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AlexB67 last won the day on October 4 2013

AlexB67 had the most liked content!

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About AlexB67

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    Bristol UK

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  1. I still got me old Pentax XL 10.5mm, the predecessor of the XW 10mm but got at about half price years ago, it was my first high end ep. I still love it, I vouch for Pentax, the few eyepieces that remind me of ortho likes views but with wider views, comfort and eye relief to boot. It took me a couple of nights to get the adjustment right, but then I never looked back. Keep an eye out on the second hand market, You never know, but I expect XLs may be relics by now, and more likely to score an XW. If you are like me I get a kick out of buying something used at half price when it still wor
  2. Congrats, Looks like a very nice scope. the weight of it is even significantly less then my 10 inch Skywatcher Flextube ?. Even got the curved spider vanes design, nice thought, and a friendly F ratio. My only deterrent would be the assembly time if you have to do that each time, taking it out of the house, or fitting it in car. The main reason l love the flextube design is for travel in a small car , yet it is very quick to setup each time. The tube is build like a tank too which make it quite heavy, but you'll not dent it .... unlike the much more expensive Orion UK Dobs I saw last y
  3. Years ago I set out to write a little project learning a little C++ and Qt, coming from a fortran C background already, not a pro developer, but just in the sciences mainly, it was around the same time I got heavily into visual astronomy. As time went by I often saw the same questions asked, about calculating magnification, exit pupils and more advanced things. I Discovered along the way there were several websites aound calculating this, that or the other. which inspired me to put it all in a little calculator application, which kept growing over the years. I then left it and did not devel
  4. Personally I am happy with the smaller FOV, the widest I have is 72 degrees, and I have one 2 inch 68 degree Maxvision which I have used a lot (more at darker sites). My policy has been to optimise transmission and FOV and avoid big towers and barlows with extra optical elements and an overall heavy kit . In my case my decision was also driven by having a good quality performance across the entire FOV. At f4.7 I would really want a coma corrector for the ultra wide 2 inch eyepieces to do them justice , and that is extra baggage I rather live without. My mantra has been to keep it simp
  5. Starting out, I would pick my eyepieces first of all for the scope I use for serious viewing, not the most used scope. While it's true I have used my small 5 inch Dob more than the bigger 10 inch over the years , it has been totally worth it to optimise my set around the bigger scope first of all. The smaller scope has mostly been a secondary consideration in my choice. It is often said that 3 magnifications for each scope will go a long way, something in the range of high, medium and low power, I think there is a lot of truth in that.
  6. I recall this video from way back touching on the subject. I'll leave it to the cosmologist to elaborate. To me it seems to ask some more questions that leaves me scratching my head, but it is an interesting gedanken-experiment nonetheless.
  7. What I can say from experience that there is an observable difference with the 8mm BST I had versus a well corrected eyepiece such a TV Radian in my F4.7 scope, but you need good conditions to really find out, which I did few years ago. Back then Jupiter was high up in the sky, I used to do 2 - 4 hour marathons on that object alone. I could see the image degrade gradually. My viewing habit was to use around 2/3 of the view, then I would nudge the scope to get the best out of it. Also, IMO, as John said, it becomes a lottery anyway at that magnification.
  8. It depends if you are happy keeping away from the edges. In my experience with 8mm and 25mm. I only had the 5mm for a while years ago, but gave it away. They are not sharp over all the field at f4.7 , but it has been a while since I used them. Other than they give pleasant views IMO. From memory I also recall some field curvature resulting in out of focus stars the closer you got to the edges , perhaps the 25mm mainly. Sorry I can't help more since I am a bit vague on them at this stage. Note, I am a bit picky about aberrations, however at such high magnification ( I have never
  9. I am trying to focus. One thing I remember the lounge was very good is offering another 10 million options just at the point when a choice has been made, and also stretching your wallet, but then I did ask for it. ? but reading reviews is always fun.
  10. It had an encounter with an oily puddle (which had some nasty additives I guess) it wasn't the same after that even with cleaning, RIP ?. First accident I had with any eyepiece, hopefully last. Robin thanks, another distraction ?. I think I have made up my mind more or less ... F15 rules , it may have been you I bought it from coming to think of it ... small world. btw I love what they have done with the forum, kudos to those looking after it. I didn't post for many a year but never stopped stargazing. The forum seems a much quieter place now from what I remember.
  11. I had a chat with my telescope. My telescope says you only live once so buy what you want. I must say I enjoy the 60 degree FOV of my Radian and how it holds up across the field, The delite is a now stronger contender. I am sure if it is anything like my Delos optically, I suspect it is, it will indeed be a delite ? and I can pay homage to my long standing avatar. I am also fishing for a second hand 5mm Pentax XW if I can find one. In my heart I know anything TV or Pentax I bought to date so far, I will never sell. I am most proud of my Pentax XL 10.5mm since it a bit of rarity these d
  12. Now that the cat is out of the bag so to speak I will elaborate a bit in addition to the great post above. My other main reason for not using wide angle eyepieces is coma. For me if I went much wider than 70 degrees I would find it really bothersome, I don't mean it's like an on/off switch with a hard value of course, but it gets worse the further off-center you go. I would really want a coma corrector for the ultra wide angle eyepieces in an f4.7 scope, it is extra gear I rather avoid, I am happy with the smaller views anyways, as long as they good are sharp. For planetary viewing I
  13. I had great views of faint planetary nebulae with the 6mm Radian where I thought it might struggle, it is a strange beast in some respects, The edge to edge views are superb as with all TVs. In my experience, which is not nearly as great as yours of course, When I compared my 8mm radian on m57, even the 8mm BST has a tiny bit more pop, as well as stars. doubles etc. On jupiter, it is almost as if there is a subtle filter, for that particular application I really love it, I think it also depends on wavelength, so result vary. I even did a little review here way back. In any case, I wou
  14. I am an idiot, I never realised that it could be locked into place, I forgot about it over time. In fact, I just took it out and indeed confirmed it can be very solidly locked into place via rotation. I always had in a semi stiff position and used it like that just sliding into position ever since and forgot over the years ? My score for that mechanism has now gone up tenfold. It never prevented great views mind. If the like button had a double trophy I would give it to you. I think the delites are designed like this too correct ?
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