I have been using the Pixel Remote Timer
TW-283/E3 for astrotracer astrophotography and cannot imagine life without it.
It has a programmable handset that can directly plug into the camera with a cable (or) be used as a wireless (2.4gHz) remote that connects the included multichannel receiver that plugs into the camera and can mount on the hotshoe. Claims 80m range, but I've never pushed it beyond 10m. Usually I am using the handset directly wired to the camera and velcro'd to the tripod. I've had it over a year and it seems to be holding up fine.
I appreciate the options of using standard bulb "hold the button" mode, fixed time exposure and a fully programmable mode. These really help me when star hopping, as does the backlit display. It has autofocus half-press communication ability. Make sure to get the Canon/Pentax flavor, as there are different models for each brands' cable pinout.
The only negative is the sequencing programming is not intuitive (for me) and the instructions are not altogether clear. There are several good user videos out there and I recommend practice before heading to the field for real work.