SkyTools works primarily on multiple star systems, not individual pairs.

[theskyhound]

By the way I no longer believe this is a problem with the algorithm. I think it is a database issue related to the magnitude of the secondary component in the DE pair. It is a very big task to bring all of the different pairs into a single system (regardless of whether you understand the utility of doing so) for hundreds of thousands of stars. Very different magnitude data are often presented for the same star from different sources. I believe what is going on is that SkyTools is using a brighter magnitude for the E star than the one that is being displayed. This can happen because there are ultimately two separate databases that the data is stored in. Normally both databases would have the same magnitude, but in some rare circumstances they hold a different number, having to do with the way the database was built, and how terribly inaccurate the WDS catalog was at the time (and still is, really).

In fact, I suspect that that DE pair is a duplicate observation of AB pair, likely the result of an erroneous observation included in the WDS. My algorithm that built the database attempted to fit the data from the UCAC and other catalogs to the WDS and this is what it came up with.

There are two ways to look at double star catalog errors. You can get upset that the data isn't perfect and tell me I should fix it, or you can see it as an opportunity to do some exploring on your own to find out what is really there. I myself find the second approach to be much more interesting, so I would love to hear from someone who has observed this system to know what stars are really there.

It saddens me to know that this age of exploration that we live in now with respect to double stars is about to be over. The Gaia data is going to provide exact positions for these historical mysteries, and while that will make software like SkyTools much more reliable, it will also take a lot of the fun out of observing double stars.