia.net\/beltofvenus\/category\/general\/"},"img":{"alt_text":"","src":"http:\/\/www.assoc-amazon.com\/e\/ir?t=thbeofve-20&l=as2&o=1&a=0387262407","width":350,"height":200},"classes":[]},{"id":321,"url":"https:\/\/perezmedia.net\/beltofvenus\/2007\/03\/05\/pi_lupi_hj_4728\/","url_meta":{"origin":328,"position":3},"title":"Pi Lupi (HJ 4728)","author":"jperez1690","date":"March 5, 2007","format":false,"excerpt":"Pi Lupi","rel":"","context":"In "Double Star"","block_context":{"text":"Double Star","link":"https:\/\/perezmedia.net\/beltofvenus\/category\/double-star\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":332,"url":"https:\/\/perezmedia.net\/beltofvenus\/2007\/06\/12\/crux\/","url_meta":{"origin":328,"position":4},"title":"Crux","author":"jperez1690","date":"June 12, 2007","format":false,"excerpt":"Crux","rel":"","context":"In "Constellation"","block_context":{"text":"Constellation","link":"https:\/\/perezmedia.net\/beltofvenus\/category\/constellation\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":64,"url":"https:\/\/perezmedia.net\/beltofvenus\/2004\/12\/06\/astro_and_lunar\/","url_meta":{"origin":328,"position":5},"title":"Observation Record Forms and Templates","author":"jperez1690","date":"December 6, 2004","format":false,"excerpt":"Observation Record Sheets","rel":"","context":"In "Tools and Techniques"","block_context":{"text":"Tools and Techniques","link":"https:\/\/perezmedia.net\/beltofvenus\/category\/tools-and-techniques\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/posts\/328","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/comments?post=328"}],"version-history":[{"count":0,"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/posts\/328\/revisions"}],"wp:attachment":[{"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/media?parent=328"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/categories?post=328"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/perezmedia.net\/beltofvenus\/wp-json\/wp\/v2\/tags?post=328"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}