Your mileage may vary. Obviously bright objects like Jupiter or The Moon show the reflections. Most amateur astronomers are familiar with a Barlow lens (or a focal extender), a negative or diverging lens that effectively increases the focal length and the focal ratio of a telescope's objective lens. Getting the proper back-focus for your imaging camera is a vital step in getting the best data possible out of your telescope imaging/research rig. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. . 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. 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. The key points are as follows: So just remember that a smaller distance (from the camera or eyepiece) means a lower amount of reduction (and vice versa). Despite never removing it no matter what I was looking at. This Antares 1.25" 0.5x focal reducer lens (tele-compressor) is used under the Orion brand name to thread into the nosepiece of Orion StarShoot Solar System cameras and StarShoot Deep Space Color Imaging Camera. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. No experience with the Antares reducers, but I haven't personally seen a difference between Celestron and my current pair of made in Japan Meade reducers. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. All Rights Reserved. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. It's usually specified from the base of the mounting threads on the reducer's housing, and this is the most practical way of providing this specification. My application is mostly visual now, but I'm looking to do more astrophotography over time. A focal reducer does just the opposite of a Barlow lens or focal extender. 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. Thanks for pointing this out. All rights reserved. At least these two units I tested make the answer - whatever. He tested this on an 8 Celestron , I have a Celestron 6SE. He received his first telescope at the age of 5 and completed his first university course in astronomy at the age of 12, eventually receiving a master's degree in the subject. 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). I have had the Japan unit on the back of my C5 since 1994 or thereabouts. For the best experience on our site, be sure to turn on Javascript in your browser. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Melotte 15 - First Process in PixInsight (easy! It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. All rights reserved. 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. Please note, orders placed after 10am on 2/28/2023 will be delayed. 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. The threads were similar on the eyepiece end, but a bit smoother. InternetSales@optcorp.com, 800-483-6287 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. 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. We tested GSO's 1.25" 0.5x focal reducer at a variety of operating distances and calculated the field of view through a telescope to derive the actual reduction factor that is plotted below. Can these economical focal reducers from GSO and other vendors result in good images? In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Hmmm . Celestron Nexstar+ 127 SLT, several budget plossl eyepieces, Celestron 8-24mm zoom EP and a 12.5mm illuminated double reticle EP, Svbony SV205 camera w/.5 focal reducer, Celestron SkyMaster 20x80 binos on a 40 yr old QuickSet PanHead tripod, Stellarium, Sharpcap and ManyCam on my laptop, SkyView and Nightshift on my phone and a dandy little $9 . Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. Meade once made an f/3.3 focal reducer for SCT scopes. First, let's have a look at some key optical parameters are needed to understand focal reducers. It must be in stock at the time of Price Match for us to make a guarantee. 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. I have both the Antares and the Celestron reducers. The price for an item/offer must be listed and valid at the time of match. Explore Scientific Keys to the Universe Sale, Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes, Skip to the beginning of the images gallery. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. 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. 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. First, I wanted to compare the actual reduction provided by these competitors, as many threads here cite different ideal spacing from the reducer to eyepiece focal plane to achieve the correct f/6.3 result. Again, these focal reducers are often provided by the telescope manufacturer. Hello! Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. CPWI has an extensive object database, employs PointXP mount modeling, and more. Your price: $579.00. Well done. Antares or Celestron? They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. The more focal reduction, the further inward the focal plane will be. I think there may be some confusion here, because Antares makes a variety of reducers for eyepieces and scopes in addition to this SCT R/C but this definitely is a reducer/corrector. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads 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. The reducer fits all Meade and Celestron . But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? I found both to be very good. InternetSales@optcorp.com. Also read the reviews here, including those at 4 stars. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. It's important to match the back focus to within a millimeter or two to get an optimal image, especially with cameras with larger sensors. The previous post shows the reducer on what appear to be two different refractors. The Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes is a low-price option for reducing the focal length of your Schmidt-Cassegrain telescope from f/10 to f/6.3. Right off the bat, I was struck by how similar the two R/Cs were. This article explains the basics of how focal reducers work with an astronomy telescope. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. Many Ritchey-Chretien telescopes available today are made by GSO. JavaScript seems to be disabled in your browser. When using the diagonal, keep the field stops of the eyepieces under 20mm. 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. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. Powered by Invision Community. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Reducer - Corrector 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"). In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). Reviews. 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. Torazz No difference. 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. Contiguous US Customers:All items we sell ship for free within the Contiguous US. No small animals were harmed in making these observations. The working distance (backfocus) of the Celestron f/6.3 reducer is specified to be 105mm from the base of the male SCT thread on the camera side. Just one question. The Reducer/Corrector can also be used for terrestrial digiscoping. 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, the focal reducer for an 8-inch Celestron EdgeHD telescope has a design reduction factor of 0.7x and a specified working distance (or back focus) of 105mm. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. We have placed cookies on your device to help make this website better. 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. In such cases, we will be happy to take the item back as per our standard return terms. Try & buy if you like - usual mates rates. I use the Celestron version and it seems OK for both visual and imaging. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. Once focused it's pretty good. With this telescope and this focal reducer, it does not help to move to a 2" eyepiece and a 2" diagonal as the visual view will be akin to looking through a porthole within the larger apparent field of view of the eyepiece. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. Unlike . It seems right to put some distance between the camera and the focal reducer, right? Figure 7 shows an example of an image of the Dumbbell Nebula taken with a 1.25" GSO focal reducer at a reduction factor of 0.63x with an 85mm f/7 refractor and a QHY5III-290M camera with a sensor with a 6.4mm diagonal. The nominal design reduction factor of these reducers is typically 0.5x. I doubt there is any difference between the Antares and the Celestron except price. The amount of reduction is simply the percentage by which a reducer shortens the effective focal length of a telescope and is calculated as (1 Reduction Factor) x 100%. For the best experience on our site, be sure to turn on Javascript in your browser. Scope size might influence choice as well, as a C6 might benefit from the Antares' transparency, while larger scopes might benefit from the Celestron's higher contrast. This is the simplest way to attach your ASI121 to your telescope. All Rights Reserved. Explore Scientific - Keys to the Universe Sale. 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. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. I don't know. Please Log in to save it permanently. Generally, views through the Antares seemed a little more transparent and brighter. On the camera side, the focal reducer has male M42x0.75 or M48x0.75 threads that attach directly to the T-ring (with an M42-M48 adapter if necessary). 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. Like you, I am primarily visually observing but I have everything together now that so I am going to start experimenting with photography so we'll see how it does there. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. 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. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. Start here to find the perfect telescope for you! 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. If used before or beyond the working distance, unwanted image distortion may result. Theres a long-running debate in these forums and even statements from some reputable dealers that the Antares is just a reducer (even though it is labeled Reducer/Corrector), whereas the Celestron is a true R/C, which flattens the SCTs naturally curved field and provides some edge correction. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Completely stuck, completely frustrated. Never used one, but read the reviews here that suggest a coating problem. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. This is a. By Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. 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. None of this was offensive, nor did it interfere with views in any significant way. I think that the FRs made in Japan in the day may have been better. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. That means the base of the mounting threads of the focal reducer needs to be 55mm from the camera sensor to achieve the design reduction factor, which is usually 0.8x or 0.85x. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. Place the plastic covers on the lens when not in use to reduce the dust collection. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. because they really dont matter. The brightness, shape, and distortion of specific stars in the exact same position at the edge of the field was precisely identical in both reducers. I wont bother with differences in packaging, caps, etc. All additional accessories mount onto the exterior/male threads. I use the same back spacing for both on a small 6" Celestron SCT. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. 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. Fumbling around in the dark, fine threads might be a problem. Will not focus with the stuff I have. Sign up to get exclusive deals, observing tips, and new product announcements. In both cases will end with a similar tfov. 2. I've never found my 0.63 reducer causing CA when used with my SCT. control and Sky Viewer display makes selecting your target easy. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. 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. Practical Considerations of Focal Reducers, 4.2 Back Focus Requirements of Focal Reducers, GSO makes focal reducers for their line of Ritchey-Chretien, Celestron makes a series of focal reducers for the Edge HD line, 0.75x focal reducers for these telescopes, focal reducer for an 8-inch Celestron EdgeHD, A Primer on T-Rings and T-Adapters for Astronomy and Astrophotography, Choosing the Best Telescope for Beginners 2023, Top Night Sky & Astronomy Events in August 2022, Top Night Sky & Astronomy Events in July 2022, Selecting a Baader Planetarium Star Diagonal, A Guide to Choosing Astronomy Eyepieces for Binoviewers, Choosing a Magnifying Finder Scope for Your Telescope, A focal reducer will provide its design reduction factor only when it is placed at the exact working distance from the focal plane of the eyepiece or camera, Reducing the operating distance, that is, moving a focal reducer closer to the eyepiece or camera increases its reduction factor, or conversely reduces the amount of focal reduction. Now It only focuses near things, like some kind of macro zoom. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. 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. Some third-party vendors also make reducers for SCT scopes. How does it look thats what matters. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation.
