SingAstro

Hey is a refractor better or reflector better for dso astrophotography . I seen many people use around 100mm refractor for dso astrophotography . I dont get it , all refractor have long focal length and to do dso photo you need larger fov plus big aperture . Then the refractor have slow focal ratio compare to reflector.one last question does any know where to mod their dslr for astrophotography

Read this: http://www.singastro.org/viewtopic.php?t=8638

Hi,

leehai1980 wrote:Hey is a refractor better or reflector better for dso astrophotography . I seen many people use around 100mm refractor for dso astrophotography . I dont get it , all refractor have long focal length and to do dso photo you need larger fov plus big aperture . Then the refractor have slow focal ratio compare to reflector.

It's all depend on what you want to shoot, your equipment and your personal preference. Actually, most refractor use in astrophotography had shorter focal length than reflector.

leehai1980 wrote:one last question does any know where to mod their dslr for astrophotography

I also like to know who and the cost of modding... I not quite confidence in doing it myself...

Have a nice day.

ermm...

does this count?

http://www.hutech.com/AstroCamera.htm

A reflector generally have the focal point very close to the tube, and it might not reach focus with the DSLR chip embedded within the DSLR camera. Furthermore, the secondary obstruction will result in diffraction spikes. the fast focal ration might work to your disadvantage when imaging under light polluted skies.

As for apo refractors, ppl usually do photog with a focal reducer & field flattener, which can bring the focal reducer down from a general f7 to f5.
Most astrophotographers prefer the apo refractor due to sharper stars and also mobility when carried to uluh dark places taking stars.

Refractor can be used for both photog and viewing, but specialized astrophotog reflectors or RC astrographs are only meant for astrophotography (you can do visual with it, but the oversized secondary will result in loss of contrast and optical quality).