Take control of your telescope! But while the image gets brighter, the size of the image circle gets proportionately smaller. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. 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. Still not sure what is the right gear for you? The equations in the Appendix show how this all works. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. 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. Celestron or Antares f/6.3 focal reducer for SCT? Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. Copyright 2003-2022 Agena AstroProducts. 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. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? 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. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. It is recommended for . Thanks for any advice or experience you could share. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. Try & buy if you like - usual mates rates. The most significant mechanical variation, however, is the quality and precision of the threading. Reducer - Corrector Not one detectable iota of discernable difference. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. You need to be a member in order to leave a comment. 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. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. Meade once made an f/3.3 focal reducer for SCT scopes. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. How does it look thats what matters. The Antares FR2-0.7X is the same 4-element f/6.3 lens system used for f/10 Schmidt-Cassegrain telescopes but in a 2" barrel threaded for standard filters. 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. Reducer Lens .7x - EdgeHD 800 Learn More. Meade and Celestron both sell such SCT-T adapters with the correct optical length. Thanks. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). Here, there was a subtle difference . I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. My application is mostly visual now, but I'm looking to do more astrophotography over time. Any comments gratefully received. Over the course of a several nights of general observing, I swapped back and forth between the Antares and Celestron R/Cs on a wide variety of objects open clusters, brighter galaxies, a couple of nebulae, and globular clusters as well. Your price: $579.00. M44 was a perfect target for this, as its large size maxes out the FOV on a C8 with a corrector, and its bright stars make great targets for measuring the very edge of the visible field. 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. 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. 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 925 Learn More. However, doesn't fit in the telescope and even if it did wouldn't work. Not a bit. 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. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. Fumbling around in the dark, fine threads might be a problem. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. I wont bother with differences in packaging, caps, etc. I've only used it a few times but it looks good to me. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. But when not in the box or on the telescope, there is no cover for the other end. The threads were similar on the eyepiece end, but a bit smoother. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. A few large telescopes and mounts are excluded from this free shipping offer. We will match any online price that we confirm as valid. Explore Scientific Keys to the Universe Sale. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. 800-483-6287 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). It is not a corrector or flattener. which looks like the same one. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. All additional accessories mount onto the exterior/male threads. The visual back must be removed first. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. Opticstar F6.3 Focal Reducer / Corrector. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. Many Ritchey-Chretien telescopes available today are made by GSO. 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. 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. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. When using the diagonal, keep the field stops of the eyepieces under 20mm. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. Contiguous US Customers:All items we sell ship for free within the Contiguous US. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. 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. 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. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. No idea what the issue is. For the best experience on our site, be sure to turn on Javascript in your browser. I use the Celestron version and it seems OK for both visual and imaging. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? This would tell us exactly how well aberrations are corrected. Each focal reducer has a fixed specification called the working distance or required back focus. The price for an item/offer must be listed and valid at the time of match. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. Explore Scientific - Keys to the Universe Sale. 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.