The author finds differences in throughput and color balance, but then says he thinks the lenses are identical and he reaches his conclusions based on very long observing session. These 0.63x focal reducers were originally designed to optimize for an image circle to match 36mm x 24mm film or its digital equivalent for astrophotography. As mentioned in Section 2.3, the reduction factor for these focal reducers can be varied by adding spacers to move the reducer further from the camera sensor or eyepiece. Unique focal reducer and field corrector lens accessory Reduces the focal length and f/ ratio of your Schmidt-Cassegrain telescope by 37% Provides a dual focal ratio instrument, without sacrificing image quality Compatible with all Schmidt-Cassegrain telescopes (see compatible list in description) Share Customers Also Purchased Description The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. This article explained the basics of how focal reducers work with various kinds of telescopes and how their working distance affects their reduction factor, and it provided sufficient detail to help amateur astronomer choose and use the right focal reducer for a particular application. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. The distances d1 andd2 can also be expressed in terms of the focal length of the focal reducer FR with the lens equation: Using Equation 2, Equation 1 can also be expressed in terms of d2: The focal reduction factor of the focal reducer depends on its focal length and its distance from the focal plane of the objective as shown by Equation 4: Again, for example, when the focal reducer is placed at the original focal plane of the objective, d1=0 and MR=1, which means there is no focal reduction. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. I have the Antares and am not unhappy with it, but for AP I would want more back focal distance if those numbers are accurate. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). However, I noticed immediately that the Antares had a bit more of an heft to it, giving it a solid feel the Celestron didnt possess. There are many different types of focal reducers and they all effect. This is the distance at which the reducer must be placed in front of the eyepiece or camera focal plane in order to operate at the design reduction factor. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. This would tell us exactly how well aberrations are corrected. Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd Enter it during checkout! As often noted in reviews and forum threads, Antares products tend to have threads that are a little less precise, and this specimen certainly demonstrated this. Copyright 2003-2022 Agena AstroProducts. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Like many of us with SCTs, I have bought and sold a number of f/6.3 reducer/correctors over the years, and I have always been curious how they really stack up to each other. When placed in the focal plane in front of a camera or eyepiece, a focal reducer leads to a wider field of view and a brighter image of extended objects, which is important for reducing the exposure times when imaging faint extended objects like nebulae or galaxies. Its a good thing I have the super lube handy or my neighbors wont be happy with me.come to think of it, Im sure the small mammals here wouldnt be thrilled either! Celestron Reducer Lens .7x - EdgeHD 925 The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 925 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object 5-element lens design Maintains similar. These reducers have a back focus (or design working distance) of 80mm. - thanks. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. To test this, I used three set-ups: 1. At least these two units I tested make the answer - whatever. The working distance or required back focus, explained above, is usually specified and is far more important in practice. Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! Sign up to get exclusive deals, observing tips, and new product announcements. Things change but when I rebought I got an Antares and it seems about the same to me. All Rights Reserved. However, these will not impact optical performance. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. The female end attaches to the rear cell of the telescope. I have the Antares and have no complaints. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. The stars at the edge could be worse or better. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? StevieDvd Members 1,182 1,812 Location: Stevenage, UK Posted March 9, 2021 (edited) Don't know but your welcome to try out my Meade 6.3 sct reducer next time you are passing. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. Nada. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. Photographically you also get a wider field and much shorter exposures. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. For the best experience on our site, be sure to turn on Javascript in your browser. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. Reducer Lens .7x - EdgeHD 1100 Learn More. For imagers using longer focal-length refractors and SCTs, especially when using smaller sensors that place less demand on the focal reducer, there are economical alternatives for focal reducers from manufacturers such as GSO, Agena, and Antares. Celestron or Antares? Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. Perfect for the serious student, professional scientist and discriminating hobbyist. EclipSmart solar products feature Solar Safe filter technology providing the ultimate protection from harmful solar radiation, including both IR and UV light, and filters 99.999% of visible light. Copyright 2021 Stargazers Lounge It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. Hi. This superb fully multi-coated multi-element focal reducer takes advantage of the latest computer aided design techniques to achieve the highest standards of performance set by the brand leaders at a fraction of the cost. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. I have both the Antares and the Celestron reducers. During checkout, you may also be shown other optional faster shipping choices.US Customers in Hawaii and Alaska: Free shipping applies to almost all products. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. Your mileage may vary. JavaScript seems to be disabled in your browser. I use the same back spacing for both on a small 6" Celestron SCT. 2.2 Using a Focal Reducer at the Working Distance, 2.3 Adjusting the Reduction Factor of a Focal Reducer, 3.3 Focal Reducers for Compound Telescopes, 3.5 Focal Reducers for Ritchey-Chretien and Field Flattened Scopes, 3.6 Focal Reducers in 1.25" and 2" Barrel Formats, 4. I wish there was. High power views will provide flatter fields all the way to the edge, both visually and photographically. Copyright 2003-2022 Agena AstroProducts. Now It only focuses near things, like some kind of macro zoom. In this configuration, the 29.5mm camera nosepiece and a 6mm extension ring positions the reducer at a working distance of 53.5mm from the camera sensor, which is located 12.5mm inside the front edge of the camera. When you said, "in some cases" a focal reducer also works as a flattener/corrector, are you saying that not all focal reducers are flatteners/corrector? It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . If a stronger level of focal reduction is used, say 0.5x, then the image circle may be too small to fill the sensor of larger cameras. It is not a corrector or flattener. Explicitly designed for Celestron Schmidt-Cassegrain telescopes, this unique lens reduces your telescopes focal length and f/ ratio by 37%, turning your long focal length telescope into a fast, short focal length instrument. If used before or beyond the working distance, unwanted image distortion may result. The reducer fits all Meade and Celestron . However I've also read that the back focal distance on the Celestron is 105mm while the Antares is 81mm so they couldn't be identical. Focal reducers for refractors with focal ratio of f/7 to f/9, roughly, have a design reduction factor of about 0.75x to 0.8x and produce a flat field by correcting for the curvature of the objective lens. A reducer is a set of converging (or positive) lenses that cause the light from a telescope objective to converge at a steeper angle to the focal plane as if it were coming from an objective with a faster (lower) focal ratio and a shorter focal length. How does it look thats what matters. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. Product Details Antares' f/6.3 focal reducer provides a faster f/6.3 system for imaging or visual use when used with an f/10 SCT or other compatible telescopes.
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