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Alan64

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Everything posted by Alan64

  1. It's definitely a "Bird-Jones", or a "Jones-Bird", reflector, and at f/9. It contains a poor optical lens assembly which barlows the main mirror's inherent, shorter focal-length. Pass that one by. 4.5"(115mm) is a nice portable size. This what a 114mm f/8-f/9 really looks like... http://agenaastro.com/celestron-powerseeker-114eq-telescope-21045.html But I'd go with this instead... http://www.telescope.com/Telescopes/Reflector-Telescopes/Reflector-Telescopes-with-Altazimuth-Mounts/Orion-StarBlast-45-Astro-Reflector-Telescope/pc/1/c/11/sc/342/p/102010.uts
  2. Yes, I recommended an f/5, in light of that very thing. One does get ample contrast for DSOs with a larger secondary; a larger cataract. It just wouldn't be suitable for the fine details on the planets which require telescopes of longer focal-ratios, for both improved contrast and greater magnifications. Then there's that pesky coma which increases the faster the telescope, robbing from an image further. I feel that the atmosphere rules instead. Opinions will differ, to be sure.
  3. Indeed, as much as one may get, but contrast is not as critical for DSOs; aperture is however.
  4. Under dark skies, you can certainly use an f/4 for visual, but perfection in collimating will be more critical for best image, and a coma-corrector preferred. At f/4, it will be decidedly for deep-sky, therefore a contrast-robbing secondary is less of an issue as it would be for the Moon and planets. Going a step slower, with an 8" f/5, would allow for both, deep-sky and the solar system. Said Atlas can easily handle an 8" f/5 for visual, and under dark skies will keep you busy for years... http://www.telescope.com/Telescopes/Reflector-Telescopes/Reflector-Optical-Tube-Assemblies/Orion-203mm-f49-Reflector-Tube-with-Crayford-Style-Focuser/pc/1/c/11/sc/345/p/9788.uts Or... http://www.teleskop-express.de/shop/product_info.php/language/en/info/p49_GSO-200-mm-f-5-Newtonteleskop-Optischer-Tubus---2--Crayford-Okularauszug.html
  5. The Heritage-100P will be great fun, and will show things that relatively few people have ever seen, and for years to come. The included 1.25" eyepieces are larger and much easier to look through than those that came with telescopes when I was young. I started out, at the age of 8 or 9, with a 60mm telescope, and saw Saturn for the first time, and with the yellow eyepiece seen on the right within the following image. Those that come with the 100P will be as those on the left; an extraordinary difference... Telescopes that first appeared on the mass-market back in 1950s and '60s were akin to microscopes, and the eyepieces of that time reflect that; but no more. However there are some who use eyepieces intended for microscopes with their telescopes, and to this day.
  6. Here's M13 when viewing through my 6" f/5 Newtonian(left), and when viewing with my Takahashi FS-102 102mm f/8(right)... The globular cluster appears brighter in the Newtonian, but only slightly. M13 glistened, sparkled even, when I viewed it live through the Takahashi, and when the photograph was taken. But not so when I observed it through the Newtonian; no, not at all. That's one of the advantages of refractors; the best image per inch of aperture, and beyond even in the case of a fine apochromat. At the time I decided upon the Takahashi, there was only one other apochromat that I had considered: the Tele Vue TV102. In the end, the fact that the TV102 exhibited more light-scattering was the deciding factor. What accounts for the FS-102's exceptional control of light-scattering lies within its exquisite calcium-fluorite doublet, not to mention what I describe as its "delicious" multi-coatings... Said control allowed me to split Sirius A and B("The Pup") back in 2003 when the two were practically adjacent to each other. The intense glare from Sirius A could not hide "The Pup" from the Takahashi. Perhaps astoundingly, around the same time, I had read that a 102mm telescope could not split the two.
  7. Hello, I view the act of owning and maintaining a Newtonian telescope as working one's way towards the observing of the heavens. Newtonians require occasional maintenance, in the act of collimation; that is aligning the two mirrors, the primary and secondary, in respect to one another, and to ensure that the telescope provides its very best image. In return one is rewarded with wonderful views, not only within the solar system but also beyond into deep space. If your grandson likes to tinker with things, then a Newtonian would be ideal. The greater the aperture, that is the diameter of the primary mirror, the more that is seen, and what is seen grows brighter and more detailed as the aperture increases. A Newtonian with a primary mirror of 150mm is bright, and will show the young man many objects in space: something new and different one night, or a favourite object revisited on another, and for many years to come. The question is, which 150mm? An f/8, favouring observing within the solar system; or an f/5, which is nicely balanced between observing both: the solar system and deep space? Here is the aforementioned 6" f/8 "Dobsonian"... http://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-150p-dobsonian.html It would be comparable in performance to an unobstructed 120mm f/10 apochromatic refractor. PROS: Simple alt-azimuth motion Collimation less critical, however longer tube makes collimation more difficult Lessened coma More forgiving of eyepiece design and quality Superior lunar and planetary performance CONS: Longer optical tube compared to a 150mm f/5 Newtonian and a 150mm f/10 Schmidt-Cassegrain; less portable Alt-azimuth base of particle-board weighs 10 kg; optical tube weighs 8 kg; entire kit: 18 kg Fixed focusser-position; cannot rotate optical tube for more comfortable eye-placement Narrower field-of-view per eyepiece compared to a 150mm f/5 Mount will not accommodate any other telescopes that may be acquired in future Expensive laser-type collimator may be preferred for longer optical tube The 150mm f/5 with traditional alt-azimuth mount... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ota.html http://www.rothervalleyoptics.co.uk/skywatcher-az4-1-alt-az-mount-with-aluminium-tripod.html Or, the optical tube bundled with the same mount-head but with heavier steel tripod... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-az4-mount.html It would be comparable in performance to an unobstructed 120mm f/6 apochromatic refractor. PROS: Wider fields-of-view per given eyepiece Simple alt-azimuth motion OTA with tube rings rotatable for comfortable eye-placement Lighter weight; entire kit weighs less than 11 kg, with aluminum tripod Shorter OTA; portable; travel-friendly More balanced than a 150mm f/8 between solar-system and deep-sky observations; more versatile Ability to mount other telescopes in future; more versatile CONS: More expensive Collimation more critical, however easier with shorter tube and a passive, non-laser collimator Offsetting of secondary mirror recommended Increased coma Barlow is more of a necessity for highest lunar and planetary magnifications possible per a 150mm aperture That said, I get great views, both within the solar system and beyond into deep space, with my 150mm f/5 mounted on a traditional alt-azimuth... M42, the Orion Nebula... M13, the great globular star cluster in the constellation Heracles... M45, the Pleiades, aka "The Seven Sisters"...
  8. MrCat, Any and all eyepieces that you might acquire for your present telescope can be used for telescopes that you may acquire in future. Optically, eyepieces are fully the other half of the telescope. One cannot be used without the other, and are as Punch and Judy; inseparable. Therefore, think nothing of getting one better-quality eyepiece at a time, and so to build a truly fine set; over the weeks, months and years even. Eyepieces are a constant; telescopes less so. This 8mm would be an excellent higher-powered ocular, and with a respectable wide field... http://www.skiesunlimited.co.uk/SLT2/telescope%20eyepieces.html...top, center. The 60° eyepiece is also sold under various house-brands, and praised on both sides of the Atlantic.
  9. The level of said aberration is noticeable within this afocal photograph taken with my Antares 80mm f/6... The camera however, a Canon S110, tends to intesify it, especially the blue. Even less is seen live at the eyepiece. I feel that I received a well-controlled example, per its focal-ratio, but it is nonetheless like playing roulette when considering any fast-achromat manufactured in China, particularly the ever-popular Orion ST80 80mm f/5 sold in the U.S., along with its house-branded siblings sold throughout the world. I almost purchased an Orion ST80 myself, until I discovered and purchased the Antares 805 instead with its superlative 2" GSO rack-and-pinion focusser; and the optical tube of all-metal construction save the focusser knobs and the focusser-drawtube baffles, the latter having been removed upon their discovery and for fear of their cutting into the light-cone. Then there are those who find it bothersome with an 80mm f/11 or a 102mm f/10. It's all a matter of individual preference. I had a Vixen 102mm f/10 for a very short while, then returned it and got a Takahashi 102mm f/8 apochromat instead...
  10. That one will make for a very good starter 'scope. It has a parabolic primary mirror, and keeping it aligned(collimated) in relation to the secondary mirror, for best image, will be easier as it is fixed into a permanent position. It's a bit fast at f/4, and therefore well-suited for observing the brighter deep-sky objects. The included 2x barlow will allow you to bring the features of the Moon and planets up closer, especially when combined with the 10mm eyepiece. It will perform similarly to at least an unobstructed 70mm f/6 achromatic refractor, but without the chromatic aberration that plagues fast achromats, and all within a much smaller, compact kit. The telescope is virtually identical to the Orion "SkyScanner" sold in the States... http://www.telescope.com/Telescopes/Reflector-Telescopes/TableTop-Reflector-Telescopes/Orion-SkyScanner-100mm-TableTop-Reflector-Telescope/pc/1/c/11/sc/340/p/102007.uts?refineByCategoryId=340 There are 67 user-reviews, and overwhelmingly in its favour. It had piqued my interest when I first saw it, as a grab-and-go, and I'm still considering it. Good choice!
  11. To ensure your child's interest in future, wow them with this... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-az4-mount.html I take lovely afocal photographs with my 150mm f/5, and simply by holding a point-and-shoot camera up to the eyepiece. What you see in the following images is what is seen live at the eyepiece... "The Moon Maiden Looking Out to Sea"... M13, the great globular cluster in the constellation Heracles... M42, the Orion Nebula... Jupiter and two of its moons... My kit, as illustrated, is with the tripod's legs fully extended and the mount-head atop a pier extension. The kit sold by FLO would not be as tall.
  12. MrCat, Per your video, I see that your mount isn't up to snuff at the moment. I have a mount that's very similar, and for this 60mm refractor... Although I received the telescope as brand-new old-stock, the mount-head was not in the best condition. Here's a close-up of the mount-head. with successive images illustrating what I did to improve it. Hopefully you might get an idea of what may need to be done to get yours in working order... First, I disassembled the head and permanently immobilised the utterly useless fine-adjustment mechanism by inserting a brass shim into the lowermost portion's opening, then hammered the upper portion(circled) into the shimmed opening... Afterwards, I reinstalled the fine-adjustment mechanism and tightened it as far as it would go, never to be utilised again. It is and was of an extremely poor design... The mount-head's two components are now as though they are one. I then turned to the optical tube's yoke, or fork, with its shaft, which is inserted into the mount-head's opening. I shimmed the full length of the yoke's shaft with phosphor-bronze sheet, and to elimnate any and all slop. Lithium-based grease was used throughout... I added a large flat washer for a bearing between the yoke and the mount-head, and before combining the two... The yoke was secured to the mount-head from the bottom by a simple bolt and washers, but I thought it to be inadequate, so I created a spring-loaded bolt out of parts acquired locally... The spring-loaded bolt, and bronze shim, allows for smooth, slop-free rotation in the azimuth, without binding nor with the bolt to loosen in future. Where the optical tube joins within the yoke, I replaced the metal washers with those of nylon, and added even more for a snug fit, filling the gaps between the optical tube and the yoke's arms, and lubricated with Superlube, a Teflon or PTFE-based lubricant... It's now the very best it may be, and for decades to come...if not a century or more. I sincerely hope that this has been of some help. Cheers, Alan
  13. Agena Astro in the U.S. also carries these 2x and 3x Antares barlows, with the optics of both made in Japan... http://agenaastro.com/antares-1-25-2x-barlow-lens-ub2s.html http://agenaastro.com/antares-1-25-3x-barlow-lens-ub3s.html
  14. I'd get an 8mm and a 15mm Vixen, although eye-relief would be tight with the 8mm, as with all Plossls... http://www.firstlightoptics.com/vixen-eyepieces/vixen-npl-eyepieces.html A 9mm orthoscopic would have slightly better eye relief, but they're more expensive and have a narrower field-of-view. Or, the Vixen 15mm and a 2x barlow. The two combined would simulate a 7.5mm(200x). Now, if you can find one of these... http://www.scopesnskies.com/prod/GSO/barlow/deluxe/2x%20-and-1.5x.html ...then you can remove the bottom portion of the barlow and attach it to any ocular and for a 1.5x reduction in addition to the 2x. The 15mm would then become a simulated 10mm(150x). The GSO is favourably reviewed... http://agenaastro.com/gso-1-25-2x-achromatic-barlow-lens.html
  15. Halli, the RC8 takes such exquisite photographs. That image of M33 is an absolute knockout!
  16. MarsG76, that barred spiral is beyond wonderful.
  17. Not too dreadful of a pic, although that shot of the Moon was taken under considerable magnification. I have a Canon S110 point-and-shoot. I take afocal photographs of the Moon and other objects on a regular basis, and simply by holding the camera up to the eyepiece... M13, the great globular cluster in the constellation Heracles... M42, the Orion Nebula... ...and, of course, the Moon... Your Nikon should perform similarly. You would then take the sharpest of the photographs and sharpen them further within a program like Photoshop or Paint Shop Pro, and in an effort to recreate the live view. Of course, with the described afocal method, the camera will most always fall short in that. I have a steady hand when so doing, but here some aids for point-and-shoot cameras, albeit from a U.S. vendor... http://www.telescope.com/Astrophotography/Camera-Adapters-T-Rings/Orion-SteadyPix-Deluxe-Camera-Mount/pc/-1/c/4/sc/62/p/5338.uts http://www.telescope.com/Astrophotography/Camera-Adapters-T-Rings/Orion-SteadyPix-Pro-Universal-CameraSmartphone-Mount-125/pc/-1/c/4/sc/62/p/103503.uts
  18. This 5" f/5, and a bit more manageable, would serve for both visual and imaging... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html The Cassegrain family of telescopes, particularly the Maksutov, were created in the desire for a long-focal planetary refractor, but folded within a tube roughly a third its length. A rough rule of thumb: f/10 to f/16 for planetary; f/5 and faster for deep-sky.
  19. What type of mount do you have? If it could support, say, this... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-ota.html ...then that might be a viable option, and for imaging, too.
  20. One has to wonder as to what came over them in so doing. Actually, with the 2" diagonal at focus, and with the 20mm Erfle, the drawtube extends out quite a bit; and it would even moreso via straight-through viewing... You have no idea as to how relieved I was in discovering and then plucking those two baffles out from the drawtube. The feeling was not unlike that of narrowly escaping a pit of crocodiles.
  21. I'd love to have one of those 6" Maksutovs myself, and well over and above a less-than-comparable 6" Schmidt; again my congratulations, and thank you!
  22. The 805 has been available of late, but as to whether or not it's still in production, only time will tell. I consider mine to be little more than of guidescope-quality, optically and per its star-test, despite my having seen the combined Airy disc of the "C" double-star within Orion's Trapezium under considerable magnification, and rather distinctly. Also under said magnification, whilst the surrounding nebulosity was colourless it nonetheless exhibited a delightfully misty, even ghostly appearance. The ED "Sentinel" variant, which is listed, is no longer available for purchase. Its doublet, and perhaps that of the 805 in addition, reportedly having been produced by Long Perng of Taiwan. The 805's optical tube, dew shield, and all-metal lens cell perhaps, are manufactured there in Canada. The 805's GSO focusser is perhaps its finest component, and identical to that of the discontinued yet well-received StellarVue AT1010 "Nighthawk"... The drawtube rides on a trio of Teflon strips, but I didn't care for the reflective surface within, so I deadened it with ultra-flat black spray... ...and after I had first removed these two shiny plastic baffles, which, given the considerable length of the drawtube jutting into the optical tube, were perhaps cutting off the light cone... While I was at it, I cleaned and re-greased the rack and pinion with a Teflon-based lubricant; Superlube, and food-safe, incredibly. There are to be other and few improvements to make, but not too terribly difficult, and to ensure the refractor performs at its very best. Why, it even came equipped with its very own vampire-star and victim... The doublet's coating are quite nice.
  23. Congratulations! Your new 150mm f/12 Maksutov will be comparable to a 120mm f/15 apochromatic refractor, hence rendering the 120mm f/8 achromat nigh-redundant. Even though it won't perform quite as a long-focal refractor on the splitting of tighter double-stars, with all its other advantages combined it will make for a fine compromise and substitute. The Cassegrain family of telescopes were created to simulate long-focal refractors, and within a compact tube roughly a third of the length. Insofar as a complement to the Mak, think nothing of considering, for instance, an 80mm f/6 fast-achromat, like this one... For the lower magnifications; wide-field, deep-sky; an RFT it is. It can even be turned towards the Moon at quite a bit more than half-phase, and with little chromatic aberration. I've found it to be well-corrected for colour... The stock Antares 805 comes with a marvelous 2" rack-and-pinion focusser and a 5° field, and over a stock Orion ST80-A. Also, the build-quality of the Antares is much better than that of the Orion. I purchased mine from a vendor in Canada, whilst taking advantage of the exchange rate. I owe the avoidance of the Orion and the acquisition of the Antares instead to a gentleman's post within another astronomy site... http://www.ontariotelescope.com/Antares-80480-refractor-OTA_p_115.html
  24. I'm near-sighted, and have worn glasses since my relative youth. In any event, what I had meant by my statement regarding the camera's shortcomings, is in that it fails to capture the sharpness of a live view. This is a photograph I took with the Tanzutsu 60mm f/15... It appears nice and sharp, eh? Ah, but not nearly as sharp as the live view at the time the photograph was taken. Here's a close-up... During the live view, within the circled portion, I saw what appeared to be dozens if not hundreds of what I term "hills and dales", within that ridge. The event has me almost convinced that the achromatic doublet was not manufactured by Tanzutsu, but by the Japanese optical house, Towa, instead. The two companies were in collaboration with one another at some point in the past. I wouldn't be surprised if the doublet was a part of Towa's old stock, and possibly from at least a decade prior to the refractor's manufacture.
  25. A 5" Zeiss apochromat might exhibit only one thing: perfektion.
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