Astrophotography tips for a beginner? Is it me or my out of date camera?

Beginner here, I've been getting into photography over the past 8 or 9 months or so. Recently tried my hand at photographing the stars and have had mixed results. I'm using a nikon D50. I've been experimenting with my 18-55 lens and have had bad results. With my 50 mm prime lens I get decent shots. I'm shooting from a tripod, I use a 2 second timer to reduce camera shake, I've varied from f5.6 to f1.8, 200 iso to reduce noise, and shutter speed anywhere between 10-25 seconds. I think my white balance set to direct sunlight has done the best. I can take several shots using same settings, some blur and some don't. I've removed the filter in hopes to reduce any glare. Any tips? How do I get good photos of the stars? I'm also interested in trying this with my 35 mm slr if anyone has any additional info.

The autofocus is likely to struggle in the dark. It can help if you have a tripod with a quick release plate. Compose
Remove camera with plate from the tripod.
Point at a distant street light to lock in autofocus.
Switch to manual focus, being careful not to upset the focus or zoom setting.
Place camera with plate back on the tripod.
Shoot.

A prime lens with distance scale can make this easier. Some distance scales are inaccurate, and you need to experiment to find the real infinity. Zoom lens focus is often upset by zooming, and their distance scales are often inaccurate and inconsistent.

You need to attach your fine old D50 to a proper telescope using T-mount adapters, one for the camera and one for the telescope.

You can find a good 700 mm Newtonian telescope with 76 mm aperture for under $230

http://www.opticsplanet.com/celestron-76lcm-computerized-76-mm-newtonian-reflector-telescope.html

If you are taking photos of the moon, the exposure is going to be the same as the one you use when shooting here on earth in bright sun. You see the same sun shines on the moon as the earth, so your exposure will be something close to f/11 @ 1/2xISO of your sensor or film.

Focus manually. Auto focus will struggle with the night sky.
Make sure your tripod is on really firm ground.