This would tell us exactly how well aberrations are corrected. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. You attach the focal reducer to the rear port on a SCT and can keep it covered. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. JavaScript seems to be disabled in your browser. The review is a subjective visual impression, which is interesting but not best evidence. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. All rights reserved. Weasner's Meade and Antares Focal Reducers Review With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. 800-483-6287 However, in principle, the reduction factor of a focal reducer can be varied by changing the distance from the back of the focal reducer to the camera or eyepiece. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; 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). 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! Is that distance D= Fo-d1=Fo-(d2/MR)? The design reduction factor of a focal reducer is the relative amount by which the effective focal length of the telescope is reduced when the focal reducer is used at its specified working distance or back focus. Fastar Technology allows imagers the option of drastically increasing the speed and sensitivity of their Celestron optical tube, allowing bright, detailed images with short exposures. In this case, an additional T-adapter (with an optical length of 50mm) is needed to get the spacing correct for a DSLR or other camera with a 55mm back focus. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. In such cases, we will be happy to take the item back as per our standard return terms. For visual use, this means you get lower power with the same eyepiece and a wider field of view. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. I'm going with the Celestron. 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. The price for an item/offer must be listed and valid at the time of match. 2023 OPT Telescopes. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. I focus using a moonlight electronic focuser and focusmax. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. This means that there must be sufficient travel on the telescope focuser to make up for this. - thanks. The Antares focal reducer comes in small box. Focal reducer for 8SE - Celestron vs. Antares - Cloudy Nights The camera side of the focal reducer is threaded for a T-adapter with wide M48 threads, or in some cases, with smaller M42 threads. These reducers have a back focus (or design working distance) of 80mm. Contiguous US Customers:All items we sell ship for free within the Contiguous US. No results, please adjust your filters. The Celestron f/6.3 is ~150 compared to the Antares at ~70. A few large telescopes and mounts are excluded from this free shipping offer. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. This telescope control software replaces the hand control and allows the user to remotely control their Celestron computerized telescope from their personal PC or laptop. 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. Focal Reducers | Celestron He also holds a Ph.D. in engineering physics from McMaster University. 2023 Celestron, LLC. Meade and Celestron both sell such SCT-T adapters with the correct optical length. Does anyone have any experience with the Celestron and Antares focal reducers? It's easy! If the focal reducer is to be used for visual observation, the visual back is threaded onto the eyepiece side of the reducer, and then a star diagonal and eyepiece are installed as usual. Several functions may not work. On the trail, at the job site, in the classroom, or simply sitting at home relaxing the Celestron Elements ThermoTank 3 will keep your hands toasty. And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. While most Barlow lenses and focal extenders work with most kinds of telescopes available to amateur astronomers, focal reducers are designed to work in a narrow range of focal ratios of a telescope objective. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. Clean, fun jokes the tradition continues - Page 106 Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. Reducer Lens .7x - EdgeHD 925 Learn More. I have the Antares and have no complaints. It might work but it does not tell us anything about how well or to what extent the product works to correct the field of an SCT. Have a promo code? Torazz Much to my surprise, swapping back and forth between the two correctors using all three diagonal configurations, I also could detect absolutely no change in reduction between the two reducers. 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. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. The designed reduction factor (0.5x in the case of the GSO reducer example above) should be considered a rule of thumb or approximate value in most cases, rather than a very precise number. Some coma is visible in the corners, but the image is quite good for EAA applications. 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. Unlike . I have had the Japan unit on the back of my C5 since 1994 or thereabouts. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. because they really dont matter. This fully multi-coated lens provides maximum light transmission with near full-field illumination. Thanks. Reviews. There are also third-party vendors such as Hotech. Increase that distance, and greater reduction results and visa versa. In this case, d2 = FR/2, which means the back of the focal reducer is located at a distance FR/2 from the camera or eyepiece. Brian Ventrudo is a writer, scientist, and astronomy educator. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. This is one of our best-selling items, and customers have reported that this product is at least as good as, and probably better than, other leading f/6.3 focal reducers sold on the market for a lot more. The equations in the Appendix show how this all works. Keep in mind that these differences were very subtle, and could be due to normal variations in coatings among different runs, and not necessarily unique to the brands. Reducer Lens .7x - EdgeHD 1400 Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd Using these numbers in equation 4 in the Appendix, below, we can easily calculate that the focal length of this unit is approximately103mm (it will be 103mm plus the small amount by which the rear lens surface of the reducer is recessed beneath the reducer housing). As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. With the Celestron Reducer/Corrector Lens, thats precisely what you get. Product Details. These scopes are compatibles with focal reducers. For these items, please contact us to obtain a shipping quote before you check out using the online shopping cart.International Customers:Free shipping does not apply to international orders. 3. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. I use the same back spacing for both on a small 6" Celestron SCT. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. Reducer - Corrector ), but stars seemed a bit tighter and their colors were richer and more dramatic. It must be in stock at the time of Price Match for us to make a guarantee. Very helpful, thanks a lot for this article! Back-Focus 101: DSLR Cameras & the Celestron f/6.3 Reducer - YouTube Free shipping $189.95 But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? More details are found in the Appendix of this article. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope Meade once made an f/3.3 focal reducer for SCT scopes. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. I wish there was. In practice, it's important to remember that you will rarely operate at the exact working distance and at the exact reduction factor that is specified. 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. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). Blue Fireball M42 T/T2 Thread Camera Adapter for Prime Focus Photography - 2" # P-06, Celestron T-Ring for Canon EOS Camera # 93419, GSO 2" Crayford Focuser for SCTs - Dual Speed, Length of male SCT thread = 5mm (0.2") but this is preceded by an unthreaded part on the eyepiece side making the total length = 8.8mm (0.35"), Length of female SCT thread = 7.5mm (0.3"). Celestron or Antares? Using one on such a scope would make demands on the eyepiece design and increase the exit pupil to an extent that focal reduction on fast Newts is not practical. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a Hyperstar 7,758 views Mar 28, 2018 145 Dislike Share Ray's Astrophotography 42.3K subscribers Note: I am not paid or. For both imaging and visual observing, these reducers also improve image sharpness at the edge of the field by correcting for coma and field curvature. They are reported as identical. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. However, doesn't fit in the telescope and even if it did wouldn't work. Or, when the distance of the focal reducer to the focal plane of the objective d1 equals the focal length of the focal reducer FR, the reduction factor MR = 0.5x. I am new to these optic topics, and I want to ask you what happens with Masutov like SW or Celestron 4 or 7 inches. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. I doubt there is any difference between the Antares and the Celestron except price. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. Please re-enable javascript to access full functionality. 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. 2. Obviously bright objects like Jupiter or The Moon show the reflections. Focal Reducer for SCT - ACF - Stargazers Lounge The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. For example, with a 0.8x focal reducer, a telescope with a focal length of 800mm will operate at 800 x 0.8 = 640mm when the reducer is placed at the working distance specified by the manufacturer. Many reducers, such as the Celestron HD focal reducer mentioned above, and many focal reducers for apochromatic refractors, are meant to be used within a few millimeters (or less) of the specified working distance to achieve the best possible image results. Again, swapping back and forth for a couple of hours on M44, M35, and several brighter stars, I examined the shape of specific stars near the edge of the field with both correctors. GSO, for example, has a 0.75x reducer for RC scopes with a back focus of 80mm, which is usually enough room for a wide range of astronomy cameras and accessories and spacers as needed. So, if you have a filter that is 3mm thick, you need to add 1mm of spacing to your imaging train to retain the correct back focus. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a Telescope Focal Reducers & Correctors - High Point Scientific Because of their distinct optical design, slower Schmidt-Cassegrain telescopes (SCT) with focal ratios of f/10 require a different design of focal reducer compared to refractors. Using an eyepiece with a 27mm field stop with the reducer will illuminate the edge the same as using an eyepieces with a 42.9mm field stop without it. Great report and verifies what I had thought all along, Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. 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. So, this past week I challenged the Antares and Celestron models to a head-to-hear on my C8 on some decent nights of good seeing and transparency in my Bortle 5-6 urban skies. Benefits limited to hardware and conditions? This should not be the case if they have their purportedly different focal lengths. Can you help me? Hence, there is a chance that you may not be able to thread your SCT diagonal or other SCT accessory on to this reducer for these or for any other brand. The f/6.3 reducer is operating at f/5-f/5.5 with a 2" diagonal, depending on the back focus length of the diagonal. As mentioned in Section 2 of this guide, the reduction factor of a focal reducer depends on its position in the optical path relative to the eyepiece or camera. This is very impressive performance given how hard this problem is to mitigate in general. It threads onto the rear cell of 5" to 16" Celestron and Meade Schmidt-Cassegrain telescopes, making it possible to have a dual focal ratio instrument without sacrificing image quality. Antares F/6.3 SCT Focal Reducer | OPT Telescopes If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. The previous post shows the reducer on what appear to be two different refractors. Not one detectable iota of discernable difference. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. This standard distance is a consequence of the design of DSLR cameras for which the distance of the sensor to the outer edge of the flanges is about 45 mm, while the T-ring that attaches to the flange for astrophotography is about 10mm thick. No retailers currently carry this product. 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 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. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. Reducer Lens .7x - EdgeHD 925 ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. Reducer Lens .7x - EdgeHD 800 As I understand it, compared to the old Meade SCT's, the ACF is already "coma corrected", so the standard Meade, Celestron etc F6.3 focal reducers are not suitable and will only worsen the images. Right off the bat, I was struck by how similar the two R/Cs were. Advanced designs for Schmidt-Cassegrain scopes such as the Meade ACF or Celestron Edge HD have optical elements in the tube to correct for coma and field flatness. Wonder how they would stack up with a Japanese 6.3. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. Can these economical focal reducers from GSO and other vendors result in good images? Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. The working distance of the GSO 0.5x focal reducer with 1.25" barrel and the GSO 0.5x focal reducer with 2" barrel is about 51mm to 53mm, approximately, from the middle of the metal cell that holds the lens. Celestron or Antares f/6.3 focal reducer for SCT? I was originally hoping to do this with a made in Japan Celestron, but ended up with a newer China version but thats probably better in the end since it is the version now available, with the Japan ones rarer and only available used. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. For the best experience on our site, be sure to turn on Javascript in your browser. Reducer Lens .7x - EdgeHD 1100 Learn More. At least these two units I tested make the answer - whatever. Once focused it's pretty good. Antares Click Lock Visual Back - posted in Cats & Casses: Here is the situation:I bought a Celestron CPC 1100 for visual use.Want to put on the scope simulteanously a6.3 focal reducer, filter wheel, and aneyepiece turret. Yet, the Antares still easily and fully threaded without any hitches. The Antares is supposed to be pretty comparable. The two samples I have PERFORM IDENTICALLY. Reducer - Corrector | Celestron Try & buy if you like - usual mates rates. There are many different types of focal reducers and they all effect. All Rights Reserved. Antares f/6.3 Focal Reducer for SCTs - Awesome Astro No difference. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. This rugged, 3-in-1 device features a true tactical 3-mode flashlight, a hand warmer, and a portable power bank for recharging your personal electronics on the go. JavaScript seems to be disabled in your browser. I have this one Opticstar F6.3 Focal Reducer / Corrector. Because I have not heard any complaints about the made in China R/C. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. By When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. Copyright 2003-2022 Agena AstroProducts. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. At a significantly lower price point, the Antares is a steal, and theres no need to upgrade to the Celestron if you already have one. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. However, these will not impact optical performance. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. 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. And when d1 = FR, that is, when the focal reducer is placed at a distance from the focal plane of the objective that's equal to the reducer's focal length, the focal length of the combined optical system is Fo, so it acts as a 0.5x reducer. Turn it on and push Align. In about three minutes, youre ready to observe! Hi. If I had to go out on a very thick limb, I would have to say that these two reducers/correctors are, indeed, identical the exact same glass in slightly different housings with different lettering. Even though the manufacturer did not specify the working distance or focal length of this reducer, it is easy to see from this plot that this item provides its stated reduction of 0.5x when it is placed at a working distance of 51.5mm between the base of the threads on the mount and the focal plane of the eyepiece or camera. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? Read our guide! As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes.

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