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brianb

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Everything posted by brianb

  1. The Introduction to Webb's "Celestial Objects for Common Telescopes" is probably a good source ... Webb being a clergyman it's an expanded and poetic version of "the heavens above declare the glory of God" but, to those of us who lack religious faith, astronomy may be a sort of surrogate. BTW Webb's book - first published over 150 years ago - remains a valuable resource to visual observers with small(ish) telescopes; our understanding of the science may have been altogether transformed in the interim, but the view through the eyepiece remains pretty much the same.
  2. Very nice image! Yeah, like a lot of old myths ... nevertheless a 14" f/10 would probably work better ... as would a 16" f/4.8.
  3. IIRC the Klingons spoke Klingon as well (or Klingonese in an early show). I guess the sound recordist had a Babel fish in his ear ...
  4. I did have one ... the balance issues with a 80mm frac were just about manageable, with anything much heavier there would be a real chance of the whole tripod tipping in some scope positions. The T mounts are far superior in every respect. The SW Skytee 2 (with slow motions) mounted on an HEQ5 or EQ6 type steel pipe leg tripod would be very satisfatory indeed with a ST120 on it (and you could mount a smaller frac or a Mak up to about 125mm as well). Seriously. A rickety mount is the best way to get fed up with a scope. Mount the scope properly - or overmount it - and enjoy using it.
  5. There are thousands of assorted bits of space junk out there ... a slow moving object in the equatorial sky could well be a discarded upper stage from a satellite heading for geosynchronous orbit.
  6. Sorry but I don't think an AZ3 is ever going to work well with an ST120 ... it's OK with a 80mm frac or 90mm Mak but not suitable for anything much bigger IMHO.
  7. 1. We won't be able to pronounce them, or understand what they're talking about. 2. In any case, the names will all have changed many times before the issue needs to be addressed.
  8. Probably not. The image rotation can make mosaicing of lunar images a nightmare though.
  9. Only if it's very vell ventilated ... the Meade LX90 7" Mak (discontinued) was great when it was at ambient but took all winter & half of spring to get near ambient ....
  10. Baader also sell a "IR Pass" filter with the cutoff at 685 nm ... intermediate between an ordinary deep red pass filter and the PP 742. It's actually very deep red to the eye, much darker than the Wratten 29 but the Imaging Source cameras seem to get about the same exposure with the 685 as with the W29.
  11. You need to completely exclude all light shorter in wavelength than 640 nm ... that's a fairly deep red filter, about equivalent to the Wratten #29. Even then keep the intensity as low as possible.
  12. Wow! Great subject, good seeing, excellent scope, great processing ...
  13. Is the object the one which is prominent on the section shown below? (2044 UT Apr 9th) If so I think it's the west (IAU) wall of the crater Scott - but the Virtual Moon Atlas image I'm working from for identification is not great for objects right on the limb.
  14. Same equipment & method as the Apr 07 version. Hazy sky made capture & processing a challenge, and slow boiling didn't help either. 2011 Apr 08, 2028 - 2036 UT. William Optics FLT 110 4.3" f/7 fluorite triplet refractor, Wratten 29 (deep red) filter, 2x Powermate, Imaging Source DMK41 camera. 5 frame mosaic, 24% resize; full size version here. Diameter 30.74 arc min; colongitude 335.2 deg; illumination 23.8%; libration in latitude -00 deg 29 min; libration in longitude -07 deg 19 min; altitude 34 deg. Transparency poor with cirrostratus cloud sheet. Seeing moderate but sharp, with slow large amplitude boiling motion. Temp +09C; wind S force 1-2; baro 1026 mb, falling slowly.
  15. Activity stretched right along the northern tropical zone & was best captured by making a 4 frame strip mosaic: 2011 Apr 08, 1105 - 1110 UT. William Optics FLT 110 4.3" f/7 fluorite triplet refractor, Solarscope SF-100 Ha filter set (single stack), 2x Powermate, Imaging Source DMK41 camera. 27% resize; full size version Celestial north is at the "eleven o'clock" position; the solar axis is tilted because of the tilt of the ecliptic as well as its own offset. Full report with lots more images here.
  16. Yes, well, of course that's safe too, once the (supplied) ND 3.0 filter is installed on the output side of the wedge. You'll probably want some more filtering to be comfortable, the Baader Solar Continuum filter is very good, an ordinary green or deep yellow filter is nearly as good & a lot cheaper. Deep red (Wratten 29) is excellent for imaging with a monochrome camera.
  17. The "emergent beam" of the Lunt wedge doesn't emerge ... it hits a heat sink at the back which gets midly warm to the touch with my WO FLT 110. Older wedges often allow the waste beam to escape the diagonal where it has been known to ignite ties. But no danger to optics.
  18. How much / how far to you have to move it? What objects are you most interested in observing? Do you have power at your site, or are you prepared to buy a decent large capacity deep cycle battery?
  19. More (linear) aperture gives a BRIGHTER image at the same focal length - same shutter speed & f stop (with the same ISO) irrespective of the focal length of the lens. Of course the light is more spread out as the focal length increases but if the aperture increases in proportion (which is what the same focal ratio means) then the image brightness remains constant. (For extended objects)
  20. I like to use a netbook for image capture (for the long battery life) but the processing power is limited for general use & the keyboard & screen aren't good enough either. In fact I've never found a keyboard on any laptop or recent desktop that is anywhere near as good as the 24 year old IBM PS/2 keyboard I'm typing on at the moment.
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