Sherm’s  “Current Feature” Archive
 
 

May 20 Annular Solar Eclipse (only a partial in Western Canada). It will be seen as an annular eclipse in some parts of Pacific Ocean and south-western USA. What is visible depends upon where one is located. What is an annular eclipse of the Sun? This link tells about various aspects of the eclipse (TIME). Also, one can link to SpaceWeather for similar information.

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Early April, 2012: Venus and Jupiter still make a great view in the western sky following sunset.   Mars is shining brightly, the brightest star-like object showing in the southward sky, under the belly of LEO, The Lion. 
April 3 feature: Venus has temporarily become a brilliant member of the Pleiades  star cluster (M45).  Photos were taken April 3, 2012.  Venus is so bright that the camera overexposed the planet in order to capture the stars.   Light from Venus requires about 5 to 6 minutes to reach Earth, whereas, light from the Pleiades star cluster, requires about 400 years to reach our eyes (400 light years away from us).


The Pleiades is part of the constellation, TAURUS, The Bull. The Bull’s face is represented by the “V” shaped star cluster called the Hyades (captured in the 2nd photo).  Pleiades marks the Bull’s shoulder. Most stars in The Hyades are part of a related cluster of stars about 150 light years away. The brightest star in the Hyades is Aldebaran and is not actually part of the star cluster.  Aldebaran is about 65 light years from Earth.


The second photo shows the Hyades, Pleiades and Venus. Click on each photo for an enlargement. The exposures were taken by me at Horton Bluff using an ordinary point-and-shoot, digital camera mounted on a tripod.


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Venus and Jupiter’s Move into Conjunction March 12, 13, 14, 15. (Clicking here or on the photo above gives another rendition of their arrangement March 12th which was a beautifully clear evening here at Horton Bluff).  Note this ASTRO Photp of the Day


     The paths of Venus and Jupiter, two of the brightest planets, have been converging in the southwestern sky through February and now into the first half of March. Their paths will appear to cross forming a Planetary Conjunction March 12th to 14th. They will pass within 3° of each other. 

    As the two bright planets converged in the same part of sky in February , there were appearances of the Crescent Moon and Mercury, especially on the dates that are highlighted and linked. Feb 25th the thin lunar crescent was close to Venus, a spectacular sight, especially in early evening twilight!

    The evening of February 26th (as shown in this diagram for 6:30 p.m.), the Crescent Moon was between Jupiter (top) and Venus (brightest), Mercury is shown near the horizon (west).
   (Photos by Nova Scotia Observers)   (photos by Erica taken in Cuba)


January 26th, Venus and the Crescent Moon made an eye-catching view in the early evening sky. This photo was taken by Roy Bishop in Avonport, N.S. Considering photographing such arrangements like these? Here is a quote from Roy:

    “There is a narrow time window when skylight and moonlight provide the best aesthetic balance, and that is a difficult call because the eye has a much broader dynamic range than does the sensor chip in a DSLR.  I stopped down to f/8 for a good depth of field, and increased the sensitivity to ISO 400 so as not to exceed 4 s in order to avoid trailing”.  

Clicking on the photo gives a larger format.
(photo technical information: Jan 26, 2012, 18:06 AST, 65mm, f/8, 4 s, ISO 400, Canon XTi with 24-105 L lens).

    Venus and Jupiter will  appear close to each other from about March 7th to March 18th  They will appear closest to each other March 12th to 14th (linked diagram is for 8 p.m. ADT). More later.


A video reference via NASA

(Diagrams were made using Starry Night Pro)




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NEPTUNE: Close to its 1846 discovery position.

Oct 18th:   22:15 to 22:35 ADT,  Observation of Neptune’s Position in Aquarius

    This evening I located Neptune and added its location to the chart I’ve been keeping. This year the distant planet has returned to the location in which it was discovered 165 years ago. It took that amount of time for Neptune to complete one orbit around the Sun.

  Neptune is not visible naked-eye, but being familiar with the section of sky and pattern of stars in which Neptune is situated,  it was located fairly quickly using a pair of 10x50 binoculars. Neptune’s brightness is about magnitude
7.8, a rather dim, insignificant speck of light even in binoculars.  If one has not been observing Neptune regularly, a detailed star chart is needed to show Neptune’s ever changing location among the pattern of fainter  background stars (I use Starry Night, and the 2011 RASC Observer’s Handbook, pp234,235).

    What I find most interesting about Neptune at this time, is it being so very close to where it was located the historic night of first discovery, September 23, 1846.  Johann Galle, a German astronomer at Berlin Observatory, located the planet, using predictions he had received from Urbain LeVerrier.  Mathematicians, LeVerrier from France, and John Couch Adams in England, had separately calculated, with amazing accuracy, where a planet should be found. The teamwork of Galle (at the telescope eyepiece) and his assistant, Heinrich D’Arrest (studying the star chart  D’Arrest had recommended) soon located the uncharted “star”. It was less than 1° from LeVerrier’s prediction! A few months later the newly found planet officially became known as Neptune.

     Neptune is currently about 5° NE of Delta Capricornus and just above Iota Aquarii, a 4.3 magnitude star. At the time of this observation, the area of sky was about 30° above the horizon in the SSW (az. 200°). My Oct 18th observation showed Neptune being 6 or 7 minutes of arc (about 1/5 of a Moon diameter) east of its discovery position.  Even though Neptune’s natural motion is eastward, in my chart Neptune appears to be moving westward (to the right).  This is retrograde motion, an apparent motion, created by Earth moving in its orbit during the period when both planets come into alignment (with Sun’s centre) on the same side of the Sun (to astronomers -Neptune would be at opposition). As Earth moves into and out of the alignment or opposition stretch of its orbit with Neptune, Neptune appears to reverse its path against the starry background (retrograde motion). Early in November, Neptune will stall in its apparent westward motion and gradually resume its normal eastward track. (An observation update chart)

       It takes nearly 165 years for Neptune to complete one orbit. Its first orbit since discovery was officially completed July 12, 2011.  Neptune passed near its discovery position in early February 2011, but the bright Sun also occupied this part of the sky. Fortunately, thanks to retrograde motion, we are having a replay.  Several generations must pass before Neptune once again comes this close to where it was first found. This perspective turns the current period of Neptune observations into a significant lifetime event. 

     Officially Neptune is the outermost of Sun’s planet family and requires 164.8 years to complete one orbit.  Light from Neptune currently requires about 4 hours to reach observers on Earth, whereas light to travel Sun’s distance to Earth (150 million km) requires only about 8.3 minutes.  (If it helps your perspective, note that the signal of a cell phone call travels at the same speed as light. A one way call to Neptune would take 4 hours to get there.)


Links:  http://en.wikipedia.org/wiki/Neptune

http://www.wired.com/thisdayintech/tag/heinrich-louis-darrest/

http://www.space.com/12249-neptune-completes-orbit-discovery-1846.html

http://azureworld.blogspot.com/2011/07/neptune-completes-first-orbit-since.html

Yellow Lady Slipper (Cypripedium Calceolus) photogrophed June 5, 2011. The blooms were at the roadside looking down at me from the top of a gypsum embankment, part of a cut  through which the highway passes. The Yellow Lady Slipper is an orchid that likes the calcium-rich soil provided by gypsum deposits that are a major part of the bedrock in the  Windsor area of Nova Scotia.   More Lady Slipper photos



(C/2009 P1) has been a recent observing project. The e-sketch was based on eyepiece views from my Coulter 254 mm reflecting telescope, and it records the observations made between 02:30 and 04:40 UT, Aug 2, 2011.  Observing the comet was interesting during August 1st, 2nd and 3rd while it was passing near a globular cluster, M15 (Messier 15). The two objects were near enough in the starfield that they could be seen in the same view of my telescope’s low power eyepiece. In reality they are very different. In time and space, they are very far apart, and there is a tremendous difference in size.

    The comet is a small icy body, something like a very large, dirty snowball. It is currently orbiting in our region of the Solar System. Because it is close to our star (Sun) it warms and melts, producing a glowing cloud (coma) around its centre (nucleus) and a trail of dust and gas (a tail). The reflected sunlight from the comet currently takes about 12 minutes to reach Earth (12.4 light-minutes away). The main central mass of the comet is a few thousand metres in diameter ( Comat Garradd’s Track to Sept 29)

    Compared to the comet, M15 is huge! It is a group of more than a hundred thousand suns concentrated by gravity to form a cluster. It can be found just beyond the star, Enif, in the constellation Pegasus (as darkness arrives in August, Pegasus is midway above the southeast horizon). M15 is part of our Milky Way galaxy; light from its stars took nearly 34000 years to reach my telescope eyepiece (a distance of 33600 light years). On that same time and distance scale, anything moving at light speed would require 175 years to travel across the Messier 15 cluster.

    Rotated 180° (as in the eyepiece) an enlarged copy of the e-sketch above. For the full diagram with its background notes and showing motion over time, click here.  (more on Comet Garradd also a page by “Astro Bob”   Comet Garradd’s Track

(New:My e-sketch Comet Garradd Aug 17, 22:15 ADT)    


(Oct 2, 2011) Comet Garradd continues to be an interesting object in my 255 mm Coulter reflecting telescope.  Although it can be spotted in binoculars, it is primarily a telescope object. The comet has been passing through a very rich background of stars ( a segment of the Milk Way, in the south corner of the Summer Triangle). In addition to its passage near the globular cluster, M15,  described above,  clear skies the night of August 26-27 made it possible to see the comet pass very near another globular star cluster, M71, in Sagitta, (the Arrow). This photo was taken the same night by Blair MacDonald who was at the same location as I was (Nova East Star Party). (Also a You Tube video) A week or so later it was located among the stars of a bright open cluster known as The Coathanger.   Garradd will continue to be an object of interest into 2012.


Exciting SOHO Moments (Pick of the Week)

(SOHO is an orbiting solar observatory satellite, a project of international collaboration between ESA and NASA to study our star, Sun, from its deep core to the outer corona and the solar wind.)


Oct 14th:

Spurts of Plasma Shoot from an Active Sunspot Region  Spurting Active Region


Oct 3rd

Fascinating CME-Comet event! A solar grazing comet was caught recently on SOHO cameras. The white circle is Sun’s 1.4 million kilometre diameter; its intensely bright surface is covered by an eclipsing disc mounted on the SOHO satellite so that features in Sun’s outer atmosphere can be photographed. Recently the cameras were able to monitor a comet as it plunged toward the Sun.  Follow the link to see what happens.

http://sohowww.nascom.nasa.gov/pickoftheweek/old/03oct2011/


DANGER: a quick look at the graphics alone, could result in misconception. Reading the commentary is suggested, especially the critical analysis.


This link leads to a video clip presenting an interesting followup discussion around the whole topic of solar CMEs and solar grazing comets (at the site, the video is below the Sun-Comet photo).


(SOHO is an orbiting solar observatory satellite, a project of international collaboration between ESA and NASA to study the Sun from its deep core to the outer corona and the solar wind.)