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jnb

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Everything posted by jnb

  1. Could I ask for some feedback on some videos we were trying to create recently? There are things in there which I think are wrong but the person doing the filming insisted on leaving in definitely things which could be improved but feedback from others is always useful. Mars in 15 minutes Life on Venus If there's anything obviously wrong with the production could I ask that you comment here rather than in the video comments (unless it's appropriate to post there as well obviously) Thanks.
  2. Feel free to strike as many matches as you want ... no free oxygen!
  3. If all they hope to do is a destructive dive into Venus atmosphere and sample the atmosphere en route then yes. To get to a useful, stable, low orbit takes more effort. You can to some extent offset that by repeated aero braking but that is destructive on the spacecraft. The problem with atmosphere sampling from a space craft is that there is a choice between destructive, extremely short duration missions, or high altitude passes that will gather far less data from regions that are not those that interest us. The region that seems to host the phosphine is about 60 - 70km up. Passing through that with a spacecraft would allow a single pass of a few minutes through that region. Though I have to admit I originally assumed you were referring to a sample return mission.
  4. But yes it does give a lot of impetus to the arguments for more Venus missions, if not sample return.
  5. Not too sure about that. Then energy requirement of getting to Venus is vastly higher than that of getting to Mars so payloads will be correspondingly smaller. If you want to "scoop" the atmosphere you may have to decelerate anyway and then accelerate to avoid the inexorable grip of gravity. At least with a lander you only need to worry about airbraking to get down.
  6. Jupiter has a low temperature and high pressure atmosphere which would allow phosphine to persist. In the conditions of the Veneral upper atmosphere (low pressure, relatively high temperature, high acidity) phosphine is unstable. I saw an account from the observatory science centre which pointed out that it depends on an unknown life process existing to survive in Venus atmosphere but if you are going to suggest that then you might as well suggest an unknown chemical pathway.
  7. I don't think anyone has ever assumed that you need "perfect" conditions but it is very easy and reasonable to assume that our conditions must be optimum. There are good reasons to make some of those assumptions. Possibly the biggest one is that you need some sort of solvent in which reactions can occur. Piles of dry chemicals don't tend to do much! Water is perhaps the best solvent as is is stable and liquid over a wide range of conditions. Water remains liquid over 100°C range whereas, for example, methane can be a solvent but is only liquid for a range of about 20°C. Possibly the biggest problem would be that the acidic conditions would dehydrate most mixtures removing the solvent and so stopping any reactions. That's not impossible to overcome but would be difficult. There are acidophile extremophiles we have found on Earth but they live in conditions which are mild compared to Venus I remain to be convinced about this as life. Partly because of the extreme conditions to overcome but also because we have been here before with ALH84001 and methane on mars. Evidence yes, conclusive no.
  8. Tell her that you are going to put a second 14" dob in the living room. When she complains you can 'compromise' on a binoviewer.
  9. Consensus seems to be settling on phosphine in Venusian atmosphere
  10. Phosphine is an automatic byproduct of phosphorous acid decomposing. My first thought is that finding phosphoric acid on Venus really wouldn't be surprising, hence finding phosphine wouldn't really be a surprise. That said my expertise is not in biology so I'm always inclined to imagine that a chemical route to producing these things is more likely.
  11. I don't get on with them either. I have always had a suspicion that the problem is that the light levels of most astronomical objects can be so low that there are not enough clues to allow some people to effectively merge the two views. So I have always found them fine for day time use or for the moon but as soon as it is separate stars I end have two separate images.
  12. That one's more bright orange than green!
  13. My (serious this time) guess would be exobiology but within the solar system. That said it will probably turn out to be something quite technical and to the public quite unexciting, perhaps dicovery of or evidence for amino acids on comets beyond just glycine.
  14. In the nature of these things it will probably not be anything astounding (as far as the rest of the world goes) Because of the long lead time it will be something that has turned up in data analysis rather than obvious in the data. If it was obvious in the data then many more people would have noticed it. Also last weekend in the Q&A at the Observatory Science Centre festival Dr Joanna Barstow made a comment about knowing the co-authors which implies a paper based on data and not the data itself. It is also probably not exoplanets because in the same Q&A all the attendees were asked what excited them in astronomy at the moment. Chris Lintott made the comment that as he knows what the announcement is he couldn't say that but "someone has to say exoplanets" which kind of implies that it isn't an exoplanet discovery. or we could just wait!
  15. This is my Bresser 102 That photo definitely looks more like a 102 than a 127. Also comparing the 2" fitting at the eyepiece and the overall diameter it does not look large enough to have a 127mm lens cell.
  16. I think the observatory at Herstmonceux might have let something slip about it https://youtu.be/k-VlV6zq-Y4 (with due apologies for the weekend silliness!)
  17. Though I did hear one suggestions that it would be the UK government announcing that they are seeking a trade deal with Mars.
  18. Just to clarify. Is that an OTA for €270 or OTA and mount? If it is just the OTA I would go for a new one or haggle a bit on price. If it is OTA and mount then definitely get it.
  19. Recordings of the event can be found at Astronomy festival playlist and individual items are being added to the rest of the channel
  20. I suspect we all know that there is some announcement on Monday about something. Hence the reason Sky At Night has been pushed back by a day and why Chris Lintott turned his camera off when the Q&A panel he was on at the weekend was asked about it but what I can't find is who it is who is announcing the "something". Anybody know?
  21. A little bit more information ... " Our 16th Astronomy Festival is on-line on Saturday 5th September https://www.the-observatory.org/astronomy-festivals This event is FREE! You can register here: https://www.eventbrite.co.uk/e/herstmonceux-astronomy-festival-tickets-116994496689 This is a fund raising event and we have a Crowdfunder page https://www.crowdfunder.co.uk/keepingastronomyandourheritagealive "
  22. I've been to this in the past and obviously due to the state of covid in the UK its not happening as a physical event but this looks interesting ... (particularly the "all free of charge" bit)
  23. Has anyone got any experience with attending or presenting courses online? If so what worked well or what didn't?
  24. I have acquired an old brass telescope; age unknown, manufacturer unknown. It's a 9cm refractor, approximately F12 - F15 (condition is too poor to be certain as yet). The objective is filthy, inside and out so I need to open up the lens cell to extract, clean and reinstall the lens. A bit of context. This came from someone who had the box and tripod sitting in a garage for years and they know nothing of it's provenance. The box for the scope is rotten and rusted. The scope itself is corroded (not just patina but actual corrosion), the eyepieces are in reasonable condition but the objective is close to opaque. I have cleaned off the front surface of the lens but most of the grime seems to be on the inner surface, confirmed with a checking the scope from the inside with an endoscope. Looking at the inside with the endoscope showed no obvious joints where it should disassemble. Stripping and cleaning the focus with a wire wheel on a dremel and some patience has the mechanics moving again but the lens cell remains the problem. A couple of images to show what I have. The lens cell as is the way of these things has multiple grooves and ridges some of which may be joints most of which are probably decorative. There is a knurled ridge around the front of the scope at the front of the very first ring which suggests it may unscrew but if that has been sitting there for decades it may be difficult to remove and as the first ring is only a few mm deep there's not a lot to grab hold of. I have cleaned it a little (and yes I know about people's opinions on whether you should or shouldn't clean old telescopes but I don't know how old this is and without doing a little cleaning I can't see where I might get into this.) BTW that image is the cleaned condition. Yes that is the "clean" lens! So how might I open that lens cell? Suprisingly enough with a lens in there I don't want to put it in a vice and twist
  25. Apart from a few showers this morning which might make the ground damp for pitching tents it's looking very good.
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