For astrophotography you need a wide aperture
F 2.0 Long shutter speed of 30" seconds
Never go higher than Iso 3200 .
Use a tripod and remote for detailed video check out canon's astrophotography in YouTube by Canon Australia.
ASTRO photography requires a few things.
1. Location. Has to be somewhere with close to zero light pollution
2. Light source : always nice to light up something in foreground for balance against the sky.
3. Lens. Low aperture lens. I use rokinon 12mm at 2.0 which on my crop sensor gadgets gives me 18mm wide shots
4. Tripod. Invest in this. Because quality matters. If you can't afford to buy a Manfrotto rent from someone. This is important.
5. Exposure time. You are looking at a plus 20s. Get a remote if you can. 6. Have fun.
You must have tripod. Use 10/5/3sec delay to shutter release so due to hand shake there won't be any blur in image. For sharp results use little high shutter if you have full frame camera. F should be around 5.6 or less than 8 also works. Iso upto 3200 or 6400 for full frame. And if you have APSC format normal dslr then fon't go above 3200 (else images will be little noisy. For full frame dslr no need to worry till ISO 6400). Shutter should at least 20 sec and it also depends on camera body and its cropping factor. Try experimenting with 15sec, 20sec, 30sec. The more you keep shutter time you will get star displacement in frame so keep this in mind. F 2.8 / F3.5 / F5.6, F8
Shutter 15sec to 30sec