Petr Pravec ppravec at asu....cz
Fri Jan 19 10:20:52 CET 2001

Mili pratele,

Forwarduji vam mail, ktery mi poslal jeden italsky kolega, kdysi
jsem spolu fotometrovali jednu blizkozemni planetku.  Ted to vypada,
ze by stal o spolupraci na jedne CV.  (Rudolf asi o tom bude vedet
vice nez ja.)  Posilam vam to pro pripad, ze byste to chteli a mohli
pozorovat.  V Ondrejove se k tomu nejspise nedostaneme, protoze mame
nabity program s NEAs, ledaze by nastala serie jasnych noci
a nase cile nam dosly.  (Ale to se asi nestane.)

Zdravim,   Petr

---------- Forwarded message ----------
Date: Thu, 18 Jan 2001 18:03:35 -0500 (EST)
From: Stefano Giovanardi <stefano at astro....edu>
To: ppravec at asu....cz
Subject: photometry again

Dear Petr,

this is Stefano,
how are you?
It's a long time we don't hear from each other, and in the meantime a lot
has changed.
I am now doing a PhD in astronomy at COlumbia university in New York; I
don't work on asteroids now but on Cataclismic Variables.
Still, the experience in photometry gained at the times of Camillo was
very useful.
(how did that work end, by the way?)

I have thought of you because I am about to go to Kitt Peak for an
observing run on the CV star BH Lyn, an eclipsing system with period of
3.74 hours and an amplitude of about 1.5 mag.

I will be there taking ligthcurves of the star from tomorrow (19/1) to
30/1. This is part of a project with Joe PAtterson in which we are trying
to study the eclipses and also detect other periodicities superimposed
(due to the precession of the accretion disk, etc.)

Since we are trying to get the most continuous monitoring of the
ligthcurve possible by coordinating with other observers at different
longitudes (with Joe's CBA, Center for Backyard Astrophysics) I am
wondering if you would like to join in the observing campaign!
Given your experience in photometry of asteroids and the characteristics
of this star it could be interesting and easy for you!
So if you will have some time during the next 10 days (nights!)
and you are interested in participating, we would really appreciate your

The star is of mag V=15.5 outside eclipse, and we just need differential
photometry, possibly with a frequent sampling (short exposures of about a
minute or less should be all right), this is especially useful during the
eclipses, when the magnitude varies of 0.1mag/minute.
V magnitudes would be great, but even unfiltered photometry is good.
It would be useful to run observing sessions of a few hours (say, at least
one entire period): it's better to have a long session even on only one
night rather than many short sessions (1/2 hour or 1 hour) on different

Please let me know if you are interested, so I can send you more details
about the observations and the star (including a finding chart with
comparison stars).
MEanwhile you can also find information on the CBA at the web page:

I hope to hear from you soon!
best regards,
Stefano Giovanardi

More information about the CCD mailing list