Recently Browsing 0 members
No registered users viewing this page.
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 )
By Astro Buer
I'm looking for any recommendations for a good little refractor as a companion for my Star Adventurer for astrophotography.
Little (in weight) being the operative word given the 5kg payload capacity of the mount!
Currently I am shooting with an Sony A7S and guiding with an Orion Starshoot and Orion 50mm guide scope. So there's a little bit of weight on there already.
Looking at refractors with a focal length of 400-600mm which are proven performers for imaging.
So far contenders are:
Stellarvue 80mm ED
TS-Optics ED 70mm f/6
William Optics Gran Turismo 71 APO Refractor
Any advice/images of rigs/example images/etc would be greatly appreciated!
Thanks in advance :-)
Im living in a fairly light polluted area, and have a Skywatcher 200p on an eq5 pro mount. I've been using my phone to take pictures of varies objects with varying degrees of success ( mainly due to mounting my phone to the telescope) but ive decided id like to take imaging a little more seriously and am looking to get a DSLR with the interest of deep sky astrophotography. having said that i dont have £5k for blow on a camera and am looking to spend around the £100 mark, but dont know cameras and dont know what the best camera in my price range would be. I realize i wont be able to do too long a exposure because of my mount being unguided and it being a eq5 pro not a Heq5. any recommendations or advice would be greatly appreciated.
Just purchased a Skywatcher ED80 refractor and apart from the supplied 2" 28mm LES eyepiece I have the Ultrawide 6mm Skywatcher 1.25" and the Skywatcher Super Plossl 40mm.
I am looking at purchasing a 2x or 2.5x Barlow and was after any recommendations? Also have I read somewhere that I have to have a certain 'type' for the supplied 2" star diagonal? Would I better be off purchasing one that can fit both 2" and 1.25" eyepieces or for optical quality sticking with just a 1.25" (does it affect optical quality even?) Celestron Luminos for example
My other question is can this scope take (visually acceptable) a 2.5mm eyepiece and take it to the max possible magnification if I required max even.
Last question is Sky-Watcher SWA 70° Eyepieces on offer at FLO at the moment, anybody have any thoughts or feed back as I was thinking about an Hyperion to add to the eyepiece collection. (thinking about 13mm-17mm)
Sorry, a load of questions but I live in West Wales and have no local suppliers within 100 miles, I'm happen to be going past FLO at the end of the week and I've a credit card .....gulp!
SO - for a while now I've been interested in trying my hand at night-sky photography. I'm actually planning a trip to Namibia next year, around the new moon on 9th Sept. 2018. (Not just for night-sky, but wildlife, sand-dunes and local culture too.)
For now I'm immersing myself in online articles, books, videos etc. I shoot Micro-Four Thirds, and so the newly released Laowa 7.5mm f/2 seems perfect timing.
HOWEVER, I am aware I will probably need the SkyWatcher Star Adventurer bundle to get the most out of the skies.
All the articles etc are fine for theoretical what-to-do's, but I was wondering if anyone knows of people who run demonstrations, or even workshops, for how to practically use and get-to-grips with the gear?
I'm not that keen on going the whole hog and buying a Sw SA before trying one first.
Any help or leads people can offer would be greatly appreciated.