FWIW I've done some imaging with an Orion Sky Glow Imaging Filter at SPOC where the skies are not as dark as they used to be and had good results. This filter is not as narrow as an OIII or SII but does a good job on generic suburban light pollution it also does not shift color much which is a nice benefit if you are not doing monochrome imaging. This filter is designed for Suburban or up to medium light pollution imaging as opposed to urban or very heavy light pollution imaging. So if you live in the burbs you might find this works very well. The advantage is that exposure times are shorter with this filter than with an OIII or SII. Exposure times are about double compared to no filter. Bob -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Tyler Allred Sent: Wednesday, November 10, 2010 8:30 AM To: 'Utah Astronomy' Subject: Re: [Utah-astronomy] ST Dec 2010 Urban narrow band imaging Kurt, Even when I lived in Orem and had terrible light pollution, I could do narrowband imaging. Hydrogen-Alpha is particularly easy. You can do 20 minute exposures, from a light polluted site, with a fast scope, and still get a background that is almost black, with no gradients. Oxygen (OIII) is more sensitive to the light pollution, but still pretty easy to do compared to visible light. I have only done Sulpher (SII) imaging from the new observatory and my light pollution isn't too bad here, so I can't comment directly. However, I have seen exceptional narrowband images taken from big cities, that use all three bands effectively. That is my 2-cents worth. Cheers, Tyler PS - I am beginning to see some images that use Hydrogen-Beta wavelengths as well. -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Canopus56 Sent: Tuesday, November 09, 2010 10:08 PM To: Utah Astronomy List Serv Subject: [Utah-astronomy] ST Dec 2010 Urban narrow band imaging The Dec 2010 issue of ST at 72-75 by N. Fleming suggests that useble imaging can be done from an urban location by using narrow band OIII, Ha and SII filters. The article includes, on page 73, an excellent image taken from "the suburbs of Boston, Massachusetts." I was wondering if anyone locally had done any "urban imaging" using this technique and what they thought of the idea. Clear Skies - Kurt