MESSAGE OF THE MONTH<\/span><\/strong><\/p>\n\n\n\n I would like to raise a question about the Hubble Constant. I have been reading about the discrepancy with this \u2013 in that the further away we look, the quicker galaxies are moving apart \u2013 but, every explanation presents the theory of dark energy to explain the discrepancy.<\/p>\n\n\n\n In my layman\u2019s mind surely the discrepancy is explained because the expansion of the Universe is slowing down and not accelerating? My rationale is that the further away we look, the further back in time we are looking, and the expansion is faster there, so does that not mean that the expansion is slowing down?<\/span><\/p>\n\n\n\n I have not seen an explanation that spells out why my thinking is wrong; none mention time as a factor to be discounted. I am not looking at the detailed science, as I would not know how to start; that\u2019s why I am hoping to see an answer that explains why I am wrong and puts me back in my place as an IT guy!<\/span><\/p>\n\n\n\n Stuart Buchanan, via email.<\/strong><\/p>\n\n\n\n Thank you for your thought-provoking message, Stuart! Scientists do take time into account when they\u2019re looking at the expansion rate of the Universe over cosmic distances, with what\u2019s known as the Hubble Parameter. Roughly speaking, this shows changes in the expansion rate over time, while the Hubble Constant is the expansion rate at a specific point in time \u2013 now. As the Hubble Constant is a greater value than the Hubble Parameter in the past, it implies that the expansion rate is accelerating. <\/span>\u2013 Ed.<\/strong><\/em><\/p>\n<\/div><\/section>\n\n Using my Canon EOS 600D DSLR camera and a standard lens, this was a hastily grabbed shot of the Moon as it was rising over the rooftops. I even slightly overexposed the Moon to give the effect of a Christmas tree with a giant light on the top branch. It\u2019s the ultimate Christmas decoration!<\/span><\/p>\n\n John Consadine, Dereham, Norfolk<\/strong><\/p>\n\n In Chris Lintott\u2019s \u2018Comment\u2019 in the December 2021 issue (\u2018Bulletin\u2019), he mentioned the Huygens spacecraft nearly missing out on sending data back from its landing on Titan. There was also another issue with the mission: Huygens was supposed to send back 700 photos during its descent, using two channels, A and B, so that one photo would go into channel A and the next would go into channel B. But Cassini was missing the command to turn on channel A, and the<\/p>\n\n 700 photos from Huygens all went into channel B\u2019s 350-photo storage location. As only 350 were stored, one photo overwrote the other and half were lost forever.<\/p>\n\n John Fairweather, via email<\/strong><\/p>\n\n I was woken early by my son and was treated to an unexpected clear morning, giving great views of Mercury and the crescent Moon over Glasgow (pictured, above). I was unprepared, but managed to grab my camera and get some photos before Mercury faded into the dawn.<\/span><\/p>\n\n Daniel Gilroy, Glasgow<\/strong><\/span><\/p>\n\n I have no more than a layman\u2019s understanding of astronomy, and one thing that often baffles me is how ancient astronomers knew so much about our Solar System. For example, ancient Greek and Roman civilizations conflated planets with deities \u2013 Mars, the god of war; Venus, the goddess of love and beauty; Mercury, the god of commerce and communication, and so on. <\/span>They ascribed supremacy to Jupiter and endowed that god with specific properties (such as Jupiter\u2019s ancient Greek equivalent, Zeus, assuming many disguises), which are remarkably close to the properties of that planet discovered later with modern technologies.<\/p>\n\n How did the ancient Romans know that Jupiter was the largest planet in our Solar System when they didn\u2019t have telescopes? To some extent the properties of Mercury, Venus and Mars are less baffling and could be the result of simple observations like the speed of Mercury across the sky, the beauty of > the evening star, or the red colour of Mars. But surely Jupiter and the outer planets were only dots of light to the Romans?<\/span><\/p>\n\n Syd Palmers, via email<\/strong><\/p>\n\n I have found the sky charts in the otherwise excellent Cambridge Double Star Atlas <\/em>to be rather inaccurate for observers here in the northwest of England. In an attempt to improve matters, I have developed a simple aid (above) which addresses this shortcoming! <\/p>\n\n Richard Newstead, Macclesfield<\/strong><\/p>\n\n In October, York Astronomical Society (YAS) organised an evening of music and astronomy with the York Railway Institute Band. The collaboration between two historical York societies created an inspiring atmosphere. The brass band played a wide variety of music inspired by the night sky, each piece accompanied by a backdrop of images of planets, galaxies and nebulae captured by the Hubble Space Telescope and YAS members. Music ranged from Holst\u2019s <\/span>The <\/em>Planets <\/em>to David Bowie\u2019s \u2018Life On Mars\u2019.<\/p>\n\n YAS was formed in 1972 by a group of enthusiasts in response to the excitement generated by the Apollo Moon landings, and is now a registered charity (#1174488). We currently have 77 members, many of whom have an expert knowledge of the Moon and deep-sky objects. Many are also astrophotographers, with a keen interest in live stacking and plate-solving using the ASIair Wi-Fi control unit.<\/p>\n\n We meet twice a month, and run an outreach programme in which we host schools and other local groups at our observatory on the outskirts of York. We also hold public star parties in and around York, including at Fountains Abbey. In October we held an event at Sutton Bank to celebrate the North York Moors achieving International Dark Sky Reserve status. The skies were crystal clear and many members of the public joined YAS members in enjoying spectacular observing and imaging opportunities.<\/span><\/p>\n\nRates of expansion<\/strong><\/h4>\n\n\n\n
![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/JET0SAK4V9447B810H49DJ103E23-1024x1024.jpg\")
Ready for Xmas<\/strong><\/h4>\n\n
![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/U0HS7Z64O281Y985VM0C57A30G7J-789x1024.jpg\")
<\/figure><\/div>\n\nLost in space<\/strong><\/h4>\n\n
Morning pair<\/strong><\/h4>\n\n
![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/482d21cb-2645-4160-bc45-ff40fc88c5db.jpg\")
By Jupiter!<\/strong><\/h4>\n\n
Reality check<\/strong><\/h4>\n\n
![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/G37NBO254IC0V4SJTUA0F083TL08-1024x696.jpg\")
\n\nSociety in focus<\/strong><\/h4>\n\n
![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/92NN42727AY4UC8V5P40NJW8FL81.jpg\")
![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/edec7b60-39d6-4cb9-b877-adaea7492a6e.jpg\")
<\/figure><\/div>\n\n![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/722decf5-e36b-4019-9987-b38419e315f7.jpg\")
<\/figure><\/div>\n\n![\"\"](\"https:\/\/dj9jqhxgw9833.cloudfront.net\/uploads\/sites\/77\/2021\/12\/Layer-0-640x1024.png\")