[vsnet-chat 2733] (fwd) Takamizawa Variables which are AC2000 single images

[Taichi Kato <tkato>]

Date: Sun, 12 Mar 2000 17:26:40 +0000
From: JG <jgts@jgws.totalserve.co.uk>
Subject: Takamizawa Variables which are AC2000 single images

Dear Taichi Kato

I have of late been investigating the 200,000 objects flagged as 'single
images' in the AC2000 (Urban et al 1997): that is images on AC plates
where no counterpart has been found/identified in HIP, TYC, ACRS or GSC.

Comparing these objects against a list of Takamizawa variables obtained
as NEWVAR.CAT at the VSNET website I found the following 5 potential
matches (where BT is Tycho B magnitude and the RA and Dec end figures
from the respective catalogues are given):-

TmzV        RAs     DEs   magrange     AC2000     RAs      DEs
BT       AC Epoch (year)

TmzV052   49.16   55.3   11.2 <13.9p   2538861    49.124   55.74   11.09
1906.704
TmzV111   45.83   47.4   11.9  15.0p   2901644    45.788   46.81
11.85  1913.026
TmzV117   24.63   07.3   12.4  14.8p   1586380    24.485   08.01
11.94  1903.116
TmzV326   36.03   36.2   13.4  14.3p   2395138    36.143   35.62
11.33  1903.238
TmzV337   52.01   22.5   11.3 <14.7p   3054292    52.136   22.46   12.07
1913.578

Note that AC2000 BT magnitudes are not too accurate, but do equate
passband-wise to photographic blue.  Thus it seems that at the epoch of
the AC plates these objects were near maximum.  TmzV111 appears also to
be GSC 6484 0290 of GSCmag 14.3: the disparity of the GSC and AC2000 BT
mags probably being responsible for these two catalogue objects not
being identified as the same.  None of the other four are listed in the
GSC.

Note also that this cross check does not preclude other Tmz variables
appearing in the AC2000 archive.  In this instance only those objects
flagged as _single images_ [ie not necessarily found in other
catalogues] in that dataset were cross checked as this flag is already
suggestive of something out of the norm.


AFTERTHOUGHT

As part of this process I generated some working files that observers
can utilise with the planetarium program Guide 7 from Project Pluto
[www.projectpluto.com : the latest upgrade download will be needed].

That program allows simple scripting languages to be used for data
portrayal and access etc.  Enclosed is an ETB and TDF setup for the
Takamizawa variables [zipped to ensure that the ascii files are not
garbled via email transfer].  Users placing the TmzVars.ETB file in
their Guide directory will find that they have a look-up table in TmzV
number order which will enable them to 'go to' any of these variables
on-screen via a shortcut dialogue box [under
Tables-Misc.Tables-Takamizawa Variables].  Once at those positions, and
if they've also copied TmzVars.tdf and TmzVars.dat to their Guide
directory and activated the data via the 'Toggle User Datasets' dialogue
box, they will find a skyblue cross marking the position of the Tmz
variable as per the VSNET file NEWVAR.CAT and denoted by the appropriate
Tmz number.  Help information is also available in the usual way,
utilising data from NEWVAR.CAT.

In this way Guide users can plot their own charts and or examine
visually the field surrounding this object for anything else of note in
the area [it is especially wise in these instances to have all other
approrpiate datasets turned on to aid in quick cross referencing work,
or to note possible problem causing object].

The files are in flat ascii and can readily be amended/appended by the
users.

Thank you for your time

Yours

John

John Greaves
UK

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