{"id":2812,"date":"2018-01-22T19:28:40","date_gmt":"2018-01-22T19:28:40","guid":{"rendered":"http:\/\/www.popastro.com\/main_spa1\/variablestar\/?page_id=2812"},"modified":"2018-01-22T19:38:40","modified_gmt":"2018-01-22T19:38:40","slug":"three-eclipses-from-january-2018","status":"publish","type":"page","link":"https:\/\/www.popastro.com\/variablestar\/three-eclipses-from-january-2018\/","title":{"rendered":"Three eclipses from January 2018"},"content":{"rendered":"

The UK weather doesn’t often allow whole eclipses to be followed in full.<\/p>\n

However, three eclipses have been well observed during January.<\/p>\n

AB Cassiopeiae : 2018 Jan 19<\/u><\/span><\/strong><\/p>\n

This eclipse was observed by David Smith<\/strong>, who adds “These readings were taken with a William Optics Megrez 90 and Atik 460EX CCD camera with a Johnson V filter. Each image was just 10s exposure<\/em>.”\u00a0 The gap during the fade was due to a technical issue.<\/p>\n

\"\"
David Smith’s light curve for the AB Cas eclipse on 2018 Jan 19<\/figcaption><\/figure>\n

The period of AB Cas is 1.367 days (approx 33 hours), with eclipses lasting for about 5.5 hours.<\/p>\n

As can be seen from the accompanying light curve, which runs from 18:00 to 00:00, AB Cas faded by 1.6 magnitudes during the eclipse.<\/p>\n

The predicted time of this eclipse using the latest “Krakow” elements was 21:47 UT and David’s light curve shows that the eclipse was more or less on time.<\/p>\n

AB Cas is an Algol type eclipsing variable. The “V” shaped nature of the eclipse shows that the eclipses are partial rather than total.<\/p>\n

RZ Cassiopeiae\u00a0 2018 Jan 8<\/u><\/span><\/strong><\/p>\n

This eclipse was observed visually by Tracie Heywood<\/strong>, using 11×80 binoculars. Brightness estimates were made every 20 minutes or so.<\/p>\n

\"\"
Tracie Heywood’s light curve for the primary eclipse of RZ Cas on 2018 Jan 8<\/figcaption><\/figure>\n

Eclipses of RZ Cas last\u00a0 for 4.8 hours, during which time RZ Cas fades by more than a magnitude.<\/p>\n

RZ Cas is an Algol type eclipsing variable with a period of 1.195 days (approx 29 hours). Eclipses are “V” shaped, indicating that they are partial rather than total.<\/p>\n

Eclipses of RZ Cas are currently occurring around 2 hours later than predicted by the GCVS elements in the General Catalogue of Variable Stars (GCVS), but are more or less in line with predictions based on the “Krakow” elements”<\/p>\n

Nevertheless, the period of RZ Cas continues to change slowly and continued monitoring is required in order to revise the “elements” and thus keep predictions accurate.<\/p>\n

U Cephei\u00a0 2018 Jan 7-8<\/u><\/span><\/strong><\/p>\n

This eclipse was observed visually by Tracie Heywood<\/strong> using 11×80 binoculars. Brightness estimates were made around every 30 minutes.<\/p>\n

\"\"
Tracie Heywood’s light curve showing the primary eclipse of U Cephei during 2018 Jan 7-8<\/figcaption><\/figure>\n

U Cephei is an Algol type eclipsing variable. Primary eclipses occur every 2.5 days and last for approx 9 hours.<\/p>\n

During primary eclipses, U Cephei fades by approx 2.5 magnitudes. The eclipse is flat-bottomed, indicating that it is a total eclipse.<\/p>\n

Eclipses of U Cephei are currently occurring around 5 hours than would be predicted using the GCVS elements, but are more or less in line withn the latest “Krakow” elements.<\/p>\n","protected":false},"excerpt":{"rendered":"

The UK weather doesn’t often allow whole eclipses to be followed in full. However, three eclipses have been well observed during January. AB Cassiopeiae : 2018 Jan 19 This eclipse was observed by David Smith, who adds “These readings wereRead more<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"class_list":["post-2812","page","type-page","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t