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michael.h.f.wilkinson

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michael.h.f.wilkinson last won the day on May 22 2018

michael.h.f.wilkinson had the most liked content!

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About michael.h.f.wilkinson

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    Neutron Star

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  • Website URL
    http://www.cs.rug.nl/~michael

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  • Gender
    Male
  • Interests
    Astronomy, computer science, photography, wildlife, cookery, life the universe and everything
  • Location
    Groningen, The Netherlands
  1. michael.h.f.wilkinson

    New EP or just a Barlow?

    Before I had an extensive EP collection, I did use one or two Barlows, including some cheap ones which really degrade image quality. All Barlow designs (whether singlet, doublet or triplet negative lenses) increase eye relief, and can cause vignetting in wide-field EPs. However, the tele-centric design (usually one negative and one positive doublet design) used in TV PowerMates, Meade TeleXtenders, Bresser SA-Barlows, and ES Tele Extenders is such that I do not really see the difference in quality between a Meade 14mm with 2x TeleXtender or at its native focal length. There is no change in eye relief, and I see no vignetting. The image does get 4x dimmer in terms of surface brightness, simply due to the increased magnification. Even a few percent loss in transmission pales in comparison.
  2. I eagerly await their 85.3° range I must say I am slightly intrigued by this range. I have a couple of Vixen SLVs, mainly for travel, and these are really exquisitely sharp and comfortable, holding their own against the mighty Pentax XW line-up I have for home use, in all areas except FOV. I was half expecting this range of ES to go head-to-head with the SLVs, but the eye relief at the short end is not really as long as I would like. They only get 15-16mm which is borderline suitable, and what with the recessed eye lens, taking I would guess a mm or so off, I would struggle. The SLV line has 20mm eye relief throughout, which makes them preferable in my view.
  3. michael.h.f.wilkinson

    Welcome from Sale

    Welcome to SGL!
  4. michael.h.f.wilkinson

    New EP or just a Barlow?

    I personally prefer using different EPs on planets , rather than faffing around with a Barlow (or even the better tele-centrics, like TV PowerMates, or Meade TeleXtenders I have for imaging). My planetary EPs are all par-focal, or have been made so with a suitable ring, and that means that I do not have to refocus when switching magnification, e.g. due to changes in seeing. With a Barlow or tele-centric I need to refocus a lot, which takes up valuable observing time. Of course, the luxury of having a range of planetary EPs comes at a cost, and a Barlow does add flexibility
  5. michael.h.f.wilkinson

    Lunar Eclipse 21st January 19

    I will give it a shot. Clear skies would be the best birthday present
  6. michael.h.f.wilkinson

    Got a break in the seeing last night

    Nice work. Crisp images for just a single shot
  7. michael.h.f.wilkinson

    APT 3.63 - Important Fix

    Thanks! I will probably be using APT for the lunar eclipse (weather permitting), so well before it gets smaller.
  8. michael.h.f.wilkinson

    Exp Sci ED80 Apo Triplet - First Impressions

    Very nice first light report. I must say I love my 80mm F/6 APM triplet. Very versatile and sharp. The views with the 31T5 and 22T4 Naglers are just breathtaking.
  9. michael.h.f.wilkinson

    Hello from North East US

    Welcome from the north of the Netherlands. Looking forward to seeing your scope build
  10. michael.h.f.wilkinson

    Preparing for the upcoming lunar eclipse

    APT stands for AstroPhotography Tool
  11. michael.h.f.wilkinson

    Preparing for the upcoming lunar eclipse

    I plan to use manual control through APT. I aim to use one exposure time for most of the eclipse, switching to a sequence of longer exposure times around totality. I hope to use my C8 with focal reducer, which should fit the entire moon neatly. Alternatively I will use my APM 80mm F/6 with Meade 2x TeleXtender (like powermate)
  12. michael.h.f.wilkinson

    'Scope No. 7 Has Arrived!

    Nice little scope. I have an APM scope which I think has the same optics. Really nice wide-field and DSO imaging scope, also no slouch at solar stuff
  13. michael.h.f.wilkinson

    Histogram in APT for flats

    You could perhaps up the brightness a bit, but beware you don't cause any saturation in any of the channels. A brighter image means a better S/N ratio, but you can always simply take more exposures to compensate. As flats are taken at a short exposure time, that is not much of a pain.
  14. michael.h.f.wilkinson

    What lens is best

    That looks like a type with 900mm focal length (so F/7.9), which would mean an EP around 8mm focal length would be optimal. The ubiquitous Plössl design is good quality-wise, but has a very short eye relief (distance from lens to optimal eye position) at these short focal lengths. This is not a great problem if you don't wear glasses when observing. However, if you need glasses when observing (e.g. due to cylindrical astigmatism), so-called "Planetary" eyepieces are rather more comfortable, and often have a slightly bigger field of view. They are pretty cheap too. The more expensive Vixen SLVs are great, both in terms of eye relief and image quality. Please note that Mars is rather far away at the moment, and will show only as a very small red disk, or perhaps a slight gibbous phase. The above EPs will also serve you well on the moon.
  15. michael.h.f.wilkinson

    January 12, 2019: First lunar image of the year

    Made use of a quick break in the clouds to grab the moon with my Canon EOS 80D and 100-400 mm L zoom. One hundred images stacked in AS!3, converted to luminance and sharpened in ImPPG, sharpened L and non-sharpened RGB combined in FITSwork. Not my best, but good to have some data AT ALL to work with
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