Shaun,
Welcome to IIS
An 8" dob is a great starter scope, great choice.
As for extras:
- Observing chair otherwise you will get dobber's back. Many people just use an old office chair, drummers stool or even a fold up camping stool.
- Cheshire eyepiece (a long one like the Orion one from Bintel) to help with collimation.
- Red torch to preserve your night vision.
- Planisphere to help you map your way around the sky.
- Lots of warm clothes, especially in a Canberra winter.
- Copy of Stellarium or Cartes du Ciel (both freeware for windows) fantastic planisphere applications.
- Copy of RTGUI (freeware for windows) very useful for planning your sessions.
- Copy of Virtual Moon (freeware for Windows) cannot say enough good things about this program.
- Polarising moon filter for observing the fuller moon when its too bright to look at any other way.
Don't get into buying accessories too soon otherwise you will end up with a heap of paperweights. Take your time and get to know your scope and your observing style then you will make good and informed descisions.
A few tips:
- Ensure your scope is collimated as well as you can, this will get quicker and better as you practice and will ensure you get the best possible images your scope is capable of under the prevailing conditions.
- Let your scope cool before trying to observe through it. If the mirror is not near ambient you get boundary layers and thermal currents in the tube. These wreck your images so on a good evening when you get home from work just chuck your scope out and let it cool for a couple of hours as the sun goes down. This will help but, if the temperature keeps dropping as it does in Canberra, the mirror may never catch up and you may need to set up a fan eventually.
- If you need a fan and don't want to put one on your scope for a while then use an ordinary fan blowing into the back of the scope while it is cooling. This will help but turn it off before trying to observe.
- While your scope is cooling cruise with your binos and planisphere to map out the areas you want to observe with your scope.
- Take your time with your sessions and keep a record of what you see, even sketch things, and over time you will see a great improvement in your observing skills.
Enough rambling, just enjoy your new toy