The most significant mechanical variation, however, is the quality and precision of the threading. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. 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. 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. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. Field stop diameters are one of the specified specs of eyepieces. SKU: CEL-94245. Sky recognition technology that has revolutionized the manual telescope by eliminating the confusion common among beginners and enhancing the user experience for even seasoned telescope users. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. I don't know. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). There is a way to make subjective data more useful and that way is proper blind, or better still. Photographically you also get a wider field and much shorter exposures. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. CPWI has an extensive object database, employs PointXP mount modeling, and more. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. Stock focusers in an SCT move the mirror of the scope to change the position of the focal plane, and they have sufficient travel to accommodate a focal reducer. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras.
0.5X focal reducer for Celestron, Meade, and Orion CCD imaging cameras Your mileage may vary. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. The Antares is supposed to be pretty comparable. Turn it on and push Align. In about three minutes, youre ready to observe! The equations in the Appendix show how this all works. There are many different types of focal reducers and they all effect. I use the Celestron version and it seems OK for both visual and imaging. The internal surfaces are blackened and glare-threaded to provide the highest contrast. We only send interesting emails and will never sell your data. Edited by bluewater, 05 September 2020 - 11:27 AM. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. The nominal design reduction factor of these reducers is typically 0.5x. control and Sky Viewer display makes selecting your target easy.
Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope However, with appropriate spacers and a camera with a known back-focus, it is easy to determine the exact amount of focal reduction for a given setup (some imaging software packages will also let you derive this from images). Start here to find the perfect telescope for you! All Rights Reserved. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. Celestron makes a series of focal reducers for the Edge HD line that are matched to the 8", 9.25", 11", and 14" apertures of these scopes. That said any comparison reviews are helpful. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off.
I have/had both the Celestron (Japan) and Antares units. I've never found my 0.63 reducer causing CA when used with my SCT. Reducer Lens .7x - EdgeHD 1400 Learn More. Read our guide! Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. Some are available in 1.25" barrel format but with C threads. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. 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. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. 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. 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. It must be in stock at the time of Price Match for us to make a guarantee.
Reducer - Corrector | Celestron Still not sure what is the right gear for you? I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. Unlike . They are also less expensive than many external focusers of similar build quality. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. 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. Brian Ventrudo is a writer, scientist, and astronomy educator. Reducer - Corrector Most focal reducers are designed to operate optimally at the working distance in the optical path to achieve their specified reduction factor, which is usually between 0.5x and 0.8x. What I do know is that the Antares and the Celestron samples that I have perform exactly the same from the center right out to the edges. Most Feather Touch focusers cost between $300-$350. Perfect for the serious student, professional scientist and discriminating hobbyist. But I am rusty, can you condense a bit for me please? The visual back must be removed first. 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. The click-lock with a 2 dielectric diagonal with a somewhat shorter light path, using both a 2 ES 28mm/68 and the same low-profile adapter with a 1.25 ES 24mm/68. 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. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. 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. However, some focal reducers can be used over a wider range of working distances, especially those with simpler optical design, and especially when used with cameras with smaller sensors. They never really recovered from selling a few 15 years back with element reversed. Is that distance D= Fo-d1=Fo-(d2/MR)? Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. 3. Never used one, but read the reviews here that suggest a coating problem. 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? The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. We have corrected # (iii) after equations 6 & 7. Theoretically each of these combinations all varied-length light paths should have resulted in slightly different reductions between the Celestron and Antares, since they supposedly have different focal lengths. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. The reduction factor MR can also be written in terms of d2 as: When the focal reducer is placed at the working distance, D, that is when d2=D, then the reduction factor MR is equal to the design reduction factor MRD: Equations (6) and (7) imply these important considerations: Most manufacturers do not publish the focal length of their focal reducers, so it is not usually possible to calculate the working distance and design reduction factor. 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. Reducer Lens .7x - EdgeHD 925 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. More about this below. Reducer Lens .7x - EdgeHD 1100 Learn More. Explore Scientific Keys to the Universe Sale. 2023 Celestron, LLC. From the SkyProdigy, a telescope so smart it can align itself, to our high-performance EdgeHD optical system, weve revolutionized the hobby of astronomy for beginners and advanced amateurs alike. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. Meade does not make an equivalent line of focal reducers for the ACF scopes, although some models of Meade ACF are already at f/8, faster than the f/10 ratio of Celestron Edge HD scopes. 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). The reducer fits all Meade and Celestron . Any comments gratefully received. Focal reducers (and focal reducer/field flatteners combos) are usually used with two types of telescopes, refractors and compound telescopes such as Schmidt-Cassegrain or Ritchey-Chretien. The Best Dedicated Astronomy Cameras for Beginners, Astronomik OIII 12nm CCD Filter - T-Threads, Pegasus Astro Dual Motor Focus Controller, 10 Micron 12kg (26.45lbs) Stainless Steel Counterweight- GM 2000, I would like more information regarding stock availability dates. To test this, I used three set-ups: 1. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. Who cares? I even lost track of which reducer I was using. My Celestron was made in China and the Antares in Canada. 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). 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. Not a bit. Orders placed over the weekend will be shipped on the following Monday. He tested this on an 8 Celestron , I have a Celestron 6SE. I use the same back spacing for both on a small 6" Celestron SCT. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. 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. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. ), 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. No results, please adjust your filters. You may need spacers or a T-adapter to ensure the correcting working distance.
Focal Reducer, 2", 0.7X - Antares To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. 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. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. It is not a corrector or flattener.
Focal Reducer for SCT - ACF - Stargazers Lounge I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. I've looked through one from Meade and first impression was that it was like the Celestron version. It covers the basic optics and design specifications of a focal reducer, and goes through some practical factors to consider when selecting and using a focal reducer. No idea what the issue is. Celestron's EdgeHD reducers feature a custom 5 element optical design engineered to maintain the flat-field performance of our award-winning EdgeHD optical system. 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. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. The Reducer/Corrector can also be used for terrestrial digiscoping. Focal reducers for SCT, RC, and field-flattened Edge HD or ACF telescopes thread onto the back of the telescope tube with 2"-24 or 3"-28 SCT threads. Reducer - Corrector Learn More. Will not focus with the stuff I have. 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. control and Sky Viewer display makes selecting your target easy. I have both the Antares and the Celestron reducers. A few large telescopes and mounts are excluded from this free shipping offer. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. . We reserve the right to verify a competitor's advertised price and the availability of the item. 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. Wonder how they would stack up with a Japanese 6.3. 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.
The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. We do not price match competitors if they are out of stock. Have a promo code? 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.
Reducer Lens .7x - EdgeHD 1100 - Celestron This is a. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. Some coma is visible in the corners, but the image is quite good for EAA applications. This fully multi-coated lens provides maximum light transmission with near full-field illumination. The most popular accessories for your new telescope! Clearly cost is a big factor for satisfied users. Wow, that is a very detailed discussion! InternetSales@optcorp.com. Some manufacturers will specify the working distance from the middle of the rear lens surface, and this number must then be converted into a practical working distance number by subtracting the amount by which the rear lens surface is recessed in its housing. No negative issues to report. 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. I wish there was. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. Hi - most interesting - may I ask .. the brighter guys - "if a camera sensor is too small for a n adaper, will a focal reduer allow me to get greater use from the camera?
Antares F/6.3 SCT Focal Reducer | OPT Telescopes If used before or beyond the working distance, unwanted image distortion may result. I'm going with the Celestron. However, manufacturers virtually never provide this specification. 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. Meade and Celestron both sell such SCT-T adapters with the correct optical length. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. Some third-party vendors also make reducers for SCT scopes. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm.
Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a None of this was offensive, nor did it interfere with views in any significant way. 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. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. 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. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope.
Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd ), but stars seemed a bit tighter and their colors were richer and more dramatic. Images made with my ZWO 533 camera testing both show them to be essentially the same. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. The Celestron f/6.3 is ~150 compared to the Antares at ~70. 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. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; 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. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. 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. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Try & buy if you like - usual mates rates. I wont bother with differences in packaging, caps, etc. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. 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. Very helpful, thanks a lot for this article! For the best experience on our site, be sure to turn on Javascript in your browser.