Who says you can’t shoot faint emission nebulae with a stock, unmodified, DSLR?
This is IC 1805 and LBN 667, the Double Nebula, in the constellation of Cassiopeia near the border of Perseus and Camelopardalis.
http://www.astropix.com/Double_Nebulae.html
Click on the link to see a larger version with more information.
It certainly is much easier to shoot emission nebulae with a modified camera, because the long-wavelength filter has been removed it passes almost all of the wavelengths of hydrogen-alpha light which give emission nebulae their distinctive color.
But you can make up for the wavelengths that get filtered out by just using more exposure. This is the price you have to pay.
A secret to being successful at this is to also use a light-pollution filter. These filters remove other wavelengths from light pollution and airglow and allow longer individual exposures that capture more hydrogen-alpha wavelengths in an individual exposure. Then you just stack a bunch of individual frames to equal one really long exposure – in this case, the equivalent of almost 5 and a half hours of total exposure in a stack of 41 eight-minute single exposures.
This image of the Double Nebulae was shot with a stock, unmodified, Nikon D5300 and a Nikkor 180mm f/2.8 lens working at f/3.46 with a 52mm IDAS LPS filter.
Jerry
