{"id":42393,"date":"2023-03-06T14:20:48","date_gmt":"2023-03-06T14:20:48","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=116619"},"modified":"2023-03-06T14:32:37","modified_gmt":"2023-03-06T14:32:37","slug":"a-guide-to-the-constellation-gemini","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/a-guide-to-the-constellation-gemini\/","title":{"rendered":"A guide to the constellation Gemini"},"content":{"rendered":"

How to find the constellation Gemini, and deep-sky targets to observe within its boundary. <\/p>

By Pete Lawrence\n \t\t<\/p>

Published: Monday, 06 March 2023 at 12:00 am<\/p>

\n\n

Gemini, the twins, is a constellation in the northern hemisphere that can be found sitting between Cancer<\/a> and Taurus<\/a>.<\/p>\n

The constellation is noted for its two brightest stars Castor and Pollux<\/a> (Alpha and Beta Geminorum), which mark the heads of the mythological twins.<\/p>\n

The constellation Gemini can be found easily by star hopping<\/a> to it from the constellation Orion<\/a>.<\/p>\n

Find Orion in the night sky, then draw an imaginary line going from Rigel \u2013 Orion\u2019s right foot, from the viewer\u2019s perspective) \u2013 through the red star Betelgeuse<\/a> (Orion\u2019s left shoulder).<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>\n

Continue on and you\u2019ll come to two bright stars sitting close to one another. These are Castor and Pollux.<\/p>\n

Once you\u2019ve located Gemini, there are plenty of deep-sky targets to explore with a telescope within the constellation\u2019s boundary.<\/p>\n

Read on for our pick of 6 of the best deep-sky objects in Gemini.<\/p>\n

For help locating the targets, download our chart 6 deep-sky objects in Gemini (PDF)<\/a>.<\/strong><\/em><\/p>\n

6 deep-sky objects in Gemini<\/strong><\/h2>\n

NGC 2371\/72<\/b><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Credit: Harald Strau\u00df \/ CCDGuide.com<\/span><\/figcaption><\/div>\n

NGC 2371 is catalogued twice, as NGC 2371 and NGC 2372, a consequence of it appearing as two separate objects. A mag. +11.3 planetary nebula, NGC 2371\/72 is located 1.7\u00b0 north of mag. +3.8 Iota (\u03b9) Geminorum.<\/p>\n

A 150mm scope shows a faint haze with an embedded star-like feature. A 250mm scope reveals the dual nature, two lobes connected by a haze, the southwestern lobe brighter and tighter with a star-like core. The central star sits between lobes, requiring a large scope to see at mag. +14.8. The pair are fittingly known as the Gemini Nebula.<\/p>\n

NGC 2331<\/b><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Credit: Donald Pelletier \/ Digitized Sky Survey \/ archive.eso.org\/dss\/dss<\/span><\/figcaption><\/div>\n

Head 4.6\u00b0 southwest for open cluster NGC 2331. Also lying 3.1\u00b0 south and a fraction west of mag. +4.4 Tau (\u03c4<\/span>) Geminorum,\nNGC 2331 is probably best located via mag. +5.8 47 Geminorum, the cluster 1.1\u00b0 to the west-northwest of this star. NGC 2331 has an integrated magnitude of +8.5, its members scattered across an area slightly larger than the apparent radius of the Moon.<\/p>\n

It\u2019s not overly concentrated though and fairly easy to overlook. A 100mm scope reveals around 20 individual stars over an area 19 arcminutes in diameter. NGC 2331 was discovered in 1785 by the English astronomer William Herschel using an 18.7-inch reflecting telescope.<\/p>\n

NGC 2341\/42<\/b><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
NGC 2342. Credit: Harald Strau\u00df \/ CCDGuide.com<\/span><\/figcaption><\/div>\n

NGC 2341 and NGC 2342 are located 6.7\u00b0 south and a fraction east of NGC 2331. Your best guide is mag. +4.0 Mekbuda (Zeta (\u03b6) Geminorum), NGC 2341 lying 1.2\u00b0 east of this star. Both objects are galaxies, NGC 2342 being slightly brighter at mag. +12.6. It sits 2.6 arcminutes northeast of mag. +13.7 NGC 2341. Through a small instrument, only NGC 2342 is obvious.<\/p>\n

A 300mm scope shows an oval glow 1.0 x 0.7 arcminutes in size. The glow only appears to have a very subtle core brightening. NGC 2341 has a similar surface brightness, appearing round in shape with an apparent diameter of 20 arcseconds. Unlike NGC 2342, NGC 2341 appears to brighten towards a tiny core.<\/p>\n

NGC 2339<\/b><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Credit: Aladin Sky Atlas, the Strasbourg Astronomical Data Center, Pan-STARRS<\/a><\/span><\/figcaption><\/div>\n

Our next target is NGC 2339, another galaxy. This one is marginally brighter than NGC 2342, with an integrated magnitude of +11.6. It\u2019s located 2.1\u00b0 south-southeast of Mekbuda and best seen with larger instruments. It was discovered by William Herschel in 1789 and has a low surface brightness due to being face-on.<\/p>\n

A 250mm scope shows a roughly circular 1.5-arcminute glow with a bright core. A 300mm scope starts to show mottling, caused by the knotted spiral arms contrasting with the gaps in between them. The core appears around a third of an arcminute across through such an instrument.<\/p>\n

NGC 2392<\/b><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Credit: Dieter Retzl \/ CCDGuide.com<\/span><\/figcaption><\/div>\n

Our penultimate object is one of the more famous deep-sky targets in Gemini: NGC 2392. This bright planetary nebula has an integrated magnitude of +9.2. Visually it has a similar apparent size to Jupiter, covering an area 47 x 43 arcseconds. It\u2019s found 2.3\u00b0 east-southeast of Wasat (Delta (\u03b4) Geminorum), 0.6\u00b0 southeast of mag. +5.2 63 Geminorum.<\/span><\/p>\n

The nebula sits 1.4 arcminutes south of a mag. +8.2 star. A 150mm scope shows it easily, along with its bright mag. +10.5 central star. It appears blue through a 250mm scope and mottled at high magnification. Larger apertures show an extended bright region around the central star.<\/span><\/p>\n

NGC 2420<\/b><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Credit: Ron Brecher<\/span><\/figcaption><\/div>\n

NGC 2420 is an eighth-magnitude open cluster visible in small scopes as a 10-arcminute glowing smudge, 2.3\u00b0 east-northeast of NGC 2392. It sits midway between two ninth-magnitude stars aligned north\u2013south, and two eighth-magnitude stars aligned northeast\u2013southwest. Larger aperture resolves more stars in the glow, a 250mm scope showing 20 members scattered against a 6 x 4-arcminute mottled, elliptical haze.<\/span><\/p>\n

A 300mm scope almost doubles the number of stars seen, increasing the cluster\u2019s apparent diameter to around 8 x 6 arcminutes. Astrophotography can resolve the cluster stars with relative ease, revealing a cluster occupying much of the 13-arcminute distance between the two north\u2013south aligned ninth-magnitude stars mentioned earlier.<\/span><\/p>\n

This guide originally appeared in the March 2023 issue of <\/strong><\/em>BBC Sky at Night Magazine<\/strong>.<\/strong><\/em><\/p> <\/body><\/html>\n

","protected":false},"excerpt":{"rendered":"

How to find the constellation Gemini, and deep-sky targets to observe within its boundary. <\/p>\n","protected":false},"author":24,"featured_media":42394,"template":"","categories":[1],"acf":{"readingTimeMinutes":"5"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini.jpg",1200,800,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini-1024x683.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini.jpg",1200,800,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/a-guide-to-the-constellation-gemini.jpg",1200,800,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":"How to find the constellation Gemini, and deep-sky targets to observe within its boundary.","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/42393"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/42394"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=42393"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=42393"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}