Specially-designed focal reducers are available for use with these telescopes. 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. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. 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. This article explains the basics of how focal reducers work with an astronomy telescope. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. First, let's have a look at some key optical parameters are needed to understand focal reducers. I have/had both the Celestron (Japan) and Antares units. You don't need to follow these equations to use a focal reducer, but they do show how the reduction factor changes with the placement of the reducer. I use the same back spacing for both on a small 6" Celestron SCT. ), but stars seemed a bit tighter and their colors were richer and more dramatic. 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. 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. Just one question. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. 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. 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. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. Given past experience with them, I decided not to include the Meade version in my little experiment, as I have never met one I liked from getting one of the too-short focal length models, to one with some overflow cement in the doublet, to focus difficulties with some eyepieces. The reducer fits all Meade and Celestron . All Rights Reserved. Contiguous US Customers:All items we sell ship for free within the Contiguous US. 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. I only have the Celestron f/6.3. For imaging, a T-adapter is threaded to the camera side of the focal reducer, which in turns connects to the camera with the appropriate hardware. JavaScript seems to be disabled in your browser. I have the Antares and have no complaints. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. Yet, the Antares still easily and fully threaded without any hitches. Sign up for OPT news, exclusive offers, and updates on the latest gear! Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. I don't know. Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd Figure 2 shows the effective of a focal reducer on the light from a telescope objective. 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. Torazz 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). A few large telescopes and mounts are excluded from this free shipping offer. Brightness, color, and contrast were subtly different, but could be as much the day they were coated as any real difference in the two brands. For example, many focal reducers designed for f/7 or f/8 ED refractors such as those from Tele Vue, William Optics, Sky-Watcher, and Meade are designed to have a working distance (or back focus) of 55mm. Again, these focal reducers are often provided by the telescope manufacturer. Hmmm . and you will be fine. Does anyone have any experience with the Celestron and Antares focal reducers? If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. Completely stuck, completely frustrated. The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 1100 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object . This is a. You currently have javascript disabled. Not one detectable iota of discernable difference. We will be glad to help. CPWI has an extensive object database, employs PointXP mount modeling, and more. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. Michael 1 ronin Members In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? We process your personal data as stated in our. However, manufacturers virtually never provide this specification. There are many different types of focal reducers and they all effect. Meade once made an f/3.3 focal reducer for SCT scopes. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. This means that there must be sufficient travel on the telescope focuser to make up for this. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. Benefits limited to hardware and conditions? Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. 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? As a real-world example plot showing the above relationships, let's look at the 1.25" GSO focal reducer that provides a design reduction factor of 0.5x. It's easy! The lens is housed in machined aluminum for are machined aluminum black anodized. Some refractors such the TeleVue Nagler-Petzval (NP), the Takahashi "FSQ", and the William Optics Redcat/WhiteCat 51 have inherently flat fields because of internal optical elements. Based on Test 1 and Test 2, I think there is perhaps more validity to opposing statements here in these forums that the Antares and current China-made Celestron do, indeed, have exactly the same optics just with different housings and branding. They never really recovered from selling a few 15 years back with element reversed. Fumbling around in the dark, fine threads might be a problem. All additional accessories mount onto the exterior/male threads. Enter it during checkout! The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. By using this site, you agree to our Terms of Use. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. We have corrected # (iii) after equations 6 & 7. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. Increase that distance, and greater reduction results and visa versa. Reducer Lens .7x - EdgeHD 1400 It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. 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. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Imagine having two telescopes in one a long focal length instrument for lunar and planetary work and a short focal length scope for deep sky observing and astrophotography. Most refractor manufacturers such as William Optics, Tele Vue Optics, Explore Scientific, Sky-Watcher, William Optics, and Stellarvue make their own focal reducers optimized for use with their telescopes. It was used strictly for imaging, not visual observing. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. My Celestron was made in China and the Antares in Canada. They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. 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. 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. The nominal design reduction factor of these reducers is typically 0.5x. A couple of tiny dust particles between lens elements, uneven lens edge blackening, very minor coating blemishes, or even a very small fine lens scratch or two are very common in this Antares product and must be accepted as normal for this item. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. Not noticed any optical problems. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. Normal shipments will resume on Monday, March 6, 2023. nleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. 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. Please note, orders placed after 10am on 2/28/2023 will be delayed. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. Increasing the operating distance, that is, moving a focal reducer away from the eyepiece or camera reduces its reduction factor, or conversely increases the amount of reduction. We will match any online price that we confirm as valid. You cannot, for example, use a 0.63x focal reducer intended for a standard Celestron or Meade SCT and use it on a Celestron Edge HD or a Meade ACF. 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, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. This focal reducer from Celestron reduces the effective focal length by 0.63X Enjoy the wider field of view & faster exposure times at f/6.3 with f/10 telescopes f/11 telescopes, such as the C14 will perform at f/7 The Celestron f/6.3 Reducer has four fully-multicoated elements Reduce your exposure times by a factor of 3! Reducer Lens .7x - EdgeHD 800 Learn More. 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. Thanks guys, appreciate the feedback. You need to be a member in order to leave a comment. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. It must be in stock at the time of Price Match for us to make a guarantee. 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. 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. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. I wish there was. It's usually specified in millimeters. How to Set the Correct Back Focus for Your Telescope (Guide) It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. What is likely is that fatigue sets in, and also that as the targets move toward or a way from the meridian there will be changes for that reason alone. I have the Japanese version and although I haven't used it in quite awhile, the views through it were superb with no internal reflections at all. If I had to guess, the difference is maybe 10-15 grams. During a twenty-year scientific career, he developed laser systems to detect molecules found in interstellar space and planetary atmospheres, and leveraged his expertise to create laser technology for optical communications networks. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? No negative issues to report. Read our 101 article or get in touch. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). To further factor out my natural astigmatism (I normally wear glasses while observing), I did the tests with my regular progressive lenses, single vision glasses I use when observing, and naked eye. control and Sky Viewer display makes selecting your target easy. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. I'm going with the Celestron. I was going to measure the difference in grams, but my lovely wife caught me trying to use her precious, high-tech kitchen scale for the cause, and put the kibosh on it. Reducer - Corrector The working distance or required back focus, explained above, is usually specified and is far more important in practice. For Stephen Wilkerson: The ZWO ASI120MC-S does come with a wide angle lens, HOWEVER, it is NOT intended to used when you are using the ASI120 camera attached to your telescope. If you are using a camera that has a back focus of less than 55mm, additional spacer rings will be required between the reducer and the camera. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. I am a purely visual observer, so will evaluate for visual use only. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Focal Reducer for SCT - ACF - Stargazers Lounge 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. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. looks virtually identical, except for the lettering. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. That's partly because focal reducers correct for field curvature, which itself depends on the focal ratio and other optical design factors of the telescope. October 11, 2010 in Discussions - Scopes / Whole setups. Celestron & Antares f/6.3 Reducer/Corrector Shoot-out The easiest way to use a focal reducer is to make sure you place it at the specified working distance in front of your camera or eyepiece. All Rights Reserved. Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope Article Agena AstroProducts, 2019. To test this, I used three set-ups: 1. ), ASI Air Plus - Connected items are 'greyed out', Cost of ordering used equipment U.S. - Can can more than double figure, Tuthill Isostatic Mount and Star Trap Power Module.
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