If your telescope comes with so-called UHTC, Ultra-High Transmission Coatings, do you still need a UHC filter?

The answer is yes, especially if you are trying to observe in light to moderate light pollution conditions. If you are observing in heavy light pollution only the brightest objects will be observable, but a UHC filter may help to boost the contrast and block the light pollution. If you are at a dark site a UHC filter can help to boost the contrast on the really faint and diffuse objects.

The UHTC is misleading. Most mirror coatings only reflect 88% to 90% of the light that is reflected by them. UHTC may bring that up to 95%. Depending on mirror size that may not even be noticeable. IMHO all amateur astronomers should have a UHC filter in their accessory case.

The combination of high transmission coatings and the proper filters can tease faint objects out of the sky, as with just UHTC may not. Filters are a must some times even at the darkest of sites.

JJ

  Thanks for the response, JJ.  I wasn't sure if it was necessary.  I do live in a low light pollution area- there is a town of 9000 off to the west and that is about it.