Monday, April 16, 2018

Southern Belle

 Rain, rain, rain... my astronomical activities are certainly taking a bath right now. Fortunately, in this age of the internet, I can hook up with some remote-control telescopes, located in areas which are much more likely to have clear skies. One such telescope is located in Chile and is made available to members of, an organization oriented to the world-wide astronomical community.

Some of the most impressive astronomical objects are located in the southern sky, visible at night only from areas close to, and south of the Earth's equator. One of those objects is Eta Carina.

Here is a quote from Wikipedia, the free encyclopedia:

The Carina Nebula (catalogued as NGC 3372; also known as the Grand Nebula, Great Nebula in Carina, or Eta Carinae Nebula) is a large, complex area of bright and dark nebulosity in the constellation Carina, and is located in the Carina–Sagittarius Arm of our galaxy (Milky Way). It has an estimated distance between 6,500 and 10,000 light-years (2,000 and 3,100 parsec) from Earth.

The nebula is contains many other objects, from the intrinsically brightest star in our galaxy to several star clusters, gaseous star-forming regions, and other interesting sights.  It is one of the largest diffuse nebulae in our skies. Although it is some four times as large and even brighter than the famous Orion Nebula, the Carina Nebula is much less well known due to its location in the southern sky. It was discovered by Nicolas-Louis de Lacaille in 1752 from the Cape of Good Hope.

a wide-field view of (η) Eta Carina

Here's a larger image of Eta Carina Nebula's core.

At this time, we have no plans to travel south; from a narrow point of view, to take a photo of this nebula/star assembly remotely saves the money. None-the-less, it would be nice to see this southern belle directly, it is a beauty even in binoculars, though you won't see the colours seen in the two images.

Saturday, April 7, 2018

Astronomical gems

Something which is unfortunately not seen from our latitude is one of the oldest and likely the largest concentrated accumulation of stars in our galaxy. It is a globular cluster, of which there are about 200 or so associated with "us". These clusters are very old, they have been around for about 10 to 12 billion years. Our own universe is calculated to be about 13.7 billion years old, so they have existed for most of that time.

This particular one is best seen from the night sky close to, and at latitudes below Earth's equator. It can be seen by the naked eye as a fuzzy star in the constellation Centaurus, and is accordingly named like a star: "Omega Centauri" (a mix of a Greek letter and Latin constellation name). It turns into an amazing view when seen through a pair of reasonably large binoculars or wide-field telescopes. As a photographic object, it truly "shines", much like a box of diamonds.

Since it is unobservable from our area, and since the current weather prevents any outdoor observing of the sky, I decided to resort to "old trusty", and acquired an image of Omega Centauri via a remote-controlled telescope, located in Chile. This is a favorite object for many astrophotographers and has been recorded thousands of times. Robert Conrad, the Observing Director in our Vancouver centre of the RASC posted his excellent photo in NOVA (March/April edition), our bimonthly news letter.

Here is my wide-field image of Omega, cropped to centre it in the frame:

Omega Centauri

This globular cluster contains about four million stars. That is about 10 times the number contained in M13, the most impressive globular in our sky (but not visible with my unaided eye, at least). Some estimates say that the average distance between the stars in Omega Centauri is less than one light year. Can you image the blazing night sky you would see on a planet that orbits one of those stars?

The orbits of planets around any of these stars would likely be perturbed by the other close near-by stars to make them unstable, with local climate subject to large swings from hot to cold. That would make an evolution of life as we know it unlikely. Well, it's nice to speculate.

Sunday, April 1, 2018

Something "new"


N CMa 2018

At left of the two pictures below is the pertinent cropped section of the nova image I obtained using a remote-controlled telescope. For reference, I reproduced a section of the map produced by Robert Conrad, using the American Association of Variable Star Observers AAVSO Variable Star Plotter regarding the AAVSO Alert Notice 627 in relation to the discovery of the nova. The nova was discovered in Japan on March 24 by Yuji Nakamura in Japan using a 4" photographic reflector telescope (called an astrograph). Robert Conrad, who is our Director of Observing at our Vancouver RASC centre, and who diligently digs out and observes new events in the sky, notified our observers about this. Spectroscopic observations, using larger, professional telescopes, classified this nova as the classical type.

 Left: Image of Nova      Right: A section of AAVSO map of Nova location.

Here is an excerpt from Wikipedia:

Classical nova eruptions are the most common type of nova. They are likely created in a close binary star system consisting of a white dwarf and either a main sequence, sub-giant, or red giant star. When the orbital period falls in the range of several days to one day, the white dwarf is close enough to its companion star to start drawing accreted matter onto the surface of the white dwarf, which creates a dense but shallow atmosphere. This atmosphere is mostly hydrogen and is thermally heated by the hot white dwarf, which eventually reaches a critical temperature causing rapid runaway ignition by fusion. From the dramatic and sudden energies created, the now hydrogen-burnt atmosphere is then dramatically expelled into interstellar space, and its brightened envelope is seen as the visible light created from the nova event, and previously was mistaken as a "new" star. A few novae produce short-lived nova remnants,[1] lasting for perhaps several centuries. Recurrent nova processes are the same as the classical nova, except that the fusion ignition may be repetitive because the companion star can again feed the dense atmosphere of the white dwarf.

Novae most often occur in the sky along the path of the Milky Way, especially near the observed galactic centre in Sagittarius; however, they can appear anywhere in the sky. They occur far more frequently than galactic supernovae, averaging about ten per year. Most are found telescopically, perhaps only one every year to eighteen months reaching naked-eye visibility. Novae reaching first or second magnitude occur only several times per century.

More details can be obtained by linking to .

You can't be bored if you are interested in astronomy. There is always something new in the sky.