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bob1957

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About bob1957

  • Rank
    Star Forming

Profile Information

  • Gender
    Male
  • Interests
    Stellar spectography and solar observation
  • Location
    Holmfirth, West Yorkshire, UK
  1. Maxwell was very much a man who was ahead of his time. The scientific community during his life had great difficulty understanding what his electromagnetic theory of light really meant. It is probably this and the fact that he died at a very early age meant that his genius has been so overlooked. Compared with Einstein the public generally has no idea who Maxwell was, but Einstein himself often paid tribute to Maxwell and also had a photograph of Maxwell on his study wall. For a first rate book on Maxwell's life, science and legacy read Basil Mahon's "The Man Who Changed Everything". Cheers, Bob
  2. bob1957

    SGL XI Chit Chat

    Cheers John. All I've got to do know is buy a caravan which is the planned for end of January.
  3. bob1957

    SGL XI Chit Chat

    Cheers guys. Looking forward to my first SGL star party and meeting you all. Bob
  4. bob1957

    SGL XI Chit Chat

    Is there an update of the pitch plan available as I've booked but it's not yet showing. Cheers, Bob
  5. Got it. So re-reading the NASA press release the water is flowing just below the surface trapped in the salts and is released when temperature conditions are right.
  6. It's unlikely that flowing liquid water, such as we see here on Earth, will be seen. The low atmospheric pressure and temperature of Mars would surely mean that water evaporates very quickly soon after the water ice melts. So what we are seeing are the salts left behind after the water has evaporated. Unfortunately this may not capture the public's imagination of what they expect in terms of water on Mars.
  7. I did, but only because I needed to get up to go to the loo (one of the disadvantages of being the wrong side of 50). Stuck my head out the door and surprise, surprise eclipse was in it's early stages. So went back to bed for another hour!
  8. Lujendra Ojha, also one of the participants, is a graduate student who has been studying gullies on Mars that seemed to indicate past water activity along with Alfred McEwan when at the University of Arizona, see here http://www.sciencemag.org/content/333/6043/740. Ojha continued this work at Georgia Tech, possibly with Mary Beth Wilhelm. So it's possible that they've found water in these gully areas.
  9. Hi Shelby, welcome to SGL from a fellow SGL member located in misty Holmfirth so I can empathise. I had the pleasure of visiting San Francisco at the height of summer in 1980 and witnessed the spectacular Golden Gate bridge shrouded in fog. Beautiful city you live in. Best wishes, Bob
  10. Good point Olly. The panel area decreases as the angle towards the vertical increases as the Sun passes overhead, unless as you say the panels can track the movement of the Sun for optimum area.
  11. Good point Olly. The panel area decreases as the angle towards the vertical increases as the Sun passes overhead, unless as you say the panels can track the movement of the Sun for optimum area.
  12. Ronnie, a. First you will need to calculate the flux (watts/km2) which falls on the Earth's surface from the Sun. You have the Sun's luminosity as 4.0E33 erg/s which is equal to 4.0E26 Watts. Using the distance from the Sun to the Earth of about 1.5E8 km calculate the surface area of a sphere using this distance as the radius. Divide the power from the Sun by the surface area and this will give you the flux at the Earth's surface. You know you need 1 Gigawatt (1E10 Watts) output power from the solar array, but remember it's only 10% efficient so you need more power going into the array, i.e. 1E10 Watts. Now divide this required input power to the array by the flux falling onto it and it should give you the area of the array in square kilometres. b. Here you can you use the small angle approximation which basically says that the angle (in radians) formed by a small object at a very large distance can be calculated by dividing the size of the object by it's distance (all in metres). So if you know the angle (in this case the angular resolution) you can rearrange it to find the distance in metres by dividing the size of the object (in metres) by the angle (in radians). But you will have to convert the angular resolution of 0.5 arcseconds into radians. If you are not familiar with this multiply the number of degrees by pi and divide by 180. Remember there are 60 minutes in a degree and 60 seconds in a minute so one degree equals 1/3,600 arcseconds. c. For diffraction limited optics you will need to calculate the angular diffraction. For this you will need the diameter of the optics in this case the Keck which I believe is 10 metres diameter and also the wavelength of light which you can approximate to 500 nm (5E-7 metres). The angular diffraction is calculated by dividing the wavelength of light by the diameter of the optics and multiplying by 1.22. This gives you the angular diffraction in radians. You can then use the small angle approximation outlined in b. to work out the distance using the angular diffraction you have just calculated and the size of the object. I hope all of the above helps. Cheers, Bob
  13. I had the same problem using a 1.25" EP's in a 2" Lunt wedge with a 102mm wide field refractor. The result was I had insufficient back focus with the 1.25" EP's because too much travel was lost using the 2"/1.25" adaptors. My solution was to use a 28mm 2" Skywatcher long relief EP. You can get low profile adaptors and that may give you sufficient back focus, but if you want to use the 2" wedge then you may need to use 2" EP's. Alternatively, if you want to use 1.25" EP's than as Moriniboy has suggested return it and get the 1.25" wedge instead.
  14. FLO have recently moved to larger premises and according to their recent post (see link below) it is large enough for a showroom, but that apparently is for the future. I'm sure Steve will let us know when. So as Ant says FLO are web based, but ring them if you want to visit. A number of people on SGL have done that. Don't now if anybody would be available at the weekend though. http://stargazerslounge.com/topic/248956-we-are-moving/
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