You can make a great start in night sky photography with just your DSLR and a tripod. However, these accessories will all help once you start getting serious:
- Dew Heaters & Lithium Batteries (see separate page)
- Timer Remote/Intervalometer
- Red LED Head Torch
- Camera DC Power Supplies
Timer Remote/Intervalometer
If you search on eBay for 'timer remote' and your model of camera you will find loads of cheap options. The Phottix Nikos wired timer remote is good (choose your camera model cable to go with it), or you can get the expensive but robust genuine versions from Canon/Nikon etc.