Starship Asterisk*

Andy Campbell wrote: ↑Thu Feb 14, 2019 4:07 am

dmiladinovich wrote: ↑Wed Feb 13, 2019 11:16 pm I am incredibly interested on how this photographer took this with his telescope over 3 months and 74 hours of exposures. Are there any references or materials describing how he did it? This is beautiful.

Hi there - I'm the photographer so will attempt to answer : )

The camera is attached to a telescope which in turn rides on a mount that rotates parallel with the earth's core.
Guiding software allows me to leave the shutter open for 30 mins at a time, over several clear nights.
I use a purpose built Astro camera loaded with short bypass wavelength filters that allow only the light emitted by the nebula's individual gases to be captured. The idea is to build up the exposure over many nights to overcome the signal to noise ratio & get a nice clear picture.
As the outer regions of this nebula are so feint, I needed months of clear nights to gather enough data for these to show up clearly!

These sub-exposures are then stacked to create master files for each filter, which are then assigned as R, G & B layers RGB in Photoshop.
The resulting image is then fine tuned in processing to yield the best details & colours.
Short RG&B exposures are taken seperately to capture the natural colours of the stars themselves.

Best results are usually obtained from remote dark sites unaffected by light pollution.
Unfortunately, my suburban backyard is not like this as I live in a city of 5,000,000 people, so everything is just that much more difficult!

Hope that helps!
Cheers

Andy
https://www.facebook.com/AndysAstropix

Cousin Ricky wrote: ↑Wed Feb 13, 2019 1:34 pm

orin stepanek wrote: ↑Wed Feb 13, 2019 12:18 pm Just look me in the eye! Actually; a great photo of a stellar's demise!

The world is so exquisite, with so much love and moral depth, that there is no reason to deceive ourselves with pretty stories [the afterlife] for which there’s little good evidence. Far better, it seems to me, in our vulnerability, is to look death in the eye and to be grateful every day for the brief but magnificent opportunity that life provides. —Carl Sagan, “In the Valley of the Shadow,” Parade, March 10, 1996 [emphasis mine]

neufer wrote: ↑Wed Feb 13, 2019 5:08 pm

Ann wrote: ↑Wed Feb 13, 2019 4:20 pm

APOD Robot wrote:

A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.

To me as an amateur, the gas knots at the inner edge of the Helix Nebula seem straightforward enough. They would be at least somewhat similar to the "Pillars of Creation" in the Eagle Nebula, and they would be caused by a related phenomenon: The strong wind and energetic photons produced by extremely hot stars, that eat away at the edge of a dusty and gaseous nebula of some sort.

• But a dusty and gaseous nebula of WHAT sort
  
  And why so thin & straight with knots all along?

juliajoy@comcast.net wrote: ↑Wed Feb 13, 2019 11:18 pm AWESOME! From a backyard telescope, at that. Congratulations on a marvelous image, and thanks for all the time you spent to give it to we who love looking at space and its objects.

dmiladinovich wrote: ↑Wed Feb 13, 2019 11:16 pm I am incredibly interested on how this photographer took this with his telescope over 3 months and 74 hours of exposures. Are there any references or materials describing how he did it? This is beautiful.

Ann wrote: ↑Wed Feb 13, 2019 4:20 pm

APOD Robot wrote:

A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.

To me as an amateur, the gas knots at the inner edge of the Helix Nebula seem straightforward enough. They would be at least somewhat similar to the "Pillars of Creation" in the Eagle Nebula, and they would be caused by a related phenomenon: The strong wind and energetic photons produced by extremely hot stars, that eat away at the edge of a dusty and gaseous nebula of some sort.

• But a dusty and gaseous nebula of WHAT sort
  
  And why so thin & straight with knots all along?
  
  Nancy Pelosi: “He's already backed off of the cement – now he's down to,
  I think, a beaded curtain or something, I'm not sure where he is,”

https://en.wikipedia.org/wiki/Helix_Nebula#/media/File:Comets_Kick_up_Dust_in_Helix_Nebula_(PIA09178).jpg wrote:

Outer gaseous layers represented in blues and greens

---

This infrared image from NASA's Spitzer Space Telescope shows the Helix Nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. Planetary nebulae are the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years. In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died. The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded. So far, the Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found. This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns; green shows infrared light of 5.8 to 8 microns; and red shows infrared light of 24 microns.

APOD Robot wrote:

A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.

orin stepanek wrote: ↑Wed Feb 13, 2019 12:18 pm Just look me in the eye! Actually; a great photo of a stellar's demise!

The world is so exquisite, with so much love and moral depth, that there is no reason to deceive ourselves with pretty stories [the afterlife] for which there’s little good evidence. Far better, it seems to me, in our vulnerability, is to look death in the eye and to be grateful every day for the brief but magnificent opportunity that life provides. —Carl Sagan, “In the Valley of the Shadow,” Parade, March 10, 1996 [emphasis mine]