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digitization: "B-R" column

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BBI
BBI's picture
digitization: "B-R" column

Does anybody know what the values in the "B-R" column mean? And is it somehow useful to have it in the database?

thx!
BBI
 

ThomasK
ThomasK's picture
B-R

I think B-R stands for Beobachtet - beRechnet, or O-C Observed - Calculated in english. It is how much this maximum deviate from the period elements for the star. I don't think it is that relevant to digitize as it is dependent on the elements of the star at the time of writing.

Thomas Karlsson

HTY
HTY's picture
O-C?

Hi Bruno,

It would be helpful if you could provide a reference to the publication that you have illustrated above.  However, I'll speculate that this looks like a table of observed maxima and not observations per se.  If so, it looks like B-R might be the difference between the observed date of maximum minus the calculated time of maximum. 

Of course I may be totally wrong. It's been known to happen.

Tim (HTY)  

BBI
BBI's picture
O-C?

Hi Tim,

The paper (http://cdsads.u-strasbg.fr/full/1914AN....197..375E) gives indeed only observations near maximum. So B-R is probably the days before/after calculated maximum. I'll try to find the paper somewhere with all observations, which is better to digitize and add to the database.

BBI

BBI
BBI's picture
Another question

@Thomas: Thx!

Another question concerning digitization of old data. In the screenshot below, I see in the time of observation daytime values (M.E.Z. 7h35, 8h05, ... 17h05). Observations were made in Norway where M.E.Z. = UT + 1h

Was this a common practice to be able to work with low numbers? Should I add 11h (M.E.Z = UT + 1h) to calculate the julian date? This implies that the date Jan. 6, 17h05M.E.Z. becomes Jan. 7, 4h05UT in the morning.

(paper: http://cdsads.u-strasbg.fr/abs/1906AN....171..219E)

edit: He also has a few observations at 13h, 14, 15 ... (not included in the screenshot, but included in the original paper). They were made in February, but even in Dombås (62° 4′ NB) it should be too bright to observe a mag.9 star?!

ThomasK
ThomasK's picture
M.E.Z

I think M.E.Z stands for Mitteleuropäische Zeit, so you are right that MEZ = UT + 1. That mean you have to subtract 1h to get UT. Jan 6 17h05m MEZ will then become Jan 6 16h05m UT. That is the time you enter to the JD calculator.

Sigurd Enebo was a very famous and enormous productive Norwegian observer, but I have no idea how he could observe SS Cyg at 13h in February...

Thomas

HTY
HTY's picture
Another question

Is it possible that because of the very long winter nights very far north in Norway that the times are not unreasonable? Just a thought.

Tim (HTY)

BBI
BBI's picture
Another question

Hi Tim,

That could be possible, but Enebo also has a few observations at 13h, 14h, 15h. Even in Dombås, Norway (62° 4′ NB) it would be bright during daytime.

I remember vaguely reading somewhere that in those days, to make work easy, they subtracted 12h? A bit like the Greenwich Mean Astronomical Time (GMAT).

This seems to support it: (from http://www.britannica.com/science/Greenwich-Mean-Time) "In accord with astronomical tradition, astronomers had always used Greenwich Mean Astronomical Time (GMAT)—the same as GMT but with the day beginning at noon. In 1925 GMT was adopted by astronomers so that the astronomical day began at midnight, the same time as the civil day."

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