Jump to content

548140465_Animationchallenge.jpg.32379dfa6f3bf4bba537689690df680e.jpg

Andrew_B

Members
  • Posts

    265
  • Joined

  • Last visited

Everything posted by Andrew_B

  1. Either that or overcome his fear of becoming a werewolf.
  2. I've also found that reading those websites seems to lead to a sudden influx of Taks and a reduction in one's bank balance! Those are some beautiful scopes and thanks for writing such a good summary of this remarkably capable and flexible system. My setup is pretty similar to your and I think I might have the same or nearly same Manfrotto fluid head as in your first pic. I started off with an FC-76DCU plus extender but it was built from parts and due to use a Feather Touch focuser. That's still on back order and I couldn't cope with having most of a telescope and not being able to use it so when I saw an ex-demo FS-60CB on FLO I couldn't resist its allure. I keep it set up permanently either on a tripod like yours or it sits in its clamshell and dovetail on a shelf in a little bookcase that's now become my shrine to Takahashi. I love every configuration and they all have their strengths such as the peerless high magnification performance of the FC-76 in Q-mode or the cuteness of the FS-60CB which never ceases to put a smile on my face with the views it gives. The FS-60Q makes the perfect spotting scope with the Baader Hyperion Mk IV zoom with its very useful 25-75x magnification range and the regular DCU is a brilliant and compact grab and go for the Moon and planets. When the focuser arrives I'll be able to keep the FC-76DCU set up permanently but I'll still be left with an empty shelf on the bookcase. That FC-100DC is looking awfully tempting!
  3. Totally agree, and I should have made it clear that I was talking about designs preferred for very large optics that are far beyond the budget of any amateur that are used for space telescopes and the latest observatory-class instruments. The great thing about a Newtonian is that your budget only needs to pay for a single large, curved mirror so you should be able to get more aperture and better quality for the money than with any other design. One of the more interesting concepts I've seen is unobstructed reflectors based on three-mirror designs which could have incredible performance but the need for asymmetric optics would presumably make them expensive and keep them out of the amateur market for a while yet.
  4. I should have qualified that by high end I mean the kind of optics used in spy satellites and state-of-the telescopes like the ELT. I don't know if there's any three-mirror designs (three curved mirrors, not just a Nasmyth-Cassegrain) on sale aimed at the amateur market. If you're an amateur and especially one who's interested in visual observing then you'd be hard pressed to beat a good Newtonian.
  5. Newtonians have their advantages but there's a reason that two, and increasingly three-mirror designs are the standard at the high end. More mirrors allow you to have greater correction across the entire field but they obviously cost more to make and collimation is more of an issue.
  6. My guess would be that it's residue from using the wrong cleaner, a lens cloth that wasn't clean or that it hasn't been cleaned enough to completely remove whatever was on it. The hard coating for those fluorite lenses is apparently much harder than you would expect so it's not that easy to damage.
  7. What's the padding like in those Geoptik cases? The smaller version seems like it could be a reasonable choice for my FC-76DCU but I've never seen any pictures of the inside showing the thickness of the padding.
  8. That is a really nicely made dovetail but it is a little bit narrower than some others (41mm) which can be an issue with some clamps and saddles - ADM's Vixen-type dovetail adaptor for the AZ GTi comes to mind. Worth checking the minimum width in advance.
  9. Don't forget that you also need to keep it in an atmosphere that's been completely purged of oxygen and water vapour to prevent mould and bacterial growth inside the lens cell. It's a wonder any of these pieces of junk work at all.
  10. Thanks Jeremy. I've now had the chance to give it a quick go in my little FS-60CB to look at some terrestrial targets and yet again the ortho has been impressive. It's super sharp and seems to get that little bit extra resolution and contrast out of the scope that I don't remember seeing before (although I should do a proper side by side comparison). That sharpness extends right to the edge of the FOV and distortion is non-existent, and in combination with the shallow DOF of the baby Tak it gives that perfect snap into focus that's a sign of good optics.
  11. Modern doublets can be so good that for visual use you might not see any difference compared to a triplet. They also cool down faster, weigh less, and tend to be a bit easier to mount and balance due to being less lens-heavy which also makes them a better fit for a grab-and-go scope. If your budget can stretch to a 4" apo then I think you'd really enjoy it and it would make a great companion to your dob.
  12. Thanks to Japanese efficiency, my 6mm Fujiyama ortho which had only left the factory on the 23rd and was dispatched from Kyoto on the 24th, arrived just after lunch on Monday and by some sort of miracle there was a long enough spell of clear skies for it to see first light a few hours ago. I tried it with the following configurations of my little Tak: FS-60Q - 60mm aperture, 600mm focal length (f10) FC-76DCU - 76mm aperture, 570mm focal length (f7.5) FC-76Q - 76mm aperture, 954mm focal length (f12.6) I was able to view Jupiter and Saturn with the first two and the Moon with the latter using the 6mm ortho to give magnifications of 100x, 95x, and 159x respectively. Seeing was okay to begin with but worsened significantly towards midnight and I had clouds and reducing transparency to contend with as the night wore on. Despite this the little eyepiece delivered impressively sharp views of all targets with plenty of detail visible in Jupiter's atmosphere and the moons rendered more clearly as tiny disks than I've seen with any other eyepiece so far (BST 8mm, Nirvana 4mm, Hyperion Mk IV Zoom with and without 2.25x Barlow). Saturn was very low but some banding was visible and the shadow of the planet on the rings was surprisingly crisp in moments of better seeing. Unfortunately the Cassini Division was much harder to spot and far from clear when it was visible, but this was obviously the result of the planet's position in the sky rather than any shortcomings in the eyepiece. It was too windy to bother with the longer FC-76Q outside but I set it up looking out of a bedroom window to observe the rising Moon around midnight. Seeing had deteriorated significantly and being indoors won't have helped, with the view of the Moon being obviously affected by the turbulent atmosphere even at just 27x magnification using a 36mm PlΓΆssl. Upping the mag to 159x using the 6mm ortho I was pleasantly surprised by the brief but absolutely razor sharp views it gave me during moments of better seeing that suggested both scope and eyepiece had plenty more to give. Unfortunately the appearance of fairly thick haze meant that this wasn't going to be the night to explore those limits. To summarise if you don't mind the relatively narrow FOV (not an issue for planetary observing IMHO) and the contact lens-like eye relief then the little Fujiyama will deliver remarkable views in a tiny and lightweight package that's the perfect match for a small refractor or other lightweight grab-and-go scope. The price is a step up from budget eyepieces but I think it represents very good value for money given how well it performs, and I'm keen to try out some of their longer focal length orthos when funds permit.
  13. I thought the big boys had moved on to 16" and upwards RCs, CDKs, and weird astrographs with ultra-fast focal ratios and unpronounceable names! SCTs seem to be positively old hat at the high end of the "amateur" market. Some of the imaging gear being used by hobbyists these days wouldn't be out of place in many smaller professional observatories. To answer Fedele's question, I'm not sure the jump from 180mm to 210mm would be enough to justify the effort and expense. You're talking about an improvement in resolving power of less than 17% which I doubt you'd notice, and an increase in light grasp of 36% which again isn't that much.
  14. I have the same diagonal (assuming it's the 1.25" version) and it's got a relatively long optical path compared to the prism I'm currently using with my new scope. I haven't been able to find the figure for the optical length of that particular model, but a similar looking one from Astro-Tech apparently has a 94mm path length. What that means is that without the diagonal in place and with the focuser at the same position, you would need to add 94mm of extension to allow your existing eyepieces to reach focus.
  15. The thing about the Mewlon 180 design is that although you get 6 spikes instead of the usual 4, they'll be fainter than you'd see from a conventional spider. I'm surprised nobody's offered an unobstructed Cassegrain or three-mirror design given their advantages and appeal to the discerning amateur but perhaps they're too hard to design and make for anything other than very high-end gear.
  16. I've ordered a 6mm Fujiyama which should arrive this week so no doubt the weather will be terrible! I found that for high magnification planetary observing I don't particularly like wide fields or lots of eye relief so it'll be interesting to see how I get along with this and the 6mm focal length should be a good fit for my gear.
  17. I've got that and it works well. The Double Double was a surprisingly easy split with the Nirvana in my little FS-60CB at 89x. The only negative point is that I sometimes find it harder to get my eye in the right position to get the best sharpness than I do with my 8mm BST Starguider. I don't know whether that difference is a function of the focal length difference or whether it has more to do with the fundamental design of each eyepiece.
  18. How are these chairs on softer surfaces like a lawn? Are they usable and stable or do they tend to dig in and topple over?
  19. I remember reading about that. Companies like Kodak and Bausch and Lomb had these glass furnaces with solid palladium or platinum linings, crucibles, and stirrers and when catalytic converters started being added to every car the demand for these precious metals went through the roof and the price rose accordingly so they scrapped the furnaced and sold the metal. Staggeringly short sighted. Presumably all the glass for US-made high end optics is sourced from overseas then now? The optics divisions of these companies still exist, just under different names and often catering to defence clients. Leica Canada is now Raytheon ELCAN and Kodak divested that part of their business as Itek which is now part of L3Harris - they're the folks who make the optics for spy satellites and have done since the 60s.
  20. Good question. Optron is one of a handful of fluorite manufacturers - the main use for the stuff is industrial optics and in photolithography machines in particular which is why it's available as extremely high quality blanks far larger than is available with comparable optical glasses. Blanks of sufficient quality for telescope optics are made up to 440mm - can you imagine what one of them would cost I think the TSA uses FPL-53 and the TOA models definitely do so presumably Canon would be buying the blanks for those from Ohara. I wouldn't think they'd make the mating glass in-house either so that probably comes from Ohara or Schott, but I could be wrong because in one of Canon's videos about their lens making they appear to be producing glass from the raw materials.
  21. I've read of it happening with the occasional older Astro-Physics scope but it seems to be one of those very rare issues that if it does occur then you're going to hear about it. Bacterial growth and mould on lenses of any type is more common but often that's a result of people putting scopes and camera gear in cold and damp attics or leaving thing for long periods in sheds and garages. My stuff stays in the front of the house where it's warmest and driest.
  22. From what I've read Canon Optron have been Takahasi's supplier of lenses since at least the late 70s and that it was they who approached Tak about making a Fraunhofer fluorite scope after they'd developed a method for hard coating the stuff. Apparently when they were testing the prototype lens they went as far as scrubbing the surface with a wire brush and it did nothing! There was a suggestion of using this in the marketing to show how durable the coatings were but it was quickly shot down as they didn't want to encourage people to do stupid stuff like that. Lens design is done in-house, as is manufacture of lens cells and the grinding and polishing of mirrors.
  23. Also I wouldn't want to have to mess around changing the oil and the filter every 15,000 light years!
  24. Those are some great images and I can well believe that the flattener helps with blue correction because I'm pretty sure I've seen that mentioned as a property of some other flatteners and reducers. Calling it a glorified achromat is pretty ridiculous. I've never read anything to suggest it's less than a superb visual apo or that it's actually bad for imaging, just that other exceptional scopes might be better.
  25. I think I need to try that because I often find myself squinting and it quickly gets uncomfortable. Just the one question, is the wooden leg and parrot included or do you have to buy them separately?
Γ—
Γ—
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.