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Dave R

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Everything posted by Dave R

  1. WaveSoarer - thanks. bri - good luck with yours. Coco - thanks for the tip.
  2. This is 10 x 30 seconds at ISO 800. 150mm Newtonian on EQ6. Nikon D60 at prime focus. I forgot to take dark frames and flats are beyond my level yet. I used GCX for stacking and the GIMP to adjust curves/levels.
  3. World chess champion Vishy Anand and Grandmaster John Nunn. They're doing a talk at the London Chess Classic on Wednesday.
  4. This isn't a question of views or opinions. It's a question of historical fact. People who deny historical facts are on the fringe, at best. Please explain exactly what you mean by that. The supposed "anomalies" in photographs are simply cases where the reality of photographs taken on the moon does not match the ill-informed expectations of members of the public, usually lead on by con artists like the one you link to below. Jack White deliberately uses dishonest tricks like this and common misconceptions about perspective like this to mislead people. Most, if not all, of these are covered at Clavius or have been dealt with on its forum and/or at the Bad Astronomy and Universe Today forum. If you have any evidence please provide it. And I mean evidence, not the unsubstantiated claims of conspiracy nuts and/or con artists. Begging the question. Before asking what someone's motive might have been, you need to provide some evidence that they have done whatever it is you are accusing them of.
  5. Do you have any reason that isn't dealt with here?
  6. Here's what I use... Sky charts and planning: XEphem. Webcam capture: Qastrocam-g2. Centering planetary images before stacking: Ninox. Stacking: Registax (v4 and v6) running under Wine. Post processing: GIMP.
  7. I've been using a non powered mount for webcam shots for a while. Just got my first powered one a few days ago. I've found that while Registax manages with sequences where the subject drifts across the field of view, it often doesn't work when you combine several runs which cause larger jumps in the position of the subject. You can get around that by centering the subject before you use Registax. There are a few programs that will do that for planets. I've had good results using ninox. For the moon I've not had any decent results using Registax 6 (may well be my fault rather than the program), but Registax 4 has worked for me as long as I stick to a single alignment point. I haven't tried version 5, so you may be better off with that rather than 4. I haven't combined separate runs for the moon. I guess it's possible but I couldn't automate it so I didn't think it was worth the effort.
  8. Here's what Dr Van Allen himself had to say about it... Clavius: Environment - radiation and the van allen belts
  9. It took an image of Copernicus crater. (The Apollo hardware is far too small to be seen by Hubble -- it can resolve down to about 90 meters on the moon.)
  10. You can get them if you turn up the gain, overexposing Jupiter. Then paste a separately processed Jupiter over the overexposed one.
  11. Those are amazingly sharp. Well done! Is it bigger on the inside or what?
  12. These are taken with a 150mm f/5 Newtonian with a 5x powermate, at about 2AM UT, 3rd September. The main image is 30 frames stacked and processed in Registax 6. I don't have a motor drive so I just capture as it drifts across. Levels were adjusted in GIMP. The other one is a composite made in GIMP, capturing the moons without the powermate. From left to right the moons are Ganymede, Io, Callisto and Europa.
  13. This is addressed here (bottom of that post): Also here:
  14. No, all the known forcings are taken into account. Also bear in mind the major uncertainty in that quoted range is future emissions. For a doubling of CO2 the expected global mean temperature rise is 2 to 4.5 degrees with a best estimate of 3. It isn't, as demonstrated above. Solar variation did account for a proportion of the warming in the early part of the 20th century, but not in the second half, as solar activity did not increase during the second half.
  15. Feulner & Rahmstorf 2010 (PDF here) covers this. See also articles on it here (from the previous round of this meme), here (with video debunking the "news" articles about this) and here (blog post by the lead author of the above paper). ----------- From the OP: Yet the only one they quote about that says precisely the opposite: "Even if the predictions [of an extended solar minimum] are correct, the effect of global warming will outstrip the sun’s ability to cool even in the coldest scenario. " ----------- Edit: There is a stronger effect on northern European winters than there is globally, because solar minimum can affect the path of the jet stream: Lockwood et al, 2010: Are cold winters in Europe associated with low solar activity?.
  16. Oops. I mixed up some miles and kilometers there! Not sure if I understand your second point. The idea was to work out the proportional change in speed using p^2 = r^3. Isn't it valid to do that, or did I miss something else? edit: I guess finding the speed change doesn't tell you how different it will look from here as the height has changed too.
  17. Increasing a circular orbit from 200 miles to 240 miles should make it about 150mph (about 1%) slower, so that should give a rough idea of the effect. calculated using: sqrt(((6400 + 200) / (6400 + 240))^3) * 17000 = 16847
  18. There is lots of uninformed opinion on this currently in newspapers and blogs, most being spread deliberately by climate change deniers to deceive the public. There is no truth in the claims that it would cause cooling. (BTW, their claim is that it would increase the amount of cloud). What if the sun got stuck? Feulner & Rahmstorf 2010: On the effect of a new grand minimum of solar activity on the future climate on Earth (PDF!)
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