Alan64

"Slow" and "fast" are photographic terms. They do not apply to telescopes, per se; only when a camera is combined or contemplated with a telescope. If you were to attach a camera to that 32" f/2.8 Newtonian, would an image be collected fast, or slowly, given the telescope's 2276mm focal-length?

Well, I simply narrowed it down a bit. Each and every telescope should be evaluated individually. How would you classify this 32"(812mm) f2.8; f/2.8, yet with a focal-length of 2276mm... ...keeping in mind that eyepieces range, in general, from 4mm to 40mm. I would also think that, if on a motorised equatorial platform, that a camera's CMOS sensor would take its sweet time collecting those precious photons of light.

The 90mm is a Maksutov-Cassegrain; the 114mm, a Newtonian. The Maksutov should arrive with its collimation spot-on. Views of Luna, with a 32mm Plossl, and at the lowest power for each... 90mm Maksutov(39x)... 114mm Newtonian(16x)... The Maksutov would get you closer, further, and more easily. Between the two, the Maksutov would be the better choice, albeit arguably. If you're game, a 127mm Maksutov is the sweet-spot among the varying apertures of the design.

Stu, that's a Celestron "AstroMaster" 70/900. It has a dreadful, proprietary focusser, and the mount that came with it, a CG-2(EQ-1), is too small for it. I have had it up to 225x, with little image-breakdown, on Polaris.

Newtonians: f/3 to f/5(fast), f/6 to f/7(medium), and f/8+(slow) Refractors: f/4 to f/6(fast), f/7 to f/11(medium), and f/12(medium-slow) to f/20(slow) Maksutovs/Schmidts: f/10 to f/15(slow)

Hi Neil, In so far as Newtonians, a faster and fast telescope requires corrective and therefore more costly eyepieces. At f/5, this 150mm Newtonian of mine is considered fast... ...but I don't have any particularly expensive eyepieces for it, and I get great views without them. Although, when you start going up in aperture at f/5, the eyepieces required for distortion-free views become more complex and therefore expensive. A 300mm f/5 Newtonian is another animal compared to my 150mm f/5. I can get by with cheaper eyepieces, but the owner of the 300mm f/5 would need much more corrective, and expensive, eyepieces. Then, wide-angle eyepieces are more costly than the standard Plossls. The more costly and wider-angle eyepieces oft contain more lenses to effect the corrections, and the wider view. A 200mm f/6 Newtonian-Dobson, or "Dobsonian", can get by with less-expensive eyepieces. But a 250mm f/5 Newtonian-Dobson is going to require the more costly for distortion-free views. It's the steeper curve of the faster primary-mirror of a Newtonian that requires correction. A 250mm f/5 might even require a coma-corrector in addition. The faster the Newtonian, the worse the coma. Coma is evident when the outer edge of the view of an eyepiece shows stars that are not round, but appear as streaks, lines or "teardrops" instead. Coma can also affect the center of the view, rendering it less sharp. With medium-to-slow Newtonians, like our 114mm f/8 Newtonians, the need for corrections are not needed. However, everybody wants a short-compact telescope nowadays; the shorter the better. They're easier to handle, store, and are travel-friendly. Faster telescopes are more costly to manufacture, their lenses and mirrors. With refractors and Newtonians, what you see is what you get. If the telescope has a short tube, it will be faster, and will have a shorter focal-length. If a longer tube, it will be slower, and with a longer focal-length... Those are the two, main staples of amateur-astronomy: refractors and Newtonians. They are also the oldest designs of telescopes, 1608, and 1668, respectively. The only other design you will encounter, generally, when shopping for a telescope, is a catadioptric: either a Maksutov-Cassegrain, or a Schmidt-Cassegrain. They came about much later, in the 1940s, but are based upon the classical-Cassegrain of the 1600s. This is my 127mm f/15 Maksutov-Cassegrain... It has a short tube, as you can see, but it has a very long focal-length inside: 1900mm(!). In the cases of Maksutov- and Schmidt-Cassegrains, what you see is NOT what you get. Both are slow telescopes, the Maksutov being very slow. Therefore, they can use the most inexpensive eyepieces on the planet, particularly the Maksutov, and for sharp, pleasing views. I suspect that some are drawn to them for their short tubes(easy to manage, store, and travel with), but upon arrival quite a few new purchasers encounter more than they had bargained for, or less rather, and in the form of narrow, drinking-straw like views of the sky, even at the lowest power. The interior of a Maksutov, its folded focal-length, in action... But such telescopes are excellent for views at high magnifications; for the Moon, the planets, and the double-stars.

I've always held that the best EQ-3 is an EQ-5. I have a Celestron CG-4(EQ-3), yet I've never used it, and not likely to ever. The EQ-5 is the sweet-spot among equatorials; one mount for a myriad of different sizes and types of telescopes, and for whichever purpose. As I understand, the C6N is capable of reaching focus with a camera. You could go with a manual EQ-5 and motorise only the RA-axis, in the beginning. I would suggest renovating the mount, whether new or used, prior to use for either visual or imaging, particularly for the latter.

Hauling an EQ-5 round, not to mention aligning it, might, would perhaps, be like dragging a block to Stonehenge, and there to rest under a full Moon. An EQ3-class mount would lighten the load a bit; for example... https://www.firstlightoptics.com/skywatcher-mounts/skywatcher-eq3-pro-synscan-goto.html There may very well be used examples of that in the marketplace as well. This would seem to be the ideal in your case... https://www.firstlightoptics.com/reflectors/sky-watcher-star-discovery-150i.html The OTA of that kit is comprised of a good deal of plastic, and is therefore lighter; not as much strain upon the mount. But I feel that the OTA isn't designed and constructed as well as the one you have at present.

You can line the underside with a circle of aluminum-foil, the dull side, and for improved illumination of the collimation scene. As John had mentioned, a star-test is the final test of how well the telescope was collimated. A basic star-testing tutorial... https://www.skyatnightmagazine.com/advice/how-to-star-test-a-telescope/

The more I look at your first image, it appears that the reflective disk has come loose, and is now askew. The cross-hairs, on the other hand, appear to be correct.

It appears that a component of the tool has slipped out of alignment. Are you able to repair the tool? I probably could if I had it before me. Orion(of California) Newtonians come with a collimation-cap. I have the Orion "StarBlast 6" kit, and this is the one that came with it... Did you get one with yours? If not, are you the original purchaser of the kit?

Stellarium is useful for finding things in the sky, and in real-time... https://stellarium.org/ ...and it's free. I plan to use that original finder on one of my smaller telescopes, but first I'll have to modify the stalk to fit into a Vixen-type base.

Hi Neil, My point being only that the original finder-scope is not rubbish, after all. Still... I took the one off of my "PowerSeeker" 127/1000 and installed a Vixen-style finder-base... Now I can add any type of finder under the Sun, swapping them back and forth. I used the original holes in the tube to mount the base... The base, there on the left, is a common and secure way to mount a finder. It does require different screws, nuts, and perhaps washers, to install... I use stainless-steel screws, with the rest being of zinc-plated, common steel. The screws may have to be cut down in length so as not to have the tips protruding into the main mirror's light-path.; simple measurements and a hacksaw are all it takes... To be on the safe side, I like to have the tips of the screws nigh flush to the outside surfaces of the nuts. I then matte-blacken only the parts on the inside of the tube. You don't want anything reflective or shiny inside the tube, save for the two mirrors. I have a Meade 114/900, and virtually identical to your Celestron... 114/900 Newtonians have been round and quite popular for decades. The 900mm focal-length is ideal for working with the 4mm-to-40mm range of eyepieces, and with the ability to observe practically everything in the sky satisfactorily. I've only observed with that Meade once, but from that experience I do know this: you and yours will have a wonderful time. Cheers,

You can motorise an equatorial, and to where the object would stand still there in the centre of the eyepiece, and for as long as you'd like. It's easier to break down an equatorial into smaller pieces, for travelling, but then it would have to be put back together upon arrival. Actually, it wouldn't be that many parts: tripod, mount-head, and counterweight(s). They all go back together rather quickly. For visual-use, with eyepieces, no camera, an equatorial doesn't have to be aligned perfectly with the NCP/Polaris the north star. There are also somewhat budget-friendly go-to kits to consider for group-viewing... https://www.firstlightoptics.com/az-goto.html https://www.firstlightoptics.com/sky-watcher-az-gti-wifi.html

No, you would have to get a mount for the 130P-DS; and yes, eyepieces, 1.25" and 2", would fit into it. In so far as the 130P/EQ-2 kit, the visual-back of the focusser may in fact be threaded for attaching a camera, as this one is... That's the one from my 150mm f/5, and made by the same manufacturer of the 130P/EQ-2 kit. I wouldn't expect long exposures however with a DSLR camera. The 130P/EQ-2 kit would be best suited for afocal-photography. That is, holding the camera up to an eyepiece and snapping a shot, like you would of a bird in a tree during the day. That method is limited to the brighter and brightest objects in the sky. This is a collage of afocal-shots that I've taken over time, with that method... EAA would also be possible, and with a webcam-type camera... https://cosmicpursuits.com/2204/the-basics-of-electronically-assisted-astronomy/

I'm thinking that you have this kit... https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-eq3-2.html ...without go-to, and from what I had read within one of your previous threads. In any event, a camera's sensor collects a lot more light than the human eye. Therefore, for imaging, a telescope with a large aperture is not required, however there is the increased resolution(detail) that comes with a larger aperture. I would suggest this one, as it's configured for imaging, and can be used as well for visual-use with eyepieces... https://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html Here's a long-running thread about imaging with the 130P-DS... https://stargazerslounge.com/topic/210593-imaging-with-the-130pds/

The original 5x24 finder-scope that came with my Celestron "PowerSeeker" 127EQ is not bad at all, although perhaps limited by its 24mm aperture. Still, the view through it, albeit during the day, was most satisfactory; rather a wide view, bright, sharp and clear, and defying the usual first impressions of such an accessory. The solution to most-easily aligning the finder-scope to the telescope is painfully, quite, and woefully simple... The finder-scope, the tube, must fit snugly there at the front of the holder. I used about a 12mm wide strip of flocking, all round. A few thicknesses of tape will work, in a pinch. After that's done, aligning the finder-scope to the optical-tube with the three adjustment-screws becomes painfully, quite, and woefully easy.

If that is the kit you intend to purchase, then you may want to know a few things about it. One is that the go-to mount comprises the bulk of the purchase-price, and with the build and quality of the telescope itself taking a back seat. On the plus-side, the mount can be used manually in the event of battery, computer and/or motor failures; if I'm not mistaken. Another plus is that the back of the telescope is sealed, in so far as keeping foreign matter from entering the tube. I would suggest adding a dew-shield to the front of the telescope when used outdoors, and to protect the front opening, the secondary-mirror in particular. Then, a 150mm f/5 telescope doesn't really need a go-to mount to find objects in the sky; unless one observes under a light-polluted city-dome. Go-to mounts are generally for telescopes with long focal-lengths, as they need help in the hunting of objects, like these Maksutov-Cassegrains on go-to mounts... https://www.firstlightoptics.com/maksutov/skywatcher-skymax-127-synscan-az-goto.html The mount of that kit cannot be operated manually in the event of said failures. https://www.firstlightoptics.com/maksutov/sky-watcher-skymax-127-az-gti.html The mount of that one can be operated manually. The focal-lengths of each of those two Maksutovs are twice as long(1500mm) as the Newtonian(750mm) of the "Star Discovery" kit, and for observing objects up close, easily, and with the static 4mm-to-40mm range of eyepieces. Telescopes vary considerably in their focal-lengths and -ratios, and therefore must conform and work with that range of eyepieces. Where you would need barlows to reach the higher powers with a Newtonian, a Maksutov doesn't really need one. Then, a Maksutov is something of a specialty telescope, for medium-to-high powers; no low-power, wide-field views are possible with a Maksutov, if that is of concern to you. The most versatile focal-length, given said range of eyepieces, is at about 900mm, and for observing most everything in the sky satisfactorily; most versatile it would be. The used Helios kit for example, or this new kit at the top of the page... https://www.sherwoods-photo.com/meade_astronomical_telescope/meade_polaris_reflectors.htm Ignore the two kits listed below that one. Those are just examples of what's out there in the marketplace.

Rather, folks will end up buying those lesser kits if they do not seek our counsel here in the astronomy fora worldwide. When, by chance, they do wander in, whilst we lie in wait twiddling our thumbs, we then do our collective and level best to persuade them otherwise, and with nigh to a 100% success-rate. Then, any pair of binoculars or telescope is better than none at all, like this one for example... https://www.harborfreight.com/10-x-50-wide-angle-binoculars-94527.html That pair is actually a great deal, but you might have to return them once or twice for a replacement, and to get a really good one; a pair that will not produce eye-strain and/or a head-ache.

I got this Barska 70mm f/4.3 achromat recently, but ultimately as a finder, I'm hopeful, for my blind-as-a-bat f/15 Maksutov with a 1900mm focal-length... Needless to say, a kit like that should never be considered by those first starting out, nor that Barska 70/400 so much. Although it is almost at f/6, but still no cigar.

I found this video interesting... https://www.youtube.com/watch?v=BkgR_307OEo The secondary-hub and -mirror do not seem to be that obstructive, as is usual with f/4 Newtonians; but then, the primary-mirror itself is quite small, and not parabolic as it should be. I had gone with the Zhumell Z100 as it has a parabolic primary-mirror, although not guaranteed to be "diffraction-limited", as omitted within the specs for the identical Orion "SkyScanner" 100mm.

I never suggest nor recommend f/4 Newtonians to those first starting out, as an f/4 Newtonian is rather difficult to collimate, not to mention unsuitable for reaching the higher powers of which this aperture and that are capable. F/5 is the minimum I suggest for Newtonians; f/6+ for achromats, and both for a lasting and versatile experience. The general range of eyepieces from 4mm to 40mm doesn't work well with all telescopes on the market.

A quality 2x-barlow might be a welcome addition to the eyepieces that come with the kit, and for closer views of this object and that. I have a 150mm f/5 Newtonian that's similar to the one within that go-to kit. I use a 3x-barlow even, and for getting the magnification up to nigh 200x and beyond. I combine the 3x-barlow with a wide-angle 12mm, for a simulated 4mm, and at 188x. With the automatic tracking of the mount, even higher powers can be realised; for the Moon, the planets, and double-stars. This wide-angle 12mm is quite popular... https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-12mm-ed-eyepiece.html Barlows... 2x... https://www.rothervalleyoptics.co.uk/antares-x2-achromat-fmc-barlow-lens-125.html 3x... https://www.rothervalleyoptics.co.uk/antares-x3-achromat-fmc-barlow-lens-125.html I have both, and they've performed wonderfully with my 150mm f/5... ...along with all of my other telescopes.

The kit you have there is quite similar to my Celestron "PowerSeeker" 127EQ... https://stargazerslounge.com/topic/340294-celestron-powerseeker-127eq/ It is not a classical Newtonian per se, but rather a catadioptric, or compound, design; also known colloquially as a "Bird Jones" reflector. In a nutshell, what the designers did in the case of our telescopes was to take a fast(f/4 or so) spherical primary-mirror and combine it with a correcting/barlowing, cemented-doublet lens. That lens extends the focal-length and focal-ratio to 1000mm and at f/9 in the case of your own; 1000mm and at f/8 in the case my own. It does behave in some ways like a fast Newtonian. For example, at the low-powers the views are plagued by coma. It is, rather, at the medium to high powers where the telescope will excel, and for which it was designed, configured and intended. Our telescopes are economical alternatives to the much-costlier Schmidt-Cassegrain design, like the Celestron C5; a long focal-length crammed into a short, compact optical-tube. To collimate the telescope properly, the cell containing the doublet-lens should be removed/unscrewed from the end of the focusser's drawtube, and then to collimate it in the manner of a classical Newtonian. Do not remove the doublet from its cell, as that is unnecessary. I then used a sight-tube, and a collimation-cap to tweak, and I couldn't be happier with its perfomance.

Could you take and post an image of the cross-hairs of the Cheshire, like this...