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Space and Astronomy Thread |
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#2276 |
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..and of course - the Ice Warriors are back on Dr. Who this season!!!
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#2277 |
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Join Date: Jun 2012
Location: Josameto
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..and of course - the Ice Warriors are back on Dr. Who this season!!!
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#2278 |
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Join Date: Jan 2012
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Last week when on holiday in Gran Canaria, I saw Jupiter & the Moon up close through telescopes in the hotel grounds (they weren't there every night), I saw the craters of the Moon - it was fascinating.
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#2279 |
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#2280 |
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Join Date: Nov 2002
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I haven't seen the comet at all................it's been cloudy for a month..............
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#2281 |
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Join Date: Nov 2008
Location: London
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Clear skies in London tonight. My first chance to see the comet.
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#2282 |
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Join Date: Nov 2002
Posts: 76,816
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I'm in London and have been looking for the last hour as the Sun was setting.....as you say, first clear sky for months......I thought I found the comet but when I looked through my bins it was an aeroplane..........
![]() What direction should we be looking in? |
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#2283 |
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Another beautiful day today. The next few days it should be easyish to locate, just to the right of the Andromeda galaxy. I am going to be more dedicated tonight and go out with the bins.
Also I think it's high enough now that you can wait for an hour or 2 after sunset, because I doubt if you'll see it in twilight. |
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#2284 |
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Posts: 2,090
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Starwatch, in yesterday's newspaper, said PANSTARRS will be considerably dimmer than last month, though visible for much longer: http://www.guardian.co.uk/science/20...rion-leo-april
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#2285 |
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Join Date: Jan 2003
Location: Wiltshire
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Quote:
Starwatch, in yesterday's newspaper, said PANSTARRS will be considerably dimmer than last month, though visible for much longer: http://www.guardian.co.uk/science/20...rion-leo-april
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#2286 |
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Quote:
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#2287 |
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Join Date: Jun 2010
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Eventually found it. A faint star with a smudge, and that's through some decent bins too. Oh well, let's hope the one in November is as good as it's been hyped to be
![]() I saw it briefly last week through a pair of bins but it was already dimmer than mag 4 and there weren't a good set to look through. I'm kinda hoping for better things when ISON arrives. |
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#2288 |
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Join Date: May 2002
Location: Bishop-Auckland / Darlington
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I was out with an observing buddy at our regular dark-sky site last night, and we managed to get some really good views of PanSTARRS.
I did spot it around mid-March... But last night was far better, even though it's now down to about magnitude 4.8. Now that it's further from the Sun, it's possible to see it a good couple of hours after sunset, so the sky behind it is much darker, and it stands out significantly better. Sunset was about 7:45 last night, and we met up as usual, about 15 mins after sunset - I took an 8" SCT telescope with me, and 20x80 binoculars (tripod-mounted) - my mate also had binocs of the same size, and an 8" Newtonian reflector telescope. We went through our usual routine of setting the scopes up - then a bit of a chat, and a cuppa from a thermos, while the scopes cooled to ambient temperature - by about 8:45 it was dark enough to see Polaris, and polar-align our mounts - then after spending 15 mins or so on Jupiter, the sky to the NW was dark enough to see a few stars near the horizon. Earlier in the day I'd looked up the comet's position, and knew where it should be - so starting from the easiest visible nearby star (Mirach, in Andromeda) - panned the binocs to the right, going past the star 'nu andromedae', then between 'mu' and '32' andromedae, (the usual way I star-hop to the Andromeda galaxy) - then from the galaxy, down and to the right a little to where the comet should be - At first, and just for a second, all I registered was an unfamiliar star coming in at the edge of the binoculars' field of view - then as it tracked into the middle of the view, that 'star' looked fuzzy, and the tail swam into view. "Got it", I said to my mate - who was still looking at Jupiter in his 'scope' - This would be just after 9pm. The view was roughly comparable to the view I'd had a few weeks ago - but tonight I had a reasonable-sized scope with me, and the next job was to get it in the scope. I popped in a 40mm wide-angle eyepiece, to give me 50x magnification, and a true field of about 1.4º, and homed in on it with the scope. With the light-grasp of the scope it was absolutely beautiful, and the fan-shaped tail stretched almost all the way acoss the field of view. We stayed until after midnight, and kept coming back to PanSTARRS, in between looking at other things - The views of the comet gradually got better and better, peaking at about 10:30, when the NW sky was darker than it had been earlier, and just before the comet dipped too low into the murk that you always get just above the horizon. It was visible to the naked eye by then - even though it's now at almost 5th magnitude. In the binoculars, both the Andromeda galaxy, and the comet could fit in the same field of view, with the galaxy at upper left, and the comet at lower right, with the tail fanning upwards across the view - wonderful sight. I'm now hoping that we get a clear sky one night between the 18th and 23rd of April, as it passes through Cassiopeia, close to some of my favourite star clusters
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#2289 |
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Join Date: May 2002
Location: Bishop-Auckland / Darlington
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Anybody else been watching comet PanSTARRS..?
I've been viewing it whenever I've had a clear night, watching it climb slowly up from Andromeda to Cassiopeia. It's circumpolar in UK skies now - which means it's visible all night, so long as there's no clouds in the way. I did this sketch a couple of nights ago.. 4B pencil on standard printer paper - After scanning I inverted the field of view to white on black (to match the actual view) The smallest (dimmest) stars in the picture are around 10th magnitude - the labelled star (Lambda Cassiopeia) is magnitude 4.8, just on the edge of naked-eye visibility Comet PanSTARRS is around 6th magnitude at the moment. http://i49.tinypic.com/5d1ldt.jpg 20x80 binoculars, tripod mounted - There was a thin haze, limiting how much of the tail I could see. A few nights earlier the tail spanned about 1/3rd of the field, but a hazy sky will soon kill any delicate detail in things like nebulae - and comet tails
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#2290 |
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Join Date: May 2004
Location: Storbritannia
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Quote:
Anybody else been watching comet PanSTARRS..?
I've been viewing it whenever I've had a clear night, watching it climb slowly up from Andromeda to Cassiopeia. It's circumpolar in UK skies now - which means it's visible all night, so long as there's no clouds in the way. I did this sketch a couple of nights ago.. 4B pencil on standard printer paper - After scanning I inverted the field of view to white on black (to match the actual view) The smallest (dimmest) stars in the picture are around 10th magnitude - the labelled star (Lambda Cassiopeia) is magnitude 4.8, just on the edge of naked-eye visibility Comet PanSTARRS is around 6th magnitude at the moment. http://i49.tinypic.com/5d1ldt.jpg 20x80 binoculars, tripod mounted - There was a thin haze, limiting how much of the tail I could see. A few nights earlier the tail spanned about 1/3rd of the field, but a hazy sky will soon kill any delicate detail in things like nebulae - and comet tails ![]() Whilst I remember, here is some encouraging astro news: Kepler telescope spies 'most Earth-like' worlds to date But researchers tell Science magazine, they are an exciting discovery. "They are the best candidates found to date for habitable planets," stated Bill Borucki, who leads the team working on the US space agency Nasa's orbiting Kepler telescope. http://www.bbc.co.uk/news/science-environment-22200476 Orbital's Antares rocket makes test flight The 40m-tall Antares vehicle lifted clear of the Wallops Flight Facility in Virginia at 1700 local time (2100 GMT). The apparently flawless 10-minute ascent should lead to it being allowed to propel an unmanned cargo ship towards the ISS later this year. http://www.bbc.co.uk/news/science-environment-22193330 ...and now for something pretty to look at: Horsehead Nebula: Herschel telescope images astronomical classic Europe's Herschel space telescope has imaged one of the most popular subjects in the sky - the Horsehead Nebula - and its environs. The distinctively shaped molecular gas cloud is sited some 1,300 light-years from Earth in the Constellation Orion. It is in a region of space undergoing active star formation - something Herschel has been most keen to study. http://www.bbc.co.uk/news/science-environment-22217334 |
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#2291 |
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Thank you for the excellent drawing, Carlos_dfc. I assume that the comet is getting increasingly distant and faint now somewhere in the region of Andromeda/Cassiopeia. Dare I ask what the visual magnitude is now?
PanSTARRS is around 7th magnitude now - still visible in standard 50mm binoculars if you can avoid urban light-pollution. It's currently within the 'W' shape of Cassiopeia - roughly ¼ of the way from the right-most star of the 'W' to the centre star. Headed roughly North at a rate of just under a degree per day - and will have faded to around 8th magnitude in about a fortnight. Beyond mag 8, it'll get very difficult to spot unless you have a 'scope, or large astronomical binoculars. I managed to view it for a couple of minutes tonight - between cloud banks - 7th mag is still reasonably bright in large (20x80) binoculars - nice to see it in the same field of view as the open cluster ngc129. Shame the clouds didn't clear long enough for me to sketch that - but that's what it's like being a visual observer in Britain - it's a constant game of 'Dodge the clouds' |
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#2292 |
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Join Date: May 2004
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Quote:
Hi TVU
PanSTARRS is around 7th magnitude now - still visible in standard 50mm binoculars if you can avoid urban light-pollution. It's currently within the 'W' shape of Cassiopeia - roughly ¼ of the way from the right-most star of the 'W' to the centre star. Headed roughly North at a rate of just under a degree per day - and will have faded to around 8th magnitude in about a fortnight. Beyond mag 8, it'll get very difficult to spot unless you have a 'scope, or large astronomical binoculars. I managed to view it for a couple of minutes tonight - between cloud banks - 7th mag is still reasonably bright in large (20x80) binoculars - nice to see it in the same field of view as the open cluster ngc129. Shame the clouds didn't clear long enough for me to sketch that - but that's what it's like being a visual observer in Britain - it's a constant game of 'Dodge the clouds' , Carlos_dfc. It's unfortunate that this particular comet wasn't well placed for northern hemisphere observers so that when PanSTARRS did eventually arrive it was a puny relic and a bit of a disappointment to say the least. Let's hope that Comet ISON puts on a better display later on in the year: http://www.dailymail.co.uk/sciencete...arth-2013.html
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#2293 |
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Join Date: Jun 2012
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SpaceX's Grasshopper VTVL takes a 820' 'flight' and lands again.
http://www.youtube.com/watch?v=NoxiK7K28PU Very weird to watch. |
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#2294 |
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SpaceX's Grasshopper VTVL takes a 820' 'flight' and lands again.
http://www.youtube.com/watch?v=NoxiK7K28PU Very weird to watch.
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#2295 |
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Join Date: May 2004
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SpaceX's Grasshopper VTVL takes a 820' 'flight' and lands again.
http://www.youtube.com/watch?v=NoxiK7K28PU Very weird to watch. Quote:
Very optimistic, I am still a fan of the old school, A man who smokes a pipe and owns a garden shed always tend to come up with bright ideas....
![]() ...and now for some potentially good light pollution news: LED streetlamp aims to improve public's view of stars Researchers believe they have come up with a new type of LED-powered streetlamp that could radically reduce light pollution...According to the researchers, conventional street lamps - which use high-pressure sodium or mercury vapour - scatter up to 20% of their energy horizontally or vertically because it is difficult to control their beams. It is easier to direct light from LEDs because it is being emitted from a smaller area. http://www.bbc.co.uk/news/technology-22292129 |
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#2296 |
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Not sure if I'll be able to explain this properly, but I'll have a go.
Episode of QI on Dave the other night where the question was "buzz when the sun has set" - watch that section here. Now, I'm happy with the explanation given in the programme that when the sun's lower edge has reached the horizon, due to the bending of light through the atmosphere the sun is really lower than it appears and the top edge is actually completely below the horizon. Fine. However, there must be a point in time during sunset when the lower edge of the sun actually is just above the horizon and there's not yet a mirage effect. So what happens during that transition when the sun is above the horizon to when it appears to an observer to have disappeared? Does it's descent speed increase at some point, or once the mirage begins to take effect does it appear to slow down as it moves through the sky (or more acturately as the earth continues to turn)? |
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#2297 |
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Join Date: Oct 2003
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...and now for some potentially good light pollution news:
LED streetlamp aims to improve public's view of stars Researchers believe they have come up with a new type of LED-powered streetlamp that could radically reduce light pollution...According to the researchers, conventional street lamps - which use high-pressure sodium or mercury vapour - scatter up to 20% of their energy horizontally or vertically because it is difficult to control their beams. It is easier to direct light from LEDs because it is being emitted from a smaller area. http://www.bbc.co.uk/news/technology-22292129 http://www.lightsoninhampshire.co.uk/Public/Faq.aspx Quote:
2. Why are we doing this? In practice though, all you notice is a horrible cold grey light replacing the older warm yellowy ones. I dislike the new ones - though I can't deny the energy saving they probably provide, and it may stop that yellow glow in the sky and so prove beneficial for viewing the night sky. Will have to wait until they've all been done though, to judge that.It's simple - thousands of older street lights are in a poor condition and need replacing. Some are more than 40 years old and just don't meet modern standards. Orange light makes it more difficult to see colours at night and the older designs shine light in all directions, including into the night sky. The new white lighting will be directed onto roads and pavements, helping to reduce traffic accidents, crime (and the fear of crime) and make the streets safer. As for new LED lamps... roll on 2040!
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#2298 |
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Join Date: Nov 2008
Location: London
Posts: 4,020
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Quote:
...and now for some potentially good light pollution news:
LED streetlamp aims to improve public's view of stars Researchers believe they have come up with a new type of LED-powered streetlamp that could radically reduce light pollution...According to the researchers, conventional street lamps - which use high-pressure sodium or mercury vapour - scatter up to 20% of their energy horizontally or vertically because it is difficult to control their beams. It is easier to direct light from LEDs because it is being emitted from a smaller area. http://www.bbc.co.uk/news/technology-22292129 Quote:
According to the researchers, conventional street lamps - which use high-pressure sodium or mercury vapour - scatter up to 20% of their energy horizontally or vertically because it is difficult to control their beams.
why wouldn't properly placed reflectors direct more of the light downwards?The University of London Observatory at Mill Hill had a big problem with the lighting on the adjacent A41 dual carriageway. For years they tried to persuade the authorities to turn off the lights late at night when there was little traffic with no success, but eventually did manage to get them to install the current efficient light fittings, and the effect was so dramatic that the observatory then had to install safety lighting in its own grounds. In addition, from the hills above Guisborough the part of the town that has these lights is in semi darkness compared to the rest. So if these new LED units are a significant improvement on that then it really will be amazing. |
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#2299 |
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Join Date: Nov 2008
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Now, I'm happy with the explanation given in the programme that when the sun's lower edge has reached the horizon, due to the bending of light through the atmosphere the sun is really lower than it appears and the top edge is actually completely below the horizon. Fine. However, there must be a point in time during sunset when the lower edge of the sun actually is just above the horizon and there's not yet a mirage effect. So what happens during that transition when the sun is above the horizon to when it appears to an observer to have disappeared? Does it's descent speed increase at some point, or once the mirage begins to take effect does it appear to slow down as it moves through the sky (or more acturately as the earth continues to turn)? |
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#2300 |
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There will be a gradual increase in the refraction effect as the Sun descends towards the horizon, as the light has to pass through more and more atmosphere. So I would say it will appear to gradually slow down.
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