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Astrophotography

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https://www.barthmobile.com/eve/forums/a/tpc/f/5931087061/m/4963981587

04-23-2015, 12:33 AM
Rusty
Astrophotography
Doubtful you were wondering how we astrophotographers get images, but here is a brief explanation.

I have several astro-cameras, among which are:

• A dedicated monochrome CCD camera that images through six filters - Red, Green, Blue (for "natural" color), Hα (Hydrogen), OII (Oxygen), and SIII (Sulfur). Straight-through, no filter, is "luminance". Most images I take are "LRGB": Luminance/Red/Green/Blue. A typical exposure of a distant galaxy would get 120 minutes of each, consisting of 6x20 minutes. The resulting images are "stacked" to get the desired definition, and processed with special software to render the final image. Software also can render the image in the "Hubble Palette", which uses different colors from LRGB to represent emissions from different elements.

Obviously, long exposures require pointing accuracy, and the camera above has an output for correcting tracking errors, and all my mounts can accept it. For the other, non-guiding cameras, I have a separate guider camera that looks through a second scope for corrections.

• A modified (IR filter replaced to allow better sensitivity to infrared) Canon DSLR. This is an example of an OSC (One-Shot Color) with a less-capable CMOS sensor. Exposures can be as short as 1/50 sec (for planets) or several minutes (deep sky). Additional mods to the camera firmware lock the mirror, increase sensitivity, and allow RAW (uncompressed) images. These are converted to the equally lossless FITS format.

• A specially-constructed, very sensitive, video camera, which is also OSC. Exposures can run from fractions of a second to (in my version) 96 seconds. While this camera can capture and record those videos, the real charm is that it can display the images immediately after the exposure is complete. With my computer-controlled scope mounts, I can view images from the comfort of my Barth, while my friends are dealing with 25°F temps.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
04-23-2015, 01:16 AM
dr. bart
Rusty... Isn't there some sort of a meteor ahoy now ?
04-23-2015, 01:07 PM
Rusty
The Lyrids would have peaked last night, but some strays will continue tonight and tomorrow. The best time for any meteor shower is between midnight and 3AM.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields