[Wavytone]

Joe it’s going to be very hard with a 130, even if you had an AP130GT.

One issue is to make sure you use enough magnification to be sure what you’re seeing is actually B and not one of the other comparisons. Hence why I used 450X with approx a 3 arc min field. At lower power I expect you’ll mistake one of the other companions for B.

Next problem is having any useful way to estimate separation at this scale - I don’t have a filar micrometer. Instead I’ve worked out the spacing of the minima of the diffraction rings (ie the gaps) in arc seconds for my scope so can estimate separation from that, seems to work on the occasions I’ve tried it. The radius of the inner dark ring in my case is 0.6 arc sec. Second ring 1.1, third 1.6 and so-on. In your scope 1.1, 1.9, 2.8... so the separation is about the diameter of the second dark ring.

Next problem is the dim companion vs the diffraction rings from A. In a smaller scope the diffraction pattern will be wider (in arc seconds) and for smaller apertures B may be buried under a diffraction ring.

Last issue is optical fatigue within your eye from the brightness of A, you’re likely to be unable to see B. Some means of blocking A may help eg shift it just off the field of view, or using an occulting bar if you can arrange one in your eyepiece. A premium-contrast Kellner, ortho or plossl could be adapted for this.