Affiliation
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Fri, 03/15/2013 - 13:28
Bill Wilson (WWJ)
Whilst pausing over Z Cam longer than usual, I'm noticing small amplitude fluctuations around 0.4 mag, in a cycle of 40 seconds; as far as I can judge - I take an average time from 5 cycles on the stop watch.
Am I being deluded? If so, the impression just won't go away! I've put a “D” against my recent contributions, and a comment, but there's been no confirmation nor refutation from other observers, as yet.
In passing; I wonder whether the change in format from “Quick Look” doesn't discourage dialogue, as expansions are not immediately apparent. One does like to earn a credit, or to be smartly “put right”, in either case
.
To be quite honest, Bill, in 50 years of VSO only on just a couple of occasions have I definitely witnessed very rapid and obvious changes in a dwarf novae's visual brightness and never in Z Cam. I know others sometimes report such in various eruptive stars and I'm sure that we'll hear from a few in this thread, but it troubles me that with my long experience of nightly observations that I've almost never encounter such. As a result I've often thought that most of these situations are more likely caused by some sort of oddities in human vision rather than actual variations in the star (some of these oddities I've seen manifested myself).
BRJ
Thanks John, for your attention to this. I accept that if you haven’t seen anything like this, it's rather unlikely to be objectively real, and one must start thinking in terms of some physiological phenomenon, such as the circulation of blood in the visual apparatus...or just plain auto-suggestion! I am puzzled, however, by the recent scatter in observers estimates. Perhaps, at the back of my mind, I've been looking for a reason for this.
There, we must leave it, for the time being.
Bill.