EXPLORE SCIENTIFIC Extension Ring Set M48x0.75 - 5 pieces (30, 20, 15, 10 and 5 mm)

Fast 90 mm high-performance astrograph for demanding astrophotographers and observers with 5 lens elements in 5 groups. Due to the complex optical structure with five lens groups and five elements (quintuplet), including two SD (Super ED) lenses and an ED lens (Extra-low Dispersion) , a virtually aberration-free optical system was created. This revolutionary astrograph is compatible with a full-frame digital DSLR or an even larger 44x33 mm camera. The 90 mm astrograph with fast aperture ratio delivers exceptionally sharp, high-contrast and small point stars from the centre to the corners of the field of view. In addition, it is also ideal for visual observation with a very large field of view but also for planetary observation with high magnification. The VSD90ss is designed so that there is a "long peak range" in the adjustment accuracy of the sharpness, so that photographers can always achieve satisfactory results in astrophotography. Even if the focus is not quite precise, round and sharp stars are still shown throughout the entire image field. Illumination without vignetting In most cases, an astrograph also produces optical vignetting (a gradual decrease in light rays towards the edge of the image) This is mainly caused by rear lenses being shaded by the front lenses. Because of this darkening, it is relatively normal for the photographer to have to further edit the image after taking the picture and also have to do some additional so-called flats before taking the picture. To solve this problem, the VSD90ss uses wide aperture lenses in the rear elements, securing over 90 % of the light volume at the edge of the 60 mm image circle. Since the light intensity is uniform throughout the entire image field of the VSD90ss, there is no need for complex technology to prevent edge darkening. The VSD90ss is coated with the most modern coatings of extremely high reflectivity. These coatings have been specifically developed to optimize the properties of each individual lens element without degrading contrast and light intensity across multiple lenses. Numerous gradations of light bring beautiful point-like stars into the image field The low optical vignetting ensures sufficient illumination and thus eliminates the asymmetric flare caused by bright, diffraction-limited stars. It prevents stars at the edge of the 60 mm image circle from exhibiting deformations such as comets, astigmatism or coma. Since the illumination of the image field is relatively similar from the center to the edge of the image, you can expect excellent star imaging. Please note: *Depending on the recording system used, mechanical vignetting can still occur due to the camera body or incorrect adapters. 96.7％ Strehl for impressive visual observations The VSD90ss offers a flattened large field of view with a low magnification wide angle eyepiece. Even with a high-quality wide-field eyepiece with a large field of view, you can get sharp images of stars in the entire field of view when visually observing! In the centre of the field of view, a Strehl intensity of an impressive 96.7% is achieved at visible wavelengths. This Strehl ratio exceeds that of the SD81SII apochromat at 95.7%, which is known for its excellent optical properties, and this also works excellently when observing the moon and planets at high magnification. The versatile large and stable focuser The VSD90ss has a large focuser with a diameter of 87.5 mm to make optimal use of the large illumination field of 60 mm. With the large extension that is compatible with many accessories, it is perfect for astrophotography up to large format or 35 mm full frame DSLR cameras. Thanks to its precise manufacturing, it is also suitable for very heavy cameras without tipping. The precision locking lever of the eyepiece extension The focuser's extension tube has a locking lever that holds the extension tube firmly in position even when using heavy cameras such as large format cameras or CCD cameras with a large sensor. The locking lever clamps the rack gear to the extension barrel so that the viewing angle or focus on your camera does not shift. Compatible with motor driven focusers An optional two-speed motor focuser (not included) is available for the VSD90ss to provide sensitive focusing. An EAF (Electronic Automatic Focuser) from ZWO or equivalent can also be retrofitted. Optional VSD Reducer for even faster results The tried and tested optional VSD reducer, which was also used on the predecessor, the VSD 100, is also compatible with the VSD90ss. The photographer gets even faster results in astrophotography with an aperture ratio of 1:3.9. CHARACTERISTICS 90 mm aperture, 495 mm focal length (F5.5) Needle-fine stars up to the image field edge in 44x33 mm format 5 lens elements in 5 groups Image illumination up to 60 mm Resolution power: 1.29 Limit size: 11.5 Light gathering capacity: 165x Illumination: 60 mm Dimensions: 115 mm diameter x 600 mm length (476 mm length for storage) Weight: 4.3 kg Connections/Thread: Size thread/84 mm (pitch 1 mm), 60 mm (pitch 1.0 mm), 42 mm for T-ring push fit / 60.2 mm, 50.8 mm and 31.7 mm Solar observation: separately available solar projection approach B Optional VSD100 reducer compatible (opening ratio F: 3.9) SCOPE OF DELIVERY VSD90ss high performance astrograph

NEW - now including a high-quality lens solar filter for the safe observation of sunspots, eclipses and planetary transits. A high quality telescope for night and solar observation.The BRESSER Messier 10 "Dobsonian is something very special. Despite the low price, it offers a variety of functions and quality that are sometimes unavailable in considerably more expensive telescopes. With its 254 mm diameter optics, this telescope is not limited to solar system observation of the Moon and brighter planets - you can also observe far out into the universe and see globular clusters, nebulae and galaxies. Details become visible in most deep-sky objects: globular clusters are broken down into individual stars and nebulae, which are only hinted at in smaller scopes, show considerable structure. This Dobsonian is unsurpassed in versatility within its price range: the excellent, large Hexafoc focuser has an opening of 65 mm - so even with large wide-field eyepieces, there is no noticeable vignetting from the eyepiece extension tube. The large elevation wheels also hold the telescope level with just the right amount of "sticktion", even when heavier eyepieces are used. And when a lot of heavier accessories are attached, such as the Bresser Binoviewer attachment, then the entire telescope tube can be moved within the tube rings - and everything is balanced again in a flash. The unsurpassed rigidity of the focuser makes it easy to focus - photography with this OTA is no problem either as the supplied extension tube for the focuser can be removed and a camera easily bought to a prime focus position. This is another strength of this universal telescope: if you want to take photos, you can simply unscrew the elevation wheels from the tube and place it on an equatorial mount with a standard dovetail rail - other rival Dobsonians do not offer this level of flexibility or pathway to more expansive astrophotography use. An optional dual speed 10:1 gear reduction for the focuser is available for those who need extra fine control of focus. If you consider that the focuser is the telescope part that is used most often, the supply of the Hexafoc on this telescope is a quantum leap for this price range.With the initial equipment you can observe immediately - a 6x30 viewfinder and a 25mm SPL eyepiece are included within the package.  If you want to transport the device as compactly as possible, it is easy with the new 10 "BRESSER Messier - the rocker box can be dismantled in a few simple steps, as the parts are assembled with metal quick-release connectors. A bulky rocker box quickly becomes a handy flat package of boards within a few minutes. This is a telescope whose versatility, performance and ease of use set new standards in this price range.Please note that while Newtonian type reflecting telescopes are very good for astronomical observations in the night sky, they not well-suited for observing nature and landscapes during the day. We therefore recommend BRESSER refracting or Cassegrain designs of telescopes for additional nature and landscape observations.PROPERTIESType: mirror telescopeMirror diameter: 254mm / focal length: 1270mm / F / 5Maximum useful magnification: 508 timesTelescope for night and solar observation2.5" HEXAFOC focuserMain mirror made of special glass, with low thermal expansionHassle-free focusing, even with heavy accessoriesEasy to move tubeDismountable rocker boxTube mounting on altitude bikes using clampsUse of the optics on other mounts as wellAdjustment and construction screws of different sizesBase diameter 54cmWhat's IncludedTube with Newtonian opticsFull aperture Solar filter6x30 viewfinder25mm Super Plössl eyepiece (Ø 31.7 mm / 1.25 ")1 extension tube 37.5mm for 2.5 " Hexafoc1 eyepiece adapter 1.25" to 2"/31.7 to 50.8 mm2 Tube Rings2 Altitude support wheelsRocker box with 2 base plates and mounting material (disassembled for self-assembly)Shipping dimensions Box1: 134x44x44cm - 19.0kgShipping dimensions Box2: 61x61x24cm - 17.0kg