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The Great Barred Spiral Galaxy ( NGC 1365 ) in the Constellation Fornax
( edit - star chart added )
The Great Barred Spiral Galaxy ( NGC 1365 ) - Chart ( please click/tap on image see larger and sharper version )
A full size ( 6200 x 4407px ) image can be downloaded from here.
Below the equator, not seen from much of the Northern hemisphere, NGC 1365 passes very nearly directly overhead an observer situated near Cape Town, as Sir John Herschel was in November of 1837 when he discovered this “remarkable nebula” that is numbered 2552 in his book of observations from the Cape.
Not called a “nebula” now, of course, this striking object is one of the nearest and most studied examples of a barred spiral ( SB ) galaxy that also has an active galactic nuclei resulting in its designation as a Seyfert galaxy.
At around 60 M light years from Earth, NGC 1365 is still seen to occupy a relatively large area ( 12 by 6 arc minutes ) due to its great size; at some 200,000 light years or so across, NGC 1365 is nearly twice as wide as the Milky Way and considerably wider than both the Sculptor and Andromeda galaxies.
This High Dynamic Range ( HDR ) image is built up from multiple exposures ranging from 4 to 240 seconds with the aim of capturing the faint detail in the spiral arms of the galaxy whilst also retaining colour in the brightest star ( the orange-red 7th magnitude giant, HD 22425 ). Also, scattered throughout the image, and somewhat more difficult to see, are numerous and far more distant galaxies.
The Great Barred Spiral Galaxy
New General Catalogue - NGC 1365
General Catalogue - GC 731
John Herschel ( Cape of Good Hope ) # 2552 - Nov 28, 29 1837
Principal Galaxy Catlogue - PCG 13179
RA (2000.0) 3h 33m 37.2 s
DEC (2000.0) -36 deg 8' 36.5"
10th magnitude Seyfert-type galaxy in the Fornaux cluster of galaxies
200 Kly diameter
60 Mly distance
Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ).
Corrector: ASA 2" Coma Corrector Quattro 1.175x.
Effective Focal Length / Aperture : 1375mm f4.7
Mount: Skywatcher EQ8
Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2
Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels)
Blue Mountains, Australia
Moderate light pollution ( pale green zone on darksitefinder.com map )
Capture ( 3, 7 & 8 Dec 2018 )
7 sets of sub-images with exposure duration for each set doubling ( 4s to 240s ) all at unity gain ( ISO 250).
140 x 240s + 10 each @ 4s to 120s
total around 9.7 hrs
Processing ( Pixinsight )
Calibration: master bias, master flat , master dark
Integration in 7 sets
Image Plate Solution
Resolution ........ 0.586 arcsec/px ( full size image )
Rotation .......... -0.003 deg ( North is up )
Field of view ..... 58' 37" x 38' 55"
Image center ...... RA: 03 33 36 Dec: -36 08 27
The Rosette Star Cluster and Nebula ( NGC 2244 & 2237 ) ( please click / tap on image to see larger )
This is the Inverted B&W version buried in my previous post ( I quite liked the way the inverted B&W brings out the star cluster and so I thought it deserved its own thread )
A new High Dynamic Range image of the Sculptor Galaxy ( NGC 253 ) captured over a number of nights in mid-September 2017 and processed with PixInsight using the DrizzleIntegration and PhotometricColorCalibration tools.
The Silver Coin or Sculptor Galaxy ( NGC 253 ) in the Sculptor constellation.
( please click / tap on image to see larger and sharper )
On the 23rd of September 1783, sitting before her telescope in the field behind the house she shared with her brother William at Datchet, near Slough in the south of England, Miss Caroline Herschel "swept" the sky searching for new comets and never before seen star clusters and nebulae. On this occasion, way down in the sky, not far above the Southern horizon, in an area of the southern sky that Nicolas de Lacaille had called the “Apparatus Sculptoris” or “the sculptor’s studio", Miss Herschel saw and noted down a very bright and large nebula where one had never before been recorded. This event was later recognised by her brother, Sir William Herschel, as the discovery, by Caroline Herschel, of the nebula he listed in his catalogue as H V.1. In later years, her 'beloved nephew', Sir John Herschel, William's son, would record this 'nebula' as entry # 138 in his General Catalogue of Nebulae and Clusters of Stars ( eventually becoming the 253th entry in the New General Catalogue, NGC 253 ).
Whilst relatively close to us compared to the billions of far more distant galaxies in the Universe, the great size of the “Sculptor Galaxy” and the huge distances involved are still hard to comprehend. To put this into some perspective, the light that is just now reaching one edge of the great disc left the opposite edge when the Earth was in the grip of last great Ice Age 70,000 years ago and the light we now see has been travelling towards us for over 11 million years.
More information on the discovery of the Sculptor Galaxy by Miss Caroline Herschel, as well as the later observations by both Sir William and Sir John Herschel, can be found in my Stargazerslounge blog, “The Sculptor Galaxy ( NGC 253 )”
This image was captured over a number of nights in the middle of September 2017 and processed on the 23rd; exactly 234 years from the day of its discovery by Caroline Herschel.
With over 18 hours of total exposure, this HDR image attempts to capture the huge range of brightness levels; from the brightest stars and the core of the galaxy through to the numerous 'tiny' galaxies scattered throughout the image ( the total magnitude range is from around mag 8.8, for the brightest star, to 22+ for the faintest stars and galaxies visible in the image).
Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 )
Corrector: ASA 2" Coma Corrector Quattro 1.175x
Effective Focal Length / Aperture : 1410mm f4.7
Mount: Skywatcher EQ8
TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2
Camera:Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels)
Location: Blue Mountains, Australia
Moderate light pollution ( pale green zone on darksitefinder.com map )..
Capture ( 16, 17, 19,20,22 Sept. 2017 )
8 sets of sub-images with exposure duration for each set doubling ( 2s to 240s ) all at ISO800
273 x 240s + 10 each @ 2s to 120s
total around 18hrs
Calibration: master bias, master flat and no darks.
Drizzle Integration in 8 sets.
Pixinsight & Photoshop
23 Sept. & 8 Oct 2017
Image Plate Solution ( this cropped image )
Resolution ........ 1.324 arcsec/px
Rotation .......... -180.00 deg ( South ^, East > )
Field of view ..... 57' 57.5" x 38' 40.1"
Image center ...... RA: 00 47 32.809 Dec: -25 17 04.48
Designations and alternative names for the Sculptor Galaxy:
CH10 ( Caroline Herschel # 10 )
H V.1 ( William Herschel, Class V ( very large Nebulae ) # 1 )
H 61, H 2345 ( John Herschel observations identifiers )
GC 138. ( John Herschel’s - A General Catalogue of Nebulae and Clusters of Stars # 138 )
NGC 253 ( John Herschel’s catalogue updated by Dreyer - The New General Catalogue of Nebulae and Clusters of Stars # 253 )
Silver Coin Galaxy
Silver Dollar Galaxy
Annotated image of the Sculptor Galaxy ( NGC 253 ) - showing the brighter stars ( from the Tycho-2 catalogue ) as well the galaxies recorded in the Principal Galaxies Catalogue ( PGC ). I have yet to complete identifying and annotating the very large number of ‘tiny’ galaxies in the image.
( please click / tap on image to see larger and sharper )
After a month of chasing the Moon, not always successfully, I have finished my Moon Phase chart for November.
Original fullsize, 6800 x 4337px, 2.7MB image here - http://www.sacarr.co.uk/astro/moon/2016_moon_phases.jpg
Across the month, I've missed a weeks worth of phases, mainly due to weather. Unfortunately after twelve consecutive days of capture, the weather again let me down for the last two tiny crescents which I'd hoped to catch at Moonrise. So I've managed twenty phases captured, plus of course the New Moon which is too close to the Sun to see. The phases I missed have been ghosted in behind the clouds with Stellarium screen grabs. My previous best was February 2015, when I caught seventeen phases, and thirteen consecutively.