https://community.usa.canon.com/t5/General-Discussion/Good-introduction-to-serious-astrophotography/m-p/268367#M18781 <P>Keep in mind the title is "getting started" ... there's quite a bit not included in this article.</P><P>&nbsp;</P><P>Part of the challenge of astrophotography is "image data acquisition" ... and part of the problem is "image integration and processing". &nbsp;</P><P>&nbsp;</P><P>The author didn't mention a lot of the special types of exposures that are gathered (lights, darks, bias, &amp; flats) as well as the image processing steps involved (special software that deals with image calibration, registration &amp; integration ... this is fairly unique to astrophotography). &nbsp;Ultimately you get a combined "master" integrated image ... but that's just the starting point for the rest of the image processing &amp; adjustment steps.</P><P>&nbsp;</P><P>The cameras tend to be specially modified for astrophotography. &nbsp;You can use a normal camera, but the sensitivity will be weaker and the amount of exposure time will be increased. &nbsp;The Canon 60Da (the "a" suffix is for "astrophotography) was pre-modded by Canon to remove the normal filter and replace it with a more permission filter. &nbsp;Normal cameras are filtered so that the light collected will match the sensitivity of the human eye. &nbsp;But human eyes aren't equally sensitive to all wavelengths across the visible spectrum. We are not especially sensitive to the "reds". &nbsp;90% of the normal matter in the universe is Hydrogen. &nbsp;The dominant emission wavelength for Hydrogen is mostly the Hydrogen alpha wavelength (656nm). &nbsp;Human eyes are only about 20-25% sensitive to this. &nbsp;Normal cameras gradually ramp up the blocking starting at around 550nm and increase it block 100% by the time they get to 700nm (the end of the visible spectrum on the IR end). &nbsp;At 656nm, a normal camera blocks around 75-80% of the light. &nbsp;But this means you have to run much longer exposures to collect this light. &nbsp;Modded astrophotography cameras replace the factory filter with a much more permissive filter. &nbsp;</P><P>&nbsp;</P><P>&nbsp;</P> Tue, 26 Feb 2019 02:10:46 GMT TCampbell 2019-02-26T02:10:46Z https://community.usa.canon.com/t5/General-Discussion/Good-introduction-to-serious-astrophotography/m-p/268346#M18780 <P>From lens rentals:</P><P><A href="https://www.lensrentals.com/blog/2019/02/getting-started-in-deep-space-and-astrophotography/" target="_self">https://www.lensrentals.com/blog/2019/02/getting-started-in-deep-space-and-astrophotography/</A></P> Mon, 25 Feb 2019 15:19:29 GMT https://community.usa.canon.com/t5/General-Discussion/Good-introduction-to-serious-astrophotography/m-p/268346#M18780 kvbarkley 2019-02-25T15:19:29Z https://community.usa.canon.com/t5/General-Discussion/Good-introduction-to-serious-astrophotography/m-p/268367#M18781 <P>Keep in mind the title is "getting started" ... there's quite a bit not included in this article.</P><P>&nbsp;</P><P>Part of the challenge of astrophotography is "image data acquisition" ... and part of the problem is "image integration and processing". &nbsp;</P><P>&nbsp;</P><P>The author didn't mention a lot of the special types of exposures that are gathered (lights, darks, bias, &amp; flats) as well as the image processing steps involved (special software that deals with image calibration, registration &amp; integration ... this is fairly unique to astrophotography). &nbsp;Ultimately you get a combined "master" integrated image ... but that's just the starting point for the rest of the image processing &amp; adjustment steps.</P><P>&nbsp;</P><P>The cameras tend to be specially modified for astrophotography. &nbsp;You can use a normal camera, but the sensitivity will be weaker and the amount of exposure time will be increased. &nbsp;The Canon 60Da (the "a" suffix is for "astrophotography) was pre-modded by Canon to remove the normal filter and replace it with a more permission filter. &nbsp;Normal cameras are filtered so that the light collected will match the sensitivity of the human eye. &nbsp;But human eyes aren't equally sensitive to all wavelengths across the visible spectrum. We are not especially sensitive to the "reds". &nbsp;90% of the normal matter in the universe is Hydrogen. &nbsp;The dominant emission wavelength for Hydrogen is mostly the Hydrogen alpha wavelength (656nm). &nbsp;Human eyes are only about 20-25% sensitive to this. &nbsp;Normal cameras gradually ramp up the blocking starting at around 550nm and increase it block 100% by the time they get to 700nm (the end of the visible spectrum on the IR end). &nbsp;At 656nm, a normal camera blocks around 75-80% of the light. &nbsp;But this means you have to run much longer exposures to collect this light. &nbsp;Modded astrophotography cameras replace the factory filter with a much more permissive filter. &nbsp;</P><P>&nbsp;</P><P>&nbsp;</P> Tue, 26 Feb 2019 02:10:46 GMT https://community.usa.canon.com/t5/General-Discussion/Good-introduction-to-serious-astrophotography/m-p/268367#M18781 TCampbell 2019-02-26T02:10:46Z