Alan64

It's anastigmatic. I would hope so.

In a Newtonian's favour, aperture-fever cannot be remedied with a refractor, true, but at times one does prefer that qualitative over that quantitative. And then, I had started with a pea-shooter of a refractor, yet the mold was set nonetheless. I suppose that makes me a bit partial. Acquiring that 80mm 20 years later was most welcome, and exciting. Then, about ten years later, I got a 102mm achromat, but returned it shortly thereafter. At about the same time, I got an 8" f/5 Newtonian, but I've yet to observe through it, as I had gotten an OTA only. I do want to see what it may show to these ever-aging eyes.

I love his books, particularly the older publications. I like the "Sky at Night" video of Sir Patrick, in 1961, with his assistant, and the 24" Newtonian. Unfortunately the clouds rolled in, and just as they were about to observe.

"...a 6-inch Cooke refractor and a 12-inch cassegrain...", according to observatory's website. The refractor is physically longer than the Cassegrain. Perhaps they used both for the viewing, if both were present at the time. I didn't see it in 1986, as it was too far away. At that time, all I had was this, a 60mm... I didn't have binoculars, either. But by the early 1990s I had an 80mm, and saw the dark pock marks left behind on Jupiter's surface when the remnants of Comet Shoemaker-Levy impacted the planet. That comet had disintegrated, and never to be seen again. It turns out that the comet had been captured by Jupiter about 20 to 30 years before, and began orbiting the planet. Imagine, what a horrific thing if that happened here. The use of drugs would skyrocket, I expect, and in not knowing when the inevitable was to occur. My maternal grandfather, in a later recollection, saw Halley's at the age of 5, but that was during its last visit in 1910. It was so close to the Earth that a telescope wasn't needed. Photographs were taken of the comet in 1910... Note how Halley's speeds up as it nears the Sun... https://en.wikipedia.org/wiki/Halley's_Comet#/media/File:Halley's_Comet_animation.gif Yes, indeed, that 127mm will be an eye-opener for you. Incidentally, the shorter 127mm that John is considering would also be ideal for comet-hunting.

A 127mm aperture would be for the increased resolution(detail) only I would think, whilst observing the Sun; certainly not for the increase in brightness. Wouldn't false-colour intrude in that as well.

Hi Neil, Have a look at this... I don't know if you've ever seen one, or have ever owned a smaller refractor like that one. That one being a 50mm f/12, 10mm smaller in aperture compared to the ubiquitous 60mm instruments produced for decades. I had blackened and flocked it throughout, as well as updating a feature or two on the outside. I've observed with it after the fact only once. I saw a globular-cluster through its "eye", M22 I think. It wasn't all that dim, and with averted-vision I was able to detect the "diamonds" sparkling within. Now, I never suggest a refractor that small to those first starting out with a refractor, with 80mm being the suggested minimum. You do want one's interest to be held in the beginning, and to grow. That's another nice thing about refractors, the sparklings oft seen, as if the object is alive, a sentient-being even. Case in point: on the left, M13, the great globular-cluster in Hercules, and as seen through my 150mm f/5 Newtonian. On the right, M13 as seen through my 100mm f/8 refractor... Now, I'm not an imager; visual-use only. When I observed M13 through the Newtonian, the image was pleasing enough, but I saw no sparkling within. Needless to say, I did see that wonderful characteristic through the refractor; glorious.

This is the collimation-scene of an 80mm f/6, a crown-and-flint achromat, which did not require collimation upon arrival... Well, perhaps a slight tweaking is necessary, particularly since it is at f/6. You do want to push one for all it's got, in magnification, per its aperture. Alas, it exhibits a blemish, and when having observed Sirius in this instance... I see that all the way until it's at perfect focus. It doesn't seem to degrade the images however; I hope, I trust. On the other hand, the collimation scene of a 70mm f/13 achromat... That's not so good. But what I found, mainly, in that instance, was a wonky focusser.

It is not impossible to collimate a triplet in a home setting. The OP would need to research to go about that, if collimation is in fact required.

I've already hinted that it requires collimation. I, too, am suspecting that, and as you did, and in agreement with John.

You asked for information.

My reply was in reference to the problem with misalignments that occur with triplets, the subject of this thread at present, and other objectives with more than two lens-elements.

I was referring to refractors only, and to the OP's Tele Vue NP101is, a quadruplet-apochromat.

Triplet-apochromats are favoured by imagers, although they are used on occasion for visual-use. Incidentally, your Tele Vue is a quadruplet. Consequently, you'll want to handle that one as one would a newborn babe. Then, for visual-use only, a doublet-apochromat serves admirably, and are, generally, problem-free. Triplets, if misaligned, are usually not an at-home repair. They are sent off instead, for servicing.

I read once where two friends compared their telescopes one night. The visitor brought their 127mm refractor, albeit an apochromat possibly. The host brought out their 200mm Schmidt-Cassegrain. The host had a sidekick for the 200mm, an 80mm refractor. But the 80mm, apparently, wasn't that much of a competitor to its perhaps unsuspecting owner, and to their 200mm reflector. After the session was over, the host sold the 200mm reflector shortly thereafter. It is not known, however, if it was replaced with a 127mm, or even a 150mm refractor. I found that result rather interesting.

Yes, I was working outside after midnight, and during a break I walked down the driveway and looked into the sky, and there was Mars rising in the east. It had cleared the tops of the trees. I waited until it climbed a bit higher and brought a telescope out... I had been wanting to test that 100mm f/4 Newtonian further, as it's not really suitable for the higher powers, but since it has a 4" aperture I'm determined to push it. I did just that, that morning, and then snapped this afocal-shot of the planet at a power of 200x... Mars is bright, and closer to the Earth during this time. It's going to get brighter still over the coming weeks. Opposition of the planet will occur on October 13th, when it will be at its very brightest, and a little larger even. I'll be testing that star-box further still near that time, but I'll need to dim the planet down a bit with a filter, and perhaps to see its details a bit better.

In the above, the poster has a point about a 127mm f/10 achromat being a beast, but I have to disagree as to the first part, for it is a refractor, and a 200mm instrument would be ££££, and for an achromat even; not to mention the debilitating expenditure in acquiring a mount just to support it, to get it off of the ground. It is also interesting to note that the gentleman above has no refractor listed within his signature; an oversight perhaps, or not. But it's not about the aperture of a refractor competing with the aperture of a mirrored telescope. Quite frankly, mirrored telescopes spend their days attempting to emulate the level of sharpness and contrast that only a fine refractor can provide, for a refractor uses lenses instead of mirrors, is 100% unobstructed, and generally requires no maintenance. It is the very first and oldest design of telescope. "The Original & Best", like a bowl of Kellogg's corn flakes, albeit for the lack of a better analogy. Then, we have Mother Nature. Our own eyes, which utilise lenses by which we may see, and most clearly in youth. If that were not enough, there are far-away galaxies that act as telescopes themselves, which are known as lensing galaxies. Peering into my crystal ball, albeit cracked, I see, in the OP, a desire to see with his own eyes what a refractor is really like. I suggest that an 80mm f/8 or f/11 is capable of demonstrating that. But no need to worry, for even though a mirrored behemoth, relatively, may beckon with its brighter reflections, the refractor will always be there, waiting, and beckoning in its own not-so modest might and right.

Yes, I'd get that holder shimmed, there at its front. You'll be amazed at how much easier it will be to adjust. Jacksonville is at 30°, here in the northern hemisphere. Therefore, Polaris will appear in the north part of the sky 30° above the horizon... When aligning your EQ-1 mount, for tracking objects, you want to set the latitude-scale to 30°... The setting-circles, one for each axis, with numerals all round, are pretty much useless. It is assumed that one would dial in the coordinates of object with those circles, but the ones provided with our EQ-1 mounts are not up to the task. I have the next size up in an equatorial mount, an EQ-2. I replaced the numbers on its setting circles with clowns... That's about how useful they are. Now, once you set the latitude-scale to 30°, that's it. You'll never have to touch it again, unless you relocate a considerable distance to the north or south. Miami is at 25°, therefore you would need to change it to that if you relocated there. Once it's set, you take the kit outside and aim the body of the RA-axis towards Polaris... You will need to level the mount, with its retractable legs, then loosen the mount-head under the tripod's hub, and aim the RA-axis at Polaris. You don't need to adjust the latitude-scale again, as it's already set to 30°. Once the RA-axis is pointed at Polaris, tighten the mount-head's clamp, unclamp both axes, and revolve the telescope round and about the sky, like a gyroscope(for the lack of a better analogy)... Once you find an object, you center it in the eyepiece, lock both axes, and use the slow-motion controls to track the object. You'll get the hang of it with practice.

I'm in the same boat, and with this Celestron 70mm f/13 achromat... It came with a focusser from Hades... I'm always on the hunt for a conventional focusser for that one, either of metal or plastic, no matter. Metal is preferable, of course. Best wishes in sorting your own out.

As you go up in focal-length(eyepieces) -- 28mm, 30mm, 32mm, 38mm. 40mm -- that's where, and only, you'll find 2" eyepieces. It takes that wider barrel to provide a wide view at those focal-lengths. This is an example of the shortest focal-length with a 2" barrel... http://www.televue.com/engine/TV3b_page.asp?id=20&Tab=EP_ETH-17.0 ...and the AFOV at 100°; very wide indeed. However, that eyepiece is an exception, due to its construction, and cost. For us mere mortals, the vast majority of eyepieces at around that focal-length have 1.25" barrels. There are no 6mm, 8mm, 10mm, or 12mm eyepieces with 2" barrels, as the wider barrel is not needed to provide a wide view at those focal-lengths. There would be no benefit. I would suggest what the others have, combine it with a barlow or two(2x and 3x) of better quality, and ramp up the power. Telescopes, in the first place, are for seeing faraway objects up close, the closer the better. Else, one may make do with binoculars.

A Newtonian, particularly at f/5, requires collimating on occasion, upon arrival quite possibly, and thereafter. Collimation consists of aligning the two mirrors within the tube in unison, and for sharp, pleasing images. You may wish to consider a refractor instead, which normally does not require collimation... https://www.astroshop.eu/telescopes/bresser-telescope-ac-102-1000-messier-hexafoc-ota/p,14192 https://www.astroshop.eu/alt-azimuth-without-goto/gso-atz-mount/p,4944 ...or... https://www.astroshop.eu/equatorial-without-goto/skywatcher-mount-eq5/p,16081

This is a Celestron 70mm f/13 achromat... At f/13, the effects of the aberration are reduced considerably; no filters required. But then, it's rather long, not as ergonomic, and requiring a larger, more-supportive mount to reduce vibrations. With achromats, one chooses either ergonomics over optical-performance, or vice-versa. I had gotten tube-rings for it, there on the right; on the left, with the bar affixed to the tube, and as it arrived. With a longer dovetail-bar, you can balance the telescope, in sliding it back and forth, forth most likely, and when attaching your DSLR. Tube-rings make that possible, and more. Or, you can attach a longer bar to the telescope directly, although that's not as versatile.

What you have discovered is what I've known all along. With entry-level telescope kits, you get what you pay for. As you've found, you do get a good telescope, the optics, the objective of the telescope, and where it really counts. But the mount, the accessories, oft fall short of the mark I'm afraid. I've known this each and every time I've bought an entry-level kit for myself. This is, or rather was(discontinued), the best 102/660 kit that Celestron offers... https://www.harrisontelescopes.co.uk/acatalog/celestron-omni-xlt-az-102mm-refractor-telescope-22150.html It hasn't been discontinued for long. If you'd prefer that kit you may be able to find one. Regrettably, Celestron has replaced it with this... https://www.celestron.com/products/starsense-explorer-dx-102az ...and in "zooting" the discontinued kit up a bit with push-to technology. Both kits come with a superior, metal focusser, and a somewhat better mount. You'd still need a star-diagonal for best results at night.

Your telescope, a 70mm f/10 achromat, has a focal-length of 700mm. That's what you use to choose your eyepieces. The 20mm "SuperView" has a power of... 700mm ÷ 20mm = 35x That's a fairly-low power, and not too difficult with which to see Jupiter. Your telescope has a finder-scope, just like this one that came with my own "PowerSeeker" kit... I found it to be not a bad little finder. It's a 5x25, the front lens 25mm in diameter, and the magnification at 5x. You will need to set up the telescope during the day. Locate a tall object towering in the distance, a half mile to a mile away. Use the 20mm eyepiece to aim the telescope at a feature of the object, like a mast or a flag, anything. Once you get that feature centered in the eyepiece, lock the telescope in that position so it won't move. Then, adjust the finder-scope to aim at that same feature of the object. To make the finder easier to adjust, shim its holder... ...and for a tighter fit. I had to shim mine, and it's a safe be that you will need to as well. You can use blue painter's-tape from Dollar Tree, and about two, three or four layers round. You want the front part of the holder to hold the scope firmly, stiffly even. That makes it so much easier to adjust with three screws at the back. Once you get what the finder sees aligned with what the telescope sees, you're golden, and you can then use it to find most anything in the sky. Once an object is located in the find, you look into a low-power eyepiece and you should see the object. When aligning the two to each other, if you use a higher-power eyepiece, like a 9mm or shorter even, the finder will be that much more accurate. If there are no objects in the distance during the day, there is one you can use at night: Polaris, the North Star. I don't know where in Florida you live, and therefore your latitude. Florida's latitudes vary from 25° to 31°. I live just south of Memphis. My latitude is 34° to 35°, therefore Polaris is 34 or so degrees up from the horizon... 0° is at the horizon, the ground, the dirt. Straight up in the sky is the zenith, and at 90°. Therefore, Polaris is a little over a third of the way up, between the horizon to the zenith. Polaris appears a bit small in the sky, but it's far larger than the Sun... Polaris Aa is the star you can see in the sky with just the eyes. Polaris doesn't move. Well, it moves, but in such a tight circle that it's very difficult to tell that it's moving. Polaris does not move across the sky like the Sun, the Moon, the planets and the stars, so you can use it to align the finder to your telescope. You will need to align the two before you start hunting for objects. Eventually you may want a barlow, a 2x, and to reach the higher powers where the planets become exciting to look at. I've had my own 70mm f/13 up to 150x, and even 225x, trained on Polaris. With a 2x-barlow, you can convert your new 20mm wide-angle eyepiece into a 10mm wide-angle, and for a power of 70x. If you insert the barlow into the telescope first, then the diagonal and eyepiece, the 2x will simulate a 3x-barlow, and the 20mm will simulate a 6.7mm eyepiece(104x). To reach 150x... 700mm ÷ 150x = a 4.7mm eyepiece Combining a 2x-barlow with the 9mm = a 4.5mm(156x) Combining a 3x-barlow(simulated) with a 12mm = a 4mm(175x), and so on and so on... Back to the finder, if you find that you don't like the one that came with the telescope, you can get a red-dot finder and give that a whirl. For example... https://agenaastro.com/celestron-star-pointer-finderscope-51630.html

Longer refractors do benefit from pier-extensions, and for more comfortable eye-placements. These issues would vanish into thin air with a Maksutov instead. No false-colour, no diffraction-flares or -spikes, and with the smallest secondary-obstruction among mirrored telescopes per its length, and longer even. A refractor like this one would be ideal... https://www.altairastro.com/starwave-ascent-102ed-f7-refractor-telescope-geared-focuser-468-p.asp Apparently, it's quite popular. I'd save up for that one. By that time they may be back in stock. If I'm not mistaken, it's the same one sold here... https://www.teleskop-express.de/shop/product_info.php/info/p4964_TS-Optics-ED-102-mm-f-7-Refractor-Telescope-with-2-5--R-P-focuser.html ...and here... https://www.astronomics.com/astro-tech-at102ed-4-f-7-ed-refractor-ota.html?___SID=U That would be all the refractor one would ever need. It may also be the only refractor ever acquired.