Daily Archives: August 4, 2014

Shadows and Plumes Across Enceladus 

Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

 Why does Enceladus have ice plumes? The discovery of jets spewing water vapor and ice was detected by the Saturn-orbiting Cassini spacecraft in 2005. The origin of the water feeding the jets, however, remained a topic of research. A leading hypothesis held that the source might originate from a deep underground sea, but another hypothesis indicated that it might just be ice melted off walls of deep rifts by the moon’s tidal flexing and heating. Pictured above, the textured surface of Enceladus is visible in the foreground, while rows of plumes rise from ice fractures in the distance. These jets are made more visible by the Sun angle and the encroaching shadow of night. Recent study of over a hundred images like this – of geysers crossing Enceladus’ South Pole, together with regional heat maps, indicate that these plumes likely originate from a hidden sea, incresaing the chance that this frosty globe might be harboring life.

APOD NASA 04-Aug-14

The Sun Online and solar activity. August 4, 2014

Flaring is currently at low C-class level. The largest flare since our last bulletin was reported to occur this morning in NOAA AR 2126 (CAT 27) with peak time 00:53 UT. This region is currently turning over the west limb, however we expect more C-flares with a chance for a low M-class flare, especially from NOAA regions 2130, 2132 and 2134.
A small filament erupted in the western hemisphere, just south of the equator on August 3 around 18:09 UT. An associated narrow CME was observed in LASCO at 19:24 UT, but is not earth-directed.Two small disturbances were observed in the solar wind. The first one started on August 3 around 15:00
UT, and is probably related to the arrival of the CME associated with the M1.5 flare on August 1. The second disturbance started today around 06:00 UT and is likely related to a high speed wind stream originating from the coronal hole that passed the central meridian on August 1. In both cases the southward component of the magnetic field did not turn strongly negative and the solar wind speed remained low, resulting in only unsettled geomagnetic conditions (K=3). Active geomagnetic conditions (K=4) are possible today. We expect a return to quiet conditions after that.

Equipment: Coronado 90 +  Imaging Source DMK  + LX75
Processing: Photoshop, Avistack 300 frames
Date: 08/04/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli


M17 or Omega Nebula

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The Omega Nebula, also known as the Swan NebulaCheckmark NebulaLobster Nebula, and the Horseshoe Nebula  (catalogued as Messier 17 or M17 and as NGC 6618) is an H II region in the constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is located in the rich starfields of the Sagittarius area of the Milky Way

The Omega Nebula is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years in diameter. The cloud ofinterstellar matter of which this nebula is a part is roughly 40 light-years in diameter and has a mass of 30,000 solar masses. The total mass of the Omega Nebula is an estimated 800 solar masses. It is considered one of the brightest and most massive star-forming regions of our galaxy. Its local geometry is similar to the Orion Nebula except that it is viewed edge-on rather than face-on.

Imaging telescopes or lenses: William Optics FLT98
Imaging cameras: Atik 383L+
Mounts: Skywatcher EQ8
Guiding telescopes or lenses: William Optics FLT98
Guiding cameras: Starlight Xpress Loadstar
Focal reducers: Riccardi Reducer 0,75x
Software: Fitswork 4.44, Adobe Photoshop CS3 CS3
Filters: Baader S2, Baader Planetarium Ha 7nm 2″, Baader O III 8.5nm O3
Accessories: Starlight Xpress 5×2″ Filter Wheel
Dates: June 8, 2014
Frames: 25×900″
Integration: 6.2 hours

Author: Alexander Sielski
AstroPhotography of the day by SPONLI 4 Aug 2014