Secondary eclipse of b Persei is underway

[PTS]

AAVSO Alert Notice 540
March 10, 2016

Secondary eclipse of b Persei is underway

Further to AAVSO Alert Notice 537
(https://www.aavso.org/aavso-alert-notice-537), the anticipated
secondary eclipse of b Per is underway, according to
information from campaign astronomer Dr. Donald F. Collins. Dr.
Collins writes:

"[The secondary eclipse of b Persei is underway. The forum post
I made the evening of March 9-10 UT includes] the light curve of
b Persei that shows the drastic dip in brightness tonight. Looks
like its still going down at 0300 UT. The downward drop is
observed by Paul Benni (BPAD) and me (CDK) by shooting between
the clouds. I'm almost totally socked in and b Per is setting
behind my building. Hope the western observers can take it up
from here.

"Keep on shooting, we should have a couple of more days of
in-and-out of eclipse! We expect several ingress and egress events
for the duration, and a single eclipse could last less than 24
hours. Wide world coverage is needed. Keep shooting this week even
if it means shooting between the clouds on a partly cloudy night!"

The...plot [at https://www.aavso.org/b-persei-campaign and on the
AAVSO webpage for this Alert Notice
https://www.aavso.org/aavso-alert-notice-540] shows the eclipse data
to date.

b Persei (HIP 20070, SAO 29531, HR 1324, HD 26961) is located at the
following coordinates (J2000): R.A. 04 18 14.62 Dec. +50 17 43.8

High-resolution time-series observations in V should continue at
least one week after the eclipse is over and b Per has returned to
maximum.

It is recommended to use the star HIP 20156 (SAO 39457, HR 1330, HD
27084; the star labeled '55') on the AAVSO finder chart at 5.456 V
as the comparison star. For a check star HIP 20370 (J2000 RA, dec =
04 19 13.24, +50 02 55.30) may be used if the observer's field of
view is about one degree. This star is not in the AAVSO sequence.
Any other AAVSO sequence stars may be used as check stars if
available in the observer's field of view. Charts with a comparison
star sequence for b Per may be created using the AAVSO Variable
Star Plotter (VSP; https://www.aavso.org/vsp).

Please see Alert Notice 537 for instructions for CCD observers and
for details of this campaign.

Please send observations in AAVSO format directly to
dcollins@warren-wilson.edu as well as to the AAVSO. Please use the
name "b PER" when submitting observations to the AAVSO International
Database.

This observing campaign is being discussed under the thread
"b Persei campaign" in the Campaigns & Observation Reports forum
at https://www.aavso.org/b-persei-campaign.


This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

----------------------------------
SUBMIT OBSERVATIONS TO THE AAVSO

Information on submitting observations to the AAVSO may be found at:
https://www.aavso.org/webobs

ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION

An Alert Notice archive is available at the following URL:
https://www.aavso.org/alert-notice-archive

Subscribing and Unsubscribing may be done at the following URL:
https://www.aavso.org/observation-notif ... ertnotices