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Everything posted by AlexB67

  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 works like new.
  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 year at a party. ?
  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 develop it further for many years but recently got the courage and time to finish it. I found myself actually using it quite bit and thought, this may actually be quite useful for the community and beginners, both for learning basic concepts in visual astronomy to the more advanced things. To date date it features Magnitude calculator ( extended object visibility calculations a WIP (much more tricky) calculation of various properties. Daw's limit, Magnification exit pupil, to the more obscure things like the diffraction limited field. Database of many known eyepieces and telescopes. Compare two telescopes and eyepiece combination. Spreadsheet feature. Enter your own telescopes and eyepieces. Ocular viewer with a few example objects. Interactive graphs for various telescope properties, with zoom + changing values on the fly (displayed in the graphs in real time via user controls) and more stuff. I was wondering if I can have a volunteer at this point, to just test ( for packaging reasons) that if it will run on another windows machine or if I am missing any dependencies. You do not need to be expert but familiar with basic computer operation. files and folders, how to extract contents from a zip files and just see if it runs. I'll do a proper installer later. Thanks It'll be some time for a proper release, hobbies have no deadlines ?
  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 simple, keep it light, that way I don't need counter weights, the standard focussers in both of my scopes handle that setup well.
  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 gone that high ) seeing will be quite blurry anyway. I never found it useful for planets to get out more detail.
  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 days, and a great eyepiece. I did well to bag it years ago for a decent price, well less than half an XW 10mm new, one day it will be an antique.
  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 find anything above 60 degrees plenty, I am quite used to nudging with a 40 degree ortho, though admit it can get a bit tedious at times.
  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 would not call it neutral, OTOH the 7mm pentax XW in contrast is as if there is nothing in the way ... at all. I don't know what generation optics/coatings mine are. All bought for around £100 , no regrets despite what I said above, great eyepieces that brought me much pleasure. Nothing is perfect ?
  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 ?
  15. The SLV is a strong contender, your are all making a strong case, plus, I like bang per buck views ? I'll let you know when a purchase has been made, but don't let that stop anyone making further suggestions. The only a negative I heard on the FLO website is a claim that the FOV is somewhat narrower than 50 degrees, more like 45, but that's not critical for me. The BGO was 40 degrees, and your eye has to be right up against it to see all of it.
  16. I agree, but there other factors too, I wouldn't say one is an incorrect or correct choice, depending on the situation, and what you want, but I didn't want to bias the OP either way. I think there are pros and cons one can argue for in either direction in a fast scope.
  17. Thanks, I've been eyeing it up, hmmm, perhaps for a bit less 3rd hand even if it is as new. I have bagged pentax XW for less ? I've been out of the latest developments reading reviews for a few years, so I don't know about the latest and greatest. That aside, a new TV delite is almost as expensive as a pentax XW 5mm at FLO. Given the choice I think I'd pick that new, but never tried a Delite. I do have two radians, 6mm and 8mm, as much as I love them for some objects, the so called Radian warmth and weaker throughput is noticeable, reading around, the delite seems to get positive reviews in that regard, and that issue has been addressed. In the shorter focal length however, I am a bit of a pentax fanboy from experience, for various reasons, when all things considered, not just views, but comfort, eyecup design etc. My Delos adjustable eye guard is rather prone to moving around, on one radian I have it is much stiffer. I prefer that, but on the other one it slides more easily. It isn't a big deal, it doesn't bather me during viewing, but outside of that, knowing the position I prefer, it is easy to forget where it was positioned in the dark once it does move. I prefer the Pentax design in that regard, it stays put.
  18. Thanks. I'll have a look, mind you, the SLV is cheap enough, I don't mind. I have a few weeks before I go on holiday to ponder ?
  19. MSammon, congrats on your eyepiece. I'll be interested to hear too. I addressed this in a different way in a scope the same as yours 10 inch F4.7. I have a Maxvision 28mm 68 degrees, this covers the same amount of sky as a ES 24mm 82 degrees ( roughly, top of my head, i think this is correct) . I do not wish to bias your opinion on the pros and cons of each however and see how you get on. I find it interesting that people often pick the wider FOV, as opposed to the net result of a longer focal length eyepiece with smaller FOV showing the same amount of sky.
  20. I just literally just found your review and read it , thanks John, great write up. Sounds promising. With 7 elements I would expect them to behave fairly well edge to edge over that FOV ... I suppose. I think I'll just bite the bullet and give the 5mm a go before I talk myself into another pentax XW 5mm. ?
  21. Hello dear people My BGO orthoscopic 5mm died some time ago, I am now looking for a replacement for use with my two Dobs in my signature below, I do not need a particularly wide FOV, something that offers similar levels of contrast and throughput, the nearest multi element eyepieces I have that always come to mind for such qualities are my pentaxes XW/XL, though I am happy with a smaller FOV in this case. I have never owned anything by Vixen, for around the GBP 100 mark I can get the 5mm SLV, I tend to use a 5mm a lot in my smaller Dob, the Heritage 130p, but also in the bigger brother occasionally. The 130p does not take heavy eyepieces very well, with that in mind the SLV may well tick all the boxes ... I suspect. Any opinions on the SLVs ? how do they compete with the XWs (except for the smaller FOV) ? what about the edge to edge performance in faster F ratio scopes such as mine, F4.7 and F5. As nice as the BGO has been, I fancy a change from looking through a tiny hole ? I used it so much, so I would like something a bit more luxurious this time. Who knows, I may still get another orthoscopic at some point for the company, not sure I can live without one for that manly experience ? Any other suggestions are welcome, I only just started looking and the 5mm Vixen SLV came to mind. Thanks in advance.
  22. The problem is once you know about them and see them, they'll they never go away ? thanks to my friendly F4.7 ratio. Years ago I dabbled with the idea of coma corrector, I never did, Edge to edge my Delos 14mm is still very decent in that telescope. Once you look through an eyepiece where astigmatism is pretty much eliminated and the remainder is coma, it is not at all bad IMO, I can live with it. I did stay away from the extra wide angle eyepieces. The Delos 72 degree is the max FOV eyepiece I have. I stopped collecting for many years now, but now on the lookout for a 5mm to replace my dead 5mm BGO, but that's for another thread, Neil, congrats on your plossl, I looked through a 25mm TV in Ireland last year under cracking dark skies, very nice. I never owned one.
  23. Nice. Mine is still going strong. Over the years it got more use than my 10 inch. I got some really good planetary views with it too , it got to another level when I added an orthoscopic, like my 5mm BGO instead of something like a multi element 5mm BST, I was able to eek out some extra contrast on Jupiter, and Saturn in particular it really helped. The focuser does not take too kindly to big heavy whoppers without going off-axis mind. My 14mm Delos is a good example, with large star clusters it is easily noticeable, my only long term objection. One of the nicest views for the money I enjoy would be something like M81,M82 in the same field of view, such as a 25mm. To get the same field of view in my 10 inch Dob comes with a hefty price tag !
  24. Soon after I got my Flextube Dobsonian, I took it out, but forgot to remove the lid from the lower part of the tube while it was cooling, it was so dark by then, I couldn't figure out why I wasn't getting any views looking through the eyepiece. I'll just leave out the bit how long it took me to realise the fact ?
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