Sunday 24 February 2013

Chelyabinsk Meteor Flash



Chelyabinsk Meteor Flash
Image Credit & Copyright: Marat Ahmetvaleev
 
 
Explanation: A meteoroid fell to Earth on February 15, streaking some 20 to 30 kilometers above the city of Chelyabinsk, Russia at 9:20am local time. Initially traveling at about 20 kilometers per second, its explosive deceleration after impact with the lower atmosphere created a flash brighter than the Sun. This picture of the brilliant bolide (and others of its persistent trail) was captured by photographer Marat Ametvaleev, surprised during his morning sunrise session creating panoramic images of the nearby frosty landscape. An estimated 500 kilotons of energy was released by the explosion of the 17 meter wide space rock with a mass of 7,000 to 10,000 tons. Actually expected to occur on average once every 100 years, the magnitude of the Chelyabinsk event is the largest known since the Tunguska impact in 1908.

Monday 18 February 2013

Asteroid 2012 DA14 Passes the Earth

Asteroid 2012 DA14 Passes the Earth
Video Credit & Copyright: Daniel López (El Cielo de Canarias)
Explanation: There it goes. That small spot moving in front of background stars in the above video is a potentially dangerous asteroid passing above the Earth's atmosphere. This past Friday, the 50-meter wide asteroid 2012 DA14 just missed the Earth, passing not only inside the orbit of the Moon, which is unusually close for an asteroid of this size, but also inside the orbit of geosynchronous satellites. Unfortunately, asteroids this big or bigger strike the Earth every 1000 years or so. Were 2012 DA14 to have hit the Earth, it could have devastated a city-sized landscape, or stuck an ocean and raised dangerous tsunamis. Although finding and tracking potentially dangerous asteroids is a primary concern of modern astronomy, these small bodies or ice and rock are typically so dim that only a few percent of them have been found, so far. Even smaller chunks of ice and rock, like the (unrelated) spectacular meteors that streaked over Russia and California over the past few days, are even harder to find -- but pose less danger.

Wednesday 30 January 2013

Nog `n Komeet C/2011 L4 (PANSTARRS)


Klik om te vergroot
Vir die ouens wat vroeg opstaan of glad nie gaan slaap nie.
Komeet Lemon is sterk op koers na Octans en nou is C/2011 L4 (PANSTARRS) vroegoggend in die Suid-Ooste sigbaar. Nee ek het hom nog nie gesien nie. Te laag vir my. Sal dalk die naweek probeer en op die dak klim.

Maart se Sky and Telescope sê ons kan die komeet by skypub.com/panstarrs volg. Die voorspelling is klaar daar dat dit nie so helder gaan wees as wat voorspel is nie.
Laat weet ons as jy die komeet sien. (assabfn@gmnail.com)

Skytools 3 gee hierdie voorspelling vir vannag.

On this night C/2011 L4 (PANSTARRS) is best visible between 03:29 and 04:46, with the optimum view at 04:27. Look for it in Telescopium, low in the southeastern sky during morning twilight. It is obvious visually in the Orion SkyQuest XT10 Dob. Use the Ultima 42mm for optimum visual detection. It is magnitude 5.5 with a diameter of 4.5'.
 

Saturday 26 January 2013

Friday Night (25 Januarie 2013) C/2012 F6 (Lemmon)

Friday - About 23:30 to be precise. I spent some time to find Comet Lemon with my 10X50 binoculars. With the help of my Skytools map it and the binoculars steady on a tripod it was easy. Even with the almost full moon and some street lights. A black cloth over your head will also help. 

The techno info the same: Canon 30D with a 300mm (X1.6) lens. 10 Seconds with ISO 3200. I used  Nebulosity software ( Stark Labs) to prepare the image.


Compare with the original RAW image below.


And the final image without the text.











Friday 25 January 2013

Comet Lemmon (C/2012 F6) 23 Januarie 2013

Click to enlarge

With Crux on the left and Musca to the right, Comet Lemmon (C/2012 F6) on the late night 23 Januarie 2013 is a little green spot. Photo: Hannes Pieterse

Info: Canon 30D with 50mm lens; 20 X 15 sec exposures; ISO 1600, f4. 20 X Dark frames. Images were prepared in Deepskystacker > Separate registered and dark frame subtracted images were created.  These were stacked in Rot`nStack. Final image was tweaked in Photoshop.

- A tree interfered on the right 

Thursday 24 January 2013

For the Bibliophiles: Deep-Sky Companions: Southern Gems

Hot off the Press!

Deep-Sky Companions: Southern Gems - Stephen James O'Meara

In Southern Gems, Stephen James O'Meara makes a detour beneath the southern skies, presenting a fresh list of 120 deep-sky objects for southern hemisphere stargazers to observe. Showcasing many exceptional objects catalogued by the pioneering observer James Dunlop, known as the 'Messier of the southern skies', all are visible through small- to moderate-sized telescopes or binoculars under dark skies. The list features some of the blackest dark nebulae, icy blue planetary nebulae and magnificent galaxies of all types. Each object is accompanied by beautiful photographs and sketches, original finder charts, visual histories and up-to-date astrophysical background information. Whether you live in the southern hemisphere or are just visiting, this new Deep-Sky Companion will make a perfect observing partner, whatever your background. There is no other southern sky guide like it on the market.

  • Magda Streicher a southern observer from Polokwane also contributed to make this book a must have!   

  • Publisher: CAMBRIDGE UNIVERSITY PRESS 
  • Published: 31 January 2013 
  • Hardback
  • ISBN:9781107015012
  • 450pages
  • 204 b/w illus. 114 maps
  • Dimensions: 253 x 177 mm
- Search inside the book - Amazon
-The Book Depository (Free Shipping to South Africa)  - $40.80  (Best Price)


Tuesday 22 January 2013

From Bloemfontein: Comet Lemmon (C/2012 F6)

22 January 2013 - Moves into Constellation, Musca (23:00) In spite of the moon and other lights the comet is still clearly visible
January 21, 2013 - Near Acrux, Constellation Crux

For the night owls: Comet Lemmon (C/2012 F6) is clearly visible. Bright star on the image is Alpha 2 Cru (Acrux).

Technical data: Canon 30D with 300mm X 1.6 lens. ISO 3200; Aperture f5.6 Shutter speed 5 seconds. Camera on tripod. 15 photos stacked on each other in Deepskystacker; 10 Dark frames used to remove digital noise. It is also easy visible with a 12X50 binoculars. Even better with a 20X80 binoculars. The light pollution is quite bad in Bloemfontein and the moon was still up. Despite this I found it easily. According to Skytools 3 it is magnitude 7.2.

A look or you see it tonight and let you know.

Monday 21 January 2013

Comet Lemmon (C/2012 F6) brightens faster than expected

 Comet Lemmon (Michael Jaeger)

In Crux
2013 is gearing up nicely to be a superb year for bright comets. Already we have two comets that promise to be spectacular this year; Comet PanSTARRS (C/2011 L4) should peak at magnitude -1 in March and then later in the year comet ISON (C/2012 S1) may even reach the dizzy heights of magnitude -15 in November.

There is another comet that is currently brightening faster than expected and although will probably not be bright as the above-mentioned comets, it may prove to be the surprise package of the year. Its name is Comet Lemmon (C/2012 F6).

Discovery
Alex Gibbs of the Mount Lemmon Survey discovered Comet Lemmon on March 23, 2012. The Mount Lemmon Survey is part of the Catalina Sky Survey (CSS), a Near-Earth objects searching project, specifically aimed at finding potentially hazardous asteroids (PHAs) that may pose a threat of impact to Earth. Currently there are a number of telescopes participating in the survey, each of the order of 1-metre in aperture, located at various astronomical sites. The project is producing superb results with the Mount Lemmon telescope currently the most prolific telescope in the world for discovering Near-Earth Objects.
The objects discovered are often faint; Comet Lemmon was only magnitude 20.7 when found.

More information...

Polish your metal mirror - Sir William Herschel


This is an example of a polishing machine devissed by William Herschel for small speculum metal mirrors. Image: Herschel Museum of Astronomy, Bath 

For your book shelve

From: The Complete Guide to the Herschel Objects: Sir William Herschel's Star Clusters, Nebulae and Galaxies - by Mark Bratton