Testing lens for suitability when cloudy

[TiffsAndAstro]

57 minutes ago, Ratlet said:

It might just be you're in focus is why you get the red halos.  I found best results by getting it in focus and then backing off slightly.v if you use a bahtinov mask with some vintage prime focus you'll get awful red stars.

With the takumars you get red halos on one side of focus and very light blue on the other side.  The red is very noticeable, but the blue much less.  You basically want to err on the blue side as it ends up looking like very slightly bloated stars.

I've noticed that going by Nina if I focus for the 'best' focus my stars look awful, but if I back it off slightly they look better so long as I head towards blue halos.

this might be a great help ty and will give it a go as soon as clouds go away. in a few months