by Ann » Sat Aug 18, 2012 6:35 am
Diana wrote:
Does anyone know if the Hubble ST has ever been trained onto that purple pansey-like nebula way up high in the back arm(picture perspective)?
I'd say, probably not. I googled "Hubble NGC 5033" and got only one hit,
this one. It shows the area near the center of NGC 5033.
Even if there had been a Hubble image of NGC 5033 which actually showed the part of the galaxy where the nebula is situated, it is not certain that the nebula would have looked very interesting. The reason is that the Hubble Space Telescope, when it photographs galaxies, uses narrowband filters that are usually not well suited to reveal a lot of detail in nebulae. Nebulae emit light of extremely specific wavelengths, and to detect them you need either a filter that detects that specific wavelength or a broadband filter that detects that particular wavelength along with several others. Hubble, when photographing galaxies, normally neither uses a Ha filter at 656 nm (to detect the specific red color of nebulae) nor a red broadband filter. Instead Hubble normally uses an infrared filter (often at 814 nm) or another red filter at, say, 625 nm.
Adam Block uses broadband filters, so his imagery detects details (such as color) in nebulae that Hubble would normally miss.
Ann
[quote]Diana wrote:
Does anyone know if the Hubble ST has ever been trained onto that purple pansey-like nebula way up high in the back arm(picture perspective)?[/quote]
I'd say, probably not. I googled "Hubble NGC 5033" and got only one hit, [url=http://server7.sky-map.org/imageView?image_id=905507]this one[/url]. It shows the area near the center of NGC 5033.
Even if there had been a Hubble image of NGC 5033 which actually showed the part of the galaxy where the nebula is situated, it is not certain that the nebula would have looked very interesting. The reason is that the Hubble Space Telescope, when it photographs galaxies, uses narrowband filters that are usually not well suited to reveal a lot of detail in nebulae. Nebulae emit light of extremely specific wavelengths, and to detect them you need either a filter that detects that specific wavelength or a broadband filter that detects that particular wavelength along with several others. Hubble, when photographing galaxies, normally neither uses a Ha filter at 656 nm (to detect the specific red color of nebulae) nor a red broadband filter. Instead Hubble normally uses an infrared filter (often at 814 nm) or another red filter at, say, 625 nm.
Adam Block uses broadband filters, so his imagery detects details (such as color) in nebulae that Hubble would normally miss.
Ann