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Adrian

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About Adrian

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    Proto Star

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    Male
  • Location
    Botley, Hampshire
  1. That's why I finally got round to posting it I also sent them a reply to look here
  2. I've been meaning to post this for a while in case anyone else is looking. My 10" Meade SCT came without a proper end cap, so I wanted to source a replacement, but the Meade versions were extortionate However, my endless Googling led me to the holy grail: a 300mm combined male/female end cap for air conditioning ducting! This cost me less than a tenner and is galvanised. The male part fits the front of the scope perfectly, and the female part just slips over the domed bolt heads behind. I have a spare or two to make a solar filter as well Crappy pics:
  3. Nice work, Yong. I got similar results with a Meade 10" SCT (see this thread), but I didn't go as far as measuring the path length with the different diagonals.
  4. Yup. Job done! So... surely you need a selection of scopes to use that glass in?
  5. I had that scope (See my review) - it was a reasonably decent reflector on a terrible mount (wibbly wobbly ), and only the 20mm Kellner was any use out of the accessories that it came with. to this I added a 32mm Omni Plossl to get the widest possible views, which was an excellent eyepiece. I then found an 8mm Baader Hyperion second hand for under £50 - The 70* FOV and long eye relief was a revelation after the Kellner & Plossl, and by using the optional 14mm and 28mm fine tuning rings, this can also give 6mm 5mm & 4.3mm, giving 113x, 150x, 180x and 209x from the single eyepiece, allowing me to choose the magnification to suit the conditions. The only problem is that, although at F8 the Hyperion was great, when I upgraded to an f5 scope the eyepiece struggled badly and was sold pretty swiftly, so it probably wouldn't be a "forever" eyepiece. It was replaced with an 8mm BST Explorer, if that tells you anything Smaller AFOV, but excellent even in fast scopes, and also very comfortable to use. If you can find second hand ones, an 8mm and a 5mm might squeeze into the budget with a 32mm plossl/25mm BST
  6. In the daytime the light coming through the viewfinder throws the metering off - I forgot to put the shield in place for the transit of Venus so all my pictures were underexposed. Can we go back and do that again, please?
  7. That's my eyepiece now! No more cavorting with tea mugs for that lady
  8. Whilst it pains me to defend Seben, from what I have read it is the Seben reflectors that are expensive doorstops; reviews of eyepieces have been much more positive - possibly because they are rebadged Synta (or similar) gear. Just to be clear, I would NOT advise anyone to even consider purchasing a Seben newtonian. Ever.
  9. Thank goodness for that: From the title I thought you'd dropped it! I intend to never look through a 100 degree eyepiece...ever
  10. Hi Dave I thought it was the 19mm panoptics that are stated as the best for binoviewers (21.3mm field stop per Teleview) - I would expect the 24mms to vignette as the field stop is the maximum in 1.25" at 27mm. The maxbrights seem to be 23mm at the front and 21mm at the eyepiece side, similar to most 1.25" BVs. 20mm x 57.269 / 1905mm = 0.60 degrees true FOV, compared to 0.69 degrees For the actual maximum FOV there are other factors at play - The steepness of the light cone (focal ratio) and how the focal planes line up can match up the narrow part of the cone with the narrow part of the BVs. But generally, if you put a 23mm ring in front of an eyepiece with a 27mm field stop, the ring will act as a smaller field stop and narrow the apparent FOV. This matches my experience: my 24mm maxvision vignettes significantly, the 20mms slightly vignette (like the field stop has gone fuzzy, but only on one side due to slight misalignments of field stops). A 19mm 68* eyepiece wouldn't vignette at all, hence the popularity of the panoptics (and 19mm 65* flat field eyepieces). I am always ready to be wrong, though Adrian
  11. Hi Dave - I think your calculations may be a little off here: a 32mm 60 degree eyepiece is a 2" eyepiece. Likewise, the 26mm super plossl (60 degree) will have a 27.2mm field stop, so is likely to show vignetting in binoviewers. My BVs are around 23mm clear aperture and I get a slight vignetting with the 20mm Maxvisions (approx 23.7mm field stop) and none with the 25mm plossls (approx 22.7mm field stop). The simplest approximation for field stop is (eyepiece focal length x AFOV)/57.296. Conversely 57.296 x 23mm clear aperture gives 1318. Divide this by the focal length eyepiece you want and the max AFOV will be given (or divide by AFOV for max focal length). I find (eyepiece focal length x AFOV) a useful tool - it gives a direct comparison for true FOV between eyepieces of different AFOV; in fact, to find the TFOV, just divide this figure ("focal field"?) by the scope's focal length. From the above, the maximum TFOV with 23mm clear aperture binoviewers would be 1318/1905 = 0.69 degrees. Adrian
  12. Who are you, and what have you done with Gina?
  13. Baader Hyperion clones/redressed? It will be interesting to see if these can handle faster scopes better than the Hyperions, which are great in f8 and f10 scopes but less so in f5, in my experience. Edit: M42 T thread is more useful than the Hyperion threads
  14. The thread: http://stargazerslounge.com/topic/152588-weight-of-skywatcher-skymax-150-pro/
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