{"title":"Imaging Barlows and Powermates","description":"","products":[{"product_id":"tele-vue-powermate-2-5x","title":"Tele Vue Powermate 2.5x (1.25 Inch)","description":"\u003cdiv\u003e\n\u003cp\u003eThe Tele Vue Powermate 2.5x is the perfect choice for both imaging and visual use.\u003c\/p\u003e\n\u003cp\u003eUnique Benefits and Applications for Powermates™\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eVignetting, edge field aberrations and pupil movement - all introduced when using Barlows with long focal length eyepieces, are minimized.\u003c\/li\u003e\n\u003cli\u003eTelecentric operation (field rays leave parallel to optical axis, unlike Barlow lenses which diverge rays). This is ideal for Hydrogen-alpha filter use such as with Daystar models.\u003c\/li\u003e\n\u003cli\u003eHigh performance for image amplification, CCD or film (some of the finest Earth-based planetary imaging is being done with Powermates™ ).\u003c\/li\u003e\n\u003cli\u003eFlexible for visual and imaging with all types of telescopes and eyepieces. Essentially Parfocal, and with nearly constant magnification regardless of image distance behind top surface (except 5x model which increases 1x for every 35mm of image distance increase).\u003c\/li\u003e\n\u003cli\u003eHigher magnifications are possible with high optical performance compared to \"doubling up\" Barlows.\u003c\/li\u003e\n\u003cli\u003eAll will reach parfocal point in star diagonals, except for the 2\", 2x which comes very close.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIn addition to full multi-coating, Powermates™ include other Tele Vue special touches such as safety undercuts where practical on the chrome barrel and captive lock screws that can't fall out, and filter threads. Our 100% QC program at f\/4 insures that Powermates™ will add dramatic power (and NOTHING ELSE) to your favorite eyepieces.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eIf, for example, you own a 24mm Panoptic, you'll have the power of a 12mm focal length eyepiece with the 2.0x Powermate™, 9.6mm with the 2.5x Powermate™, a 6mm with the 4x Powermate™, or a 4.8mm with the 5x Powermate™!\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eSome of the finest Solar System images have been made with Powermates™. Used singly or stacked, Powermates™ help \u003ci\u003eany\u003c\/i\u003e scope achieve the long focal-length required to image details on Solar System bodies. The increased image scale allows for imaging without an intervening eyepiece -- like in prime focus photography. Powermate T-Ring Adapters fit on the Powermate lens assemblies to allow attachment of your camera's T-Ring or other T-threaded imaging accessory.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eFor astro-imagers, the above chart indicates the magnification for each Powermate™ (2x, 2.5x, 4x \u0026amp; 5x) as a function of distance from the Powermate™ top surface to the imaging surface (CCD or film).\u003c\/p\u003e\n\u003cdiv\u003e\u003cstrong\u003e \u003c\/strong\u003e\u003c\/div\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cstrong\u003e1¼\" Powermates™: 2.5x \u0026amp; 5x\u003c\/strong\u003e\u003c\/div\u003e\n\u003cp\u003eThese models stand less than 3\" out of your focuser and the 5x takes 1¼\" threaded filters. They are parfocal in ALL 1¼\" diagonals and prisms. For this reason, they are highly recommended over standard Barlows for 1¼\" diagonals and refractors such as the Tele Vue-60.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eThe 5x Powermate™ is ideal for long focus CCD and film photography, magnifying about 7.7x. It's an attractive, high performance alternative to eyepiece projection. The 5x is also perfect for slowing down your scope for Hydrogen-Alpha solar observing.\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cstrong\u003e2\" Powermates™: 2x \u0026amp; 4x\u003c\/strong\u003e\u003c\/div\u003e\n\u003cp\u003eThese Powermates™ are a better choice for 2\" diagonals than Barlows, since they are nearly Parfocal. They are threaded for 48mm filters and their performance is excellent with every 1¼\" and 2\" eyepiece we make (yes, even the 31mm Nagler Type 5!). Both the 2\" eyepiece holder and the special 2\" flat top adapter use our brass clamp rings for secure operation. And, it also has a very unique feature: you can unscrew the 2\" eyepiece housing and screw on a special T-ring adapter for solid, compact attachment of CCD or camera equipment.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eExcellent with long eye-relief, 2\" eyepieces. Using the 4x model, imagine the quality of a 35mm Panoptic at 8.8mm with 25mm of eye relief! The Powermate™ is NOT a Barlow so the Panoptic-Barlow Interface is not needed! The 2\" Powermate™ fits all the way into 2\" Star Diagonals, requiring minimal refocus compared to a 2\" Barlow.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cem\u003e\u003cstrong\u003eNote for Dobsonian\/Newtonian Owners\u003c\/strong\u003e\u003c\/em\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cp\u003eWhen using Tele Vue's Paracorr coma corrector, the 2.5x or 5x Powermate™ should be inserted into the Paracorr's 1¼\" adapter (i.e., between the Paracorr and the eyepiece). For 2x and 4x 2\" Powermates™, first insert the Powermate™ into the focuser, then the Paracorr into the Powermates™.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"FadeBackground\"\u003e\n\u003cp\u003eAl Nagler's 4-element concept, continues the tradition of full-field sharpness with optimum aberration control. Like long eye-relief? Retain the eye-relief of long focal length eyepieces, while at high power. Enjoy, for example, the sharpness and comfort of the 32mm Plössl at up to 5 times the power!\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cstrong\u003ePowermate™ vs. Barlow \u003c\/strong\u003e\u003c\/div\u003e\n\u003cp\u003eTo understand the Powermate™, we must first understand the Barlow lens. Barlows amplify the power of a telescope. They can be considered \"focal reducers\" for eyepieces, or \"focal extenders\" for objectives. Terence Dickenson, in his Barlow test report in \u003ci\u003eSky and Telescope\u003c\/i\u003e, July 1997, says: \"Technology has erased the old objections. A modern Barlow will not degrade your telescope's optics. Anyone telling you otherwise is using outdated information. Moreover, the highly regarded Nagler eyepieces and their clones have built-in Barlows, ample evidence that the lens is not some detrimental intruder.\" Thanks, Terence, for laying the myth of the degrading Barlow to rest.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv id=\"size11px\" style=\"color: black; width: 225px; float: left; margin: .5em .5em .5em 0em; border: thin solid black;\"\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\n\u003cp\u003e\u003ca href=\"http:\/\/www.televue.com\/images\/TV3_images\/Images_in_articles\/Powermate4xParts.jpg\" rel=\"noopener noreferrer\" target=\"_blank\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xParts_sm.jpg\" alt=\"4x Powermate ...\" width=\"213\" height=\"173\"\u003e \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e4x Powermate™ shown for illustration. All 2\" models include 1¼\" adapters (left). Standard Eyepiece Adapter (middle-top) is removable to allow Photo\/Visual assembly (right) to use optional T-Ring Adapters (middle-bottom) for imaging.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\n\u003cp\u003e\u003ca href=\"http:\/\/www.televue.com\/images\/TV3_images\/Images_in_articles\/Powermate4xPhoto_VisualSetup.jpg\" rel=\"noopener noreferrer\" target=\"_blank\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xPhoto_VisualSetup_sm.jpg\" alt=\"4x Powermate ...\" width=\"213\" height=\"173\"\u003e \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e4x Powermate™ photo setup with T-Ring adapter (left).\u003cbr\u003e4x Powermate™ visual setup with 1¼\" adapter (right).\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003eA high quality Barlow must be properly designed and manufactured in order to avoid compromising a telescope's color and spherical aberration corrections. The \"invisibility\" of Tele Vue's 2-element Barlows has been noted in test reports in the astronomy magazines. However, by the nature of its negative power lens, a Barlow will do more than just increase magnification, regardless of the number of elements.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eThe diverging rays leaving the Barlow result in moving the exit pupil further out, thereby extending the eye relief. In short to medium focal length eyepieces the change is not noticeable. However, in the case of long focal length eyepieces, the increase can be significant and not without performance consequences.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eVignetting can occur due to the altered ray path, when the eyepiece's lenses are not large enough in diameter to allow all the rays to make it through. Shorter Barlows, or ones with too much magnification, only exacerbate the problem because the ray path entering the eyepiece is steeper.\u003c\/p\u003e\n\u003cp\u003eWe had to go beyond the Barlow concept to achieve the goal of a compact, high power, fully corrected image amplifier. The Powermate™ consists of a negative doublet plus a positive \"pupil-correcting\" doublet. This 4-element system provides the magnifying function of a Barlow without its limitations by restoring the field rays back to their original direction, as if the Powermate™ were not there. The result is a pure magnification increase.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003c\/div\u003e","brand":"Tele Vue","offers":[{"title":"Default Title","offer_id":42045220388933,"sku":"PMT-2513","price":490.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/tele-vue-powermate-25x-754718.jpg?v=1731541214"},{"product_id":"tele-vue-2x-big-barlow-2-inch","title":"Tele Vue BIG Barlow 2x (2 Inch)","description":"\u003cdiv\u003e\n\u003cp\u003eThe Tele Vue 2x BIG Barlow doubles the magnification of any 1.25 inch or 2 inch eyepiece in your collection. For the regular 1.25 inch variant check out the \u003ca href=\"\/product\/tele-vue-2x-barlow-1-25-inch\/\"\u003eTele Vue 2x Barlow\u003c\/a\u003e and \u003ca href=\"\/product\/tele-vue-3x-barlow-1-25-inch\/\"\u003eTele Vue 3x Barlow\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eThe chart below shows the effective magnification when spacing is introduced between the Barlow lens and image plane of your camera or eyepiece\u003c\/p\u003e\n\u003cp\u003e\u003cimg class=\"alignnone size-full wp-image-109768\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/BarlowPowerIncrease-2.jpg\" alt=\"Tele Vue BIG Barlow 2x (2 Inch)\" width=\"750\" height=\"379\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan id=\"lblExtendedDescription\" class=\"desc\"\u003eTeleVue Barlows use multi-coated high index glasses for optimum aberration correction, exceptional contrast with virtually no light loss.Observed performance is aberration free, even when tested with f\/4 scopes. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eThey even improve non TeleVue eyepieces and telescope performance.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eCompromise image quality in any part of the optical chain and you've compromised every part! \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eTeleVue product design and execution deliver consumate satisfaction. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eEvery TeleVue Barlow must pass the same rigorous f\/4, full field testing as all TeleVue eyepieces. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eOffered in a 2x magnification, the Big Barlow is ideal for Newtonian scope owners. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eIt will be parfocal with both 2\" and 1 1\/4\" eyepieces in this application. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan id=\"ctl00_ContentPlaceHolder1_lbldesc\"\u003e\u003cspan class=\"desc\"\u003eFeatures include threads for 48mm filters, captive lock screw and full milti-coatings. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eNote: The Tele Vue 2x BIG Barlow is \u003cu\u003enot\u003c\/u\u003e recommended for use with 2\" diagonals because it's length prevents it from being parfocal. With some telescopes, focus might not be reached, particularly when the Panoptic interface lens is also used with it. A far better approach with no potential problems in any scope or with any eyepieces is to use the 2\" 2x Powermate (PMT-2200), which essentially includes the Pan-Barlow Interface\u003c\/p\u003e","brand":"Tele Vue","offers":[{"title":"Default Title","offer_id":42045220552773,"sku":"BWC-2211","price":490.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/tele-vue-big-barlow-2x-2-inch-341816.jpg?v=1731541146"},{"product_id":"tele-vue-powermate-5x","title":"Tele Vue Powermate 5x","description":"\u003cp\u003eTele Vue Powermate 5x\u003c\/p\u003e\n\u003cp\u003eUnique Benefits and Applications for Powermates™\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 12px;\"\u003eVignetting, edge field aberrations and pupil movement - all introduced when using Barlows with long focal length eyepieces, are minimized.\u003cbr\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 12px;\"\u003eTelecentric operation (field rays leave parallel to optical axis, unlike Barlow lenses which diverge rays). This is ideal for Hydrogen-alpha filter use such as with Daystar models.\u003cbr\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 12px;\"\u003eHigh performance for image amplification, CCD or film (some of the finest Earth-based planetary imaging is being done with Powermates™ ).\u003cbr\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 12px;\"\u003eFlexible for visual and imaging with all types of telescopes and eyepieces. Essentially Parfocal, and with nearly constant magnification regardless of image distance behind top surface (except 5x model which increases 1x for every 35mm of image distance increase).\u003cbr\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 12px;\"\u003eHigher magnifications are possible with high optical performance compared to \"doubling up\" Barlows.\u003cbr\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 12px;\"\u003eAll will reach parfocal point in star diagonals, except for the 2\", 2x which comes very close.\u003cbr\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIn addition to full multi-coating, Powermates™ include other Tele Vue special touches such as safety undercuts where practical on the chrome barrel and captive lock screws that can't fall out, and filter threads. Our 100% QC program at f\/4 insures that Powermates™ will add dramatic power (and NOTHING ELSE) to your favorite eyepieces.\u003c\/p\u003e\n\u003cp\u003eIf, for example, you own a 24mm Panoptic, you'll have the power of a 12mm focal length eyepiece with the 2.0x Powermate™, 9.6mm with the 2.5x Powermate™, a 6mm with the 4x Powermate™, or a 4.8mm with the 5x Powermate™!\u003c\/p\u003e\n\u003cp\u003eSome of the finest Solar System images have been made with Powermates™. Used singly or stacked, Powermates™ help \u003ci\u003eany\u003c\/i\u003e scope achieve the long focal-length required to image details on Solar System bodies. The increased image scale allows for imaging without an intervening eyepiece -- like in prime focus photography. Powermate T-Ring Adapters fit on the Powermate lens assemblies to allow attachment of your camera's T-Ring or other T-threaded imaging accessory.\u003c\/p\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/PowermatePowerIncrease.jpg\"\u003e\u003cimg height=\"478\" width=\"729\" alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/PowermatePowerIncrease.jpg\" class=\"aligncenter size-full wp-image-138742\"\u003e\u003c\/a\u003e\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eFor astro-imagers, the above chart indicates the magnification for each Powermate™ (2x, 2.5x, 4x \u0026amp; 5x) as a function of distance from the Powermate™ top surface to the imaging surface (CCD or film).\u003c\/p\u003e\n\u003cdiv\u003e\u003cstrong\u003e \u003c\/strong\u003e\u003c\/div\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cstrong\u003e1¼\" Powermates™: 2.5x \u0026amp; 5x\u003c\/strong\u003e\u003c\/div\u003e\n\u003cp\u003eThese models stand less than 3\" out of your focuser and the 5x takes 1¼\" threaded filters. They are parfocal in ALL 1¼\" diagonals and prisms. For this reason, they are highly recommended over standard Barlows for 1¼\" diagonals and refractors such as the Tele Vue-60.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eThe 5x Powermate™ is ideal for long focus CCD and film photography, magnifying about 7.7x. It's an attractive, high performance alternative to eyepiece projection. The 5x is also perfect for slowing down your scope for Hydrogen-Alpha solar observing.\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cstrong\u003e2\" Powermates™: 2x \u0026amp; 4x\u003c\/strong\u003e\u003c\/div\u003e\n\u003cp\u003eThese Powermates™ are a better choice for 2\" diagonals than Barlows, since they are nearly Parfocal. They are threaded for 48mm filters and their performance is excellent with every 1¼\" and 2\" eyepiece we make (yes, even the 31mm Nagler Type 5!). Both the 2\" eyepiece holder and the special 2\" flat top adapter use our brass clamp rings for secure operation. And, it also has a very unique feature: you can unscrew the 2\" eyepiece housing and screw on a special T-ring adapter for solid, compact attachment of CCD or camera equipment.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eExcellent with long eye-relief, 2\" eyepieces. Using the 4x model, imagine the quality of a 35mm Panoptic at 8.8mm with 25mm of eye relief! The Powermate™ is NOT a Barlow so the Panoptic-Barlow Interface is not needed! The 2\" Powermate™ fits all the way into 2\" Star Diagonals, requiring minimal refocus compared to a 2\" Barlow.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cem\u003e\u003cstrong\u003eNote for Dobsonian\/Newtonian Owners\u003c\/strong\u003e\u003c\/em\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cp\u003eWhen using Tele Vue's Paracorr coma corrector, the 2.5x or 5x Powermate™ should be inserted into the Paracorr's 1¼\" adapter (i.e., between the Paracorr and the eyepiece). For 2x and 4x 2\" Powermates™, first insert the Powermate™ into the focuser, then the Paracorr into the Powermates™.\u003c\/p\u003e\n\u003cdiv id=\"FadeBackground\"\u003e\n\u003cp\u003eAl Nagler's 4-element concept, continues the tradition of full-field sharpness with optimum aberration control. Like long eye-relief? Retain the eye-relief of long focal length eyepieces, while at high power. Enjoy, for example, the sharpness and comfort of the 32mm Plössl at up to 5 times the power!\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv id=\"pageSectionTitle\"\u003e\u003cstrong\u003ePowermate™ vs. Barlow \u003c\/strong\u003e\u003c\/div\u003e\n\u003cp\u003eTo understand the Powermate™, we must first understand the Barlow lens. Barlows amplify the power of a telescope. They can be considered \"focal reducers\" for eyepieces, or \"focal extenders\" for objectives. Terence Dickenson, in his Barlow test report in \u003ci\u003eSky and Telescope\u003c\/i\u003e, July 1997, says: \"Technology has erased the old objections. A modern Barlow will not degrade your telescope's optics. Anyone telling you otherwise is using outdated information. Moreover, the highly regarded Nagler eyepieces and their clones have built-in Barlows, ample evidence that the lens is not some detrimental intruder.\" Thanks, Terence, for laying the myth of the degrading Barlow to rest.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv style=\"color: black; width: 225px; float: left; margin: .5em .5em .5em 0em; border: thin solid black;\" id=\"size11px\"\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\n\u003cp\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/www.bintel.com.au\/TV3_images\/Images_in_articles\/Powermate4xParts.jpg\" target=\"_blank\"\u003e\u003cimg height=\"173\" width=\"213\" alt=\"4x Powermate ...\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xParts_sm.jpg\" class=\"alignnone\"\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e4x Powermate™ shown for illustration. All 2\" models include 1¼\" adapters (left). Standard Eyepiece Adapter (middle-top) is removable to allow Photo\/Visual assembly (right) to use optional T-Ring Adapters (middle-bottom) for imaging.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e\n\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xPhoto_VisualSetup_sm_2016-06.jpg\"\u003e\u003cimg height=\"173\" width=\"213\" alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xPhoto_VisualSetup_sm_2016-06.jpg\" class=\"aligncenter size-full wp-image-138744\"\u003e\u003c\/a\u003e4x Powermate™ photo setup with T-Ring adapter (left).\u003cbr\u003e4x Powermate™ visual setup with 1¼\" adapter (right).\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003eA high quality Barlow must be properly designed and manufactured in order to avoid compromising a telescope's color and spherical aberration corrections. The \"invisibility\" of Tele Vue's 2-element Barlows has been noted in test reports in the astronomy magazines. However, by the nature of its negative power lens, a Barlow will do more than just increase magnification, regardless of the number of elements.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eThe diverging rays leaving the Barlow result in moving the exit pupil further out, thereby extending the eye relief. In short to medium focal length eyepieces the change is not noticeable. However, in the case of long focal length eyepieces, the increase can be significant and not without performance consequences.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eVignetting can occur due to the altered ray path, when the eyepiece's lenses are not large enough in diameter to allow all the rays to make it through. Shorter Barlows, or ones with too much magnification, only exacerbate the problem because the ray path entering the eyepiece is steeper.\u003c\/p\u003e\n\u003cp\u003eWe had to go beyond the Barlow concept to achieve the goal of a compact, high power, fully corrected image amplifier. The Powermate™ consists of a negative doublet plus a positive \"pupil-correcting\" doublet. This 4-element system provides the magnifying function of a Barlow without its limitations by restoring the field rays back to their original direction, as if the Powermate™ were not there. The result is a pure magnification increase.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Tele Vue","offers":[{"title":"Default Title","offer_id":42045220585541,"sku":"PMT-5126","price":490.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/tele-vue-powermate-5x-875901.jpg?v=1731541214"},{"product_id":"tele-vue-powermate-4x","title":"Tele Vue Powermate 4x","description":"\u003ch2\u003eTele Vue Powermate 4x - what's all this talk about Powermates?\u003c\/h2\u003e\n\u003cp\u003eUnique Benefits and Applications for Powermates\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eVignetting, edge field aberrations and pupil movement - all introduced when using Barlows with long focal length eyepieces, are minimized.\u003c\/li\u003e\n\u003cli\u003eTelecentric operation (field rays leave parallel to optical axis, unlike Barlow lenses which diverge rays). This is ideal for Hydrogen-alpha filter use such as with Daystar models.\u003c\/li\u003e\n\u003cli\u003eHigh performance for image amplification, CCD or film (some of the finest Earth-based planetary imaging is being done with Powermates ).\u003c\/li\u003e\n\u003cli\u003eFlexible for visual and imaging with all types of telescopes and eyepieces. Essentially Parfocal, and with nearly constant magnification regardless of image distance behind top surface (except 5x model which increases 1x for every 35mm of image distance increase).\u003c\/li\u003e\n\u003cli\u003eHigher magnifications are possible with high optical performance compared to \"doubling up\" Barlows.\u003c\/li\u003e\n\u003cli\u003eAll will reach parfocal point in star diagonals, except for the 2\", 2x which comes very close.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIn addition to full multi-coating, Powermates include other Tele Vue special touches such as safety undercuts where practical on the chrome barrel and captive lock screws that can't fall out, and filter threads. Tele Vue's 100% QC program at f\/4 insures that the Powermate 4x will add dramatic power (and NOTHING ELSE) to your favorite eyepieces.\u003c\/p\u003e\n\u003cp\u003eIf, for example, you own a 24mm Panoptic, you'll have the power of a 12mm focal length eyepiece with the 2.0x Powermate, 9.6mm with the 2.5x Powermate, a 6mm with the Powermate 4x, or a 4.8mm with the 5x Powermate!\u003c\/p\u003e\n\u003ch3\u003eImaging the Solar System with Powermate 4x\u003c\/h3\u003e\n\u003cp\u003eSome of the finest Solar System images have been made with Powermates. Used singly or stacked, Powermates help \u003ci\u003eany\u003c\/i\u003e scope achieve the long focal-length required to image details on Solar System bodies. The increased image scale allows for imaging without an intervening eyepiece -- like in prime focus photography. Powermate T-Ring Adapters fit on the Powermate lens assemblies to allow attachment of your camera's T-Ring or other T-threaded imaging accessory.\u003c\/p\u003e\n\u003cp\u003eFor astro-imagers, the above chart indicates the magnification for each Powermate (2x, 2.5x, 4x \u0026amp; 5x) as a function of distance from the Powermate top surface to the imaging surface (CCD or film).\u003c\/p\u003e\n\u003ch3 id=\"pageSectionTitle\"\u003ePowermate 4x with 2\" barrel diameter\u003cstrong\u003e\u003cbr\u003e\n\u003c\/strong\u003e\n\u003c\/h3\u003e\n\u003cp\u003eThe Powermate 4x is a better choice for 2\" diagonals than Barlows, since it is nearly Parfocal. Threaded for 48mm filters and its performance is excellent with every 1¼\" and 2\" eyepiece Tele Vue makes (yes, even the 31mm Nagler Type 5!). Both the 2\" eyepiece holder and the special 2\" flat top adapter use brass clamp rings for secure operation. And, it also has a very unique feature: you can unscrew the 2\" eyepiece housing and screw on a special T-ring adapter for solid, compact attachment of CCD or camera equipment.\u003c\/p\u003e\n\u003cp\u003eExcellent with long eye-relief, 2\" eyepieces. Using the 4x model, imagine the quality of a 35mm Panoptic at 8.8mm with 25mm of eye relief! The Powermate is NOT a Barlow so the Panoptic-Barlow Interface is not needed! The 2\" Powermate fits all the way into 2\" Star Diagonals, requiring minimal refocus compared to a 2\" Barlow.\u003c\/p\u003e\n\u003ch3\u003e\u003cem\u003e\u003cstrong\u003eNote for Dobsonian\/Newtonian Owners\u003c\/strong\u003e\u003c\/em\u003e\u003c\/h3\u003e\n\u003cp\u003eWhen using Tele Vue's Paracorr coma corrector andPowermate 4x, first insert the Powermate into the focuser, then the Paracorr into the Powermate.\u003c\/p\u003e\n\u003cp\u003eAl Nagler's 4-element concept, continues the tradition of full-field sharpness with optimum aberration control. Like long eye-relief? Retain the eye-relief of long focal length eyepieces, while at high power. Enjoy, for example, the sharpness and comfort of the 32mm Plössl at up to 5 times the power!\u003c\/p\u003e\n\u003ch3\u003ePowermate 4x vs. Barlow\u003c\/h3\u003e\n\u003cp\u003eTo understand the Powermate, we must first understand the Barlow lens. Barlows amplify the power of a telescope. They can be considered \"focal reducers\" for eyepieces, or \"focal extenders\" for objectives. Terence Dickenson, in his Barlow test report in \u003ci\u003eSky and Telescope\u003c\/i\u003e, July 1997, says: \"Technology has erased the old objections. A modern Barlow will not degrade your telescope's optics. Anyone telling you otherwise is using outdated information. Moreover, the highly regarded Nagler eyepieces and their clones have built-in Barlows, ample evidence that the lens is not some detrimental intruder.\" Thanks, Terence, for laying the myth of the degrading Barlow to rest.\u003c\/p\u003e\n\u003cdiv id=\"size11px\" style=\"color: black; width: 225px; float: left; margin: .5em .5em .5em 0em; border: thin solid black;\"\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\n\u003cp\u003e\u003ca href=\"http:\/\/www.televue.com\/images\/TV3_images\/Images_in_articles\/Powermate4xParts.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xParts_sm.jpg\" alt=\"4x Powermate ...\" width=\"213\" height=\"173\" hspace=\"5\" vspace=\"5\"\u003e \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003ePowermate 4x shown for illustration. All 2\" models include 1¼\" adapters (left). Standard Eyepiece Adapter (middle-top) is removable to allow Photo\/Visual assembly (right) to use optional T-Ring Adapters (middle-bottom) for imaging.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"float: none; width: auto; padding: 3px; clear: both;\"\u003e\n\u003cp\u003e\u003ca href=\"http:\/\/www.televue.com\/images\/TV3_images\/Images_in_articles\/Powermate4xPhoto_VisualSetup.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xPhoto_VisualSetup_sm.jpg\" alt=\"4x Powermate ...\" width=\"213\" height=\"173\" hspace=\"5\" vspace=\"10\"\u003e \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e4x Powermate™ photo setup with T-Ring adapter (left).\u003cbr\u003e\n4x Powermate™ visual setup with 1¼\" adapter (right).\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003eA high quality Barlow must be properly designed and manufactured in order to avoid compromising a telescope's colour and spherical aberration corrections. The \"invisibility\" of Tele Vue's 2-element Barlows has been noted in test reports in the astronomy magazines. However, by the nature of its negative power lens, a Barlow will do more than just increase magnification, regardless of the number of elements.\u003c\/p\u003e\n\u003cp\u003eThe diverging rays leaving the Barlow result in moving the exit pupil further out, thereby extending the eye relief. In short to medium focal length eyepieces the change is not noticeable. However, in the case of long focal length eyepieces, the increase can be significant and not without performance consequences.\u003c\/p\u003e\n\u003ch3\u003eNo Vignetting\u003c\/h3\u003e\n\u003cp\u003eVignetting can occur due to the altered ray path, when the eyepiece's lenses are not large enough in diameter to allow all the rays to make it through. Shorter Barlows, or ones with too much magnification, only exacerbate the problem because the ray path entering the eyepiece is steeper.\u003c\/p\u003e\n\u003cp\u003eWe had to go beyond the Barlow concept to achieve the goal of a compact, high power, fully corrected image amplifier. The Powermate consists of a negative doublet plus a positive \"pupil-correcting\" doublet. This 4-element system provides the magnifying function of a Barlow without its limitations by restoring the field rays back to their original direction, as if the Powermate were not there. The result is a pure magnification increase.\u003c\/p\u003e","brand":"Tele Vue","offers":[{"title":"Default Title","offer_id":42045220618309,"sku":"PMT-4201","price":740.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/tele-vue-powermate-4x-184901.jpg?v=1731541214"},{"product_id":"tele-vue-powermate-2x","title":"Tele Vue Powermate 2x (2 inch)","description":"\u003cp\u003eThe Tele Vue Powermate 2x is the perfect choice for both imaging and visual use especially if you want to use larger 2\" eyepieces.\u003c\/p\u003e\n\u003ch2\u003eUnique Benefits and Applications for Tele Vue Powermate 2x\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eVignetting, edge field aberrations and pupil movement - all introduced when using Barlows with long focal length eyepieces, are minimized.\u003c\/li\u003e\n\u003cli\u003eTelecentric operation (field rays leave parallel to optical axis, unlike Barlow lenses which diverge rays). This is ideal for Hydrogen-alpha filter use such as with Daystar models.\u003c\/li\u003e\n\u003cli\u003eHigh performance for image amplification, CCD or film (some of the finest Earth-based planetary imaging is being done with Powermates ).\u003c\/li\u003e\n\u003cli\u003eFlexible for visual and imaging with all types of telescopes and eyepieces. Essentially Parfocal, and with nearly constant magnification regardless of image distance behind top surface (except 5x model which increases 1x for every 35mm of image distance increase).\u003c\/li\u003e\n\u003cli\u003eHigher magnifications are possible with high optical performance compared to \"doubling up\" Barlows.\u003c\/li\u003e\n\u003cli\u003eAll will reach parfocal point in star diagonals, except for the 2\", 2x which comes very close.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eThe Usual Tele Vue Quality\u003c\/h3\u003e\n\u003cp\u003eIn addition to full multi-coating, Powermates include other Tele Vue special touches such as safety undercuts where practical on the chrome barrel and captive lock screws that can't fall out, and filter threads. Our 100% QC program at f\/4 insures that Powermates will add dramatic power (and NOTHING ELSE) to your favorite eyepieces.\u003c\/p\u003e\n\u003cp\u003eIf, for example, you own a 24mm Panoptic, you'll have the power of a 12mm focal length eyepiece with the Tele Vue Powermate 2x, 9.6mm with the 2.5x Powermate, a 6mm with the 4x Powermate, or a 4.8mm with the 5x Powermate!\u003c\/p\u003e\n\u003cp\u003eSome of the finest Solar System images have been made with Powermates. Used singly or stacked, Powermates help \u003ci\u003eany\u003c\/i\u003e scope achieve the long focal-length required to image details on Solar System bodies. The increased image scale allows for imaging without an intervening eyepiece -- like in prime focus photography. Powermate T-Ring Adapters fit on the Powermate lens assemblies to allow attachment of your camera's T-Ring or other T-threaded imaging accessory.\u003c\/p\u003e\n\u003cp\u003eFor astro-imagers, the above chart indicates the magnification for each Powermate (2x, 2.5x, 4x \u0026amp; 5x) as a function of distance from the Powermate top surface to the imaging surface (CCD or film).\u003c\/p\u003e\n\u003ch3 id=\"pageSectionTitle\"\u003e1¼\" Powermates: 2.5x \u0026amp; 5x\u003c\/h3\u003e\n\u003cp\u003eThese models stand less than 3\" out of your focuser and the 5x takes 1¼\" threaded filters. They are parfocal in ALL 1¼\" diagonals and prisms. For this reason, they are highly recommended over standard Barlows for 1¼\" diagonals and refractors such as the Tele Vue-60.\u003c\/p\u003e\n\u003cp\u003eThe 5x Powermate is ideal for long focus CCD and film photography, magnifying about 7.7x. It's an attractive, high performance alternative to eyepiece projection. The 5x is also perfect for slowing down your scope for Hydrogen-Alpha solar observing.\u003c\/p\u003e\n\u003ch3 id=\"pageSectionTitle\"\u003e\u003cstrong\u003e2\" Powermates: 2x \u0026amp; 4x\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThese Powermates are a better choice for 2\" diagonals than Barlows, since they are nearly Parfocal. They are threaded for 48mm filters and their performance is excellent with every 1¼\" and 2\" eyepiece we make (yes, even the 31mm Nagler Type 5!). Both the 2\" eyepiece holder and the special 2\" flat top adapter use our brass clamp rings for secure operation. And, it also has a very unique feature: you can unscrew the 2\" eyepiece housing and screw on a special T-ring adapter for solid, compact attachment of CCD or camera equipment.\u003c\/p\u003e\n\u003cp\u003eExcellent with long eye-relief, 2\" eyepieces. Using the 4x model, imagine the quality of a 35mm Panoptic at 8.8mm with 25mm of eye relief! The Powermate is NOT a Barlow so the Panoptic-Barlow Interface is not needed! The Tele Vue Powermate 2x fits all the way into 2\" Star Diagonals, requiring minimal refocus compared to a 2\" Barlow.\u003c\/p\u003e\n\u003ch3\u003e\u003cem\u003e\u003cstrong\u003eNote for Dobsonian\/Newtonian Owners\u003c\/strong\u003e\u003c\/em\u003e\u003c\/h3\u003e\n\u003cp\u003eWhen using Tele Vue's Paracorr coma corrector, the 2.5x or 5x Powermate should be inserted into the Paracorr's 1¼\" adapter (i.e., between the Paracorr and the eyepiece). For 2x and 4x 2\" Powermates, first insert the Powermate into the focuser, then the Paracorr into the Powermates.\u003c\/p\u003e\n\u003cp\u003eAl Nagler's 4-element concept, continues the tradition of full-field sharpness with optimum aberration control. Like long eye-relief? Retain the eye-relief of long focal length eyepieces, while at high power. Enjoy, for example, the sharpness and comfort of the 32mm Plössl at up to 5 times the power!\u003c\/p\u003e\n\u003ch2\u003ePowermate vs. Barlow\u003c\/h2\u003e\n\u003cp\u003eTo understand the Powermate, we must first understand the Barlow lens. Barlows amplify the power of a telescope. They are essentially \"focal reducers\" for eyepieces, or \"focal extenders\" for objectives. Terence Dickenson, in his Barlow test report in \u003ci\u003eSky and Telescope\u003c\/i\u003e, July 1997, says: \"Technology has erased the old objections. A modern Barlow will not degrade your telescope's optics. Anyone telling you otherwise is using outdated information. Moreover, the highly regarded Nagler eyepieces and their clones have built-in Barlows, ample evidence that the lens is not some detrimental intruder.\" Thanks, Terence, for laying the myth of the degrading Barlow to rest.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"http:\/\/www.televue.com\/images\/TV3_images\/Images_in_articles\/Powermate4xParts.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xParts_sm.jpg\" alt=\"4x Powermate ...\" width=\"213\" height=\"173\" hspace=\"5\" vspace=\"5\"\u003e \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e4x Powermate shown for illustration. All 2\" models include 1¼\" adapters (left). Standard Eyepiece Adapter (middle-top) is removable to allow Photo\/Visual assembly (right) to use optional T-Ring Adapters (middle-bottom) for imaging.\u003c\/div\u003e\n\u003cp\u003e\u003ca href=\"http:\/\/www.televue.com\/images\/TV3_images\/Images_in_articles\/Powermate4xPhoto_VisualSetup.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/Powermate4xPhoto_VisualSetup_sm.jpg\" alt=\"4x Powermate ...\" width=\"213\" height=\"173\" hspace=\"5\" vspace=\"10\"\u003e \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv id=\"caption_gray\"\u003e4x Powermate photo setup with T-Ring adapter (left).\u003cbr\u003e\n4x Powermate visual setup with 1¼\" adapter (right).\u003c\/div\u003e\n\u003cp\u003eA high quality Barlow, properly designed and manufactured avoids compromising a telescope's colour and spherical aberration corrections. The \"invisibility\" of Tele Vue's 2-element Barlows is well recognized in test reports in the astronomy magazines. However, by the nature of its negative power lens, a Barlow will do more than just increase magnification, regardless of the number of elements.\u003c\/p\u003e\n\u003cp\u003eThe diverging rays leaving the Barlow result in moving the exit pupil further out, thereby extending the eye relief. In short to medium focal length eyepieces the change is not noticeable. However, in the case of long focal length eyepieces, the increase can be significant and not without performance consequences.\u003c\/p\u003e\n\u003ch3\u003eLess Vignetting with Tele Vue Powermate 2x\u003c\/h3\u003e\n\u003cp\u003eVignetting can occur due to the altered ray path, when the eyepiece's lenses are not large enough in diameter to allow all the rays to make it through. Shorter Barlows, or ones with too much magnification, only exacerbate the problem because the ray path entering the eyepiece is steeper.\u003c\/p\u003e\n\u003cp\u003eWe had to go beyond the Barlow concept to achieve the goal of a compact, high power, fully corrected image amplifier. The Powermate consists of a negative doublet plus a positive \"pupil-correcting\" doublet. This 4-element system provides the magnifying function of a Barlow without its limitations by restoring the field rays back to their original direction, as if the Powermate were not there. The result is a pure magnification increase.\u003c\/p\u003e","brand":"Tele Vue","offers":[{"title":"Default Title","offer_id":42045220651077,"sku":"PMT-2200","price":730.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/tele-vue-powermate-2x-338922.jpg?v=1731541214"},{"product_id":"celestron-luminos-2-inch-barlow-2-5x","title":"Celestron Luminos 2 inch Barlow 2.5x","description":"\u003cp\u003eThe Celestron 2” Luminos Barlow Lens increases the magnification of your 2” and 1.25” eyepieces by 2.5x. The premium 4-element apochromatic optics are fully multi-coated for optimum light transmission and yield high contrast, true colour images.\u003c\/p\u003e\n\u003cp\u003eThe beautiful hard-anodized aluminum housing matches the eyepieces in the Celestron Luminos line. A centralized rubber grip helps to keep your hands securely on the barrel, even when your fingers are cold or you are wearing gloves. A brass compression ring just inside the top of the Luminos 2.5x Barlow grabs your 2” eyepieces gently but firmly when you turn the oversized thumbscrew. Once the thumbscrew has been secured in place, the brass ring keeps your eyepiece in the Barlow instead of relying on the tip of the thumbscrew itself, offering a better grip and protecting the barrel from scratches. A matching 2” to 1.25” adapter is included so that you can increase the magnification of all of your eyepieces, both 1.25” and 2”, in this versatile Barlow lens.\u003c\/p\u003e\n\u003cp\u003eThe insert barrel of the Celestron Luminos 2.5x Barlow is threaded to accept 2” filters. This is a nice feature, because you can change eyepieces without removing and reattaching the filter each time.\u003c\/p\u003e\n\u003ctable class=\"prodSpecs\"\u003e\n\u003ccolgroup\u003e\n\u003ccol style=\"width: 50%;\"\u003e\n\u003ccol style=\"width: 50%;\"\u003e\n\u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eSPECIFICATIONS\u003c\/th\u003e\n\u003cth\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMagnification:\u003c\/td\u003e\n\u003ctd\u003e2.5x\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Coatings:\u003c\/td\u003e\n\u003ctd\u003eFully Multi-Coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight:\u003c\/td\u003e\n\u003ctd\u003e312g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size:\u003c\/td\u003e\n\u003ctd\u003e51mm (2\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLength:\u003c\/td\u003e\n\u003ctd\u003e93mm (3.66\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWidth:\u003c\/td\u003e\n\u003ctd\u003e64mm (2.52\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Threads:\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyepiece Adapter:\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompression Rings:\u003c\/td\u003e\n\u003ctd\u003eYes on both 2\" and 1.25\" eyepiece holders\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear Aperture:\u003c\/td\u003e\n\u003ctd\u003e28mm (1.1\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSolar Warning\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Celestron","offers":[{"title":"Default Title","offer_id":42045276291141,"sku":"93436","price":275.0,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/6673\/1845\/files\/celestron-luminos-2-inch-barlow-25x-272761.jpg?v=1731540554"}],"url":"https:\/\/bintel.com.au\/collections\/imaging-barlows-and-powermates.oembed","provider":"The Binocular and Telescope Shop","version":"1.0","type":"link"}