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Everything posted by brianb

  1. And here are my definitive Saturn images for the night. 2011 Apr 08, 0018 - 0022 UT. Celestron CPC 1100, prime focus, Astronomik type 2c colour seperation filters, DMK21 camera. Red channel used for luminance. 150% resize. 2011 Apr 08, 0031 UT. Celestron CPC 1100, prime focus, Astronomik Planet Pro 742 IR pass filter, DMK21 camera. 150% resize. There seems to be something going on in the NTZ....
  2. Not at all bad, you've caught some detail in the NTB - what time was this taken?
  3. If the reflector has rotten optics or the coatings are shot or the collimation is miles out, the little frac might do as well. But really it shouldn't be a contest. Normally a 8" scope will show objects about 1.5 mags fainter than a 4" scope ... irrespective of the type of either.
  4. Not bad last night & at first today but the sky has now whitened with a cirrostratus layer that will kill any chance of observing tonight if it doesn't go away 8-(
  5. Yes ... my kit is just about capable of showing that Titan is not a point but there would be no chance of seeing any of the other moons as anything other than a starlike point & naturally no chance of seeing any detail on Titan.
  6. Managed to get some images of Saturn last night: I have a processing backlog but here's an interesting one. 2011 Apr 08, 0048 UT. CPC1100, prime focus, UV/IR blocking filter, DMK21. Heavily overexposed to show the satellites. Enceladus shows faintly just to the left of the rings. To the right, Tethys, Dione, Rhe and Titan. The faint object directly above the planet is a background star USNO J1253342-024530 mag. 11.85 according to "Starry Night Pro". Stack of 100 from 300 x 1 sec exposures, maximum gain.
  7. You need to reduce the times to your latitude, longitude & altitude ... magazines give a time for some central location, depending on the track of the moon relative to the star this can be out by up to 10 minutes for other locations in the British Isles, indeed in some cases the moon may miss the star completely!
  8. The faint star was HIP 19163 (mag. 7.9) and the bright star that you missed was 37 Tau (mag. 4.3) Don't recall anything odd about the terminator but I haven't yet processed the movies I shot last night.
  9. Venus is being really unccoperative at the moment, next Spring is great but we won't see much of her till about December this year, unless you're prepared to work in full daylight ... & even then Venus is going to be small & close to the sun, so be careful ...
  10. Don't give up ... seeing has been very bad recently due to the unsettled weather. It was a bit better last night, just marginal though. With my C11 I find throwing a towel over the tube to insulate the metal from radiation to space helps reduce tube currents. SCTs can take a l ... o ... n ... g time to cool down, especially when the air is cooling fast as it was last night. I waited till about midnight (UT) when Saturn was about as high as it was going to get before even trying.
  11. Most likely cause of "donut" shaped stars with a reflector (or Mak or SCT) is incorrect focus.
  12. You need to understand the weather patterns .... rapid changes of weather implies the jet stream passing nearby and you have no chance of getting steady seeing.
  13. Look up "Hox genes". Not the whole answer for sure; telomers (apparently unused bits of genetic information) probably also have a considerable influence, as these frequently get changed during replication, usually shortening progressively as the cell "ages".
  14. A 7' by 3.5' "flap" is more than I'd care to try to move against the sort of winds that are usual in these parts ...
  15. A very deep question ... probably the best answer that exists at the moment is that, if they did, there would be nothing to stop cancers - cell aging and death starts almost as soon as embroyological development & seems to be essential to the process of normal development and life of all earthly multicellular organisms.
  16. 1) Drips are going to be in the worst possible place. 2) The aerodynamic loads on a pent roof are upward creating a tendency to open in wind gusts, so drips are not going to be easy to avoid. 3) OTOH gravity acting on a pent roof with hinges at the eaves is going to make it awkward to operate - much more so than a roof which slides off or rotates as a single unit.
  17. The atoms in a white dwarf are "normal", with nuclei seperated by many thousands of times their diameter by electron shells. It's the point at which degeneracy pressure is insufficient to prevent the electrons being squeezed into the nuclei that things get interesting - the whole inside of the resulting neutron star becomes essentially one giant atomic nucleus, with the electrons and protons combining into neutrons. A white dwarf is planet sized, a neutron star with a similar (actually greater) mass is city sized ... the density goes up by a factor of a billion or so as a white dwarf just belo
  18. Because you cannot have negative mass/energy ... gravity is nothing more than a deformation in space/time caused by the existence of mass/energy. The strong and weak nuclear and electromagnetic forces tend to cancel out over cosmological distances, leaving the weakest "force" dominant. It's all rather straightforward & elegant ... the "electric universe" theory is about as believable as the theory that the sun is fuelled by unicorn poo and is simply unnecessary in view of the excellent fit between conventional astrophysics and actual observations on both cosmological and microscopic scales
  19. Except they would think of themselves as being composed of normal matter, our stuff would be antimatter to them.
  20. This depends entirely on the accuracy with which the components are manufactured and aligned (collimated) and the degree to which the tube is allowed to cool to ambient temperature. Maks tend to have very slow cool down times in larger sizes. Maks also have longer focal ratios - typically f/15 whereas SCTs are typically f/10 - making Maks more comfortable with high magnification but struggling to give low power wide field views.
  21. This subject comes up regularly. Clean as infrequently as possible - mirrors shouldn't need attention more often than every couple of years. Get gallons of distilled water before you start, follow the instructions & you'll be OK. Eyepieces - do NOT dismantle for cleaning, they shouldn't need it - lens cleaning fluid works well. Always use a freshly laundered but old cloth, do not wipe twice with the same area of cloth and use a sweeping motion rather than rubbing hard. Excessive cleaning should be avoided, once every month is plenty.
  22. That's not true. The chemical energy in the explosive is turned into heat energy, the resulting hot gas is denser than its surroundings so the gas expands due to the pressure gradient. The energy does not "expand", it just turns from concentrated chemical energy into widely dispersed kinetic energy. But we do - energetic photons can decay into a particle/antiparticle pair just as a particle-antiparticle pair which happen to meet will annihilate each other resulting in an energetic photon. The only "mystery" is why antimatter is apparently so rare compared with matter ... photon decay should,
  23. Indeed. Filters are no magic bullet, remember that they always absorb some of the light you're trying to capture!
  24. Very nice images and a most interesting comparison! Thanks for posting.
  25. I believe you; I hope your bank manager is as understanding
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