For an interim I have built a wedge for my evo8 until I can save up to get a GEM.
For those that have a DIY/factory wedge for a 8SE or Evo8, can you please tell me what location on the fork mount do I use to get my GC on the wedge base to mount to the tripod?
Also I have read that the angle of the wedge platform is 90° minus my latitude (Melb SE; 38°) or 52° from wedge base. Is this correct or dose this only apply to the Northern hemisphere?
The celestial pole is your latitude (degrees) above the horizon; northern or southern hemisphere. The only difference between hemispheres is which direction the pole above the horizon is, i.e. NCP is above geographic north in Northern Hemisphere and SCP is above geographic south in the Southern Hemisphere.
If you were at one of the poles your celestial pole would be overhead at zenith and the other pole below at nadir. If you were at the equator both celestial poles would be on the horizon along the geographic north-south line.
At 38 deg south the SCP is 38 degrees above the horizon due south, (geographic not magnetic). The telescope polar axis needs to match this and if an SCT then the wedge face is 38 deg from the vertical or 52 deg from the horizontal. This would be the same if you were 38 deg north of the Equator except your polar axis would then be pointing at the NCP which would be 38 deg above geographic north.
I wasn’t quite sure what you meant by your second sentence. Is GC meant to be centre of gravity? You can utilise the tripod leg positions in stabilising any CoG issue you may have with the wedge. I’ve only ever used a C14 on a Celestron wedge in an observatory on a regular basis as my own C9.25 rides on a GM8 with G11 saddle, (sold as CG-9 1/4 with heavier cylindrical legs not the usual square Losmandy GM8 offering).