Canon settings for planetary conjunctions?

[WilliamAstro]

What ISO, F-stop and shutter speed and exposure need to be to take photos of planetary conjunctions?

For an example we have Mercury and Venus and I would like to image them at 18mm and then 55mm focal length

What settings should that be for each or between 18 and 55mm?

[wxsatuser]

Your not going to get any detail, try Av mode wide open at ISO 100 or 200 and see if it gives a reasonable speed for handheld.
If you have a tripod speed will not matter.