{"id":27037,"date":"2021-12-16T00:00:00","date_gmt":"2021-12-16T00:00:00","guid":{"rendered":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/?post_type=purple_issue&p=27037"},"modified":"2022-01-11T15:56:47","modified_gmt":"2022-01-11T15:56:47","slug":"moonwatch-4","status":"publish","type":"post","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/2021\/12\/16\/moonwatch-4\/","title":{"rendered":"Moonwatch"},"content":{"rendered":"\n

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

<\/div>
\n

Nasireddin<\/strong><\/h4>\n\n\n\n

Type: <\/strong>Crater
Size: <\/strong>53km
Longitude\/Latitude: <\/strong>0.1o E, 41.0o S
Age: <\/strong>Approximately 3.8\u20133.9 billion years
Best time to see: <\/strong>First quarter (10 January) or six days after full Moon (24 and 25 January)
Minimum equipment: <\/strong>50mm refractor<\/p>\n<\/div><\/section>\n\n

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

Nasireddin is a 53km crater located in the rough textured southern badlands area of the Moon. It is a great example of how some lunar features overlap others. When this happens, it\u2019s logical to conclude that the overlapping feature is younger than the feature overlapped, a technique used to determine the relative age of surface features.<\/p>\n\n

In this case, Nasireddin overlaps 65km Huggins, the western edge of Nasireddin\u2019s rim stretching onethird of the way across the larger crater\u2019s diameter. Being the overlapped crater, the age of Huggins is estimated to be greater than 3.9 billion years.<\/span><\/p>\n\n

To the north lies Miller, a 75km crater that presents more of a problem. If you look carefully at Miller and Nasireddin, they appear to touch, but it\u2019s not obvious whether an overlap has occurred. If anything, the curving edge of Miller looks subtly dominant in that its natural curve persists along the co-joined section. Consequently, Miller\u2019s age is estimated to be in the same range as Nasireddin, about 3.8\u20133.9 billion years.<\/p>\n\n

Nasireddin has a sharp rim edge exhibiting plenty of terracing. Compare Nasireddin\u2019s rim with that of Huggins. The latter looks much smoother and rounded without much obvious terracing. Miller looks like a larger version of Nasireddin.<\/p>\n\n

Nasireddin\u2019s central floor area is very rough, its texture appearing richly detailed when the Sun\u2019s angle is low. There are a number of small craterlets visible here, along with many hill bumps. The crater is described as having a central mountain complex, but it\u2019s not immediately obvious where this starts and the surrounding hills end. Again, compare Nasireddin to Miller to the north. Miller\u2019s central complex is much better defined, with smaller peaks surrounding a main peak.<\/span><\/p>\n\n

Nasireddin has an unusual rim illumination around co-longitude 2.6\u02da. Lunar co-longitude is a value which indicates the location of the morning terminator; that\u2019s the one which creeps across the Moon\u2019s face from new Moon, through the waxing phases until full Moon. It\u2019s measured in degrees from when the terminator touches the Moon\u2019s line of zero longitude, the lunar equivalent of Earth\u2019s Greenwich meridian.<\/p>\n\n

At first-quarter Moon, the co-longitude value is close to 0\u02da. It then increases to approximately 90\u02da at full Moon, 180\u02da at last quarter and 270\u02da at new Moon. The \u2018approximately\u2019 label is due to lunar libration,<\/p>\n\n

which causes the Moon\u2019s prime meridian to shift relative to the more geometrically defined phase positions. At colongitude 2.6\u02da, the Moon\u2019s early morning light catches regions around Nasireddin\u2019s edge, causing the rim outline to appear as a series of short dashes, a clair-obscur effect we\u2019ve called the \u2018broken arc\u2019.<\/p>\n\n

Nasireddin lies 270km east of the 86km ray crater Tycho. The rugged nature of Nasireddin doesn\u2019t allow ejecta debris from the much younger Tycho to stand out, and this is evident on the dark floor of the 126km walled plain of Stofler, east of Nasireddin.<\/p>\n\n

\"\"
When morning light catches Nasireddin\u2019s edge, the rim appears as a series of dashes, forming a \u2018broken arc\u2019 clair-obscur effect <\/figcaption><\/figure>\n\n

<\/p>\n\n

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

January\u2019s top lunar feature to observe<\/p>\n","protected":false},"author":24,"featured_media":27035,"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":"January-2022","purple_custom_meta_purple_source_issue":"January-2022","purple_external_id":"January-2022-52-1","purple_custom_meta_purple_external_id":"January-2022-52-1","purple_issue_code":"|0000086548||","purple_custom_meta_purple_issue_code":"|0000086548||","purple_android_product":"com.im.skyatnight.200","purple_custom_meta_purple_android_product":"com.im.skyatnight.200","purple_ios_product":"com.im.skyatnight.200","purple_custom_meta_purple_ios_product":"com.im.skyatnight.200","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\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288.jpg","author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"acf":{"readingTimeMinutes":"3","apple_news_title":""},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288.jpg",542,542,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288-300x300.jpg",300,300,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288.jpg",542,542,false],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288.jpg",542,542,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288.jpg",542,542,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2021\/12\/ec680bb3-807d-4fd7-920e-1da9fc562288.jpg",542,542,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":"January\u2019s top lunar feature to observe","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/27037"}],"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=27037"}],"version-history":[{"count":6,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/27037\/revisions"}],"predecessor-version":[{"id":27693,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/27037\/revisions\/27693"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/27035"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=27037"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=27037"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/tags?post=27037"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}