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Found 87 results

  1. 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 ===================================
  2. The Cat's Paw Nebula ( NGC 6334 ) in Scorpius updated ( slight tweak to colour balance, a little brighter and tad more contrast ) ( please click / tap on image to see larger and sharper - a full size image can be seen here ) ...... original: ( please click / tap on image to see larger and sharper - a full size image can be seen here ) ……………………... Also known as the Bear Claw Nebula, NGC 6334 is an emission nebula near the scorpion's tail in the Scorpius constellation. Image details: Image centre ...... RA: 17 20 08.185 Dec: -35 52 30.91 Field of view ..... 57' 37.8" x 38' 51.8" Rotation .......... 0.00 deg ( North is up ) Resolution ........ 0.586 arcsec/px Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1470mm 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 ( July 2018 ) 6 sets of sub-images with exposure duration for each set doubling ( 4s to 240s ) all at ISO 250. 168 x 4 min frames plus ~10 frames each for the shorter exposures Processing: Calibration: bias, dark and flat Integration in 8 sets HDR combination Pixinsight July 2018
  3. Update: 3rd June Re-processed to remove slight magenta tint caused by the non-uniform removal of light pollution by the DBE process ( it was being fooled by the very bright image centre ). The globular star cluster Omega Centauri ( NGC 5139 ) in Centaurus ( please click / tap on image to see larger and sharper ) A full size image can be found here. original below ..... A newly captured ( May 2018 ) image of the great southern globular star cluster, Omega Centauri ( NGC 5139 ) Omega Centauri ( NGC 5139 ) in Centaurus - ( please click / tap image to see larger and sharper ) A full size ( ~ 6000 x 4000 ) image can be found here ....... This image is an attempt to look deeply into the mighty Omega Centauri star cluster and, by using HDR techniques, record as many of its faint members as possible whilst capturing and bringing out the colours of the stars, including in the core. Image details: Resolution ........ 0.586 arcsec/px ( full size image ) Rotation .......... 0.00 deg ( up is North ) Focal ............. 1375.99 mm Pixel size ........ 3.91 um Field of view ..... 58' 20.9" x 38' 55.1" Image center ...... RA: 13 26 45.065 Dec: -47 28 27.26 Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1470mm 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 ( May 2018 ) 8 sets of sub-images with exposure duration for each set doubling ( 2s to 240s ) all at ISO 250. Processing: Calibration: master bias, master flat and master dark Integration in 8 sets HDR combination Pixinsight May 2018
  4. Galaxy NGC 4945 in Centaurus Details: Galaxy NGC 4945 in Centaurus 19 May 2018 Orientation: 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 : 1470mm 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 3.91um pixels) image Plate Solver script version 5.0 =========== Resolution ........ 0.586 arcsec/px Rotation .......... North is up Focal ............. 1375.43 mm Pixel size ........ 3.91 um Field of view ..... 43' 27.2" x 28' 54.2" Image center ...... RA: 13 04 51.790 Dec: -49 30 37.17 ========== Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ) Capture ( 19 May 2018 ): 10 sets of sub-images with exposure duration for each set doubling ( 1/2th sec to 240 sec ) all at ISO250. ( 41 x 240sec + ~8 each forthe other durations ) Processing: Calibration: master bias, master flat and master dark Integration in 10 sets HDR combination Pixinsight May 2018
  5. 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.
  6. 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 Cluster ( ngc 4755 ) in the Crux constellation. ( please click / tap to see larger and sharper ) ........... Image details: Orientation: 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 : 1470mm 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 3.91um pixels) image Plate Solver script version 5.0 =========== Resolution ........ 0.586 arcsec/px Rotation .......... 0.000 deg Focal ............. 1375.43 mm Pixel size ........ 3.91 um Field of view ..... 58' 49.3" x 39' 17.8" Image center ...... RA: 12 53 40.040 Dec: -60 21 02.81 ========== Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ) Capture ( 5 May 2018 ): 11 sets of sub-images with exposure duration for each set doubling ( 1/8th sec to 120 sec ) all at ISO250. ( 10 x 120sec + at least 10 each forthe other durations ) Processing: Calibration: master bias, master flat and master dark Integration in 11sets HDR combination
  7. 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
  8. 21st April: Re-processed to better show the colour of the fainter stars ... ....... 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. 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. 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 ) 12 April 2018 ..... Image details: Field of view ..... 58' 49.8" x 39' 36.4" Image center ...... RA: 11 36 03.890 Dec: -61 35 30.17 Resolution ........ 0.586 arcsec/px ( full size image ) Orientation: 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 : 1470mm 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 3.91um pixels) Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ) Capture ( 12 April 2018 ): 11 sets of sub-images with exposure duration for each set doubling ( 1/4s to 240s ) all at ISO250. ( 70 x 240sec + 10 each forthe other durations ) Processing: Calibration: master bias, master flat and master dark Integration in 11 sets HDR combination Pixinsight April 2018
  9. Carina Nebula with the bright unstable star Eta Carinae in the centre of the image. edit ( 27 March ): Tweak to shadow levels to bring out more detail and also a slight reduction in the brightness of the highlights. A much larger version ( 4562 x 3072 6062 x 4082) is available on my Flickr page. previous version: Carinae Nebula ( NGC 3372 ) ( please click / tap on image to see larger and sharper ) From Wikipedia ... "Eta Carinae is a highly luminous hypergiant star. Estimates of its mass range from 100 to 150 times the mass of the Sun, and its luminosity is about four million times that of the Sun." This HDR image is constructed from 12 sets of exposures ranging from 1/8 sec ( to capture the bright centre of Eta Carinae ) through to 240 seconds. Total exposure time around 13 hours 17-19 March 2018 Image details: Objects in image: Hypergiant, Eta Carinae ( HD 93308 ) in the centre of the Homunculus Nebula Carina Nebula ( NGC 3372 ) Keyhole Nebula Open Star Clusters: - Trumpler 14, 15, 16 - Collinder 232 Field of view ..... 59' 18.2" x 39' 56.0" Image centre ...... RA: 10 45 01.762 Dec: -59 40 52.87 Orientation: 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 : 1470mm 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 ( 17, 18 & 19 March 2018 ): 12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO250. ( 181 x 240sec + 10 to 20 each for the other durations ) Processing: Calibration: master bias, master flat and master dark Integration in 12 sets HDR combination Pixinsight March 2018
  10. A deep look at Omega Centauri ( NGC 5139 ) edit: re-processed from the original exposures - April 2018 ........ previous version: Omega Centauri ( please click / tap on image to see larger and much sharper ) This image is an attempt to look deeply into the mighty Omega Centauri star cluster and, by using HDR techniques, record as many of its faint members as possible whilst capturing and bringing out the subtle colours of the stars, including in the core. ( re-processed from May 2017 subs - master dark added to workflow, new HDR / colour process workflow and stretched using ArcSinh ) Image details: Field of view ..... 58' 32.3" x 38' 55.6" Image center ...... RA: 13 26 50.290 Dec: -47 28 39.80 Orientation: East is up, North is to the right Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1470mm 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 ( May 2017 ): 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO800. Processing: Calibration: master bias, master flat and master dark Integration in 9 sets HDR combination ArcSinh stretch Pixinsight March 2018 Links: 500px.com/MikeODay photo.net/photos/MikeODay www.flickr.com/photos/mike-oday
  11. 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
  12. 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 :
  13. “The Blue Bunny Nebula” .......... Edit: 27 Jan 2018 - updated again to try to draw more faint nebulosity out of the background; ( 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 ! ) ) ......... Edit: 24 Jan 2018 - stars a little brighter and tighter with no change to the rest of the image ( 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 ! ) ) ................. original: Thor's Helmet ( NGC 2359 ) in the constellation Canis Major Thor’s Helmet ( Duck Nebula, NGC 2359 ) ( please click / tap on image to see larger ) This HDR image shows the bright nebula Thor’s Helmet in a sea of colourful stars against a background of red from dust and HA emissions. The stars in this image range from the brightest ( bottom right, HD 56501 ) at magnitude +7.7 to around +20 or more. HDR capture and processing allows all of the stars to be portrayed in colour without any burnt-out highlights. The colours of the stars and nebula are as close as I can get them to their "true colours" by using a "daylight colour balance" and allowing for the extinction of blue-green due to atmospheric absorption/scattering ( mean altitude during capture ~ 60deg ). The blue star in the centre of the bubble of expanding stellar material is HD 56925 ( WR7 ) - a massive, unstable and short-lived Wolf-Rayet star that one day will detonate in a supernova. Image details: NGC 2359 Thor’s Helmet / Duck Nebula: Magnitude +11.5, RA (2000.0) 7h 15m 37s, Dec -13deg 12' 8", approx. 1800 light years away HD 56925 / Wolf-Rayet 7 ( WR7 ) ( blue 11.5 mag star at centre of “bubble” ) Haffner 6 ( open ster cluster centre left of image ) Plate Solution: Resolution ........ 1.318 arcsec/px Rotation .......... 0.00 deg ( North is up ) Focal ............. 1398.41 mm Field of view ..... 57' 40.8" x 38' 29.0" Image center ...... RA: 07 18 36.509 Dec: -13 11 53.38 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 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 ( 18 & 19 Jan 2018 ) 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO 250. 116 x 240s + 5 each @ 1s to 120s Processing ( Pixinsight - 20 Jan 18 ) Calibration: master bias, master dark and master flat Integration in 9 sets HDR combination arcSinH stretch
  14. 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
  15. The Fighting Dragons of Ara ( NGC 6188 ) ( please click / tap on image to see larger ) The Fighting Dragons of Ara ( NGC 6188 ) Bright Nebula NGC 6188 and open cluster NGC 6193 are embedded 4,300 light years away in the Sagittarius arm of our Milky Way galaxy and can be seen with the naked eye south of Scorpius in the constellation of Ara. With powerful stellar winds and energetic ultra-violet radiation, massive stars sculpt the interstellar gas and dust of the nebula into wonderful shapes and cause the interstellar gas to brightly fluoresce. Closer to the hot young stars of the cluster, bright blue “sunlight” reflects off the clouds of gas and dust to produce the blue reflection nebulae seenin the image. Magnitude +5.19, RA 16h 41m 42s, Dec -48deg 48' 46". Approx. 3800 light years away. 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. ......... This is a reprocessed version using the data I captured earlier in the year...
  16. ( 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 ==========================================
  17. 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 )
  18. ( 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:
  19. The Rosette Nebula and Cluster ( NGC 2237 and 2244 ) in the constellation Monoceros edit: updated 30th Dec with improved colour balance and slightly increased brightness ... ...... original: ( please click / tap on image to see larger and sharper ) Still a work-in-progress really... with only 10 x 4min exposures for the main 'lights' before the clouds came over. I will try to add some more data when the moon has gone I am still experimenting with how to get the best out of the D7500. With the very warm nights ( low to mid 20s all night ) the 'warm pixels' are very noticeable so I reverted to my old practice of in-camera dark subtraction. This worked quite well and produced a nice smooth noise floor in the integrated images - albeit at the expense of more exposures. ................. 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 ===================================
  20. The Great Barred Spiral Galaxy ( NGC 1365 ) in the constellation Fornax edit: new version with new long exposure data ( 52 x 240sec ) and better dark subtraction / dithering to remove streaks in the noise and amp glow. This also allowed for a greater stretch revealing more faint data in the galaxy and small faint fuzzies in the image .. The Great Barred Spiral Galaxy ( NGC 1365 ) in Fornax ( please click / tap to see larger ) and below I have added a 100% crop of new version: ........ original image: NGC 1365 ( please click / tap on image to see larger ) ............... The Great Barred Spiral Galaxy ( NGC 1365 ) in the Constellation Fornax 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, or near Sydney, as I was, almost exactly 180 years later, when I photographed 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 120 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 with apparent magnitudes of 16 to 18 or greater. Mike O'Day ................. 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 ( 22 Nov 2017 ) 6 sets of sub-images with exposure duration for each set doubling ( 4s to 120s ) all at ISO400. 70 x 120s + 5 each @ 4s to 60s total around 2.5hrs Processing ( Pixinsight ) Calibration: master bias, master flat and no darks Integration in 6 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 ==========================================
  21. 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 ==================================
  22. 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 ... “
  23. 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). Mike O'Day ...................... Capture Details: 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 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, 19,20,22 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 Processing Calibration: master bias, master flat and no darks. Drizzle Integration in 8 sets. HDR combination PhotometricColorCalibration 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 ) Caldwell 65 Leda 2789 ESO 479-29 Sculptor GalaxySilver Coin GalaxySilver 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 ) .........
  24. 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 ...
  25. 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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