2020BC
20-11-2007, 10:07 PM
The Canon 350D's peak sensitivity lies almost exactly in the blue-green portion of the spectrum, which by happy chance is where some nebulae emit strongly - at the O-III and H-beta wavelengths.
Using an H-alpha filter with an unmodified DSLR would be like pushing rocks uphill, because the IR filter severely reduces the strength of the H-alpha signal. Not impossible but long effective exposures (a big stack) would be required.
Using an Oxygen (O-III) filter on an unmodified DSLR plays right to the strength of the camera. If you want to try narrowband imaging with an unmodified DSLR then an O-III filter should be your first choice.
If you want to bring out some of those hidden wispy lines of detail then an O-III filter may be the go for you. I'm very pleased with the results of this test.
Many of my astro pics, taken without filters, have large areas of blue-green nebulosity that are clearly emitting a lot of light at the O-III and H-beta wavelengths. So, I bought an Astronomik O-III filter to see if the detail in images (i.e. wispy clouds, etc..) is similar to those ghostly H-alpha shots that we all like. I have to say the results are very pleasing.
An H-alpha sensitive (modded) camera is going to be better all round, and it will capture more nebulosity. It will also let you use H-alpha narrowband, but you've got to think this O-III shot on an unmodded camera is pretty cool.
Check this out.:rofl:I'm calling it the Freak (or Boogey Man) Nebula. See if you can spot the skull.:eyepop: The image is just a stack of three x 4-minute exposures at ISO1600.
Using an H-alpha filter with an unmodified DSLR would be like pushing rocks uphill, because the IR filter severely reduces the strength of the H-alpha signal. Not impossible but long effective exposures (a big stack) would be required.
Using an Oxygen (O-III) filter on an unmodified DSLR plays right to the strength of the camera. If you want to try narrowband imaging with an unmodified DSLR then an O-III filter should be your first choice.
If you want to bring out some of those hidden wispy lines of detail then an O-III filter may be the go for you. I'm very pleased with the results of this test.
Many of my astro pics, taken without filters, have large areas of blue-green nebulosity that are clearly emitting a lot of light at the O-III and H-beta wavelengths. So, I bought an Astronomik O-III filter to see if the detail in images (i.e. wispy clouds, etc..) is similar to those ghostly H-alpha shots that we all like. I have to say the results are very pleasing.
An H-alpha sensitive (modded) camera is going to be better all round, and it will capture more nebulosity. It will also let you use H-alpha narrowband, but you've got to think this O-III shot on an unmodded camera is pretty cool.
Check this out.:rofl:I'm calling it the Freak (or Boogey Man) Nebula. See if you can spot the skull.:eyepop: The image is just a stack of three x 4-minute exposures at ISO1600.