Celestron Polarizing Filter Set

4.0 Two for one

It does the job. Low price.

Limited use. Actually dedicated to SCTs.

I purchased this filter to provide me with a better view of Mars in 2005. I had noticed the brightness of the planet was at times so great that it created a glare with any EP. On a whim I used my Moon filter and the view, though too dim, was better. I did some research and decided to try a variable polarizing filter, one with which I could adjust the level of filtering. I was not sure if it would work, but the price was right, so why not?

Prior to purchase, I had asked the dealer if this particular filter would work with my primary scope, an F6 Dob. He assured me that it would. I was a bit concerned as the reviews and literature state that this type of filter was designed for use with SCTs. I trusted the dealer. It turns out he was wrong.

Upon arrival I could tell the construction was first rate. The two filters come with an extension tube. When the filters are properly placed within the tube and the tube is inserted in the focuser of a scope, the amount of filtering is adjustable simply by turning the eyepiece. It seemed to me to be a wonderful concept and it will work if your scope has enough in-focus travel. Most, if not all, short tube reflectors do not have sufficient in-focus travel. As I could not get enough in focus to use the filter I thought it was a bust.

I was ready to send the unit back to the dealer when I had an idea. I bypassed the tube and screwed the filters into one another. I could than adjust the filtering by twisting the filters. This worked well.

The unit does just as I expected. It cut down the glare of Mars and helped provide many memorable views. I also used it with much success on Jupiter and the Moon. At times, due to different sky conditions and the inherent night to night fluctuations in the brightness of objects, a variable filter is a handy tool. In fact the filters can be unscrewed and used seperately. Thus, you can have two EPs with the same filtering.

I have used it with my F6 Dob and my 90mm F11 refractor and with all of my high magnification EPs without a problem. I tried the unit on Saturn without success; thus its use is limited to Mars, Jupiter and the Moon. However, given the low price and the great improvement it provided I can easily recommend this filter.

I would be more apt to rate this item betweem "Very Good" and "Average". IE a good, useful product.