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Found 11 results

  1. 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 ...
  2. Barred Spiral Galaxy NGC 6744 in Pavo NGC 6744 is a Milky Way like barred spiral galaxy in the constellation Pavo. Visible only from lower latitudes, the light we see now left this galaxy around 30 million years ago. Details: Spiral Galaxy NGC 6744 in Pavo. Skywatcher Quattro 10" f4 Newtonian telescope. Skywatcher AZ Eq6 GT Mount. Orion 80mm f5 guide scope and auto guider - PHD2. Baader MPCC Mark 3 Coma Corrector, no filter. Nikon D5300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. ISO800, 14bit NEF, Long Exp. NR on. 44 x 120sec 4th Sept 2016 Processed in PixInsight and finished off in Photoshop. Links: https://500px.com/MikeODay http://photo.net/photos/MikeODay
  3. Nearby spiral galaxy NGC 4945 in the constellation Centaurus. ( click on image to see full size ) ( This is an update of my image of NGC 4945 with an additional 22 x 360sec images at ISO400. ) NGC 4945 in the constellation Centaurus is a large spiral galaxy about the size of the Milkyway and around 13 million light years from Earth. It is shown here nearly edge-on and is accompanied in the image by a number of far more distant galaxies; the brightest of which is the 10th magnitude elliptical galaxy NGC 4976 (centre left of the image) which is around 30 million light years away. Links: https://500px.com/MikeODay http://photo.net/photos/MikeODay Details: RA 13h 06.5m, Dec -49 deg 33.5' Skywatcher Quattro 10" f4 Newtonian Skywatcher AZ Eq6 GT Mount Guiding: Orion Shortube 80 guidescope, Starshoot Autoguider, PHD2 Baader MPCC Mark 3 Coma Corrector Hutech IDAS D1 light pollution filter Nikon D5300 (unmodified) Long exposure noise reduction on 10 x 200sec @ ISO400 (19 Mar 2016) 22 x 360sec @ ISO400 ( 1 May 2016) Pixinsight Includes: NGC 4945 ( mag +9.3 ) NGC 4945A ( mag +13.3 ) NGC 4976 ( mag +10.0 ) PGC 45001 ( mag + 14.1 ) PGC 45317 ( mag + 14.2 ) PGC 45373 ( mag + 18.0 ) PGC 479454 ( mag + 15.9 ) PGC 480158 (mag + 16.8 ) Previous version :
  4. 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 ... “
  5. Spiral Galaxy NGC 6744 in Pavo NGC 6744 is a Milky Way like barred spiral galaxy in the constellation Pavo. Visible only from lower latitudes, the light we see now left this galaxy around 25 million years ago. NGC 6744 in Pavo ( please click / tap on image to see larger and sharper ) Capture Details: North is up. 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 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 Sept. 2017 ). 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO800. 85 x 240s + 5 each @ 1s to 120s. Processing ( Pixinsight - 5-17 Nov 2017 ). Calibration: master bias, master flat and no darks. Integration in 9 sets. HDR combination PhotometricColorCalibration Arcsinh stretch ( function written by Mark Shelley ) Image Plate Solver - NGC 6744 - Sept 17, 2017 =================================== Resolution ........ 0.586 arcsec/px ( full size image ) Rotation ............ 0.001 deg. Focal ................. 1372.24 mm. Pixel size ........ ..3.90 um. Field of view ..... 58' 30.3" x 38' 59.0". Image center ...... RA: 19 09 46.591 Dec: -63 51 13.44 ==================================
  6. Nearby spiral galaxy NGC 4945 in the constellation Centaurus by Mike O'Day ( 500px.com/MikeODay ) ( Still a work in progress really; 10 subs is not really enough for this 9th mag galaxy from my medium polluted skies. These were taken in the last minutes of the wee hours before dawn after I had finished taking subs of comet 252P/LINEAR and I have not had a chance to take any more as it has been cloudy ever since. ) NGC 4945 in the constellation Centaurus is a large spiral galaxy about the size of the Milkyway and around 13 million light years from Earth. It is shown here nearly edge-on and is accompanied in the image by a number of far more distant galaxies; the brightest of which is the 10th magnitude elliptical galaxy NGC 4976 (centre left of the image) which is around 30 million light years away. Links: https://500px.com/MikeODay http://photo.net/photos/MikeODay Details: centre of image: RA 13h 06m, Dec -49 deg 32' (nova.astrometry.net) Skywatcher Quattro 10" f4 Newtonian Skywatcher AZ Eq6 GT Mount Guiding: Orion Shortube 80 guidescope, Starshoot Autoguider, PHD2 Baader MPCC Mark 3 Coma Corrector Hutech IDAS D1 light pollution filter Nikon D5300 (unmodified) Long exposure noise reduction on Field of view (min) ~ 79.6 x 53 Downsampled image scale ~ 4.4" per pixel Stack of 10 x 200sec images @ ISO400 Pixinsight
  7. Astrophotography Scrapbook Vol. 1 Cover Page Lagoon Nebula in Sagittarius ( Messier 8, NGC 6523 ) The Fighting Dragons of Ara ( NGC 6188 ) War and Peace in Scorpius ( NGC 6357 ) Spiral Galaxy NGC 6744 in Pavo Ptolemy's Cluster in Scorpius ( Messier 7, NGC 6475 ) A Million Stars in the Deep South ( NGC 104, 47 Tucanae ) A Wishing Well in Carina ( NGC 3532 ) A Beehive in the Southern Sky ( NGC 2516 ) The Sliver Coin in Sculptor ( NGC 253 ) The Great Nebula in Orion ( Messier 42, NGC 1976 ) A Cluster of Pearls in Centaurus ( NGC 3766 ) - new 5 Dec resources: Scrapbook Template ------------------------------------- When I show my astrophotography images to my friends and family they invariably want to know what they are looking at. This led me to wonder if there was a way I could display my images on a single page together with a few notes on the target object as well as few technical details of the capture for those who might be interested. What I came up with a "scrapbook" like page that combines all of these three elements in a single PDF sheet ( or jpeg image) that ultimately I might combine together to form a PDF book that I can share online or send to friends and family. In the meantime, I thought I might post in this thread each page of my work-in-progress towards volume 1 of my Astrophotography Scrapbook. Any and all comments, observations, suggestions and constructive criticisms will be warmly received. Cheers Mike ps. The pages have been sized to fit full screen on an IPAD
  8. Aenima

    M33 2nd Try

    From the album: The next step.

    I wanted to try again on this for a while now, a gap in the clouds recently gave me the chance although it was literally twenty minutes: 19 x 60sec subs with calibration frames taken indoors. Quite surprised with the image for such a short exposure time.

    © Aenima

  9. 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 ===================================
  10. ( 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 ==========================================
  11. Seeing several excellent images of the 'Needle' posted recently by members prompted me to go back and have another go at processing one of my own efforts from a while back. I think this is a worthwhile improvement with more detail extracted in the dust lane. It's 6.4 hours luminance (1x1) and 3.2 hours RGB (2x2), taken with a SW MN190 and QSI583 with OAG. This is a crop of the central area. A wider field view can be seen here: http://universalconstant.com/NGC4565_AP_crop2.jpg
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