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This event did not last more than a few days, but one never knows how large such an event may become. I tend to wait a day or two to see how an event develops before posting an alert. The location and rapid development of this storm suggested it would reach larger proportions than it eventually did. If you obtain any observations of Mars, whether dusty or not, please send them direct to me. The 2022 blog at the Section website was recently updated. Good observing!
As to aperture, 200 mm will give you good results, but most observers seem to graduate to larger apertures. 250 mm should answer most needs, and unless you are getting excellent seeing conditions consistently (or become expert at processing) you probably will not find much advantage in going to 300 mm or more. Beyond that size, transportability will be a factor. However, for a fixed scope the focal length will be longer and longer with a larger aperture. I presume you are going for an SCT but I have had excellent reports from users of Maksutovs of around 250 mm aperture.
I would suggest that you think carefully about what focal length you will need to get a decent size of image. I use a 16 inch Dall Kirkham with a focal length of 400 inches. This enables one to get a decent size for Mars even at an aphelion opposition on the chip, without a Barlow lens, but I have actually found the image size somewhat too large for Jupiter near Opposition. I am mainly a visual observer so it does not matter too much to me. But as a Section Director I find the biggest complaint from (or obstacle for) observers is getting a large enough image. Some observers have coupled two x2 Barlow lenses together but this can lead to internal reflections and ghosting. There is a x3 Barlow on the market and that may be a better solution. If you intend to image Venus with a Barlow you should be aware that ultraviolet will be absorbed by glass and that a special Barlow will be needed, if you need a longer focal length.
Many observers have missed a discovery by taking too long to process their images, and I know several observers who always work upon them immediately after the observing run, and then send them in. So another piece of advice is not to accumulate your unprocessed images. You can always submit a better processing at your leisure, but report the result on the same day if you can. I find that some people can submit images six months late, but by that time their usefulness is much reduced.
I will leave others to give advice about manufacturers…..
It could indeed be Arthur Ransome, but in that book Dick’s telescope is more of a device for reading semaphore signals sent by another group of children. There is the stars book owned by Dick, and a few constellations are mentioned at the start. But the book is more about ice skating on the frozen lake. But yes, a brother and sister……. I find the question intriguing and at first I thought I knew the answer. But it was not so simple. On my shelf I still have an early 60s book from my childhood, Timothy’s Book of Space, but herein Timothy is the only one to receive instruction from his Dad. Although I cannot solve the riddle, instruction in the form of a series of long conversations between brother and sister is the theme of another book in my library by James Ferguson, An easy introduction to astronomy, for young gentlemen and ladies…. London MDCCLXXII. I will keep looking, but one certainly turns up interesting things along the way.
Following on from the previous post, I did take up Ron’s invitation to visit him at his home on the last afternoon of the 1983 Winchester weekend, and was about to attach my photo of him posing with his Observatory dome to this post when I realised that there was apparently no way to attach it. At the time Ron was doing good planetary photos using the Kodak TP2415 film which was the best way of securing quality results back then. A great observer, a true discoverer in the tradition of Alcock.
You can contact me with your wants list privately Paul, when you return, because I don’t look at the Forum regularly. See the back of the journal for my email address, please.
If anyone wants a particular issue, perhaps a replacement, just for the cost of postage, back to the 1946-47 Session, we do have some paper copies spare. Please ask me by private email and I shall be glad to help. I cannot make up complete sets, however.
I would be interested if any member wished to donate original copies of the Circulars from 1946 and earlier, as on the whole we have only one copy of each. I think most people treat them as ephemeral, and like newspapers they become rarities. We are also pleased to receive good copies of early journals and memoirs and handbooks, before 1934, as a few of our early ones are without covers, something that can occasionally be spotted in the scanned copies comprising the Journal CD set.
Sheridan did a great job with scanning them, and of course with the other long runs of publications.
I would like to add to the above discussion that the BAA Internet shop does not list all the available copies of the Handbook that we have for sale. The office has access to the stock for recent years, but the older stock is kept somewhere else in a storage depot out of London. In fact we have copies for sale for almost every year back to 1938, so if you need a particular issue or a run of years, before the ones available at the shop, let me know and I can advise availability, and we can arrange payment via the BAA office.
The same applies to older copies of the Journal, back to 1934, and the Memoirs (albeit a very patchy stock) back to the same time. Again please write to me as I visit the depot from time to time and can access the issues.
If any member would like a draft copy of my catalogue of every BAA publication ever produced since 1890 I shall be happy to reply to any private email. When eventually finished it will be posted online.
Let me just write that there are a great many published ephemera without any sign of a year indicated, and I hope authors will always date their publications in future for the record.
These are still available. I am sure someone would like them!
I forgot to add that in a few days’ time Mars is going to be close to Venus in the evening sky, so that will facilitate locating it. The Handbook mentions the date when they are closest.
I had an excellent view from Upper Benefield, Northants., though there were spells of cloud at times. I was able to time 1st and 2nd contacts with a 80 mm OG by direct vision. A pity the two sunspots visible are so small. There were several parts of the lunar limb showing irregularities. I hope others enjoyed the view.
I do not know anything about the other author, but I should write that Mrs Sally Beaumont passed away within the last five years or so. She was, I recall, a Latin teacher by profession. She made a number of planetary observations for the BAA.
In the light of recent Mars landings members may like to see a short National Geographic video that was uploaded last week. It mentions – in not very serious terms – the 1877 canal controversy, and I was able to supply the producers with a copy of N.E.Green’s map.
Dust now reached southern Hellespontus on the eastern side, and may start to become visible from the longitude of the USA if it spreads further east. Meanwhile UK and European observers are getting good views of the western side which reaches as far west as about Aonius Sinus, but you do need to observe early to see it near the CM: I had a good view around 17.30UT yesterday. From the longitudes of Japan and Australia the central part of the storm is well-placed. I am inclined to think it will not spread any further…… but it is an impressive sight.
The area is now visible from Great Britain in the early evening, and has grown into a significant Regional event. Being late in the season it should not reach encircling status, as no storm occurring after Ls 311 has done so.
I do not think it is appropriate that contributors to this Forum should use anything other than their real name!
I have to write, as a chemist, that amounts of phosphine in the atmosphere of Venus, however small, must be regarded as dubious. In the presence of tiny amounts of oxygen, the gas is spontaneously flammable, forming phosphorus pentoxide as a white smoke, and water vapour. We know that photolysis of oxygen-containing compounds by short-wave UV radiation can produce oxygen radicals in the atmosphere of Venus, so there is certainly going to be a short lifetime for any phosphine. By the way, I often demonstrated its flammability to my A level classes, though I don’t recommend it as a home experiment. You take a tiny piece of white phosphorus, which of course can no longer be bought, and cover it with a few cc of very concentrated NaOH solution, and heat gently it in the fume cupboard. Attach a delivery tube and after a few moments the apparatus will emit beautiful white smoke rings from the end, as each bubble of phosphine combines with the air. No need to add that caustic soda is dangerous, and white phosphorus even more so!
Dawes was a superb observer, for sure. The original drawings for 1864-65 that were used to prepare the engravings for that RAS publication are held in the Mars Section archives. The engravings are faithful reproductions. If you look at the bottom right drawing on the plate there do appear to be four forks, but the one nearest the limb is actually Margaritifer Sinus. In high resolution maps (such as Ebisawa’s, uploaded to the Section website) there is the usual partly resolved broad fork, with lighter shading between, and then a third ‘prong’ on the following or W. side, the latter (which Ebisawa called Brangaena) very thin leading to a very small dark spot at the north end. This can be seen in good current images of the region and I have seen it visually this year. It is of course harder to discover something than for a later observer to confirm it! In 1941 the Pic du Midi observers resolved the westernmost prong of the Meridiani Sinus into two closely spaced prongs, also shown on the Ebisawa map, though it is not a constant feature. So that would make four prongs. Historically there were always large differences in the drawings of this region, with some observers resolving two well-defined forks and others seeing the Sinus Sabaeus-Meridiani region like a sort of meat cleaver.
Although Dawes saw the planet briefly at the next opposition, these views of 1864-65 were his last ones. His excellent series from 1852 was reproduced in a small engraving by Proctor, and used in his well-known map, but they have never been reproduced from the originals.
It is odd that Dawes himself never tried to chart the planet.
Die-hard chocaholics might like to visit the Museum of Chocolate in Prague. It has no telescopes, chocolate ones or otherwise, but it does have many impressive wall paintings done in chocolate. (Liquid chocolate is not very different to thick oil paint, though more unforgiving to the artist as it cools.) When visiting, though probably not during a global pandemic, you are served some melted chocolate, and then you can produce your own chocolate painting on the spot (or drink it). When I went with my family, several years ago, I painted a chocolate portrait. There is scope (pun intended) for an artist to paint something astronomical in chocolate……
I have written about these at the Mars Section 2020 blog page and am about to post an update which includes some further comments on the images by David and others. These projections are always interesting to see, and I think that with the martian atmosphere having been rather free from the effects of major dust storms for several months now that there has also been the very unusual chance to observe shadows of high clouds very close to the terminator: the projections themselves are not so rare, but observations of their shadows are. Because there is always some residual dustiness in the martian air, any details of the terminator must inevitably faded by absorption and scattering of light under oblique illumination.