[vsnet-chat 5391] (fwd) Re: (fwd) observation of sgrv4641

["Berto Monard" <LAGMonar@csir.co.za>]

Dear Don and other puzzled readers,

It is very difficult to probe exactly what Toni is doing wrong. But he
is very much mistaken and he doesn't want to admit it. There is a
problem in his attitude. He has however shown the ability to deduce a
sensible limiting magnitude for his local conditions.

Considering Toni is not faking observations, he obviously looks at the
wrong star.  

Before wasting anymore time (his and ours), all that he needs to do is
:

1. To get and study one or more detailed starcharts depicting V4641 Sgr
in its MW environment. DSS images are suitable and the position
reference is possibly shown at the VSNET site. 
Rem: V4641 Sgr and GM Sgr are not the same star!

2. To apply the Henden-Summer sequence to that field and select
preferably blue stars (B-V must be small) but use the V magnitude for
comparison in visual observing (or the R magnitude for unfiltered CCD
observations). 

3. To try and make the observation at the proper position.

4. Report <12.8v or whatever is applicable.

I hope Toni will try that!


Regarding the use of different telescopes: what a luxury Don has. 
I would use the biggest one only and try to monitor faint cataclysmic
variables, mainly polars and LMXBs..

Re the present state of V4641 Sgr
Over the weekend I made another CCD run on V4641 Sgr with 10 sec
exposures. I did so after I noticed it visually at 13.2V, which can be
considered the treshold brightness between the quiescent and active
state. The measurements showed V4641 Sgr to be constant around 13.3CR (+
or - 0.1 / a bit more than the noise). No activity was seen over the
measurement period of more than 7 hours.

Regards,

Berto Monard
Bronberg Observatory


>>> Taichi Kato <tkato@kusastro.kyoto-u.ac.jp> 07/13/02 07:40AM >>>
(fwd) Re: (fwd) observation of sgrv4641

   Since this issue is apparently of public interest, and there is no
decisive interpretation of Toni's reports, I forward this query:

From: xor@beol.net 
Subject: Re: (fwd) observation of sgrv4641
Date: Sat, 13 Jul 2002 01:30:49 -0400

As a bit of an intro first let me admit I am a newbie to variable star

observing. I do have several years of "normal observing" experience
though. 
I have had an interest for some time and have been following the VSNET
list 
to gain some insight. I am starting to learn about how to take
estimates 
visually and do them correctly. I have access to an AAVSO member here 
locally. (I hope to start submitting observations to the AAVSO and/or
VSNET 
in the next couple of months. Do you have any idea what he (Toni) is
doing 
wrong so I do not make the same mistakes? I want to be as accurate as
one 
can be doing visual verification of variables. I am going to be using
three 
different telescopes to do this. I have access to a 32-inch, 14-inch
and an 
8-inch. Which telescope would be best for what type of variable?
Eventually 
I will start doing CCD as soon as I am comfortable doing visual.
Anyway, any 
advice would be helpful. 

Don Stevens
Clear Skies!
xor@beol.net 

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