AS OF THE 22/01/2021 WE ARE UNABLE TO ACCEPT ANY ORDERS ON TELESCOPES AND ACCESSORIES DUE TO THE PROBLEMS AND COSTS OF SHIPPING. WE INTEND TO HONOUR ANY OUTSTANDING ORDERS AT THE EXISTING PRICES. WE WILL BE TAKING ORDERS AS SOON AS WE HAVE THE NEW PRICES EVEN THOUGH STOCKS ARE STILL VERY SHORT AND WE ARE SEEING DELAYS ON MOST PRODUCTS.
IF NO EXPECTED DELIVERY DATE LISTED ABOVE EVEN IF THE STOCK BUTTON HAS A TICK
Please email us if this is marked as in stock and you want to order one as due to very high demand products are going out of stock very quickly.
We will come back to you as soon as we check with the warehouse (During working hours)
PLEASE NOTE THAT EXPECTED DELIVERY DATE DOES NOT MEAN THAT SOCK WILL BE AVAILABLE. IT MAY HAVE ALREADY SOLD OUT BEFORE ARRIVAL SO PRE-ORDERING IS ADVISED.
These contrast-enhancing anodized aluminium, optical glass filters are designed to block out the wavelengths of light emitted by mercury-vapour light and other common causes of light pollution, whilst providing higher transmission at critical hydrogen-alpha and hydrogen-beta lines than competing filters. Bright, light-polluted skies appear much darker, and the contrast between object and sky is improved significantly. This contrast-enhancement effect is particularly apparent on nebulae. Unlike stars, emission nebulae give off light in a very narrow range of wavelengths. These filters allow maximum transmission of the important wavelengths of H-alpha, H-beta and doubly ionized oxygen – the ones most commonly emitted by nebulae. Views of galaxies and star clusters are also enhanced, but to a lesser degree. Also improves contrast on reddish planetary detail. Works well in telescopes of all apertures but is highly recommended for use on smaller telescopes up to 114mm diameter, where conventional filters swallow up too much light. Threaded to fit either standard 1.25” astronomical eyepieces. Supplied with storage case.