AC582 1.25" IR and UV blocking filter.

Made in the UK by Astro Engineering this high-quality "hot mirror" infrared and ultraviolet blocking filter is designed for use with modern webcam and CCD imaging cameras. If you use a webcam with almost any telescope except a well-corrected Newtonian, you are likely to encounter halos around stars and a problem often referred to as "fuzzy focus". This happens because any telescope that employs any form of lens in the light path is unable to bring the whole light spectrum to a single well-defined focus. The UV and IR parts of the spectrum will be brought to different focus points to the rest of the spectrum, hence the loss of resolution and halo effects.

The AE AC582 IR block filter passes 88% average of the visible bandwidth - 400nm to 700nm - whilst blocking 98% average of the bandwidth in the range 750nm to 1150nm. The AC582 also blocks near UV energy.

SnS comment: We strongly recommend using this filter with all webcams and not just for the benefits outlined above. The filter should be fitted to the nose- piece immediately to stop dust particles entering the camera body and falling on the CCD chip once the lens is removed. Dust motes and the shadows they create - known as dust bunnies - will begin accumulating the moment the chip is exposed by removing the lens.

Supplied in a shock and dust-proof plastic storage case.