Search the Community
Showing results for tags '4755'.
Found 3 results
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.
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
This is a re-processed version of an old capture of mine taken last year when I was a two day old baby astrophotographer. Back then I was only just learing how to polar align my scope on its tripod and auto-guiding was a distant goal. This is a stack of 15 x 30sec images from my unmodified Nikon D300 ( I now use an unmodified D5300 as it is lighter and causes less flex in the focuser ). Description: The Jewel Box Cluster in the Crux Constellation ( NGC 4755 ) by Mike O'Day ( 500px.com/MikeODay ) Viewed through a telsecope, John Herschel described the Jewel Box Cluster as "a casket of varioulsy coloured precious stones" - hence the name. The Jewel Box, visible only from the Southern Hemisphere and appearing as a bright fuzzy star to the naked eye, is a cluster of around 100 ( mostly blue giant ) stars approximately 7000 light years from Earth. Links: 500px.com/MikeODay photo.net/photos/MikeODay Details: NGC 4755 - RA 12h 54.5m, Dec -60deg 26'. Skywatcher Quattro 10" f4 Newtonian. Skywatcher AZ Eq6 GT Mount. Unguided. Baader MPCC Mark 3 Coma Corrector. Nikon D300 (unmodified). Field of view (deg) ~ 1.35 x 0.90. Combination of 15 images 30 sec @ ISO800. Registax & Photoshop 24 April 2014 (re-processed Nov 2015)