Topics

1

General / Lum data in HaRGB?

« on: 2011 October 07 05:25:42 »

I've been having fun using Silvercup's new HaRGB Combination script, as well as studying Vincent's tutorial and previous posts (and Harry's video) on the subject. So far so good. But my question is what to do with the Lum data I've gathered? My options seem to be: 1) discard those images (seems like a waste), 2) create a non-linear LRGB image and combine that with the Ha, or 3) or combine the linear HaRGB image with my Lum data. Preliminary testing doesn't seem to favor options #2 and #3. My best results seem to be just sticking to R, G, B and Ha frames. Going forward, I can change my acquisition strategy for those object I plan to merge Ha data into-- but what should I do about the Lum data I've already gathered?

Any thoughts would be greatly appreciated.

-- John

2

General Discussion / Decision to use Light Pollution Filter

« on: 2011 March 15 00:44:00 »

I've been thinking about using a light pollution filter (perhaps the Astronomik or LDAS LPR?) in my imaging train and was hoping for some input from those who might be using one. My primary concern is about the difficulty of creating the proper color balance. In looking at the transmission curves for these filters, they seem to block nearly the entire spectrum for my green filter (I use Astronomik LRGB filters). I'm wondering if I'd need to take significantly more green images, than the other colors? At the moment I do a simple ChannelCombination as the first step in my work flow after calibration, but I'd be willing to change if necessary. BTW, I've pretty much given up taking Luminance frames in favor of just RGB, since I have a fixed observatory in my backyard.

I live in a suburban area of No. California that's in the "orange" section of the ClearDarkSky light pollution charts (bordering on yellow), and I've calculated my optimum sub-exposure at about 5 minutes (for the area with the darkest skies, which for me is east). I suppose this is okay, but I'd certainly like to go deeper with longer exposures (and have better results when imaging to the south and west which is the direction of light dome of the town I live in)-- but maybe not at the expense of a more complicated work flow. I can certainly just image the same object for a number of nights to make up for the lack of dark skies-- but obviously there is a limit to what I can accomplish with my location and gear.

Any thoughts would be much appreciated. Thanks.

John