[vsnet-chat 694] (fwd) on chart and seuences (Fidrich)

[Taichi Kato <tkato>]

From fidusz@zpok.hu Fri Jan 23 17:27 JST 1998
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Date: Fri, 23 Jan 1998 08:57:21 +0100
To: jbortle@aol.com
From: "FIDRICH Robert (Fidusz)" <fidusz@zpok.hu>
Subject: on chart and seuences
Cc: aavso@aavso.org, tkato@kusastro.kyoto-u.ac.jp
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AAVSO Observers Forum

Dear  VSNET and AAVSO Folks,

Sorry, but I missed almost one year from the VSNET.
If it was already discussed, please exquse me!

I downloaded some TAC/HIC/HIP charts.
Could someone inform me what kind of source of these chart are originated
(I mean the sequences?) There was no info in the SIMBAD about TAC as 
"KVI" (Istvan Kovacs) informed me.

It seems, there are some gap beetween the TAC and HIP sequesnces.
Which shall we prefer. And here is my problem. 
The are chart for many variables with different sequences.
Most of the observers use AAVSO sequ. But these are also chenging.
There are Skiff's sequences for many stars with old AAVSO sequences.
Wich sequ should we use in these cases?
If we turn to tthe new suquences, the will be some jump on the light curves.
But, if the observers can't change charts same tiime, there will be much 
larger scatter than woithout new sequences.

I think there is time to standardize the charts and sequences.
But, how to do it? Since I am dealing with the Charts Archive of the HAA/VSS
this is very important question for me.

The best choice for me:
1. Use original AAVSO sequ
2. If there is not AAVSO sequ, TAC or HIP
3. GSC mags until getting official V magnitudes

Another suggestion: to setup a team for coordinating an international 
chart making project (included AAVSO, AFOEV, BAA, VSNET chart divisions 
and some volunteers).

Another important effect: sometimes there is large difference between the 
visual magnitudes and Jonson V magn if the star has large colour index!
(See /V418 Cas?/ Kaiser, JAAVSO, 199x). Shall we correct the V magnitudes 
for visual charts? How to  do it without info of the colour iindex of the 
sequences?

Dear Mr. Bortle,

I could not subscrive to the AAVSO Observes Forum list.
Please could you help me?

Kind regards,

Robert Fidrich 
HAA/VSS

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