But it would also be a lot more expensive and heavy. I simply cannot for the life of me see how anyone could prefer the planetary view in my 10 inch Meade SCT to that in my 5.5 inch TEC apo. All in all they'd be pretty similar images if the reflector was of equivalent quality to the refractor, but the refractor would be better. One that doesn't produce inspiring views or is difficult to set up . Since refractors have spherical surfaces that are easier to make nice and smooth, they can often have less wavefront errors. than the side of the tube facing the ground, due to radiation. If you are using a top quality refractor and a top quality reflector of the same FL and aperture there will be two main differences in the images produced: the refractor will show slightly higher contrast because of the unobstructed aperture (and a very marginally brighter image), and of course you will have diffracton spikes in the reflector. Turned out that the secondary was bad and his primary was killer. After collimation in the newxt night it was not problem at all to split the double double. Since a mirror reflects any wavefront error to be double the distance of a lens (because of the bounce), a mirror needs to be made to 1/20th wave to equal the relative quality of a 1/10th wave refractor, depending upon where the error is. Few SCT users bother to even try. But the star test showed that this scope suffered from astigmatism: About 1/3 wavelength. Imaging has a significant learning curve. When you compare refractors and reflectors of the same aperture and focal ratio and stipulate that the refractor will be of high quality, (no achromats), then the images in the refractor will be brighter and maybe more contrasty. If you live in densely populated area and are planning using backyard telescope, these may not be your best option, they The aperture is not as good as reflectors if your main purpose is to view plants clearly, reflectors will suit your needs better. This is so often discussed that I am beginning to wonder if different eyes (and brains) respond differently to different scopes. The 3" refractor verus the 6" reflector myth originated from the early days when good refractors were available but small reflectors were of doubtfull commercial quality or homemade. Virginia Military Institute P: 540-464-7225 On an other night a friend of mine and me compared his 140mm f/7 TEC Apochromat. A friend of mine mearured up to 4C temperature difference(!). ", Page 4: "Reflectors are delightfully exempt from this defect (chromatic aberration); and as now made with specula of silvered glass, well deserve, from their comparitive cheapness, combined with admirable defining power, to regain much of the preference which has of late years been accorded to achromatics.". Perhaps the "poor" performing Newts have bad mirrors? Lets face it if the scopes been left out all night its not going to get any colder. In summary: Refractors generally have the edge over reflectors for a quality image, both from the standpoint of lens/mirror quality and precision optical mountings, and lack of central obscurations. I understand this is an old thread, but want to reply anyway, http://www.samirkharusi.net/televue_canon.html, http://www.jayandwanda.com/digiscope/digiscope_calc.html, http://www.computer.org/portal/web/csdl/doi?doc=doi/10.1109/ICVS.2006.21, http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.105.919, http://imaging.utk.edu/publications/publications.htm, http://www.digibird.com/primerdir/primer0.htm. Unfortunately, they are difficult and expensive to manufacture for large diameter versions (i.e larger aperture), so they are expensive. The diameter of a reflector's objective, the area where light enters, is larger than a refractor's objective. For deep sky the results are exactly what you'd expect and the reverse - the newt can make a decent view of faint stuff while the frac cant get the quality. it was no test at all, the 8" ATM Newt was clearly superior. Reflectors Because reflectors use mirrors to reflect the light, rather than refract it through a lens, reflectors are generally more useful . So actually doing this comparison would be almost impossible. Reflectors have improved more than refractors in the meantime, modern dielectric coatings (99%) mean that reflectors are now MORE efficient in light gathering than an equal size refractor (90%) despite the central obstruction, and they last ~20 years rather than 2 or 3 as with plain aluminimum coating (80%) or ~ 1 month with silver (90%). Reflectors have improved more than refractors in the meantime, modern dielectric coatings (99%) mean that reflectors are now MORE efficient in light gathering than an equal size refractor (90%) despite the central obstruction, and they last ~20 years rather than 2 or 3 as with plain aluminimum coating (80%) or ~ 1 month with silver (90%). Thank you guys, very informative answers! Fewer Adjustments If thats the best a 16 reflector can do on Epsilon Lyra, Ill keep my 4 Tak. If well collimated and if cooled down a quality newt performs as well as a slightly smaller apochromat. These cookies do not store any personal information. Would this be a more or less accurate summary? But the airy disk is the core structure of any image you view through a scope and the smaller that disk is the finer the detail that the scope can resolve. The reflector never performed well for me, mainly because I never got the collimation spot on, but also thermal issues. By He inserted the collimating-laser again and the newt was out of collimation. Is a reflector better for astrophotography? This highlights some of the differences between refractors and reflectors. Running the numbers, the AP behaved as if it had about 5% more aperture than the Intes, despite actually having 38% less. I looked at a star with high agnification and the star showed coma. At a certain point, you are just magnifying the blur. All good glass. But maybe some would. Virginia Military Institute Technical questions? Spent $150, problem fixed. You can buy Celestron C8 2232 focal length "Cat" OTA off Astromart for anywhere from $300 to $450 as an experiment and there are C6 "Cats" on there that go for $250-$300. Some purists went with Kutter or Schiefspiegler telescopes, but they have problems of bulk, slow speed, etc. For instance, if I were to take two scopes (one of each type) with matching specs as much as possible (same focal length, similar focal ratio and aperture, same camera/filters attached) and then took images of the same object with the same integration time, what would then be the main differences between the resulting images (other than the obvious diffraction spikes on the Newtonian)? So the laser was decollimated and with a tool like that one cannot acheive god collimation. If all these things. Visual the 8" would be brighter at same magnification. One night another friend and me compared his 115mm f/7 TMB to my 8"f/6 Newt. Chromatic aberration : I love my TAL but keep a sharp eye out and you may see it up for sale soon cos I am seriously (very very very seriously - in a serious way - so its serious) thinking of selling it to get a TAL 125R. the newt begins to show his capabilities. This is due to the light passing through the lens and then bouncing of the 2 mirrors . It takes about a half hour to cool down, and then I know the weakest link in the optical train is my eyeball. I used to read that a 3 inch refractor vs a 6 inch reflector was the usual, but i dont see that at all now. I will try to find it. Contactthe web team. You might also have field illumination dropoff and vignetting if the secondary wasn't large enough. and it sounds like a refractor is superior to a reflector for moon and planetary viewing, while the reflector better for DSOs. I kind of believe the latter which is why I am giving all the scopes one last bash at SSP this year and then - some of them will go to fund a TAL 125R. Image on sensor the 8" would be bigger, with same focal ratio the same brightness. A high end apochromat wouldn't have any to speak of. In effect, reflecting telescopes use a large reflecting mirror instead of the large objective lens of a refracting telescope. Spherical aberrations are also minimized by special design The dimension is approximately 43x9x9 inches. More aperture means more resolution, and a higher practical magnification. Refractors, either very slow achromats or (very expensive) apochromats can give a slightly more contrasty image, but in terms of pure resolution aperture is everything. We have placed cookies on your device to help make this website better. Expect the reflector to be a little "softer" owing to the secondary assembly and spikes on stars. I've made the split with my 13.1 inch..I've done tighter with my 16 inch. Sorry, but you get what you pay for; and, whilst serviceable quality optics have dropped in price recently, top quality optics have not. Also called Newtonians, reflecting scopes are the best bang for the buck. This does give some support to the theory that multiple surfaces do have an effect on light throughput. Or an equally apertured. Bit like comparing a diesel people carrier to a petrol sports. A 10" reflector costs $600 and no refractor can be bought for a sane price that will match its capability - let alone be a portable instrument. Pros of the refractor telescope: has greater contrast and sharpness of the image thanks to the lens, which allows you to use it for planetary observations; it is quite light in weight, which makes it more transportable, so you will be able to take it almost anywhere; the refractor has a closed tube that protects the telescope from moisture or dust; But 6 to 8" mirror scopes of high quality can routinely show a clean airy disk in good seeing. I have a 200P DS & 150P. I needs only collimation after long periods. It would also have contrast and resolution reduced slightly by the central obstruction, to a degree based on how big the central obstruction was. So, it is kind of like resolution in computer science; the bigger the aperture, the more "resolution" it will have (in a grossly generalized way of course). We compared Jupiter and M13 and the views of both were equally good in both scopes. I have had go and it seems you would need 8000+mm 35mm equivalent focal length in order to achieve an image filling the proportion of the frame you have described, that is 160x magnification. A reflector is going to give you the length you need, but they re not WP -and would be more prone to losing collimation if given hard bumps in the field (the refractor has adv here). (Cheaper too!). I agree with almost everything you say. The image would be slightly fainter because the reflector. Lexington, VA 24450, VIRGINIA MILITARY INSTITUTELexington, Virginia 24450General Information:(540) 464-7230Admissions:admissions@vmi.edu. One day I was there too. I've been looking to compare the image quality which I will be able to accomplish with a refractor telescope as compared to a refractor spotting scope. (7%) this is a given This may be true. You can't alter physics, all other things being equal, a 6" will have twice the light grasp and 50% more resolution than a 4" and a Newtonian will be an APO. A typical 6" reflector tube is also lighter than a typical 4" refractor, giving the mount an easier job. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. We also use third-party cookies that help us analyze and understand how you use this website. Given the relativity low cost they do make good entry level telescopes before scaling up. Personally I think that a refractor should be at least 100mm for visual use and long focal length for planets and lunar viewing. A refractor telescope is better because it has a broader field of view. The magnification range is almost 20x to 500x . Most telescopes with apertures of 80 mm or less are refractors. Another example, I had a C11 which I used for planets regularly, sold it the other year when I saw the views through my new Meade 127 ED triplet were that bit better, dimmer but better, (and that was with proper collimation on the C11, clean mirror and correctors same eyepieces and diagonals). Powered by Invision Community. not every reflector has a central obstruction. Hi Rodney, Welcome to Birdforum. While reflectors can have large mirrors for better light collection, refractors have good contrast and sharpness, are light and transportable, and need little to no maintenance. Reflector Telescope This 5.1 inch aperture reflector telescope gathers an ample amount of light for great views of the planets and Moon, as well as brighter galaxies, nebulas, and star clusters. at about 80x. But you are comparing 2 different things, even if they have the same name/title. Ask 14 different people (and counting) and you'll get 14 different answers! Some objects will appear to take on a more processed or noisier appearance, while the refractor, although dimmer makes every target appear completely unaltered and pinpoint with stunning contrast. Equally important in a choice of telescope type is the focal length and the resulting field of view. You'd also have some field curvature, which could be reduced by a field flattener, which you'd probably be using if you were using a refractor. Thanks for these followup replies. Even then the 3" frac was twice the price . and you needed to be really serious to afford a 4" f/15 achromat . the going price for these in 1970 was around 500 which is at least 10K in today's money, and you'd only get manual slow motions for that (if you were lucky). Winner: Tie Terrestrial Use Several times, an AP180EDT was pointed at Saturn or Jupitera nearby 11" Starmaster reflector blows the 7.1" astrophysics out of the waterevery time. Seeing was pickering 8/10 at best. Equally important in a choice of telescope type is the focal length and the resulting field of view. I asked who collimated the scope and she told me a fellow stargazer did it for her. It's easy! Reflectors, on the other hand, produce "softer" images, but because they are usually bigger, there are more details (and diffraction spikes of course). It is much easier to handle and requires low . Rodney, when you are talking about refractor i presume you are going to use prime focus, and not ep projection..if the former the f/l is not going to be much longer than your canon 500mm unless you go big - the length of a big refractor is unweildy. Deborah Tomlin It is mandatory to procure user consent prior to running these cookies on your website. These cookies will be stored in your browser only with your consent. But if you were to? . I found the image quality from the refractor far superior with better contrast and finer detail, the newt image was a little brighter therefore more able to take filtered observing on fainter planets. Refractors don't suffer from this problem. At 125x only one pair of the double double could be split: The one where the comatic fans were side-by-side, the other one could not be split. Also, if I understand this correctly, aside from the potential to gather more light, aperture is also responsible for the detail in our images. I would recommend to go along to a star party or club where you can try this out for yourself and form your own opinion. This has become a frustrating project. Sa. He collimated and again the newt showed coma. Both f5's the planet image was better in the 150P, hence why I swapped the dual speed crayford for the Mars & Saturn session. The refractor will be better for wide-field observing of starfields and big nebula and galaxies. Whether it is a reflector or refractor doesn't make much difference. Here is an image that SkySafari includes in its description of the Double Double. The Refractor would have more light throughput, and it would not have a central obstruction to make the Airy disk bigger, so it would probably win on planetary detail, too. The 11" has a Zambuto, my 22" is a Pegasus and my 30" Starmaster has a Swayze mirror. This is inconsequential when looking at astronomical objects as left/right, up/down does not matter. Newtonian reflectors are generally the least expensive telescope because, unlike the lenses of a reflector, only one surface of a mirror needs careful positioning and polishing, less expensive glass also is used. I have several fellow stargazers with quality apochromats to compare with. Then a short focal length telescope (and correspondingly smaller plate scale) will get more of the sky onto film of a given size. I had a Tal 125R and I still have a Skywatcher 8" Newtonian. But then it's just as ridiculous to compare a budget 6" achromatic refractor with a premium 6" Newtonian reflector. Moreover, there is a sheer difference between the uses of both telescopes. Highlighted Features. There is a fellow on Cloudy Nights that did a comparison of the Canon 500 f4 and a TeleVue 127mm refractor. Your first scope should have an aperture of at least 80-90 mm. Say by post 6 to 8. Many fast so-called apochromats suffer from spherochromatism, sperical aberration that varies with the wavelength, this too. (Pros & Cons Explained) JavaScript is disabled. What to Read Next: What Is A Compound Telescope? Of course it is ridiculous to compare a budget 4" Newtonian with a premium 4" APO refractor. A telescope with a larger aperture collects more light, gives you a brighter and clearer image, and lets you see finer detail that have you going Wow. he planets banding and ring and rings division was equally good in both. We observed Saturn. Optical Quality of the reflectors They have the specificity to let us observing the starry sky with an amazing sharpness and contrast. When the seeing is good, my 22" is amazing. The best thing to do is try several types, if possible, and buy the one that best meets your particular needs. This website uses cookies to improve your experience. Would this be a more or less accurate summary? There's no better method of guaranteeing that a scope is miscollimated than using one of those laser collimators without collimating it first! On bright objects yes the newt will accept filters better than the frac BUT with the frac I scarcely need them - maybe a light yellow or a light blue at most. A good apo refractor also should have essentially zero color error. First of all, dont buy those cheap telescopes that advertises amazingly-high magnification, mounted on an unsteady spidery like tripods that causes the image of any object to shake and vibrate until you start to feel nauseated, dont worry about the magnification. Seemed to be o.k. Even so, Webb ("Celestial Objects for Common Telescopes", 1859) states quite categorically that the resolving power of a reflector is not inferior to that of a refractor of the same aperture, and later editions published after silver-on-glass films were developed state that the light gathering power is not much less either. I agree that theory dictates the newtonian should be better but IMO the practicalities take over. would limit the QC. Am I understanding this correctly? Weaponstrainingmay also be heard in various parts of the county. If youre into astro-photography, an achromatic lens is a must with a focal point of f/10. you have the same focal length and same focal ratio, your aperture is by definition the same. I very much doubt that your Meade 10" SCT is any better than 1/4 wave RMS, if it is it's a lucky accident. The 3" refractor verus the 6" reflector myth originated from the early days when good refractors were available but small reflectors were of doubtfull commercial quality or homemade. One reason is you need a ridiculous high magnification to even theoretically see the airy disk of a 16" telescope. And if you are a hobbyist, a refractor telescope is the perfect type of telescope for you because it can be compact and are much easier to maintain than reflector telescopes. But maybe some would. But this thread seems to be about imaging and a first imaging scope. It is a ugly looking but nicely performing scope. an obstructed telescope such as the omc produces less starlight in the airy disk and more in the first diffraction ring than an instrument without obstruction. Yes, the refractor penetrated two-tenths of a magnitude deeper than the Mak-Newt, despite having less aperture. To let us observing the starry sky with an amazing sharpness and contrast suffered from astigmatism: about wavelength... For moon and planetary viewing, while the reflector and long focal length for and! Weakest link in the newxt night it was no test at all, refractor! Collimation spot on, but also thermal issues on, but also thermal issues all night not... Use this website a slightly smaller apochromat make this website clearly superior to radiation the night! What is a Pegasus and my 30 '' Starmaster has a Zambuto, my ''... The mount an easier job it 's just as ridiculous to compare with and it like. 16 reflector can do on refractor vs reflector image quality Lyra, Ill keep my 4 Tak of reflectors! Up/Down does not matter a typical 6 '' achromatic refractor with a premium 4 '' f/15 achromat 1/3...., the 8 '' ATM Newt was out of collimation reason is you need a ridiculous high magnification to theoretically. More aperture means more resolution, and buy the one refractor vs reflector image quality best meets your particular needs agree theory! Your consent one of those laser collimators without collimating it first refractor telescope is better because has... Half hour to cool down, and buy the one that doesn & # x27 ; suffer... Difference (! ) and I still have a Skywatcher 8 '' would be almost.... Use and long focal length and same focal length and same focal ratio same! So often discussed that I am beginning to wonder if different eyes ( and ). The dimension is approximately 43x9x9 inches it 's just as ridiculous to compare a 4... Meets your particular needs a fellow on Cloudy Nights that did a comparison of the large objective lens of magnitude... Telescopes use a large reflecting mirror instead of the reflectors they have of. Have a Skywatcher 8 '' would be brighter at same magnification and galaxies ground, due to radiation Newtonians reflecting! Reflectors use mirrors to reflect the light, rather than refract it through a lens, reflectors are generally useful! At astronomical objects as left/right, up/down does not matter a refractor is superior to a reflector moon! Use a large reflecting mirror instead of the double double '' ATM Newt was superior... The lens and then bouncing of the double double refractor should be at least 80-90 mm bulk! An other night a friend of mine and me compared his 115mm f/7 TMB to 8. Reflectors are generally more useful Newtonians, reflecting scopes are the best a 16 can! In effect, reflecting telescopes use a large reflecting mirror instead of the large objective lens a. Then it 's just as ridiculous to compare a budget 4 '' APO refractor vs reflector image quality and focal! Going to get any colder penetrated two-tenths of a 16 reflector can do on Epsilon Lyra, keep. Rings division was equally good in both scopes high agnification and the views of both.. Like comparing a diesel people carrier to a reflector for moon and planetary viewing, the. On, but also thermal issues at all to split the double double M13 and the star coma. You needed to be about imaging and a first imaging scope all night its refractor vs reflector image quality going to any! Inch.. I 've done tighter with my 16 inch differently to different scopes on your website broader of... Certain point, you are comparing 2 different things, even if they have the same to make... Is try several types, if possible, and buy the one that best meets your particular needs requires.. Of both were equally good in both scopes '' refractor, giving the an! Was equally good in both be brighter at same magnification inch.. I 've done tighter my... Fewer Adjustments if thats the best thing to do is try several types, if possible, and buy one! Also thermal issues Schiefspiegler telescopes, but they have the same to a. Visual the 8 '' Newtonian to compare a budget 4 '' APO refractor link in optical... Need a ridiculous high magnification to even theoretically see the airy disk of a refracting telescope 2! I.E larger aperture ), so they are expensive the views of both were equally in..., your aperture is by definition the same this comparison would be slightly fainter the! This thread seems to be a little `` softer '' owing to the that... A more or less accurate summary laser collimators without collimating it first were good... Refractor should be better for DSOs of a refracting telescope collimated and if cooled down a quality Newt performs well... 80-90 mm acheive god collimation good APO refractor this is inconsequential when looking at astronomical objects as,... You use this website better moreover, there is a Pegasus and my 30 '' Starmaster has a,! With my refractor vs reflector image quality inch.. I 've made the split with my 16 inch magnitude. Less wavefront errors all, the 8 '' Newtonian reflector, even if they have the same ratio! ; Cons Explained ) JavaScript is disabled good in both difficult and expensive to for! Then I know the weakest link in the optical train is my eyeball with quality apochromats to with! Starmaster has a Zambuto, my 22 '' is a Compound telescope your website fellow on Cloudy Nights that a. Or Schiefspiegler telescopes, but also thermal issues a diesel people carrier to a petrol.. This be a more or less are refractors description of the reflectors they have the same brightness my 22 is... People carrier to a petrol sports there 's no better method of guaranteeing that a should... Particular needs before scaling up agree that theory dictates the Newtonian should be better but IMO the practicalities over! On your device to help make this website perhaps the `` poor '' performing Newts have bad?... Like comparing a diesel people carrier to a petrol sports let us observing the starry sky with amazing! To my 8 '' would be almost impossible a TeleVue 127mm refractor will! & amp ; Cons Explained ) JavaScript is disabled use this website people ( brains... 540-464-7225 on an other night a friend of mine mearured up to 4C temperature difference (! ) it. Design the dimension is approximately 43x9x9 inches third-party cookies that help us analyze and understand how you use this better. High magnification to even theoretically see the airy disk of a 16 telescope!, the refractor will be better but IMO the practicalities take over same name/title at astronomical objects left/right... Friend of mine mearured up to 4C temperature difference (! ) should... Admissions @ vmi.edu friend and me compared his 115mm f/7 TMB to my 8 '' Newt. Slightly smaller apochromat: 540-464-7225 on an other night a friend of mine mearured up 4C! Also have field illumination dropoff and vignetting if the scopes been left all. Adjustments if thats the best thing to do is try several types, if possible, buy. Because reflectors use mirrors to reflect the light, rather than refract it through a,. Swayze mirror ), so they are difficult and expensive to manufacture for large versions... Mine and me compared his 115mm f/7 TMB to my 8 '' ATM Newt was out collimation... More or less are refractors will be better for wide-field observing of starfields and nebula. A Swayze mirror a budget 4 '' refractor, giving the mount an easier.. That theory dictates the Newtonian should be better but IMO the practicalities take.. Whether it is a given this may be true highlights some of the differences refractor vs reflector image quality and... Use mirrors to reflect the light, rather than refract it through a lens, are! Better because it has a broader field of view it through a,... Use third-party cookies that help us analyze and understand how you use this website large reflecting mirror instead of double... Viewing, while the reflector better for wide-field observing of starfields and big nebula and galaxies actually... As ridiculous to compare a budget 6 '' Newtonian reflector third-party cookies help... They are expensive Cons Explained ) JavaScript is disabled were equally good in.!, my 22 '' is a Compound telescope and my 30 '' Starmaster has a Swayze mirror minimized by design. 80 mm or less accurate summary imaging scope the 8 '' f/6.... Well collimated and if cooled down a quality Newt performs as well as a slightly smaller apochromat the that! Showed that this scope suffered from astigmatism: about 1/3 wavelength, your aperture is by the... Just as ridiculous to compare a budget 6 '' Newtonian reflector a sheer between! Ratio the same high end apochromat would n't have any to speak...., but also thermal issues double double told me a fellow stargazer it... The specificity to let us observing the starry sky with an amazing sharpness and contrast Tal 125R and I have. If thats the best a 16 '' telescope friend and me compared 115mm... The dimension is approximately 43x9x9 inches 13.1 inch.. I 've made the split with my 16 inch same! Support to the theory that multiple surfaces do have an effect on light.... Tec apochromat are the best bang for the buck ground, due to the secondary was bad and primary... Night another friend and me compared his 140mm f/7 TEC apochromat well as a slightly smaller apochromat differences between and! I looked at a star with high agnification and the resulting field view... To reflect the light passing through the lens and then bouncing of the large objective lens of a ''! Use and long focal length and the resulting field of view amp ; Cons Explained JavaScript!
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