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About cloudsweeper

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    Sub Dwarf
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    Physics, maths, history (family, military, social), architecture.
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    Merseyside, England

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  1. A good read - sounds like you really enjoyed yourself! Doug.
  2. Thanks! I meant all aberrations/distortions, so that's everything covered! Bottom line - these effects are not constant, but manifest differently in different EPs in different 'scopes. Thanks again, Doug.
  3. Thanks John and Louis. I'm referring to all distortions - p/c, barrel, FC, coma, astigmatism....and was wondering if they are remain the same for a given EP when it is used at different mags. I guessed those distortions would be the same (effect the same amount/region of what you see) when the mag is higher in a longer FL 'scope. Do you reckon I'm right, or is there some effect I've failed to account for? Doug.
  4. Blessed (or sometimes a tad cursed) with en enquiring mind, I was wondering - EoFD is, I gather, greater in wide angle EPs. But what about in a given EP at higher magnification ? You're still looking at the same image area through the EP, although it represents a smaller area of sky. So is edge distortion the same as at lower mags? I would guess so, but what do others think? Doug.
  5. I'll second that. Absolutely hypnotic! Doug.
  6. Thanks! Yes - apparently these planetaries blink because in DV the central star obscures the nebula, but in AV it can be seen, so the brightness fluctuates as the eye/vision shifts. Doug.
  7. Re-visiting is something we all do a lot of! A good, economical guide to many attractions up there is Sky & Telescope's Pocket Sky Atlas. Quality item, with great presentation. And although a lot of objects are out of reach without a big aperture or dark skies, there is still plenty to enjoy! Doug.
  8. Large, faint nebulae can be difficult, so take a look at The Pleaides (M45) - the main stars Alcyone, Merope, Maia, and Electra will have a "glow" around them which is not scatter due to the optics, but is actually nebulosity. Very nice! Doug.
  9. I recycle mine as pyjama tops, except for a black one which I use as a hood when I'm at a 'scope. Very effective! Doug.
  10. Fair enough Gus! It does have its advantages I suppose, and I've found that focusing is better done at the high mag end of the scale. Doug.
  11. I bought a zoom when I already have a wide range of (mostly decent) EPs. Does that count? Doug.
  12. Thanks Andrew - Yes - I'd overlooked the fact that gravitational waves (alternatively viewed as gravitons) travel at c. Doug.
  13. The only thing that can move at the speed of light is, well, light (electromagnetic radiation). So time effectively stops for a photon - a clock on a photon would not tick - and if you could "ride a photon" (how cool would that be), you would make a journey from a distant galaxy to Earth instantaneously. There is no passage of time, and distance is contracted to zero. (In that frame of reference.) Doug.
  14. 5 - 1 ........ doesn't sound much like fun (for the losers). But Yes - the real stars every time! Doug.
  15. Don't know what specs would be needed for PHD. All I can say is I recently got an HP Pavilion 15.6" specifically to run Stellarium in the shed when I'm observing, and it handles it (and everything else I use it for) a treat. Doug.