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About chiltonstar

  • Rank
    Brown Dwarf

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  • Gender
  • Interests
    Wildlife photography + astronomy of course
  • Location
    Wessex/N. Berkshire Downs
  1. chiltonstar

    The gift of excellent transparency

    Superb report! Roll on more nights with excellent transparency..... Chris
  2. It is a superb sight. The orange of Mars near to the iris blue of Neptune. Watching for half an hour, it is amazing how fast it nips past Mars. Chris
  3. chiltonstar

    Splitting the Trapezium

    I was thinking of the Mak Newt which is only 190mm and has (presumably) a 52mm or so secondary? Chris
  4. chiltonstar

    Splitting the Trapezium

    What is the obstruction with a 2 inch focuser John? More than this surely? Chris
  5. chiltonstar

    Splitting the Trapezium

    Not typical, I agree, but I took the worst case to make the graphic obvious. Chris
  6. chiltonstar

    Splitting the Trapezium

    My ED80 has managed it on two occasions. Chris
  7. chiltonstar

    Splitting the Trapezium

    The point about refractors is that they have no central obstruction, which makes the view "cleaner" and with better contrast. The greater the % obstruction, the more contrast is lost. Newtonians (dobs), SCTs and Maks all have this problem to a greater or lesser extent. This computer simulation shows the effect well, illustrated using a 150mm f7.5 refractor or 150mm f7.5 newtonian on the same double star pair:- With an "obstructed" scope, more light goes in to the first diffraction ring than with a refractor (although it does mean the central Airy disk is slightly smaller and less intense). Chris
  8. chiltonstar

    Meade 65mm 2" EP

    Maybe she could knit you some socks, and a nice woolly insulating cover for the Mak! Good luck with the EP.....worth trying on 46P. Chris
  9. chiltonstar

    Meade 65mm 2" EP

    I tried tonight wearing glasses. Almost impossible to see the field stop I would say! Definitel a problem unless you have a lens cut and inserted in the rubber cup. I tried the scope/EP combination tonight on some different targets - M81, M82 very bright and space all around in the FoV. Comet 46P Wirtanen a treat also! Chris
  10. chiltonstar

    Meade 65mm 2" EP

    Against a dark sky, it wasn't obvious (to me); against something as bright as the Orion nebula, again it wasn't obvious, whereas on a patch of sky towards the East which was brightened by the rising Moon and was slightly hazy, I could see the shadow with averted vision. Different folks eyes are different I imagine, and mine are very well-used! I can certainly see the field stop with the rubber cup in position, and lightly touching/pressing on it, but next time the sky gods bless us with a clear night, I'll try with some specs I use for night driving. If my example is typical, I wouldn't describe the "eye lens" as recessed. Chris
  11. chiltonstar

    Meade 65mm 2" EP

    I'm not completely sure. The top of the EP is a ca. 50mm diameter flat metal flange, with a lens (flat) set in it, 25mm in diameter. The soft rubber cup stands about 10mm high. For me, I can reach focus ok even above the rubber cup, so I imagine a glasses-wearer should (probably) be fine. Chris
  12. chiltonstar

    Meade 65mm 2" EP

    Well, at least the socks would be usefull for Winter observing! I hope that the Mak repair/upgrade is a success. Chris
  13. chiltonstar

    Meade 65mm 2" EP

    I put theory into practice last night after the rain stopped, giving me an hour before the moon came up. It works! I measured the real field of view at about 1.2 degrees, which gets both Sigma Orionis and Alnitak nicely into the same field, with a little to spare. Several brief glimpses of the HH, although it was not really the night for it, and a stunning view of the Pleiades. The Orion Nebula - the BatWing - was equally impressive - much brighter than I'm used to. The apparent field of view is quite a bit wider than my 40mm Plossl, and the actual FoV considerably more. It is a little awkward to use - the eye has to be positioned correctly, and for me pressing lightly down on the rubber eyepiece cup for best viewing comfort. Against a light sky background, the shadow of the secondary is visible although not a major problem. The calculated exit pupil is 3.7mm - a lot more than I can get with my next longest focal length EP (40mm). Chris
  14. chiltonstar

    Meade 65mm 2" EP

    My b'day fairy has already arrived early (this am), so now all I need is some clear sky........ Chris
  15. ....also worth looking at the threads on insulating a Mak. It certainly worked in my case, and as well as virtually eliminating the cool-down time issue (was never a huge issue for me though), it keeps the front corrector dew free for a lot longer. Chris

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