Best EP for open clusters in Auriga?

[mikeyrea]

I was treated to an uncharacteristically clear sky tonight. OK, so it was a bit breezy, but the way the weather has been recently I wasn't going to waste the opportunity to stargazing!

After a very wobbly Jupiter my targets for the evening were M36, M37 & M38, the three open clusters in Auriga, and M35, an open cluster beside the star Propus (or Tejat Prior) in Gemini.

I viewed them with my Skywatcher Explorer 200P (Ft=1000mm) through my stock 25mm wide angle EP and was thinking that although very pretty they might look more spectacular through a lower power EP, and was wondering what you guys liked to use?

I have read that after around A/7, which is 29mm in my case, the exit pupil will be getting a bit wide, and also a low powered lenses the black backdrop of barren space will start to grey out.

The moon was, of course quite, bright this evening and did seem to wash out the views.

[Moonshane]

my answer would be the widest field, lowest power eyepiece you can afford. what these parameters mean, depend on your scope and the light pollution local to your main observing site.

I generally feel that you should aim for an exit pupil of 6mm or less. the exit pupil is focal length of eyepiece divided by focal ratio of scope - f5 in your case. so to put it another way 5 x 6 = 30mm = max eyepiece focal length for your scope based on this, you could push to 32mm if you have good skies or restrict to 25mm if you have light polluted skies.

the next thing is the apparent field. personally unless you can afford Naglers etc, I'd stick to used Televue plossls, they are excellent value for money and although the field is 'only' 50 degrees, it's all sharp. my recommendation is therefore a used 25mm or 32mm Televue plossl or stick with what you have.