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NGC 1502

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Everything posted by NGC 1502

  1. There’s no doubt that a good 4” refractor gives lovely views with stars as tight points of light. But if you want to see globular clusters looking like a ball of stars rather than a fuzzy patch then a larger reflector gets the job done at a fraction of the price. The old “horses for courses” applies. Ed.
  2. Good advice already given. You’ve also mentioned the 24mm Panoptic you already have. It’s a super lightweight well corrected eyepiece. The listed eyerelief is 15mm, same as the Ethos. If you’re ok with 15mm then that could help your decision. Many would be fine with a 24 Pan for low power. However as is often mentioned, TeleVue measure the eyerelief from the glass which is technically correct but doesn’t take into account the fact that the lens elements are not flush with the upper parts of the eyepiece including the rubber eyeguard. That reduces the eyerelief from the technically correct to the more useful available eyerelief. Ed.
  3. As you already have the 12mm and 5mm BSTs if it were me I’d fill the gap with the 8mm BST. The Vixen 8mm is a good eyepiece but I think you’d miss the wider field and good eyerelief of the BSTs. I’m blown away by the price and decent performance of the BSTs.
  4. Excellent Alan, what a privilege Please don’t worry, we won’t ask you to “spill the beans”. But just watch out for bright lights and rubber cosh next time at a dark site Cheers from Ed.
  5. Most of us on SGL know exactly which dealer is being discussed. A while back I had a load of astro kit to sell and considered my options. Having tried to sell individual items previously and found it hard work, the need to hang around waiting for folks to decide, then individually packing and posting, I decided to sell the whole lot to the dealer under discussion. I worked out my price, contacted him, price accepted without haggle, sent one parcel, was paid promptly. I suppose I could have got more money if I’d been prepared to wait and put lots of time and hassle into it. But being busy even though retired I took the best option for me. I’ve also bought items from this dealer. Items were accurately described, any faults disclosed. promptly posted, and the prices whilst being at the top of acceptable, I personally consider a good deal, taking everything into account. However I do accept it’s galling when prices are clearly OTT, however if that’s the case then don’t buy it. Ed.
  6. Reading the above some love EQ mounts, some an Alt-az. When I bought my first scope in 1979, an Alt-az was regarded as very second class, a beginners’ mount if you couldn’t afford an EQ. Thankfully times have changed and the Alt-az is preferred by many including myself. If any new folks are reading this, please don’t take it that the EQ mount is not worth having. For many, EQ is the way to go, it’s simply a case of finding out what suits YOU, not someone else. Ed.
  7. Great video from Ed Ting. There’s of course so many factors to consider that will point to what’s best for us. These factors can easily change as time passes, I’ve listed few of these - Age and physical ability. Of course finances. Low tech to high tech, or the reverse if the technology is a pain in the derrière. The shift from observing to imaging or the reverse. Where we live. Who we live with. Local light pollution. The realisation that we have accumulated so much kit that rarely gets used, so declutter, sell off most of it and simplify your astronomy for the better. So much more….. Ed (not Ting)
  8. Indeed many of us have sold stuff then regretted it……. …..…like when I stupidly sold my wonderful AstroSystems 8.5”
  9. I’ve found the 5mm BST works quite well in my 10” f.4.8 Dob. It’s certainly not premium but neither is the price!! I have a set of TV Radians, they’re definitely better especially towards the edge of field. But with the BSTs, if you don’t mind extra nudging to avoid the edges I personally think they’re very good. If you also take into account the very low price of the BSTs they are excellent But you may find that in your 300p the previously recommended 8mm BST gives a high enough top magnification. Ed.
  10. Indeed that’s correct and is well worth mentioning. Having said that it can depend on what the scope will be used for. If it’s for faint galaxy hunting then a large thin mirror could rest on heavy duty bubble wrap. Hardly good enough for general use but ok for faint fuzzies. Sometimes called a “light bucket”. Ed.
  11. The primary cell on my 10” f4.8 Orion Optics Dob is also the earlier basic 3 point. And yet with such a basic support I get excellent views. I’ve always thought that Jupiter is a good test of optical quality. In decent conditions details in Jupiter’s cloud belts are a joy to see, the GRS is obvious, moon and shadow transits crisp. It does make me wonder if the later multi point cell design is really necessary. I don’t go entirely on theory, just judge by the results. Ed.
  12. Hi Stu. Indeed mirror movement can affect collimation. I feel certain you’re aware that mirrors must never be clamped in place. But I feel that can be taken too far, for instance with regard to clearance between the optical surface and restraining clips I’ve often seen “credit card thickness”. Whilst I appreciate that the intention is not to clamp the mirror, the thickness of a credit card is enormous with regard to that purpose. Perhaps the thickness of writing paper is more appropriate. Another factor is radial support. Large mirrors are often held in a sling, but somewhere around 12” diameter or smaller (in other words that’s the majority) most have radial support at each mirror clip. Again the radial supports only need a smidge clearance to avoid clamping. All of the above means that mirrors are held without clamping, but avoiding too much clearance that allows mirrors to shift, thus losing our carefully tuned collimation. Ed.
  13. From your description you have a multi point mirror cell with triangular supports, each triangular support having 3 contact points using cork pads. You’ve mentioned using double sided tape on the cork pads. You can obtain double sided sticky foam tape much thicker than the regular tape. I’ve used that to good effect by not using cork pads but instead two thicknesses of sticky foam to make a thicker pad. This supports the mirror without introducing stress on the glass but holds the mirror with less chance of it shifting around and messing up collimation especially when transporting the scope. I buy better quality outdoor foam tape rather than from Poundland or similar. If it were me, I’d dismantle the mirror and cell to investigate. Remove all bolts and run a thread cutting tap through each hole to ensure a clean easy running movement without any snagging. Do similar with all bolts using a thread cutting die. When assembling thoroughly clean the threads and use a very small amount of grease on the threads to ensure smooth snag free movement. As already suggested get some strong springs. Many collimation springs I’ve come across have been too weak. If you can compress them at all with your fingers then they’re useless. Collimation springs can be checked for adequacy before using, it should only be possible to compress them in a vice. If the collimation springs are strong enough then locking bolts can often be dispensed with, or alternatively used just tighter than by hand to give a bit of extra support to hold collimation better. My first scope was bought second hand in 1979. I quickly learned to hate those pesky locking bolts for the same reasons you’ve mentioned. Hope you sort it, Ed.
  14. Good thoughts. I’d go 25/12/8/5 myself…….but there’s so many ways to do this…….I’ve had a scope since 1979. Over the years I’ve swapped eyepieces and changed my mind so many times. It’s easy to get hung up over minute details about eyepieces and forget the magnificence of the universe we see through our eyepieces and scopes. Fussing over our equipment can rob us of the joy of……looking Ed.
  15. Of course, it’s your call. But if you have the 25mm BST, then for me the 18mm would be too close in magnification. I’d go for the 12 or 15. I prefer a larger jump from low to medium power, then closer with increasing power. As always, your mileage may vary….. Ed.
  16. Try ENS Optical Birmingham. An email may turn up something not shown in their online listings. Hope you sort it, Ed.
  17. Hmm…..so is that a Smyth lens? If it is I may be mistaken in saying the 18mm BST doesn’t have one. It’s certainly less corrected off axis than the 12mm. The 12mm definitely does have a Smyth lens within the chrome barrel.
  18. Many thanks, that’s interesting. I’ve just carefully rechecked my 18mm BST, no Smyth lens in the chrome barrel. The field stop is separate. I bought it very recently from someone who purchased it new 3 months ago. Perhaps the optical design has changed, the BST/Paradigm range has been in production for years. Considering the amazing low retail price with a discount for multiple purchase, the factory price must be incredibly low. Ed.
  19. Hi all. Could anyone let me know if the 15mm BST Starguider has a Smyth lens within the chrome barrel? (Smyth lens - extra lenses). I know the 12mm BST does have a Smyth lens, and the 18mm does not. Thanks in advance, Ed.
  20. For those focal ratios I think you should be fine. To get significantly better than Hyperions you have to pay much more. It’s always a tough call giving advice, some folk are very picky (nothing wrong with that, it’s their hard earned money) others might say - they may not be perfect but they’re good enough for me. Even top dollar eyepieces get criticised ! All the best in your choice, Ed.
  21. I think you’ll find that those that have actually used a 17mm Hyperion hold it in high regard. The Hyperions often get criticised especially when used in telescopes of f6 or below. But a member of my local club who looks after our club’s 16” f4.3 Dob owns the 17mm Hyperion. When I’ve tried it in that scope I found it excellent with good sharpness towards edge of field. I’ve also used that EP at f8 and it was excellent. With long eyerelief and 68 degree field and (relatively) low price I’d thoroughly recommend it. I’ve briefly tried the 8mm and 5mm Hyperions in my 10” f4.8 Dob (without a coma corrector) and although they didn’t match the correction of the 17mm they seemed to me to be better than their reputation. Best regards from the UK, Ed.
  22. Thanks for that, didn’t realise that the accurate timing of Jupiter’s moon events was part of solving the Longitude problem. Somewhere in my book collection I have Dava Sobel’s book, I must dig that out sometime and reacquaint myself with the fascinating history. Ed.
  23. Indeed a 14” Dob will give cracking views, especially under a good sky. If you calculate the mirror area it’s double the light grasp of my 10”. However when I borrowed my club’s 12” Meade Lightbridge Dob I found it was massively heavier than my OO 10”. When I took the Meade to my clubs dark site it was significantly more hassle. The assembled tube was too long to fit across the back seat of my car. Of course a truss tube comes apart, even then the primary mirror section was way heavier than expected, and the Dob mount far larger and heavier too. On arrival at the dark site it took a while to assemble, fit the necessary shroud, and collimate. My 10” is way less heavy and the one piece tube much more convenient. The relatively light aluminium mount comes out of the boot, tube out of the car, onto the mount, in under a minute. I’m definitely and absolutely not knocking big Dobs, I’ve had stunning views from my clubs 16” and a members 20”. Maybe I’m getting lazy but for me convenience trumps hassle. As is often said, your mileage may vary Ed.
  24. I had a great view from Essex using my 10” Dob at 150x. It was fascinating to watch Io creeping ever closer to Jupiter’s limb, then becoming a bright dot on the disk. I followed it for over 10 minutes until it became lost in the glare of its parent planet. I then watched as the shadow started as a notch in the limb and became an inky black dot. It was Danish astronomer Ole Roemer who in 1676 became the first person to measure the speed of light by accurately timing these events. I can only marvel at his intellect, no computer to crunch the numbers. Something for us all, observer imager or armchair astronomer. Ed.
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