Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN)
Transfusing sunlight through a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month above the island of Gotland, Sweden. From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds reflect sunlight even though the Sun itself is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the night shining clouds made a strong showing this July. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash. NASA’s AIM mission provides daily projections of noctilucent clouds as seen from space.
APOD NASA 31-Jul-14
The reported partial halo CME as observed on 30 July at 13:36UT by SOHO and reported by CACTUS, is actually a combination of at least 2 separate CMEs on different locations on the Sun, hence creating the illusion of a wide angle CME. SOHO, SDO and STEREO imagery indicate that the first CME seen in
LASCO-imagery at 13:36UT originates from an eruption in old active region NOAA 2113 on the backside of the Sun. This region was responsible for several M-class flares during its previous transit, and will round the east limb within the next two days. The associated CME was slow (about 300 km/s
plane-of-the-sky speed) and is directed away from Earth. The second CME originated from a filament eruption on the visible disk south of NOAA 2131 around 18:00UT, shortly after a data gap in SOHO-imagery. This was a narrow, but fast (800 km/s) CME directed to the southeast. Also this CME has no Earth-directed component.
Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Time UT: 16:00
Exposure 1/500 sec.
NGC 6822 (also known as Barnard’s Galaxy, IC 4895, or Caldwell 57) is a barred irregular galaxy approximately 1.6 millionlight-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884 (hence its name), with a six-inch refractor telescope. It is one of the closer galaxies to the Milky Way. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.
Edwin Hubble wrote the seminal paper N.G.C. 6822, A Remote Stellar System (Hubble 1925) wherein he identified 15 variable stars (11 of which were Cepheids). He also surveyed the galaxy’s stars distribution down to magnitude 19.4. He provided spectral characteristics, luminosities and dimensions for the five brightest “diffuse nebulae” (giant H II regions) that included the Bubble Nebula and the Ring Nebula. He also computed the absolute magnitude of the entire galaxy.
Imaging telescopes or lenses: Geoptik “Formula25″ Newton 10” 1250mm
Imaging cameras: Home made 450D Cmos Cooled – Baader
Mounts: Sky-Watcher NEQ6
Guiding telescopes or lenses: 60/228
Guiding cameras: Shoestring Astronomy USB Guide Port Interface, Xbox LiveWebcam
Software: Pleiades Astrophoto, S.L. PixInsinght 1.8 RC7
Filters: Hutech IDAS LPS V4
Accessories: Baader MPCC mpcc coma correcteur
Dates: Aug. 6, 2013, Aug. 7, 2013, Aug. 8, 2013
Frames: Hutech IDAS LPS V4: 72×300″
Integration: 6.0 hours
Author: Giosi Amante
AstroPhotography of the day by SPONLI 31 July 2014