G'day all
I got my first decent view of Mars last night

thanks to a break in the weather, it was nice and crisp in spite of street lights and neigbours garden lights etc. The big problem was that it was so bright I could see very little detail of the surface due to the brightness, would a neutral density filter fix this and if so at what percentage 50-25 etc?
Another question also is while doing the star test thingy ie put a star out of focus and check the Airy disc, while doing this last night I had very symmetrical rings around the star but I did notice that they were bent out of shape around the primary mirror clips, the circles sort of bent around the clips at these points, Is this normal?
thanks

Jeff