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About nameunknown

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    Chester UK
  1. I have found that "marine ply", especially the stuff with a cedar facing, can be a b*****r to paint. I took advice in the shop and they sold me the wtong stuff, so I rang the paint company (Akzo) help line and they checked the facts with the store, then gave me the right stuff for free. Ten years on and it still looks great. If a paint job is really important, or (as in my case) needed scaff, it may be as well to check the substrate with a paint company first. Rgds P
  2. Hi, Great job! - a couple of tips from experience. 1) keep one of those cheap plastic sheets that are used for decorating in the obsy, just in case it rains and something goes wrong with the roof. Then at least you can throw it over the scope or whatever. Consider it the rain equivalent of a fire blanket. Hopefully you will never need it. 2) my roll-off roof (the one in the photo) blew off in a storm (good thing I had the sheet). I had tie downs but they didn't hold (but it was a very strong storm). Why not add some reserve lock-down devices ? I use four pretty heavyweight "turnbuckles" (spanschroefen ?), which I fit if the weather is going to be bad. They are a lot less expensive than a new roof! regards, Peter
  3. Phosphine is probably a good thing even if it is not associated with life on Venus. Phosphorous is quite a rare element, but may be essential to the sort of life that can use common chemistry and its lack of abundance is one suggested "solution" to the Fermi Paradox. So finding its available elsewhere even from a non-living source helps the odds for life, a little. In terms of related chemical stories - I bought a Victorian house some years ago and on peeling off the wall-paper found a green wash on the plasterwork. This was apparently an arsenical wash intended to prevent mould growing on wall-paper paste etc. I then discovered that the bugs had a niftly way of getting rid of the arsenic - converting it into arsine gas (the analog of phosphine).
  4. My problem was wind - that big storm back in the spring. A freak gust lifted the 4th floor roll-off roof straight off, over the house and into the street, where it experienced spontaneous disassemby.. This was followed by some running about and moving stuff while the rain was pouring in. Fortunately I had a few packs of the thin (decorating) poly sheet in the obsy as an emergency rain cover. Next day I boarded it as a temp measure, then came lock down, builders merchant shut, instructions to put myself under house arrest and the price of polycarbonate sheet went through the roof (if you could even get it). I never found my wind gauge. I did contact my insurance provider and they sent someone round to have a look, who thought it was an "external door" and needed a lock. I did point out that anyone who had a helicopter wouldn't be interested in robbing me, but agreed to fit a lock. Eventually I decided that making a claim wasn't economic as the only thing that seemed to be damaged (apart from the lid) was the wind gauge and one old SLR. This week I put a newly built lid on, with even more tie-down options than the old one. While at it, I installed a locking mechanism. Then I decided that the roof needed another coat of waterproofing. So, up on the obsy roof with tin of stuff etc. At some point I needed to close the roll offslightly and forgot about well-oiled rollers and the locking device - CLICK! Mmmmm....four floors up, on a flat roof with a locked roll-off skylight having a lot of cunning self-locating pins holding it down against serious storms. Fortunately, I managed to work out a way of opening it (since fixed). Anyway, the positive side was that it reminded me that while I was restoring my composure with a stiff drink, it was time to post something on SGL after a long absence.
  5. Golden section .. yeah right: 0, 1, 1, 2, 3, 5 , 8, 13.... (pretty boring) start instead with 1 and 3: 1, 3, 4, 7, 11, 18, 29..... Then, if your are bored, subtract 1 from each... N= 0, 2, 3, 6, 10, 17, 28..... (lets call those N(x))... divide by N OK, if N(x)/N is a whole number then N is prime (forget one) That is spooky! P
  6. Between cloulds, so far not that bad at all .. but needs a better night
  7. Cheapo rack and pinion is not that bad - I packed it out with a bit of foam and it is fine. P
  8. Well, getting the 200k to sit on the eq5 mount was a bit (lot) harder than I thought. Newton-Ellis were great at making an adaptor, but the things you tighten to fit it all together tend to collide (can't give them a name for fear of the "swear filter"), and balancing is a bit of a nightmare. I'm really quite (very) "unhappy" with the supplier, but it's cooling down now and we shall see soon.... P
  9. Just built one rainy today. Used a cheap (£10 - end of range) "Tesco" scope (500mm) for the rack and pinion, dew shield and spotter - sawed the tube down to to about 10cm and replaced the objective with a lens from a set of (50p) 10x50 binos from a charity shop (they had been dropped on the floor, were "way out of line" and were about to be junked) - knackered bino's are really good, you get some prisms to play with as well as the EP lenses and a spare objective for free. All the tube needed was a bit of work with the Dremel and the objective cell from the bino's went straight in. Just clean the lot with IPA before final assembly. The 5mW laser used for rough pointing was peanuts on DX. The whole thing weighs next to nothing and with a webcam on it should make a half-decent guider. I'm going to add a RasPi to this, once I get my Pi Autoguider LINUX software finished. P
  10. Hi Guys, Thanks for the comments. Not sure we can say that LCDM acts just as ordinary matter under gravity. It certainly partakes of a gravitational interaction, we can see that by its effect on galactic rotation, but whether the Higgs mechanism gives it mass in quite the same way and to the same extent is possibly open to doubt (i.e. no reason to assume it is the same). Also, if DM falls into a black hole one has to resolve the "information paradox" Quantum Physics says information "cannot be lost", while Relativity says that BH's have "no hair" and any information chucked-in is lost (the ultimate "Del *.*"). So either the iinformation that the BH was formed (perhaps in part) from DM is lost or it isn't - there is no clear resolution of that one. Some theories say that the information can be regained from the Hawking Radiation (which isn't normally considered to be possibly DM).... P
  11. I did realise the "cooling" problem - which was the root of my comment about "they may be a little different" - i.e. the accretion process could not be the same. Of course, the hole itself (forgetting for a moment the disk, jets etc) should be the same taking the classiic, mass, spin and perhaps some "charge" model (if DM can have "charge" as EM seems out - but I doubt any "normal" BH has appreciable charge anyway). It was just a thought as to why galactic core BH's could have gotten so big (i.e so different) so early on - otherwise they don't seem to have enough time to form I did find this just now: http://www.scientificamerican.com/article/dark-matter-black-holes-destroying-pulsars/ and this... http://arxiv.org/pdf/1502.05043v1.pdf
  12. Ok, here's an odd thought, we have some issues with "large black holes" in the early Universe. What if they form of "Dark Matter". Can this happen? They might be a little different to normal black holes...
  13. mmmm... it's said of Switzerland that if there is one thing they can hide better than their money it is their sense of humour, so amateur astronomers having a rant about results at CERN might not go down too well. Pity really, in places they have quite good clear skies, although the mountains do get in the way.
  14. Yes, now I can. A nasty back complaint and early retirement on health grounds. Hve to get my blog going!
  15. "Magnificent desolation" captured in acrylic. One wonders how few have spent such time over her inconstant face in that particular medium.
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