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Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space.
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On Saturday, November 18, 2017 at 11:27:59 AM UTC-6, Razzmatazz wrote:
Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Forgot to add that this image was captured thru my 432mm F8 Astrograph using clear, red, green, blue, H-a and OIII filters over a period of 3 nights. At mag 10.1, this planetary nebula is just visible in 100mm binoculars as a fuzzy patch in Perseus overhead at 10pm local time. Razzy |
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On Saturday, November 18, 2017 at 5:27:59 PM UTC, Razzmatazz wrote:
Just before winter sets in The winter set in about 3 weeks ago. It is defined by the Polar day/night cycle where Polar noon happens on the December Solstice therefore 6 weeks either side of this date reflect the beginning and end of winter, in the Norther hemisphere the beginning is November 1st and the end is February 1st. https://www.usap.gov/videoclipsandmaps/spwebcam.cfm Astronomy appeals to the spirit of men or humanity as it connects the individual to the Universal by inspiration (spirit). |
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Excellent!
"Razzmatazz" wrote in message ... Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= |
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On 18/11/2017 17:33, Razzmatazz wrote:
On Saturday, November 18, 2017 at 11:27:59 AM UTC-6, Razzmatazz wrote: Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Forgot to add that this image was captured thru my 432mm F8 Astrograph using clear, red, green, blue, H-a and OIII filters over a period of 3 nights. It will look a lot closer to natural colours if you render OIII as cyan. At mag 10.1, this planetary nebula is just visible in 100mm binoculars as a fuzzy patch in Perseus overhead at 10pm local time. Razzy -- Regards, Martin Brown |
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On Tuesday, November 21, 2017 at 2:47:44 AM UTC-6, Martin Brown wrote:
On 18/11/2017 17:33, Razzmatazz wrote: On Saturday, November 18, 2017 at 11:27:59 AM UTC-6, Razzmatazz wrote: Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Forgot to add that this image was captured thru my 432mm F8 Astrograph using clear, red, green, blue, H-a and OIII filters over a period of 3 nights. It will look a lot closer to natural colours if you render OIII as cyan. At mag 10.1, this planetary nebula is just visible in 100mm binoculars as a fuzzy patch in Perseus overhead at 10pm local time. Razzy -- Regards, Martin Brown Thanks, will try that. However, I just like electric blue personally, so this image is according to my strange taste. Razzy |
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On Saturday, 18 November 2017 12:27:59 UTC-5, Razzmatazz wrote:
Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Which colour for double-ionized oxygen is real? Most shots I've seen, it's been green, but it's blue here. |
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On 05/12/2017 05:00, RichA wrote:
On Saturday, 18 November 2017 12:27:59 UTC-5, Razzmatazz wrote: Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Which colour for double-ionized oxygen is real? Most shots I've seen, it's been green, but it's blue here. OIII to my eyes is just on the dark green side of cyan if bright enough. With a bit of cunning you can create a plausible looking pseudo colour image from just OIII 501nm and Ha 656nm narrowband by treating stars and nebulosity differently in the post processing. -- Regards, Martin Brown |
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On Tue, 5 Dec 2017 15:16:47 +0000, Martin Brown
wrote: On 05/12/2017 05:00, RichA wrote: On Saturday, 18 November 2017 12:27:59 UTC-5, Razzmatazz wrote: Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Which colour for double-ionized oxygen is real? Most shots I've seen, it's been green, but it's blue here. OIII to my eyes is just on the dark green side of cyan if bright enough. With a bit of cunning you can create a plausible looking pseudo colour image from just OIII 501nm and Ha 656nm narrowband by treating stars and nebulosity differently in the post processing. The problem is, color isn't a physical thing, but physiological. We don't perceive color in terms of wavelength, but in terms of a function of both wavelength and intensity. Take a 501 nm source and adjust its intensity and people will see colors ranging from greenish-black to greenish-white. That is, people will identify several hundred colors by simply changing the intensity. That's why it's pretty pointless to worry about "true" or "accurate" color in most astronomical images (certainly those containing narrow band emission sources). How the output of different filter channels is mapped to the broad red, green, and blue channels of our output devices really just depends on the intent of the imager: an aesthetic result, or colors which enhance features of interest. |
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On Tuesday, 5 December 2017 10:31:35 UTC-5, Chris L Peterson wrote:
On Tue, 5 Dec 2017 15:16:47 +0000, Martin Brown wrote: On 05/12/2017 05:00, RichA wrote: On Saturday, 18 November 2017 12:27:59 UTC-5, Razzmatazz wrote: Just before winter sets in the outer arms of the Milky Way pass overhead. Embedded in them are regions of star formation and star death. M76 is a Planetary Nebula where the central star has shed its outer atmosphere shedding its hydrogen (the bright red areas) and oxygen (blue areas) into a shell, which is expanding into the surrounding space. https://www.astromart.com/common/ima...7.jpg&caption= Which colour for double-ionized oxygen is real? Most shots I've seen, it's been green, but it's blue here. OIII to my eyes is just on the dark green side of cyan if bright enough. With a bit of cunning you can create a plausible looking pseudo colour image from just OIII 501nm and Ha 656nm narrowband by treating stars and nebulosity differently in the post processing. The problem is, color isn't a physical thing, but physiological. We don't perceive color in terms of wavelength, but in terms of a function of both wavelength and intensity. Take a 501 nm source and adjust its intensity and people will see colors ranging from greenish-black to greenish-white. That is, people will identify several hundred colors by simply changing the intensity. That's why it's pretty pointless to worry about "true" or "accurate" color in most astronomical images (certainly those containing narrow band emission sources). How the output of different filter channels is mapped to the broad red, green, and blue channels of our output devices really just depends on the intent of the imager: an aesthetic result, or colors which enhance features of interest. There are a lot of (mostly men) who can't distinguish between things like certain shades of blue and green, or red and orange. I see people commenting on a colour fairly often where it's clearly not what they think it is. |
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