EXPLORE SCIENTIFIC HR Coma Corrector (Refurbished)

One of the most important obstacles for the exploration of the night sky is the brightening of the night sky by artificial lights, such as streetlights. The night sky is not really dark in the vicinity of towns or cities, which reduces the visibility of objects beyond the solar systems enormously. Depending on the type of the celestial object it is possible to increase the contrast dramatically by blocking the annoying artificial light. The EXPLORE SCIENTIFIC O-III filter uses a characteristic property of the so called emission nebulae. Those objects glow in special colours, the so called emission lines. Those emission lines are linked to chemical elements - in this case oxygen. The EXPLORE SCIENTIFIC O-III nebula filter blocks all other colours (and thereby nearly all of the artificial light) and only the two emission lines of the oxygen can pass the filter. The result is astonishing: suddenly nebulae are visible at locations that were completely empty without filters. In suburban skies for example the veil nebula NGC 6992 is almost not visible with a 200mm telescope. By using this filter you can see the nebula and its structures without problems. A must for every visual observer. The EXPLORE SCIENTIFIC nebula filters come with a individual test certificate - your guarantee to receive a premium filter.FEATURESenables the observation of so called emission nebulaeblocks almost the entire artificial lightonly the two emission lines of ionised oxygen passes the filterWHAT'S INCLUDED1x 2" O-III nebula filter

After three years of testing and refining we are extremely proud to present the new Explore Scientific High Resolution (HR) Coma Corrector. This corrector is a class of it´s own - it is fully functional for visual use and expands the focal length by only 6%! The Explore Scientific Coma Correktor is delivered as a complete set together with a rotating helical focuser with laser-etched scale, so you get a full package: corrector, adaptor to T2 (M42x0.75mm), adaptor to M48 (M48x0.75) and the helical focuser for visual fun. This coma corrector really is "high resolution" - it deliveres a visual polystrehl performance of 0,98 at f/4 and 0,96 at f/3! So it can stay in the telescope - and you will not only enjoy a tack-sharp Jupiter, but aslo sharp and defined moons in the future! What this means in terms of performance is shown in the three pictures with the graphs - the sharpness increase in those comparisons with and without corrector are stunning (examples are 400mm f/4, f/3,5 and f/3). Please notice: These graphs are for FLAT FIELD! You will get this performance without refocussing! Diameter of the field is 30mm - it doesn´t make sense to increase this with 2" and fast optical systems. Length of the 2" corrector barrel is approx. 85mm and it can be used with almost all 2" focusers on the market. To use the HR Coma Corrector visually, you need to have at least 32mm spare inward travel at your focuser, while the focus is on the same plane as the focusers end. Photographically there is no problem - the HR Coma Corrector shifts the focus outward by about 35mm, so that you will have no problem in achieving focus, when you are able to focus your camera without the HR Coma Corrector. FEATURESEliminates coma, field-curvature and astigmatism in newtonians Diffraction limited performance on axis and in the field Flattens the field Works for very fast systems down to f/3 Four-lens construction Can be used with almost all 2" focusers on the market SCOPE OF DELIVERY High Resolution (HR) Coma Corrector Adaptor to T2 (M42x0.75mm) Adaptor to M48 (M48x0.75) Helical focuser

​BRESSER Solar Filter 82,8 mm for BRESSER 4570700 NANO Telescopes Category: Spare Part for Messier Telescope Series Description: The high-quality Solar Filter with a diameter of 82,8 mm is ideal for safe solar observations with telescopes. It is suitable for the BRESSER 4570700 NANO AR-70/700 Telescopes. Please check compatibility using the product number on your optical instrument.