Peter,
There's a few things you can/should check with your scope. While we take at good faith that the scopes we purchase are made as the Real McCoy, sadly there are many short cuts that are taken with the cheaper scopes. I've seen big brand scopes have unbelievable 'cheats' taken just to save a few cents, and leave these scope essentially crippled and requiring significant modifications to bring up to scratch.
Secondary Mirror
Check to see that the secondary mirror is firstly centred in the focuser. If you don't have a collimation tool, it is easy to make a DIY tool. The plug that fits into the focuser makes for a good makeshift collimation tool. Drill a little hole (approx 3mm diameter) dead centre. Insert the plug into the focuser and have a look through this new peep hole.
NOTE: Never collimate the scope with it pointing up! If for whatever reason something falls into the tube, if it isn't pointing up then it won't hit the primary mirror.
Look to see if the secondary mirror is roughly centred in the focuser drawtube. With the scope set horizontal and pointing to the left to give us here a reference tube orientation, if the secondary mirror is set too far to the left, you will need to shift the secondary mirror to the right, closer towards the primary mirror. I've seen one scope where the secondary mirror was not only too far to the left, but the centre bolt of the secondary holder and the collimation bolts wouldn't allow the secondary mirror to be shifted far enough to be centred!!! Such a situation requires the complete replacement of the centre bolt and the collimation screws.
If you should need to replace the bolts, of course replace thread for like thread or the bolts won't wind into place.
Primary Mirror
The cell of the primary mirror should have compression springs on the collimation bolts to facilitate the alignment of the primary mirror. First, check to see that there actually are compression springs here - I've seen rubber O-rings used in some scopes!!! These will NEVER allow the primary mirror to have sufficient movement for proper collimation. These O-rings will need to be replaced with compression springs.
If there are springs, all too often these springs are way too soft to work properly, and these should be replaced too. Springs to look for should be as close to the diameter of the collimation bolt as possible (these will have less of a tendency to buckle when loaded, and so throwing out the collimation and reducing the compressive loading of the springs. If the only suitable springs are too long, then just cut them!
How strong should the springs be? For a spring with a 6mm centre hole, and 15mm long, when pinched between your thumb and first finger you should struggle to completely close down the spring on itself. Better a little lighter than heavier here though.
Collimation
Here's a link to the Astrobaby collimation guide. You can use that modified focuser plug as your first collimation tool:
Astrobaby Collimation Guide
Take your time first off. Do this during the day the first time or two so that there is no 'star gazing' pressure on you.
Mount
Don't over tighten the clamp bolts.
Loosen the Dec clamp and have the scope and counterweights set 'horizontal'. Look to balance the scope in the Dec axis, moving the counterweights up and down the shaft until the system is balanced so when you release the Dec clamp the scope doesn't rise or fall. Next, with the scope still in this position, balance the scope in the RA axis, sliding the tube up and down its cradle until it is balanced, so when you release the RA axis the focuser end of the scope doesn't rise or fall. Balancing the scope in both axis will ensure the least amount of strain being experienced by the mount. If you load the focuser with a heavy eyepiece or particularly a camera, you may need to readjust the balance situation.
These are a few things you can look at to get the most out of your scope first off
Alex.
