Surfing the Cosmos at the Berlin Zeiss Grosse Planetarium

The Planetarium Building built by the old East German Regime and refurbed in 2015-16

Whilst on a week long visit to Berlin Toot and I visited the Zeiss Grosse Planetarium. A great evening's entertainment.  The projection equipment is state of the art, it having been refurbished in the last year. Another bonus is that the dome at 25 metres diameter is one of the biggest in the world and this is a big plus when creating visual impact.

There are however three issues that would make the experience even better:

• Booking tickets on -line is next to impossible. In the end we went to the ticket office at the Planetarium and were lucky enough to get tickets for the same day.
• The Planetarium has an enormous foyer but there was little on display and there was nowhere inside to get a drink or sandwich.
• The show was delivered in German, not surprisingly in Berlin, but there were no available translations to other languages. This was quite different from our experience at the recently refurbished Berlin Opera house, where an English translation of the libretto to Mozart's 'The Magic Flute' appeared in text upon small screens affixed to the back of the seats infront of us.

The original Zeiss Projector - now an exhibit in the the Planetarium Foyer.

I was much impressed by the sole exhibit in the Foyer, the old East German Zeiss star-projector. I can remember as a lad visiting the London Planetarium in Baker Street where they had a projector just like it. More recently my son and I saw a show at the old Montreal Planetarium where one of these beasts was still operational (I believe like me it's now been retired).

One of the few astro images displayed in the foyer.

The Planetarium at night just before the evening performance - looking for all the world, like a flying saucer.

Language aside, Toot and I really enjoyed the show.  It's a great visual experience which we much recommend.

A Foggy Night on the Coast

2 images taken from our Backyard last night with a hand held Canon Compact Camera

It was quite foggy in Lowestoft last night and so the Super Moon, so called when our Moon, following its elliptical path around the centre of gravity of the Earth- Moon dynamic system, is at its closest (or perigee), was wrapped in a cloak of soft pastel blue and pink fur.

The last time the Moon appeared as large as this month's Super Moon, 69 years ago, I was but a twinkle in my late father's eye.  If I live to be 85 years old I might manage to see the Moon looking as big again on the 25th of November 2034 !

In meteorology, a corona (plural coronae) is an optical phenomenon produced by the diffraction of light from the Sun or the Moon (or, occasionally, bright stars or planets) by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface. In its full form, a corona consists of several concentric, pastel-colored rings around the celestial object and a central bright area called aureole. The aureole is often (especially in case of the Moon) the only visible part of the corona and has the appearance of a bluish-white disk which fades to reddish-brown towards the edge. The angular size of a corona depends on the diameters of the water droplets involved: Smaller droplets produce larger coronae. For the same reason, the corona is the most pronounced when the size of the droplets is most uniform. Coronae differ from halos in that the latter are formed by refraction (rather than diffraction) from comparatively large rather than small ice crystals. - credit for italic text - Wikipedia

Fields of red and gold

Poppyland  George Roberts - Oil on board October 2016

Poppyland 2 George Roberts - Mixed media October 2016

In October and November, painting and glass fusion have taken over from astronomy in the Cabine. The weather has turned cold and wet, so memories of sunny days and fields full of beautiful red poppies remind me that winters grip is short and summer is only months away.

Baking the Christmas Cake

Toot's Christmas Cake

Whilst I've been painting in the Cabine, Toot has been multi-tasking in the house. When I came into the kitchen my sense of smell was treated to the distilled essence of Christmas yet to come, the wonderous aroma of slow baked rich fruit cake with spiced rum.

Tooty used her improved version of Mary Berry's Christmas Cake recipe - which is, in my cakey opinion, 'Top Seasonal Nosh'!

Marzipan and Royal Icing to follow if you please Mrs Claus.

Reading between the lines

Spectrum of the star Vega in the constellation Lyra taken from my backyard with my homemade spectrometer affixed to my 127mm. Meade Apo refracting telescope. The wavelength is given along the X-axis in Angstrom units where an Angstrom is one ten billionth of a metre.              The spectrum has not been corrected for the camera's response or the affects of the Earth's atmosphere.  Credit: Visual Spec free software by Valerie Desnoux used for processing the spectrum.

 There are three basic types of spectra:

1. Continuous Spectra - "A hot opaque solid, liquid or gas will emit a continuous spectrum when under high pressure" Kirchoff's Laws Rule 1 - produced by by hot bodies like stars and our Sun and the result of very hot gases comprising energetic atoms colliding.
2. Emission Spectra -"A hot gas under low pressure (ie. much less than atmospheric) will emit a series of bright lines on a dark background" Kirchoff's Laws Rule 2 - produced when atoms have less energy than those producing continuous spectra.
3. Absorption Spectra - "When light from a source that has a continuous spectrum is shone through a gas at a lower temperature and pressure, the continuous spectrum will be observed to have a series of dark lines superimposed on it." Kirchoff's Laws Rule 3 - produced when photons from a continuous spectrum pass through a gas made of one or more elements, lines for each element will absorb photons of the wavelengths specific to those elements. In other words this produces a continuous spectrum with dark lines where photons of specific frequencies are absorbed. Our Sun and other stars produce continuous spectra but as the photons, created at the stellar core, pass through the stellar atmosphere some are absorbed at specific wavelengths related to the elemental make up of the star.

 Analysis of the Absorption Spectra from stars enable astronomers and astrophysicists to determine the chemical fingerprint of stars, their temperature and radial velocity. A very powerful measurement tool!

Alpha Lyrae or Vega is the third brightest star visible from the northern hemisphere. It is only 25 light years from our Solar System  a veritable neighbour. It is a very hot star, approximately 9600 degrees Kelvin, or about twice as hot as our Sun. It has a mass approximately twice that of our Sun and is spinning so fast that it shape is oblate rather than spherical. It is thought to have a protoplanetary disk of dust and rocks that spins around it.

The visual spectrum of Vega is dominated by absorption lines of hydrogen; specifically by the hydrogen Balmer series with the electron at the n=2 principal quantum number. The lines of other elements are relatively weak, with the strongest being ionized magnesium, iron, and chromium. My low resolution spectrum shows the stronger Hydrogen Balmer lines clearly demonstrating the presence of Hydrogen in the stellar atmosphere of Vega. I believe some of the Helium lines can be seen and also two lines of Oxygen in the Earth's atmosphere (the photons I collect with my kit has to pass through our atmosphere to reach my telescope. (All of this could be wishfull thinking on my part)

This is my first real attempt at obtaining information from stellar spectra. Well what did I find out?

1. Vega has an absorbtion spectrum which exhibits the Balmer Series of Hydrogen absorption lines.
2. I tried applying Wiens Law using the wavelength at which it exhibits the greatest energy flux (taken from my spectrum) to determine Vega's temperature and obtained a value 100% different from the published temperature. As Wiens Law works only for 'blackbody emitters' I came to the conclusion that Vega does not radiate energy as a 'blackbody'.

Credits: I used information taken from the following sources - Jeffrey L. Hopkins 'Using Commercial Amateur Astronomical Spectrographs'- The Patrick Moore Practical Astronomy Series by Springer. Visual Spec free software by Valerie Desnoux. Three Hills Observatory.

My homemade spectrometer under construction - made from 100 lines per mm. transmission diffraction grating and an old Logitek Webcam with the infrared filter removed.

 I think I might construct a new design  mark 2 spectrometer utilising a camera with a bigger chip! The shed beckons.