Celestron Astro Solar Filter for Nexstar 5, NexStar 130 SLT, Astromaster 130mm

SKU: CNSFC5

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2008-09-03T21:00:00

Rated 2 out of 5

Could be Dangerous!

The filter works, no question about that. When the filter is on the scope, aimed at the sun, the filter gets of course warm. This will soften the glue that holds the foil to the ring. There is no reinforcement on the back of the ring to hold the filter in place. Once the glue lets go of the foil, it will flap in the wind and can potentially expose the eye to direct sunlight. This is very dangerous, and I have a hard time recommending this filter to anybody. Once the foil is pressed on the ring again, the glue will stick again. The question is just for how long. Celestron either has to use a different adhesive, or reinforce the foil on the back so that the filter stays in place even if some of the glue comes off.

KH

Celestron 94139 Astro Solar Filter for NexStar Specifications

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About Celestron 94139 Astro Solar Filter for NexStar

Celestron Solar Filters are made with Baader Astro Solar Safety Film. Far superior than any existing glass, Mylar or polymer filters, they lead to brighter, sharper, and higher contrast images.

Enter the millennium with the finest solar filters available. Astro Solar Safety Film is clear and homogenous and attains the optical performance of high quality plane-parallel glass filters-it is diffraction limited! Double-sided metal coatings have uniform density and good color balance across the entire field ensuring razor sharp images from edge to edge.

The Sun appears in its "real "color -neutral white, not blue or orange ,and the sky adjacent to the solar limb is jet black.

You can see detail in sunspots, bright faculae near the limb and the mottled areas known as granules with these filters. The Sun offers constant changes and will keep your observing interesting and fun. Even small aperture telescopes can enjoy features of the Sun.

The Astro Solar film is completely safe and durable (won't break like glass if dropped). Its rating is ND-5 which means that the film transmits 1/100,000 of visible light (.001%) while reflecting (blocking) 99.999%of unwanted light. The film absorbs all ultraviolet rays while coating reflects infrared light rendering both absolutely harmless. For added assurance, Baader Astro Solar film has been declared safe for direct solar viewing by the German National Bureau of Standards for eye safety.

Celestron has previously manufactured high quality, plane-parallel glass solar filters (unlike today 's glass filters which generally are poor in quality with reduced contrast). Celestron has offered Mylar solar filters (they were the best previously available) but they suffer from a lot of scattered light and false color. Polymer filters suffer from not only scattered light but also have reduced sharpness and contrast due to their increased thickness. So, "we've been there and done that" and after all these years are now offering the finest solar filters available for observing. Each is mounted in a durable ABS or rubber cell that won't break.