How to open the camera lens on nikon d3000 in maual mode?

Connected to a Celestron Nexstar 5SE telescope. D3000 says there's no lens attached in manual mode. Keeps lens at F4000. How do you bring the f stop down to 5.6? And keep the shutter open longer than a second or two?

I assume you're using a F to T-ring adapter.
The telescope determines the aperture which is fixed.
In manual mode, you can adjust the shutter speed to whatever you desire by adjusting the rear thumb dial.

First, with no lens on the camera there's no aperture for the camera to control so you can't
"… Bring the f-stop down to f5.6… ".

This should help you: http://www.ehow.com/...scope.html

So should this: http://astropix.com/HTML/I_ASTROP/TOC_AP.HTM

This tutorial may help you as well: http://www.nikondigitutor.com/eng/d3000/index.html Can't hurt to watch a video by Nikon about your D3000.