Difference between refractor and reflector in splitting the double double?

[YKSE]

I've tried the split many times with my explorer 130P and 80ED. In "borderline" splitt when only one pair splitted with black line while the other pair not, the splitted pair has always been the even-magnitude pair in 130P, and the uneven-magnitude pair in 80ED. Does it make sense?

[Stu]

Are you saying you we're able to split the uneven pair but not the even pair in the 80ED? I would find this very surprising, I can't remember the last time I couldn't split both pairs in this type of scope. Sometimes it needs higher mag due to the seeing but certainly the even pair are easier.

Stu

[chiltonstar]

I've looked many times with my ED80 and I don't remember there being any difference; if the seeing is >= reasonable, then both are split - often even when my 5" Mak struggles if the seeing is not good enough.

Chris

[YKSE]

Are you saying you we're able to split the uneven pair but not the even pair in the 80ED? I would find this very surprising, I can't remember the last time I couldn't split both pairs in this type of scope. Sometimes it needs higher mag due to the seeing but certainly the even pair are easier.

Stu

There's no problem in either scopes in splitting the pairs if going to high enough mag.

What I meant is median mag, something in 60x-90x range(depending on seeing), when you JUST able to split one pair, but not the other pair.

[Stu]

No, I understand that. I guess I'm saying that when seeing and/or magnification are at the limit, I have sometimes been able to split the even pair and not the uneven pair, but never the other way round.

By split I mean clear dark line between the components, not some of the other definitions of split which I know are accepted

Stu

[John]

No, I understand that. I guess I'm saying that when seeing and/or magnification are at the limit, I have sometimes been able to split the even pair and not the uneven pair, but never the other way round....

Thats my experience too. Unequal brightness pairs are more difficult to split. You would expect that to be consistent with both scopes.

[cotterless45]

Easier in a refractor like a yard cannon ! Quite astounding some of the faint secondaries that can be seen and even blips next to very tight doubles under

clear skies,

Nick.

[Donkeiller]

Splitting the DD is always easier in my 102mm refractor- usually around X60. A bit harder with my 6SE- around x80 and harder still in my 8SE- around x100. All of these are with reasonable "seeing". If find the increased brightness of the first diffraction ring of the SE scopes makes a low magnification split harder with fairly bright doubles. However when it comes to tight (~1 arcsec), low magnitude doubles, the SE scopes really strut their stuff!

[Scooot]

I was looking at them a couple of nights ago when seeing was very poor, could barely make out Polaris with the naked eye. I could split the southern pair but not the other two at 120 mag. If seeing was better I think I would probably have been able to split both but usually Barlow them if the skies good enough.

[emadmoussa]

Easier to split doubles in refractors, especially apos.

[Stu]

Yes, but the original question was whether it makes sense for the uneven pair to split more easily than the even pair in the 130p under marginal conditions, and vice versa for the 80ED.

I can't think of a good reason for this and would have assumed the even pair would always split before the uneven pair, regardless of the scope.

Stu