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ngc 253 John Herschel in South Africa ( NGC 253, Sculptor Galaxy )
MikeODay posted a blog entry in The Sculptor Galaxy - NGC 253
Sir John Herschel at the Cape of Good Hope Having spent the years 1825 to 1833 cataloguing the double stars, nebulae and clusters of stars visible from Slough, in the south of England, John Herschel, together with his family and telescopes, set sail from Portsmouth on the 13th of November 1833 bound for Cape Town. As detailed below, in an extract from his book, the family enjoyed a pleasant and uneventful voyage and arrived some 5 months later at Table Bay with all family and instruments in good condition. Reading on however, one might very well think that it might not have ended so well had they but left shortly after ... “... (iii.) Accordingly, having- placed the instrument in question, as well as an equatorially mounted achromatic telescope of five inches aperture, and seven feet focal length, by Tulley, which had served me for the measurement of double stars in England; together with such other astronomical apparatus as I possessed, in a fitting condition for the work, and taken every precaution, by secure packing, to insure their safe arrival in an effective state, at their destination, they were conveyed (principally by water carriage) to London, and there shipped on board the Mount Stewart Elpliinstone, an East India Company's ship, Richardson,Esq. Commander, in which, having taken passage for myself and family for the Cape of Good Hope, we joined company at Portsmouth, and sailing thence on the13th November, 1833, arrived, by the blessing of Providence, safely in Table Bay, on the 15th January, 1834, and landed the next morning, after a pleasant voyage, diversified by few nautical incidents, and without seeing land in the interim. It was most fortunate that, availing himself of a very brief opportunity afforded by a favorable change of wind, our captain put to sea when he did, as we subsequently heard that, immediately after our leaving Portsmouth, and getting out to sea, an awful hurricane had occurred from the S. W. (of which we experienced nothing), followed by a series of south-west gales, which prevented any vessel sailing for six weeks. In effect, the first arrival from England, after our own, was that of the Claudine, on the 4th of April, with letters dated January 1st.(iv.) ...” “Result of Astronomical Observations, Made During the Years 1834, 5, 6, 7, 8, At the Cape of Good Hope ... “ by Sir John Herschel, 1847 John Herschel rented a property and set up the twenty foot reflector near Table Mountain, at a site, that was then, just outside of Cape Town. The Twenty Feet Reflector at Feldhausen, Cape of Good Hope, South Africa, 1834 This telescope was made by Herschel in England and transported, along with his other instruments, by ship to Cape Town and then inland to Feldhausen. The telescope is a Newtonian reflector, built to William Herschel’s design, with a focal length of 20 feet and clear aperture of 18 1/4 inches ( f13 ). The location of the telescope was established by careful survey to be: lat 33d 55’ 56.55”, long 22h 46’ 9.11” W ( or 18.462 deg E ). The site of the great telescope was memorialised by the people of Cape Town by the erection of a granite column that is still there today. ............. Observations of the Sculptor Galaxy Amongst his many thousands of observations made from Cape Town, of nebulae, clusters of stars, double stars, the sun, etc., Sir John Herschel records that he observed V.1 ( CH10 - Caroline’s Nebula - the Sculptor Galaxy ) during two different “sweeps” and gave it the number 2345 in his South African catalogue. Sweeps: 646 - 20th November 1835; 733 - 12th September 1836 At the latitude of Feldhausen, and on these dates, the Sculptor galaxy would have been at an altitude around 80 degrees above the northern horizon when near the meridian ( which was where the telescope was pointed during Herschel’s “sweeps” ). The sight afforded from this location, with the Sculptor Galaxy almost at the zenith, must have been significantly brighter and clearer than the Herschels had thus far been granted from its location way down near the horizon south of Slough. .......... Other Obsevations by John Herschel from Cape Town Also observed by John Herschel in 1835 were the people and animals that inhabit the moon ... The Great Moon Hoax of 1825 - “Lunar Animals and other Objects, Discovered by Sir John Herschel in his Observatory at the Cape of Good Hope ... “ -
Observations of the Sculptor Galaxy ( NGC 253 ) by William and John Herschel ......... Part 2. Observations of "Caroline's Galaxy" by Sir John Herschel, 1830's Sir John Herschel, the only child of Mary Baldwin and Sir William Herschel, was born in 1792 when his father was in middle age and already famous as one of world's leading astronomers. Having excelled in school, and no doubt inspired by his famous elders, John Herschel decided upon a career as a 'man of science' and set out to pursue a wide range of interests; with one particular focus being a continuation of the study of the heavens commenced by his father and aunt, Caroline Herschel. In 1820, with the assistance of his father, John Herschel supervised the construction of a new telescope at Slough in England. As described in the extract below ( from a paper presented to the Royal Society in 1826, titled "Account of some observations made with a 20-feet reflecting telescope ... " ), the telescope had a polished metal mirror with clear aperture of 18 inches, focal length of 20 feet and was modelled on the same design created by his father. It is this telescope, in the 1820’s and early 30’s, following the death of his father and the return of his aunt Caroline to Hanover, that John Herschel used to 'sweep' the night sky and extend the catalogue of nebulae and clusters of stars that was published by his father ( see W. Herschel's Catalogue of One Thousand new Nebulae and Clusters of Stars ). On the 1st of July 1833, having complied sufficient observations, John Herschel presented to the Royal Society an updated list of the positions and descriptions of the Nebulae and Clusters of Stars that he had thus far observed. As noted in the introduction to the paper published in the Philosophical Transactions, he had planned to wait before publishing until he had complied a fully comprehensive general catalogue of objects visible from the south of England. However, due to his expectation of “several more more years additional work” needed to complete the task and his assessment that he now was in a position to address, at least in part, the then current “... want of an extensive list of nebulae arranged in order of right ascension ...”, he elected to present his list, “ ... simply stating the individual results of such observations as I have hitherto made ... “. It was not until October 16, 1863, some thirty years later, that Sir John would deliver to the Royal Society his General Catalogue of Nebulae and Clusters of Stars. As well as introducing many objects that had not previously been recorded, Sir John’s list of 1833 included a re-examination of, and in some cases a small correction to, the positions of many of the deep sky objects observed by his father and noted down by his aunt. One of these re-visited objects was, unsurprisingly, the large and bright nebula discovered by Caroline Herschel in 1783 and recorded in Sir Williams’s catalogue as V.1 / CH 10 ( object number one, of class five ( very large nebulae ) / Caroline Herschel #10 ). In total, John Herschel records around 2500 observations of nebulae and clusters of stars in his 1833 paper; with observation #61 being V.1, the “ Sculptor Galaxy “ . The measured position of V.1is given in RA and the angle from the north celestial pole ( all reduced to epoch 1830.0 ). The description can be interpreted by reference to the legend in the paper. Thus, “ A vL mE vB neb “ becomes “ A very large, much extended, elliptic or elongated, very bright nebula “. He also notes that in addition to this observation, #61, noted down from sweep #306, V.1 was also observed in sweep #292, “but no place was taken”. The figure to which he refers , figure 52, is included towards the back of his paper and is a sketch he made of the Sculptor Galaxy. to be continued ...
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Observations of the Sculptor Galaxy ( NGC 253 ) by William and John Herschel The very large and bright 'nebula' discovered by Caroline Herschel in 1783, that we now know as the Sculptor Galaxy, was observed a number of times by her 'dear brother' Sir William Herschel and by her 'beloved nephew' Sir John Herschel, Baronet. Some of these observations were recorded and published in the Philosophical Transactions of the Royal Society and, with respect to those by Sir John in South Africa, in the book of Astronomical Observations at the Cape of Good Hope. ......... Part 1. Observation of the 'class V nebula', H V.1, by Sir William Herschel, 1783 In 1782, with the fresh patronage of King George III, William Herschel, together with his sister Caroline, undertook the not inconsiderable task of transferring his astronomical equipment from Bath to Datchet ( near Windsor ) in England. Shortly afterwards, in 1983, Sir William began a "sweep of the heavens" with the very large Newtonian telescope of his design and construction. With this mighty telescope's twenty foot focal length and clear aperture of a little over eighteen and half inches, William was able to see fainter objects and smaller detail than any other astronomer of that time. ( source: The Scientific Papers of Sir William Herschel, Vol.1 ) ...... On the 30th of October, 1783, in the course of one of his "sweeps" with the twenty-foot telescope, Sir William Herschel observed Caroline's 'nebula' and noted down ( or perhaps more likely, dictated to Caroline ) a description of what he saw and a reference to its position relative to a 4th magnitude star in the Piscis Austrainus constellation, #18 Pis. Aust. ( with reference to Flamsteed's Catalogue ( or HD 214748 , HIP 111954 as we might call it )). Over the course of the next three years, Sir William would go on to view the Sculptor Galaxy a total of seven more times; as recorded in his paper "Catalogue of One Thousand New Nebulae and Clusters of Stars", presented to the Royal Society on the 27th of April 1786. ( Source ) Sir William's somewhat cryptic notes can be translated by reference to the key provide in his paper and doing so reveals the following: Class: V. ( very large nebula ) Number: 1 Observed ( by WH ): 30 Oct 1784 Reference star: 18 Piscis Austrainus ( Flamsteed's Catalogue; the best reference for the time - we might use epsilon Pis. Aust. or HD 214748 / HIP 111954 ) Sidereal direction rel. to star ( following or leading ): following star Sidereal time rel. to star: 128 min 17 sec Declination direction rel. to star: north of star Declination amount rel. to star: 1deg 39min Observed: 8 times ( up until April 1786, the date of the paper ) Description: - cB: "confidently bright" - mE: "much extended" - sp: "south preceding" - nf: "north following" - mbM: "much brighter middle" - size: 50' x 7 or 8' " CH" denotes that it was discovered by his sister Caroline Herschel The note he refers to expands on details of Caroline's discovery ... ...............................................
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The Discovery of the Sculptor Galaxy by Miss Caroline Herschel in 1783 On the 23rd of September 1783, sitting before her telescope in the field behind the house she shared with her brother William in 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, Miss Herschel saw and noted down a very bright and large nebula where one had never before been recorded and that was later recognised by her brother, Sir William, as the discovery by Caroline Herschel of the nebula he listed in his catalogue as H V.1. ( circ. 1825-33, Sir John Herschel, beloved nephew of Miss Caroline Herschel ) Today we know this 'nebula' to be, not as some thought then, a swirling mass of stars and gases within our own galaxy, but rather, a galaxy not unlike our own but way more distant than the outer reaches of of own Milkyway galaxy. Given various names, Silver Dollar Galaxy, Sliver Coin Galaxy or simply by its number in the New General Catalogue, NGC 253, it is most commonly called the Sculptor Galaxy and we owe its discovery to the first female professional astronomer. Caroline Herschel ( 1750 - 1848 ) ... ( link ) ( 1782 - 1783 ) ... ... ... H V.1 Observed ( by WH ): 30 Oct 1784 128 minutes, 17 seconds following and 1 degree, 39 minutes north of referenced star Description: - cB: "confidently bright" - mE: "much extended: - sp: "south preceding" - nf: "north following" -mbF: "much brighter middle" - size: 50' x 7 or 8' from: ( link ) ............................... The location reference to H V.1 ( NGC 253 ) in William Hershel's catalogue is in relation to a star found in Flamsteed's Catalogue, 18 Pis. Aust., which is #18 in Piscis Austrainus or Epsilon PsA, the 4th magnitude star HD214748 ( HIP111954 ) ( source ) ( Plate from "Atlas Coelestis" by John Flamsteed, 1646-1719 ) ------------------------------------- William Herschel found favour with the King and was granted a position as Royal Astronomer to George III in 1782. Shortly after, William and Caroline moved from Bath to Datchet ( near Windsor ) and took up residency in a rented house which, whilst somewhat delapadated and damp, had ample accommodation and fields for William to construct and deploy the large telescopes he wished to build. It was in these grounds that Caroline set up her "Sweeper" to look for comets and doing so also discovered a number of 'nebulae' including ( in 1783 ) what was later to become known as the Sculptor Galaxy. ( The Herschel house at Datchet near Windsor ) ( The Lawn, Horton Road, Slough ( Datchet ) - Google Maps ) ............. Caroline Herschel's "Sweeper" was a 27" focal length Newtonian telescope that was supported in a kind of altitude-azimuth mount consisting of a rotating table and a small gantry and pulley system that was used to effect altitude adjustments by sliding the tube up and down against a board used to provide stability. There has been some conjecture as to the exact details of the construction, however the image below, even if perhaps not the actual instrument, gives an indication of the overal design philosophy. Late in her life Caroline Herschel recorded details of her telescope in a booklet titled "My little Newtonian sweeper": In her memoir, Caroline Herschel describes the performance of her observations as the conducting of "horizontal sweeps"; from which one might assume the task consisted of setting the altitude in accordance with the plan for the night's observing and then slowing rotating the top of the table in azimuth as one observed and noted down the objects that passed across the view in the eyepiece. However, with the arrival of this new "telescopic sweeper" in the middle of 1783, Caroline Herschel added the new method of sweeping in the vertical, as noted below in an extract from her observing book ( source for both extracts: "Caroline Herschel as observer", Michael Hoskin, Journal for the History of Astronomy, 2005 ) .... The achievement of her discovery of the 'nebula' in the Sculptor constellation was remarkable in so many ways; not the least of which being the low path in the sky that the Sculptor galaxy follows when observed from Datchet in southern England - which on the night of her observation would not have exceeded 12 degrees or so above the horizon. Today, 234 years later, and blessed with 21st century luxuries and conveniences, I write on my IPAD and flip over to my planetarium application, SkySafari, and model the sky as it was seen by Caroline Herschel from near her house on the 23rd of September, 1783 ... ( SkySafari by Simulation Curriculum )
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From the album: CCD venture
A h-alpha shot of the Wizard nebula in Cepheus. ED80 - ATK16HR - Ha clip filter - EQ6 - finderguider 9x50mm PhD2 - photoshop - DSS. -
Bright Nebula in Ara ( NGC 6188 ) source: 500px.com/mikeoday
MikeODay posted a gallery image in Member's Album
From the album: Mike's Images
Bright Nebula NGC 6188 and open cluster NGC 6193 in Ara by Mike O'Day Magnitude +5.19, RA 16h 41m 42s, Dec -48deg 48' 46" Approx. 3800 light years away Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount (on concrete pier) Orion 80mm f5 guide scope and auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S 'nebula' filter. Nikon D5300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. UHC-S - 32 x 180 sec ISO800 (14bit NEF, Long Exp. NR on). Pixinsight and photoshop 7 July 15 (processed 29 August 15) source: photo.net/photos/MikeODay 500px.com/mikeoday© Copyright Mike O'Day 2015 - all rights reserved
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messier 8 The Lagoon Nebula ( Messier 8, NGC 6523 ) in Sagittarius
MikeODay posted a gallery image in Member's Album
From the album: Mike's Images
The Lagoon Nebula ( Messier 8, NGC 6523 ) in the constellation Sagittarius - by Mike O'Day ( https://500px.com/mikeoday ) The Laboon Nebula ( M8 ) is visible to the naked eye under dark skies from most latitudes except the far north. Seemingly covering an area about three times that of the full Moon, M8 actually covers an area somewhat greater than 110 light years and is around 4300 light years from Earth in the Sagittarius-Carina spiral arm of the Milkyway galaxy. Links: https://500px.com/MikeODay http://photo.net/photos/MikeODay Details: Messier 8, NGC 6523 - Lagoon Nebula. also contains: NGC 6526 NGC 6530 NGC 6533 IC 1271 IC 4678 7SGR 9SGR Skywatcher Quattro 10" f4 Newtonian telescope. Skywatcher AZ Eq6 GT Mount. Orion auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S 'nebula' filter. Nikon D300 (unmodified) (14bit NEF). Field of view (deg) ~ 1.35 x 0.90. 20 x 120 sec ISO400. 26 x 30 sec ISO 1600. 23 x 240 sec ISO 200. PixInsight and Photoshop. 2 August 14 . re-processed 24 April 2016 to include the additional subs ( the first version only made use of the 23 x 240 sec ISO 200 subs ) and putting use the processing lessons I have learnt over the past year.© Copyright Mike O'Day 2016 - all rights reserved
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From the album: Mike's Images
NGC 3372 Eta Carinae Nebula (RA 10:44:22.47 - Dec -59 56' 36.5"). Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT (on Pier) Orion auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S (Nebula) filter, Nikon D5300 (unmodified), Long Exp Noise Reduction on, 12bit NEF, UHC-S 15 x 120 sec ISO800. PixInsight & Photoshop 19 March 15© Copyright Mike O'Day 2015 - all rights reserved
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From the album: Mike's Images
Cat's Paw Nebula - NGC 6334 ( aka Bear Claw Nebula ) An emission nebula in Scorpius (near the scorpion's tail) RA 17h 25m 39.6s ; Dec -35deg 43' 48" . 7th August 2015. Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount Orion 80mm f5 guide scope and auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S 'nebula' filter. Nikon D5300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. ISO800, 14bit NEF, Long Exp. NR on. 28 x 200sec (starting at zenith) no moon, 3deg C, 70%RH, moderate LP. PixInsight© Copyright Mike O'Day 2015 - all rights reserved
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From the album: Mike's Images
NGC 6357 in Scorpius Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount Orion 80mm f5 guide scope and auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S 'nebula' filter. Nikon D5300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. UHC-S - 100 x 100 sec ISO800 (14bit NEF, Long Exp. NR on). Pixinsight and photoshop© Copyright Mike O'Day 2015 - all rights reserved
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Alnitak on Orion's Belt with the Flame and Horsehead nebulae
MikeODay posted a gallery image in Member's Album
From the album: Mike's Images
Orion's Belt - centered on "Alnitak", a 1.7 magnitute tripple star at one end of the belt. Includes the Flame Nebula (NGC2024) and IC434 which contains the Horsehead Nebula. Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount Orion 80mm f5 guide scope and auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S 'nebula' filter. Nikon D5300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. UHC-S - 19 x 2min ISO400 (12bit NEF, Long Exp. NR on). Raw conversion, initial colour balance and shadow and hightlight recover in DXO Optics Pro, aligned and stacked in Nebulosity, processed in Photoshop 5 October 14© Copyright Mike O'Day 2015 - all rights reserved
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From the album: Mike's Images
NGC 2070 Tarantula Nebula Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount. Baader MPCC Mark 3 Coma Corrector. Nikon D300 (unmodified). 80 x 30 sec ISO800 unguided. 24 Apr 14 Reprocessed 9 August 15© Copyright Mike O'Day 2015 - all rights reserved
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From the album: Mike's Images
Cat's Paw Nebula - NGC 6334 ( aka Bear Claw Nebula ) An emission nebula in Scorpius (near the scorpion's tail) RA 17h 25m 39.6s ; Dec -35deg 43' 48" . 7th August 2015. Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount Orion 80mm f5 guide scope and auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, UHC-S 'nebula' filter. Nikon D5300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. ISO800, 14bit NEF, Long Exp. NR on. 28 x 200sec (starting at zenith) no moon, 3deg C, 70%RH, moderate LP. PixInsight© Copyright Mike O'Day 2015 - all rights reserved
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From the album: Mike's Images
30 sec subs @ ISO 800 Guided Sykywatcher Quattro 10" f4 Newtonian Baader MPCC Mk3 Coma Corrector Skywatcher AZ EQ 6 GT Mount Orion auto guider on 80mm f5 guide scope Nikon D300 unmodified© Copyright Mike O'Day 2014 - all rights reserved
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From the album: The next step.
One of my first targets but still trying to get a decent image - clusters are harder than they look to capture due to them being all stars so tracking errors and uncorrected optical problems are very quick to show up in the end result.© Aenima
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Shimmering like a pearl to the naked eye, this open cluster of mostly young blue stars ( known as the "Pearl Cluster" ) is approximately 5500 light years from Earth and was discovered by Abbe Lacaille in 1752 from South Africa. A Cluster of Pearls in the Southern Skies ( NGC 3766 " The Pearl Cluster" ) ( please click / tap on image to see larger and sharper - a full size image can be found here ) This HDR image is constructed from 11 sets of exposures ranging from 1/4 sec ( to capture the centre of the brighter stars ) through to 240 seconds ( for the fainter stars of the Milky Way ). Total exposure time was around 5 hours. ..... Image details can be found here
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( please click / tap to see larger ) Identification: The Rosette Nebula ( NGC 2237 ) is a large, circular emission nebula in the constellation Monoceros. It surrounds a cluster of hot, young stars known as the Rosette Cluster ( NGC 2244 ). ( SkySafari ) NGC 2237, 2244 Caldwell 49, 50 North is up. .................. Capture Details: Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1400mm f4.7 Mount: Skywatcher EQ8 Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 Camera: Nikon D7500 (unmodified) (sensor 23.5 x 15.7mm, 5568x3712 @ 4.196um pixels) Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ) Capture ( 23 Dec 2017 ) 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO400. 10 x 240s + 5 each @ 1s to 120s imaged ~ +/- 1.5hrs either side of meridian maximum altitude ~ 51.3 deg above north horizon Processing ( Pixinsight ) Calibration: master bias, master flat and in-camera dark subtraction Integration in 9 sets HDR combination Image Plate Solution =================================== Resolution ........ 0.633 arcsec/px ( full size image ) Rotation .......... 0.181 deg Focal ............. 1367.90 mm Pixel size ........ 4.20 um Field of view ..... 58' 59.4" x 39' 15.0" Image center ...... RA: 06 31 55.638 Dec: +04 56 30.84 =================================== ... More information, etc., here:
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The Jewel Box ( NGC 4755 ) is an open cluster of mostly hot young blue-white stars that appears to the unaided eye as a bright 4th magnitude star close to the Southern Cross. Only visible from southern latitudes, the Jewel Box was first recorded by Nicolas Louis de Lacaille during his visit to South Africa in 1751 and was later described by Sir John Herschel as "a casket of variously coloured precious stones" - hence the name "Jewel Box". The Jewel Box open star cluster ( ngc 4755 ) in Curx ( please click / tap on image to see larger and sharper ) Please see here for image details.
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( please click/tap image to see larger ) Identification: 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 ESO 358-17 IRAS 03317-3618 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 .................. Capture Details: Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1400mm f4.7 Mount: Skywatcher EQ Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 Camera: Nikon D7500 (unmodified) (sensor 23.5 x 15.7mm, 5568x3712 @ 4.196um pixels) Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ) Capture ( 24 Dec 2017 ) 7 sets of sub-images with exposure duration for each set doubling ( 4s to 240s ) all at ISO400. 52 x 240s + 5 each @ 4s to 120s total around 2.5hrs Processing ( Pixinsight ) Calibration: master bias, master flat and no darks Integration in 7 sets HDR combination Image - Plate Solution ========================================== Resolution ........ 1.328 arcsec/px Rotation .......... -0.008 deg ( North is up ) Field of view ..... 58' 8.6" x 38' 47.5" Image center ...... RA: 03 33 41.182 Dec: -36 07 46.71 ==========================================
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edit: Processed in January from data captured in June and it has been pointed out to me that, as per the rules, this image can not be considered for the competition. .............. The Fighting Dragons of Ara ( NGC 6188 ) ( please click / tap on image to see larger ) Image details: This is an HDR image constructed from exposures ranging from 2 seconds to 240 seconds in length. The aim was to capture the faint stars and details in the nebula whilst at the same time maintaining colour in the bright stars without clipping the highlights. Plate Solution: Resolution ........ 1.336 arcsec/px Rotation .......... 90.002 deg ( North is to the right ) Focal ............. 1475.57 mm Pixel size ........ 9.56 um Field of view ..... 58' 28.5" x 39' 0.8" Image center ...... RA: 16 40 09.903 Dec: -48 41 27.00 Telescope: 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 AZ Eq6 GT. Guiding: 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 ( 24 June 2017 ). 8 sets of sub-images with exposure duration for each set doubling ( 2s to 240s ) all at ISO800. 34 x 240s + 10 each @ 2s to 120s. Processing ( Pixinsight - 19 Aug 2017, 13 Jan 2018 ). Calibration: master bias, master flat and no darks. Integration in 8 sets. HDR combination
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Thor’s Helmet ( NGC 2359 ) ( NGC 2359 - Thor’s Helmet ) ( please click / tap on image to see larger and without compression artefacts ( and double click on that image if you what to see it as I posted it ! ) ) Summary: An HDR image that captures as much of the faint detail in the nebula as I can whilst also attempting to show the “true” colours of the stars ( without burnt out highlights ). Nikon D5300 ( unmodified ), taken 18/19 Jan 2018, exposures ranging from 2s to 240s ( 116 x 240 sec + 5 each for other exposures ) Full details in main post :
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At the intersection of boredom, astronomy and excel lies my analysis of the objects within the NGC (sorry if this is old news). I made these tables using the data from the NGC/IC Project. It may help in further organizing your observational data, or planning, it might not, but it's kind of neat to see the breakdown by objects within the catalog (and it was fun to put together). Let me know if you catch any errors and I can update! -Rick Some interesting findings: I knew there were a bunch of galaxies in the NGC, just was not aware that 80% of all the existing, non-duplicate objects were galaxies There are more Double Stars in the NGC than Planetary Nebulae 7840 NGC entries, but only 5724 unique and existent objects (maybe 5723, depending on NGC 1990) 234 Entries are duplicates (or triplicates) The only duplicated entries are of galaxies There are 82 entries for which objects do not actually exist 83 is probably the real count if you say NGC 1990 does not exist January-April is a great time for open clusters June-August is a great time for globulars Any month is a great month for galaxies July and August are great for planetary nebulae 257 NGC objects are stars, doubles stars or triple stars Triples, Doubles and Single Stars are fairly evenly distributed across the catalog Total Objects in the catalog by Type: NGC Obect Type # of NGC Entries Duplicated Entries # of Unique NGC Objects % of Total % of Existing Objects Most Entries by Type within One NGC Range (Ex: 1-999 or 3000-3999) NGC Range with Most Objects by Type NGC Range with Second Most Count of the Second Most Entries by Type Gxy 6271 234 6037 79.4% 80.2% 890 4000-4999 5000-5999 875 OC 678 0 678 8.9% 9.0% 245 2000-2999 1000-1999 154 GC 142 0 142 1.9% 1.9% 73 6000-6999 1000-1999 30 Star 115 0 115 1.5% 1.5% 23 1-999 4000-4999 18 Neb 111 0 111 1.5% 1.5% 47 2000-2999 1000-1999 31 Double Star 106 0 106 1.4% 1.4% 17 6000-6999 1-999 13 PN 98 0 98 1.3% 1.3% 49 6000-6999 2000-2999 14 OC+Neb 89 0 89 1.2% 1.2% 44 1000-1999 2000-2999 17 Ast 69 0 69 0.9% 0.9% 19 6000-6999 2000-2999 18 Triple Star 36 0 36 0.5% 0.5% 9 2000-2999 1-999 3 GxyCld 22 0 22 0.3% 0.3% 11 5000-5999 1-999 0 MWSC 8 0 8 0.1% 0.1% 8 6000-6999 N/A 0 SNR 6 0 6 0.1% 0.1% 5 6000-6999 1000-1999 1 HIIRgn 6 0 6 0.1% 0.1% 3 4000-4999 3000-3999 2 Neb?* 1 0 1 0.0% 0.0% 1 1000-1999 N/A 0 Nonexistent 82 0 0 1.1% ---- 19 1000-1999 7000-7840 17 Total 7840 234 7524 Neb? *refers to NGC 1990 Objects by Type and Position within the Catalog: NGC Number Galaxy Galaxy Cloud Nebula Questionable Nebula Open Cluster and Nebula Open Cluster Globular Cluster Planetary Nebula Super Nova Remant HII Region Milky Way Star Cloud Triple Star Double Star Star Asterism Nonexistent 1-999 834 6 4 0 12 49 8 4 0 0 0 6 16 23 5 8 1000-1999 646 0 31 1 44 154 30 4 1 0 0 3 13 13 10 19 2000-2999 596 4 47 0 17 245 5 14 0 1 0 9 12 17 18 8 3000-3999 873 1 8 0 2 21 1 7 0 2 0 3 15 10 0 7 4000-4999 890 0 0 0 0 12 5 2 0 3 0 2 5 18 3 7 5000-5999 875 11 1 0 0 28 15 7 0 0 0 2 14 11 2 5 6000-6999 634 0 15 0 12 120 73 49 5 0 8 6 17 6 19 11 7000-7840 689 0 5 0 2 49 5 11 0 0 0 5 14 17 12 17 Total 6037 22 111 1 89 678 142 98 6 6 8 36 106 115 69 82
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Galaxy Centaurus A ( NGC 5128 ) in the southern constellation Centaurus ( please click / tap on image to see full size ) ............ Updated again - to try to bring out more faint detail ... ............ Updated images ... ............. Originals ... ( 100% crop ) Centaurus A is relatively near to us in the local group of galaxies and is around 11 Million light years away. The unusual shape of Centaurus A is believed to be due to an ancient collision between a large elliptical galaxy and a much smaller spiral galaxy. With an apparent magnitude of +6.8, Centaurus A is the fifth brightest galaxy in the night sky and in the middle of the 20th century it was identified as being the strongest radio source in the Centaurus constellation. Details: Galaxy - Centaurus A ( NGC 5128 ) Image ( Nova.astrometry.net ): Center (RA, hms): 13h 25m 28.924s Center (Dec, dms): -43° 01' 25.486" Size: 60.5 x 41.1 arcmin Orientation: Up is -89.9 degrees E of N Telescope: 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 AZ Eq6 GT Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels) Format: 14bit NEF Long exposure noise reduction: off Filter: none Calibration: No darks, just master bias and master flat HDR combination of eight sets of exposures (27, 28 & 29 April 2017): 85 x 240 sec ISO 800 16 x 120 sec ISO 800 16 x 60 sec ISO 800 16 x 30 sec ISO 800 16 x 15 sec ISO 800 16 x 8 sec ISO 800 16 x 4 sec ISO 800 16 x 2 sec ISO 800 Pixinsight May 2017 Links: 500px.com/MikeODay photo.net/photos/MikeODay www.flickr.com/photos/mike-oday
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A very crisp and cold night. I added more luminance data and also collected some RGB for NGC 2841. There is now around 4 hours in L and an hour each in R, G and B. The subs are 114s at a gain of 139. Wikipedia: NGC 2841 is an unbarred spiral galaxy in the northern circumpolar constellation of Ursa Major. A 2001 Hubble Space Telescope survey of the galaxy's Cepheid variables determined its distance to be approximately 14.1 megaparsecs or 46 million light-years. This is the prototype for the flocculent spiral galaxy, a type of spiral galaxy whose arms are patchy and discontinuous. The morphological class is SAa, indicating a spiral galaxy with no central bar and very tightly-wound arms. There is no grand design structure visible in the optical band, although some inner spiral arms can be seen in the near infrared. The properties of NGC 2841 are similar to those of the Andromeda Galaxy. It is home to a large population of young blue stars, and a few H II regions. The luminosity of the galaxy is 2×1010 M☉ and it has a combined mass of 7×1010 M☉. Its disk of stars can be traced out to a radius of around 228 kly (70 kpc). This disk begins to warp at a radius of around 98 kly (30 kpc), suggesting the perturbing effect of in-falling matter from the surrounding medium. The rotational behaviour of the galaxy suggests there is a massive nuclear bulge, with a low-ionization nuclear emission-line region at the core; a type of region that is characterized by spectral line emission from weakly ionized atoms. A prominent molecular ring is orbiting at a radius of 7–20 kly (2–6 kpc), which is providing a star-forming region of gas and dust. The nucleus appears decoupled and there is a counter-rotating element of stars and gas in the outer parts of the nucleus, suggesting a recent interaction with a smaller galaxy. Equipment: Celestron 9.25 XLT at F10, Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope
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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. ………………………. Details: 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. ................. Identification: 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 ESO 358-17 IRAS 03317-3618 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 .................. Capture Details: 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 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 ( 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 HDR combination Links: 500px.com/MikeODay photo.net/photos/MikeODay <a href="http://www.flickr.com/photos/mike-oday">www.flickr.com/photos/mike-oday</a> 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 ===================================
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