[vsnet-chat 3719] Re: [AAVSO-DIS] Delta Velorum next eclipses

["Stan Walker" <astroman@voyager.co.nz>]

Hi Sebastian,

I'm not clear from your comments just what your visual eclipse duration is.
Does it agree with the other measures? You seem to have derived a length of
about 0.33 but you refer to the deepest part so I'm unsure whether that
includes ingress and egress. Anyway, the eclipse seems unobservable from
here at the moment but I might try to get a few snapshots on clear mornings.

Regards,
Stan

----- Original Message -----
From: Sebasti睹 Otero <varsao@fullzero.com.ar>
To: <vsnet-chat@kusastro.kyoto-u.ac.jp>;
> PLEASE, correct the following mistake and forgive me....
>
> "So, taken the 5.88877 day- period, we should see an eclipse from South
> America and South Africa next Monday, before sunrise."
>
> Of course, IT IS NEXT SUNDAY !!!!!!!
>
> Sorry again,
> Sebastian.
>
>
>
>
>
>
>
> Dear friends:
>                        In response to Dr. Sonja Vrielmann's request I've
> prepared a new ephemeris.
> I took some aspects in account.
>
>
> PART 1 - Period
>
> First of all, according to Galileo's star scanner, the observed eclipse
was
> deepest between JD 2451714.77 and 2451715.10.
> That means 0.33 fraction of a day. So mideclipse should be 0.165 days away
> from this dates.
> That is: 2451714.94
>
> According to Galileos' data, the star took several hours to regain its
full
> brilliance. "Disappearance" for Galileo means more than 0.2 mag. dimming ,
> in this case= 2.15
>
> If we take a look at Hipparcos data we'll see the following:
>
> 2448806.05313    2.212 Hp
> 2448806.06746    1.949 Hp
>
> Which is pretty interesting... and dissapointing. Too fast recovery!!!!
> Unless the first measurement has been made just at the time the eclipse
was
> ending. Then 2.15 would take place near 2448806.055
>
> If Hipparcos eclipse is real, then the period should be 5.88877 days and
> give the following predicted and observed eclipses (deepest part):
>
> JD - Begin predicted  -  End predicted   -
> Observed--to         -
> Observation by
>
> 2448805.72               2448806.06
> 2448806.0531----
> HIPPARCOS
>
> 2450631.25               2450631.58
> 2450631.4375----2450631.5417
> My visual observations
>
> 2450831.47               2450831.80
> 2450831.6409----2450831.7688
> My visual observations
>
> 2451308.45               2451308.78
> 2451308.4618----2451308.7014
> My visual observations
>
> 2451714.77               2451715.10
> 2451714.77--------2451715.10
> GALILEO
>
> The 67.7 day-period gives great residuals in the order of two or three
days
> for the first and third eclipses.
>
> Paul Fieseler, Sequence Integration Engineer of the Galileo Mission, Jet
> Propulsion Laboratory of NASA, has kindly submitted more data from the
> Galileo star scanner.
> He has prepared a chart based on the 5.9 day period and it seems there is
a
> hint of eclipses going round.
> However, it's not enough for a confirmation since most of the eclipses
> should occur just during gaps in the data.
>
> This, along with the refined period and the excellent fitting reported
> above, seems to indicte the shorter period is correct.
>
>
> PART 2 - Ephemeris
>
>
> I've been preparing a schedule for the following observations and hte
> conclussion is: BE PREPARED.
>
> Yesterday at 4 AM local time I could observe the star and it is high
enough
> to make a reliable brightness estimate, even earlier.
>
> Predicted beginning ----  ending               South America       South
> Africa
> Australia/ New Zeland
>
> 2451832.54---2451832.88     10/14-15     22.00--06.00         03.00-11.00
> 11.00-19.00/13.00-21.00
> 2451838.43---2451838.77     10/20-21     19.30--03.30         00.30-08.30
> 08.30-16.30/10.30-18.30
> 2451844.32---2451844.66     10/26-27     16.45--00.45         21.45-05.45
> 05.45-13.45/07.45-15.45
> 2451850.21---2451850.54     11/01-02     14.00--22.00         19.00-03.00
> 03.00-11.00/05.00-13.00
>
>
> If the period is 67.7 days (if so, Hipparcos eclipse and the 2451831
eclipse
> would be left aside) then the following eclipse would be:
>
> 2451850.2---2451850.5       11/01-02      14.00--22.00        19.00-03.00
> 03.00-11.00/05.00-13.00
>
>
> It's interesting to note that if the first one is correct, Australia and
New
> Zeland have no chance of detecting it while in the second option, South
> America 's got in the way.
> South Africa has the cahnce to catch both events but near the beginning
and
> near the end.
>
> We'll see what happens.
>
> Thanks again to JPL, NASA.
>
>
> Best regards,
> Sebastian.
>
>
>

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