Thanks Glen and Pete,
Pete this set was at 10C. Ambient was 22 and CCD temp 27 pre-capture.
I might have another go at this set because it was much sharper
than this. I must have messed something up on stack because
it is a bit foggy.
Beta Carinae/ SAO 250495/ Miaplacidus (09132-6943) is one of the brighter stars of the southern skies, and can be found about halfway between the Southern Cross and Canopus. From Sydney it is a circumpolar star. Although today it is in the modern day constellation of Carina, it was once, prior to the mid-17th Century, to lie within the super-constellation of Argo Navis. Later, Argo gained a new sub-constellation called Robur Carolinum. Created by Edmond Halley and officially published in 1679, Robur was made to commemorate the place known as the Royal Oak. This location protected the defeated Charles II, after his army was routed by Oliver Cromwell at the Battle of Worcester in September 1651. La Caille complained bitterly about Halley's addition because it destroyed most of the prominent stars in the Ship. (Halley, however, didn't complain. It ensured that he received his Masters Degrees by royal proclamation!) From about 1720, popularity for the constellation of 'The Oak' was slowly reclaimed back into Argo Navis. Its common usage probably ended in 1800 with Johann Elert Bode's star atlas 'Uranographica'. From then, like many others, Robur simply fell into antiquity as an obscure constellation. American astronomer Benjamin Apthorp Gould in 1879 subdivided this part of Argo Navis into smaller constellations, and Miaplacidus became part of Carina. This change was permanently adopted by the IAU in 1930.
Once known as Alpha Roburis, Miaplacidus was supposed to have been derived from the Arabic Mi'ak or 'waters', while the Latin 'placidus' was added much later. I assume that from Arabia, the Chaldeans would have seen this bright star in Summer glimmering close to the southern horizon of the Indian Ocean. Today, however, Miaplacidus is fully translated to mean 'placid waters' - appropriate because the star lies in the bilge of the ship!
This white star culminates annually at 9 pm. on the 26th March. In order of brightness, the visual magnitude is 1.674, making it 28th among the naked-eye stars. Distance is given as 26.1 parsecs (85 light-years), though the latest information of the Hipparcos astrometric satellite gives a much further distance of 34.09 parsecs (111.2 light-years). The spectrum of this giant star was for many years given as A0 III, though it has recently been downgraded to an A2 IV, indicating a surface temperature of 8 700OK. Measurements suggest an absolute magnitude of -0.4, so the true luminosity is about sixty times brighter than the Sun. Miaplacidus has been shown from the radial velocity that it is approaching us at a pedestrian 5km.sec-1. This is similar to the first measure in 1927, from the famous southern station of Harvard University in Chile. By 1970, careful inspection of the broadening of the spectral lines showed that the rotational (V.sin i.) velocity is c.145km.sec-1. Using general stellar evolution theory,
the rotation of the star would have a 'stellar day' possibly as long as c.60 hours (or 2.5 days) for its nine million
kilometre girth. Proper motion measures is 36.7"sec.arc. per century towards the constellation of Volans, which it will crawl into about the year 9 800 AD. Also in the future it will become the southern pole star in 6 200 AD, approaching by some 5O 42'. It is interesting to note that about the same time, Alpha and Beta Centauri will also be making their closest approach, at a mere 23'min.arc. Today, it stands as a lonely sentinel on the edges of the magnificent southern Milky Way.
NGC 2822/ ESO 61-4 (09138-6938) is a difficult galaxy to see because it lays a mere 10.2'min.arc. due north of Miaplacidus and hides in the glare of the star's brilliant radiance. (Figure 4) In the RNGC by Sulentic & Tufft, the object is stated as nonexistent - and it is consequently that NGC 2822 does not feature in many modern atlases used by amateurs. ie. Sky Atlas 2000.0. The basis of the deletion seems to have been from a simple comment in the mid-1950's by the famous galaxy observer and cosmologist; Gerald de Vaucoulers. Photographs produce images that cover about 3.3'x2.2', though the visual appearance is closer to about 1.4'x0.9'min.arc. (Note: NGC 2000.0 lists the size as 2.1'min.arc.) The magnitude is given as 11.7p, though visually I thought it to be nearer 12.1 to 12.4. (SIMBAD database gives V=12.01.) In the C-8, I thought I glimpsed a faint east-west smudge, by using an occultation bar placed at the focal plane in both a 12.5mm. Orthoscopic and a 20mm Erfle. Another trick was to place the galaxy just outside the visible field, though I thought the occultation bar did better. If you have a Newtonian, it is advised to make sure that the optics are perfectly aligned, as the artificial spikes will destroy your ability to see it. (This problem is similar to the faint galaxy near Leo's first magnitude, Regulus.) Doubt exists on the galaxy's morphology, but some think it maybe an elliptical. As yet, no redshift measures have been made on this object, so the distance is unknown.
