{"id":32830,"date":"2022-06-16T00:00:00","date_gmt":"2022-06-16T00:00:00","guid":{"rendered":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/?post_type=purple_issue&p=32830"},"modified":"2022-07-12T14:59:03","modified_gmt":"2022-07-12T14:59:03","slug":"the-sky-guide-challenge-10","status":"publish","type":"post","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/2022\/06\/16\/the-sky-guide-challenge-10\/","title":{"rendered":"The sky guide challenge"},"content":{"rendered":"\n

Can you observe and capture the distant dwarf planet Pluto throughout the month? <\/p>\n\n

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Globular cluster M75 is a useful target for locating the star field where Pluto is found <\/figcaption><\/figure>\n\n

Dwarf planet Pluto reaches opposition on 20 July in Sagittarius, close to the border of Capricornus. The mag. +8.6 globular cluster M75 sits even closer to the border and is a nearby navigational guide (see chart, above). In July, Pluto moves westwards, starting 1.5\u00b0 west-southwest of M75. Our challenge is to locate and capture this distant world, which appears like a 14th magnitude star in a telescope. <\/p>\n\n

The best way to \u2018see\u2019 Pluto is to use the asteroid-tracking method of recording the suspected star field over the course of several nights, looking for the faint dot that appears to be moving. During July, Pluto\u2019s magnitude remains a steady +14.3. We\u2019d normally recommend at least a 300mm scope for this, but additional aperture can only help as Pluto is quite low in the sky. There are claims that Pluto<\/span> has been seen in smaller instruments than this under pristine skies.<\/p>\n\n

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Telescope view (south up) of the star field through which Pluto will be moving<\/figcaption><\/figure>\n\n

The sure-fire way to record it is to photograph the star field where Pluto is expected to be located. Here, M75 works wonders as a starting guide. From M75 head half-a-degree to the southwest to locate mag. +7.5 HIP 98851. A fraction under half a degree south-southwest of this star lies mag. +6.4 HIP 98785, and half a degree to the west-southwest of this star is mag. +6.0 HIP 98575. Keep the line going from HIP 98785 through 98575 for approximately twice that distance again to arrive at mag. +7.6 HIP 98135. Pluto tracks parallel to the line between HIP 98575 and 98135, running slightly north of it. A minimum of a 200mm\u2013300mm lens attached to a DSLR or MILC is recommended for this challenge; use a medium to high ISO. You\u2019ll need to aim to record stars slightly fainter than the faintest shown on our narrow-field chart (below) to succeed, so a tracking mount is recommended to allow you to extend the exposure time without star trails. <\/p>\n\n

Record as many images as you can throughout the month, loading them into a layer-based editor one image per layer. Carefully align the stars between layers and flick between the frames to see if you can spot something faint moving in a straight line over the course of the month.<\/span> If you can, that\u2019s likely to be Pluto. If you can, check your results using the first few images and increase camera sensitivity (higher ISO and\/or longer exposures) if you can\u2019t see Pluto at all. Low altitude and haze will make the job more challenging, as will the presence of the Moon. The bright post-solstice skies at the start of July will also add an extra dimension of difficulty to this already tricky challenge.<\/p>\n","protected":false},"excerpt":{"rendered":"

Can you observe and capture the distant dwarf planet Pluto throughout the month? <\/p>\n","protected":false},"author":24,"featured_media":32828,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ub_ctt_via":"","purple_page_number":"55","purple_custom_meta_purple_page_number":"55","purple_seq_number":"1","purple_custom_meta_purple_seq_number":"1","purple_source_article":"article_55-1.xml","purple_custom_meta_purple_source_article":"article_55-1.xml","purple_source_issue":"July-2022","purple_custom_meta_purple_source_issue":"July-2022","purple_external_id":"July-2022-55-1","purple_custom_meta_purple_external_id":"July-2022-55-1","purple_issue_code":"|0000086554||","purple_custom_meta_purple_issue_code":"|0000086554||","purple_android_product":"com.im.skyatnight.206","purple_custom_meta_purple_android_product":"2022skyatnightJuly","purple_ios_product":"com.im.skyatnight.206","purple_custom_meta_purple_ios_product":"2022skyatnightJuly","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\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051.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\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051.jpg",1392,955,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051-300x206.jpg",300,206,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051-768x527.jpg",768,527,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051-1024x703.jpg",800,549,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051.jpg",1392,955,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/06\/8c71319b-b1c7-49f6-b360-76f031a97051.jpg",1392,955,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":"Can you observe and capture the distant dwarf planet Pluto throughout the month?","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/32830"}],"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=32830"}],"version-history":[{"count":4,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/32830\/revisions"}],"predecessor-version":[{"id":33159,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/posts\/32830\/revisions\/33159"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/32828"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=32830"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=32830"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/tags?post=32830"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}