Trap a-e ?

Hi,
Does this make sense. I live in a crazy light polluted area and I can only set up in my backyard surrounded by chimneys etc. Anyway, sometimes I get "e" and most times I don't. Tonight using a 5mm UO volcano ortho (180x) I couldn't get "e" (even when my neighbors crazy automatic light went off ) with my Meade 5000 5.5 (163x) I had a hint of "e". Could it be that the higher hag of 180x dimmed "e" enoungh so as to make it not seeable whereas the 5.5 being at 163x allowed it to be bright enough to just make out?

Itz,
Yes, that does make sense to me. But in my opinion, both powers are rather high. Dim secondaries are best viewed at the lowest power that allows separation, to minimize the washout effect.

I think excessive magnification is the bane of double observing, but I'm sort of weird that way. Even for equal pairs at Dawes' Limit and closer, 42x per inch is the most I ever use, yet can see elongations at half Dawes. My visual acuity is only average/good, nothing special. I guess it's just practice at low powers, doubly inspired by having to hand track, and the eye relief of short orthos!

Unequal doubles are just about my favorite observing subjects. With my 5-inch achromat, I like to look for E and F. I usually see E, but F requires very good seeing. If I am going to see them, I will see them at 85x. Higher power never helps.

There is one caveat to my low power rant. If your sky is monstrously light polluted, the sky-darkening effect of the higher power's smaller exit pupil might let you use slightly higher powers to advantage where the secondary is very dim.

Happy E and F-ing!
Ron

It has been my experience with my 120mm achromat, that seeing conditions affect E and F far more than light pollution. When the seeing isn't the best E can drop in and out of view depending on just how much scatter there is at the moment and F just can't be separated from its bright companion. When the viewing is like that, higher power doesn't help at all. If anything high power just makes it worse.

dan