[Aavso-photometry] Starting UP CCD Obs - Aavso-photometry Digest, Vol 42, Issue 15

[Brad Walter]

Re 2. I am no CV expert but the frequency and duration of observations
depends on what you are trying to do. If you are just trying to detect
outburst then once per night should be sufficient. If you are trying to
detect orbital humps in quiescence, or track changes in light curve during
rise or decline then you probably want to image every few minutes for at
least several hours and probably from Z= 60deg to 60deg. Take a look at the
VSNet website, http://www.kusastro.kyoto-u.ac.jp/vsnet/CVs/CVs.html, It has
a bunch of light curves of various type cataclysmics, that can help you
determine the time resolution and session duration you need. Also I have
used the descriptions in the GCVS and then looked at light curves in the
AAVSO data base, playing around with the time scale, magnitude scale, and
the types of observations to include (omitting unvalidated or "fainter
thans", for example). Also Gerald North's book, Observing Variable Stars,
Novae and Supernovae, and the CD included with it have a bunch of CCD light
curves for various types that are a good reference for time scales and
magnitudes of variations you are interested in capturing. 

Re 3. Wolfgang Renz' answer to the "Newbie Filter Question" in
Aavso-photometry Digest, Vol 42, Issue 14 is also a good answer to this
question. 

Re 4. If I recall the process correctly from the time I joined a number of
years ago, Join, which requires that you fill out the form and pay. You
receive your packet with your observer code. The vetting process is a
formality as long as you are a real person and not some spamming alias.  


----------------------------------------------------------------------

Message: 1
Date: Tue, 22 May 2007 15:30:19 +1000
From: "Greg Crawford" <gc at nelsonbay.com>
Subject: [Aavso-photometry] Starting up CCD Obs of Variable Stars
To: <aavso-photometry at aavso.org>
Message-ID: <007d01c79c32$50f09370$8e17fea9 at Greg>
Content-Type: text/plain;	charset="us-ascii"

After taking forever and a day to get ready for variable star obs, I think I
am
ready to begin. I thought I might start with the CCD observing program for
faint
CVs and LPVs. I chose a CV because I am reading about them in the book by
("the
other") Brian Warner. I like to have some intellectual input to complement
any
obs I make so I have an understanding of the physics behind it.

Given my southerly latitude (-32), I thought I'd start with UU Aql. (I had
given
some thought to RX Cen, but the comment about sequence needing extension put
me
off for a first timer).

A few questions:

1) UU Aql seems to be entered into the following table twice. I'm not sure
if
that is an error or conveys significant information. See here:
http://www.aavso.org/observing/programs/ccd/ccdlpv.shtml#table

2) How often should observations be made? I am used to tracking an asteroid
throughout the night with continuous observations from 30 degrees altitude
in
the east to 30 degrees altitude in the west. Are obs of a CV handled in the
same
way?

3) The program appears to only want obs through a V filter. After struggling
with T/Cs, FOEs and ZPs for limited all-sky photometry for asteroids, I've
discovered how easy variable star observers get it when they have a
(secondary)
standard field in the field of view. :-) (In MPO Canopus software, after
measuring the images, a few clicks gives you standardized measures using the
QuickMags method.) If I also have observations in B and R, should they be
uploaded to WebObs as well?

4) How do I get an observer code? Do I have to qualify in some way in the
same
way that minor planet observers must submit obs to the MPC?

Greg





------------------------------

*********************************************