Richard, thanks for the info and letting me know about your testing. Another question I have about filters is about the size needed. I assumed I need the...
Hi Matt, a 1-1/4" filter will certainly vignette the Canon fov, 2" filter size is best. Having said that, sometimes when using focal reducers that already...
Hi, Your un-modified XT already has an internal filter. It's not a nebula filter but it does cut out ONE strong light-pollution emission in very good...
You can fool around with all kinds of filters, but if you want to live the good life under heavy light pollution, the first priority is to mod that camera!...
Hi, I have uploaded to file folder Filter tests file CLS Filters.xls. This file has transmission tests for an Astronimik 2" CLS filter and the Astronimik EOS...
I now better understand the problem the imager had using both CLS filters. Doing a white balance of a white card doesn't work well for both filters. Because of...
Hi Richard, Just took the plunge. Traded a JMI motofocuser on astromart for an astronomiks Ha filter 13 nm. Pretty excited. Already have a televue OIII and...
... From: Steve To: Astroimaging_filters@yahoogroups.com Sent: Thursday, April 03, 2008 6:29 PM Subject: [Astroimaging_filters] Re: What filters for what? Hi...
Hi, the Astronomik EOS CLS clip filter looks like it has more capability to handle blue shift from fast optical systems compared to the Astronomik 2" CLS....
Hi Samir Kharusi, thanks for links to your site. I agree in getting the rebel XT modded, however, I disagree with your IDAS filter suggestion for 2 reasons: 1...
You think? Richard, it's obvious from your tests that there's a huge difference between filters. I've assumed both filters were tested at normal angles...
Hi George, the owner had an issue about different color balance in images, not pollution rejection. That's the difference I was concerned about. You are the...
Hi, every time we discuss sky pollution filters, there is the issue of hitting or missing spectral wavelengths of the common sky pollution wavelengths. My...
I think we would all like to know which filter you end up with that does a sensible job with high pressure sodium and is reasonably priced. Best I ended up...
Anyone out there built a clone of my Rough Science Spectrograph? http://www.samirkharusi.net/spectrograph.html If yes, just take a loooong exposure pointing at...
Hi Samir, Wonderful idea!! Seems you have the potential for an application patent, The Skylight Pollution Analyzer? If I were to make such a device I would use...
Hi Samir, Your 10nm bandpass Ha-OIII filter makes a lot of sense for modified DSLR imaging. I would also include SII in your formula. I suggest that you submit...
Larry Lopez started a thread on the ccd tech group a while back that was looking into what happens to the s/n of the image if you break up the exposure into...
Yes Richard, I have rough data for my skyfog. I'm in the process of publishing my work so I'm refraining from disseminating the info openly for now. I'll send...
Yep, everyone should build something like this. Here's mine. http://i103.photobucket.com/albums/m153/g_liv/spectrograph-camera.jpg I've been obtaining my...
Hi George, IMO getting dark sky pollution skyglow values will be very difficult indeed. If I remember correctly what some of the amature_spectroscopy group has...
Hi Richard, I'm looking for your email but can't find it. What's you're email? gliv@... ... very ... useful ... year, ... helpful ... the ... of ... and...
This is amazing work considering your 3.5 mag limiting skyglow. I too believe narrowband-pass filters should be used in severe light- pollution. There is a...
... These are visual nebula filters. The eye isn't much sensitive anymore at Halpha and has practically 0 sensitivity above 700 nm. ... bw CCDs are pretty...
That's a beautiful result! All it needs is a wavelength scale. I sometimes lust light up a green laser for calibration. You can probably get a good handle on...
A call for skylight pollution wavelength values. Hi, I have started to build the skylight pollution wavelength spreadsheet that will eventually be posted to...
Are you sure about these values? Should the 446.1 line not be 546.1 and the 567.9 not be 576.9.John H. [Non-text portions of this message have been removed]...
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