Astro photography with DSLR

[Twinkle star]

Hello to everyone,

as I am new in the forum I´d like to introduce myself at first. I live in Germany near Mainz and I am interested in astronomy and astro photography.

My equiment: Meade ETX 90 and Nikon D70 and D5000, skywatcher EQ3

I have already managed to make useful pictures of some star constellations as well as of the moon or jupiter. But what confuses me is that as soon as I try to focus nebula (orion) with my DSLR (Nikon D5000), the viewfinder is completely dark. Nothing can be seen. I suppose that the target is too dark - but what can I do about it?

Thank you for your replies.

[fatwoul]

Since everything in the sky is effectively the same distance away from the camera (infinity, for all intents and purposes), just use a bright star to focus on, lock the focus, and then move to the fainter objects you want to photograph.