AstronomyJourneys

Zubenelgenubi / Alpha Librae
(α Librae / α Lib)

Binary Star

Located 75 & 76 light years away.

Despite its 'alpha' designation, it is the second brightest star in the constellation of Libra.

The primary bright star (in center) is α2 Librae or α Librae A (Alpha 2 Librae). Mag. 2.741.
The fainter companion (its top right) is α1 Librae or α Librae B (Alpha 1 Librae). Mag. 5.153.

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Alpha 2 Librae is a spectroscopic binary system.
Alpha 1 Librae is a spectroscopic binary system, too.

That means, this is a system of not 2 but 4 (FOUR) stars; 2 pairs in sum, or 1 pair with each of 2 stars.

Further, the system may have a 5th component, KU Librae, thus forming a quintuple star system, or a multiple star system of 5 (FIVE) stars.

In spectroscopic binary systems, the separation between the stars is usually very small, and the evidence of its binary nature comes from the doppler effect on its emitted light.
It means, they will NEVER be visible visually or even in high resolution images -- due to their severe proximity.

NGC 4631 [Whale Galaxy] [Caldwell 32] (edge-on barred spiral galaxy)
with tiny NGC 4627 [Pup Galaxy] (dwarf elliptical galaxy)
and NGC 4656 [Hockey Stick / Crowbar Galaxy] (distorted edge-on barred spiral galaxy)

(Collectively, NGC 4631 & NGC 4627 are also catalogued as Arp-281 from Arp’s Atlas of Peculiar Galaxies)

In constellation Canes Venatici

Pair of interacting galaxies -- or trio

Each 60-sec exposure image

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NGC 4656 is the thinner galaxy (1st image at top right, 2nd image main one in center).
Named according to its appearance as hockey stick or crowbar (with its figure according to both objects).

NGC 4631 is the thicker galaxy (1st image at bottom left, 3rd image main one in center).
Named according to its appearance as whale, as in blue whale with its body bulge.

NGC 4627 is the tiny smudge-like galaxy in proximity to NGC 4631 (just below it in 3rd image, 1st image at extreme bottom left).
It has an apparent magnitude of 13.10.

3 GLOBULAR CLUSTERS

NGC 5897
in Libra
mag. 8.52
30-s exp.

NGC 5466
in Bootes
mag. 9.20
60-s exp.

NGC 5053
in Coma Berenices
mag. 9.96
60-s exp.

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Similar appearing (esp. first two). But all different objects, of course!
Look for patterns in star-fields to verify they are not different versions of same object(s).

NGC 3201 globular cluster
(Caldwell 79)

in Vela constellation (southern sky)

Magnitude 6.7

Single 30-sec exposure

M53 (NGC 5024) globular cluster

in Coma Berenices constellation

Magnitude 7.6

Single 15-sec exposure

Antennae Galaxies
NGC 4038 & NGC 4039
(Caldwell 60 & Caldwell 61)

in Corvus constellation

Colliding / Interacting (!) Starburst Spiral galaxies

Single 60-sec exposure

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Re-take after 11 April 2024 with SAME instruments from SAME observing site (wider f.o.v.)
Re-re-take after 18 January 2012 (pre-dawn of 19 Jan '12) from Nikaya Observatory (similar f.o.v. / more resolution)

M83 (NGC 5236)
Southern Pinwheel galaxy

Barred Spiral galaxy
magnitude 7.6

in constellation Hydra
at border of constellation Centaurus

BOTH single 30-sec exposures

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1st image -- narrow field
2nd image -- wide field

The 1st image is NOT a cropped version of the 2nd image.
They are only the 2 FOV options in the CCD camera's settings.

NGC 4945 (Caldwell 83) and NGC 4976 with NGC 4945A

in Centaurus constellation

NGC 4945 -- obliquely oriented (not perfectly edge-on), starburst galaxy (magnitude 9.3)
NGC 4976 -- elliptical galaxy, peculiar galaxy (magnitude 11.0)
NGC 4945A -- Active Galaxy Nucleus (AGN) candidate [no more information available!] (magnitude 11.64/13.01)

Digitized Sky Survey (DSS) image of the faint NGC 4945A for comparison is at LAST

Single 60-sec exposures 1st & 3rd images

NGC 4945
(Caldwell 83)

in Centaurus constellation

Edge-On Barred Spiral galaxy

Single 60-sec exposure

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Re-take after 26 August, 2022 from Namibia (wider f.o.v.)
Re-re-take after 31 January 2015 & 15 February 2015 from Nikaya Observatory (narrower f.o.v.)

NGC 4565
Needle Galaxy (Caldwell 38)

Spiral Edge-On galaxy

in Coma Berenices constellation

Single 30-second exposure
No processing

Sky reasonably dark in zenith region with only some background glow

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Re-take after 12 April, 2024 (wider f.o.v.)