Catch sight of a celestial owl flying overhead within the spring sky – Astronomy Now

April 18, 2019 - Comment

The readily identifiable constellation of Ursa Main, the Nice Bear, glides overhead as evening falls within the spring as seen from the British Isles. For scale, the seven-star asterism forming the Plough or Huge Dipper is in regards to the span of an outstretched hand at arm’s size broad. Ursa Main and adjoining constellation Canes


The readily identifiable constellation of Ursa Main, the Nice Bear, glides overhead as evening falls within the spring as seen from the British Isles. For scale, the seven-star asterism forming the Plough or Huge Dipper is in regards to the span of an outstretched hand at arm’s size broad. Ursa Main and adjoining constellation Canes Venatici (the Looking Canine) are affected by Messier deep-sky objects. Galaxy M108 and the Owl Nebula (M97) lie 1½° and 2¼°, respectively, southeast of magnitude +2.Three star Merak, the southernmost of the 2 pointer stars (the opposite being Dubhe) to the Pole Star. Area stars are proven to magnitude +6.5. AN graphic by Ade Ashford.In case you are lucky to watch from a rural space or have woodland close by, one of many joys of establishing your ‘scope and ready for darkness to fall on spring nights is the sound of owl calls. Hear for the sharp ‘kiew-kiew’ or transient, repetitive ‘woop’ of the little owl, the screech of the barn owl, or the ‘ke-wick’ and wavering ‘hoo-hoo’ of the tawny owl.

The Owl Nebula (M97, or NGC 3587) is a tenth-magnitude planetary nebula in Ursa Main. M97 is seen as a dim Three.Three-arcminute diameter glow in massive binoculars and small telescopes on moonless nights, but it surely takes no less than a 10-inch (25-cm) aperture telescope to see the owl-like ‘eyes’. Picture credit score: HyperStar-enabled Celestron C11 at f/2 with an Ultrastar C digital camera by Ade Ashford.Owls could also be scarce close to your favorite viewing spot, however the Northern Hemisphere spring sky accommodates one celestial owl which you could observe down in small telescopes – Messier 97 (NGC 3587). Generally referred to as the Owl Nebula, M97 is a planetary nebula found by Pierre Méchain in 1781 that’s at the moment ideally positioned for remark within the constellation of Ursa Main, the Nice Bear.

Virtually round in look with a diameter of about Three.Three arcminutes (about one-tenth that of the complete Moon) and barely brighter than magnitude +10, M97 will get its identify from two darkish patches within the nebula’s mushy glow lending it the looks of a barn owl’s face in sketches by William Parsons, third Earl of Rosse who considered it by way of his 72-inch (1.83-metre) aperture reflecting telescope in 1848.

Finding and viewing the Owl Nebula
At the moment of yr, Ursa Main lies overhead as darkness falls within the UK. The Owl Nebula lies simply 2¼ levels to the southeast of magnitude +2.Three star beta (β) Ursae Majoris, higher identified by its correct identify, Merak. The nebula’s mushy, round glow is seen in greater magnification, bigger aperture binoculars (although the present overhead side is hardly conducive to binocular viewing) or small telescopes.

If viewing with an undriven telescope outfitted with a well-aligned typical 6 or Eight× finder, M97 lies nearly half of the finder’s subject of view to the southeast of Merak. Recall that your telescope’s subject of view can be about one diploma (or two full Moons aspect by aspect) at 40 to 50× magnification. Be sure you use the bottom magnification eyepiece in your assortment and permit sufficient time (no less than 15 minutes) to get your eyes dark-adapted.

Upon getting the dim glow of M97 in your eyepiece, are you able to see any construction? (Keep in mind to make use of averted imaginative and prescient, or let your eye wander across the subject of view.) Seeing the owl’s ‘eyes’ requires a transparent, moonless evening and a 10-inch (25-cm) aperture telescope, ideally outfitted with a UHC or OIII filter. That mentioned, I recall one notable evening at a extremely darkish location once I noticed the eyes with averted imaginative and prescient whereas utilizing an unfiltered Eight-inch (20-cm) Schmidt-Cassegrain.

Positioned simply 48 arcminutes (zero.Eight°) northwest of the Owl Nebula in Ursa Main, Messier 108 (NGC 3556) is a magnitude +10.7 barred-spiral galaxy. In telescopes magnifying 50× or much less it’s potential to see the Owl Nebula and M108 in the identical subject of view. Picture credit score: HyperStar-enabled Celestron C11 at f/2 with an Ultrastar C digital camera by Ade Ashford.Bonus object: galaxy Messier 108
If you happen to seek for the Owl Nebula by offsetting southeast from β Ursae Majoris (Merak), it’s extremely that you’ll first encounter magnitude +10.7 barred-spiral galaxy Messier 108 (NGC 3556). Visually, there’s no mistaking the 2 as M108 is fainter and extra elongated than M97. What’s extra, in case you are utilizing a telescope magnifying 50× or much less it’s potential to see the Owl Nebula and M108 in the identical subject of view since they’re simply 48 arcminutes (zero.Eight°) aside.

In case your telescope has an precisely aligned computerised GoTo mount then it’s a easy matter to pick M97 or M108 from the Messier object sub-menu, however for those who want to leap to the mid-point of the pair then use the next J2000 coordinates: α = 11h 13.0m, δ = +55° 21′. In case your GoTo hand management or digital setting circles (DSCs) require JNow coordinates, then you need to use: α = 11h 14.1m, δ = +55° 15′ (J2019.Three).

If you happen to achieve viewing M97 and M108 collectively, ponder for a second that the Owl Nebula is about Eight,000 years outdated and lies some 2,500 light-years distant. The nebula represents the expelled outer layers of the aged Solar-like magnitude +14 central star, which is condensing to type a white dwarf. Additionally found by Pierre Méchain in 1781, galaxy M108 is round 45 million light-years from Earth – round 18,000 occasions farther than the Owl Nebula. M108 is an outlying member of the Ursa Main Cluster of galaxies within the Virgo Supercluster.

When to search for the Owl Nebula and M108
New Moon subsequent happens on four Might 2019, so from the top of April into early Might the night skies can be free from moonlight. By the top of this month, the final vestiges of astronomical twilight fade to black round 11:30pm BST for the guts of the British Isles, so deep-sky observers ought to benefit from any viewing alternatives.



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