{"id":23399,"date":"2021-09-16T00:00:00","date_gmt":"2021-09-16T00:00:00","guid":{"rendered":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/?post_type=purple_issue&p=23399"},"modified":"2021-10-22T11:44:46","modified_gmt":"2021-10-22T11:44:46","slug":"moonwatch","status":"publish","type":"post","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/2021\/09\/16\/moonwatch\/","title":{"rendered":"Moonwatch"},"content":{"rendered":"\n

October\u2019s top lunar feature to observe<\/span><\/p>\n\n

\"\"
The crater\u2019s name, Fracastorius, commemorates the Italian scholar, astronomer and poet Girolamo Fracastoro<\/figcaption><\/figure><\/div>\n\n


Fracastorius<\/strong><\/h4>\n\n

Type: <\/strong>Crater<\/p>\n\n

Size: <\/strong>124km<\/p>\n\n

Longitude\/Latitude: <\/strong>33.1o E, 21.4o S<\/p>\n\n

Age: <\/strong>Older than 3.9 billion years<\/p>\n\n

Best time to see: <\/strong>Five days after new Moon (10 & 11 October) or four days after full Moon (24 & 25 October)<\/p>\n\n

Minimum equipment: <\/strong>10x binoculars<\/p>\n\n

\"\"<\/figure><\/div>\n\n

Fracastorius is a beautiful lava-flooded crater on the southern edge of 350km Mare Nectaris. Appearing ancient and battered, it manages to maintain a resplendent dignity in much of its outline, with all but the northern section still clearly visible. The northern section could be described as \u2018almost there\u2019, hinted at by roughness in the area together with lighter surface markings.<\/span><\/p>\n\n

The eastern rim rises to a height around 1.8km. It is narrowest to the north, with a curious unnamed feature near where it loses altitude towards the surface of Mare Nectaris. The unnamed feature is 11km across and looks like three co-joined and flooded craters. The craters appear at 120\u02da intervals around their common overlap point, the whole structure showing good three-way symmetry.<\/p>\n\n

Fracastorius\u2019s eastern rim arc supports a wellaimed 3.5km craterlet. As you head south from this craterlet, the rim curves to the west, widening as it goes, until it reaches an average width of around 17km. At its southernmost point, the rim appears to widen and spill further to the south. A depression sits immediately west of this extension, formed in part from the 12km crater Fracastorius Y.<\/span><\/p>\n\n

A small crater valley chain extends northnorthwest from Y, the depressions obliterating the outer part of Fracastorius\u2019s southwest rim. The short chain ends at the north with a crater which used to be known as Romana but is now officially recognised as Fracastorius D. At 28km, D is easy to spot and is interesting in that its overall shape is more triangular than round. The rim of Fracastorius continues from the northern point of D\u2019s outer edge, passing poorly defined 21km Fracastorius H before encountering 13km Fracastorius E. The rim elevation drops sharply after E, narrowing to a point along the north-northwest boundary.<\/span><\/p>\n\n

The missing northern rim is, as mentioned earlier, hinted at by a mish-mash of features. Most obvious is a 9.3km x 12km bifurcated rectangular massif, presumably part of the original rim, high enough to withstand the incoming lava flow.<\/p>\n\n

Internally, Fracastorius is almost smooth. There are a number of craterlets which can be seen with smaller instruments, most notably 5km Fracastorius L in the northern half of the crater, and 4km Fracastorius M in the southern half. The southern half of the main floor appears rougher, covered in a number of low-level hills. There is a hint of elevation in the centre, the remains of the original central mountain complex perhaps. However, this isn\u2019t very dramatic, more a series of east-west orientated bumps rising to a peak height of around 600m.<\/span><\/p>\n\n

A fine rille (narrow channel) winds its way across the crater\u2019s floor. Orientated east-west, the rille passes south of the central \u2018mountain\u2019 complex, appearing to clip the northern edge of Fracastorius M. In high resolution images the rille appears to split as it heads east of centre but this is misleading; the main part of the rille continues as expected, eventually arcing north to run along the inside of the eastern rim. The southern \u2018split\u2019 section can be seen in high-resolution satellite images to be comprised of numerous tiny craterlets.<\/p>\n\n

IMAGES: PETE LAWRENCE<\/p>\n","protected":false},"excerpt":{"rendered":"

October\u2019s top lunar feature to observe<\/p>\n","protected":false},"author":24,"featured_media":24439,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ub_ctt_via":"","purple_page_number":"52","purple_custom_meta_purple_page_number":"52","purple_seq_number":"1","purple_custom_meta_purple_seq_number":"1","purple_source_article":"article_52-1.xml","purple_custom_meta_purple_source_article":"article_52-1.xml","purple_source_issue":"October-2021","purple_custom_meta_purple_source_issue":"October-2021","purple_external_id":"October-2021-52-1","purple_custom_meta_purple_external_id":"October-2021-52-1","purple_issue_code":"|0000086545||","purple_custom_meta_purple_issue_code":"|0000086545||","purple_android_product":"com.im.skyatnight.197","purple_custom_meta_purple_android_product":"com.im.skyatnight.197","purple_ios_product":"com.im.skyatnight.197","purple_custom_meta_purple_ios_product":"com.im.skyatnight.197","purple_web_product":"","purple_custom_meta_purple_web_product":"","purple_publication_id":"075fab74-0a21-4201-866a-899d6c41c40c","purple_migrated":"","kt_blocks_editor_width":""},"categories":[22],"tags":[14],"featured_image_src":"https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d.jpg","author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"acf":{"readingTimeMinutes":"3"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d.jpg",1625,1229,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d-300x227.jpg",300,227,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d-768x581.jpg",768,581,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d-1024x774.jpg",800,605,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d-1536x1162.jpg",1536,1162,true],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/09\/b0ae9183-0278-49b6-b29c-a25a3fc4698d.jpg",1625,1229,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"October\u2019s top lunar feature to observe","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/23399"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"replies":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/comments?post=23399"}],"version-history":[{"count":12,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/23399\/revisions"}],"predecessor-version":[{"id":24958,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/23399\/revisions\/24958"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/24439"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=23399"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=23399"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/tags?post=23399"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}