On V337 Cyg

(vsnet-obs 3705)

Dear colleagues,

Quite a number of CV observers have included V337 Cyg in their observing programmes. Yet, there exists NO 'official' finding chart for this object, i.e. a chart showing a secure position of the variable. Is someone able to retrieve the discovery paper on V337 Cyg (if it exists), which might include a chart ?

V337 Cyg definitely is a most interesting object. It is currently well placed in the sky for Northern Hemisphere observers, and deserves a close monitoring for the rest of the observing season !


Skiff's comment

(vsnet 762)

The variable V337 Cygni was reported by Walter Baade in 1928 (Astron. Nach. 232, 65), who provided a precise position for the star:

19 57 13.6  +39 01 32 (1925.0)
19 59 53.3  +39 13 55 (2000.0)

Interestingly, there is a mag. 16 star very close to this position in the US Naval Observatory "UJ1.0" catalogue:

19 59 53.6  +39 13 55 (2000.0)

which they give as mag. 16.45 from J (blue-green) plates. The Digitized Sky Survey (from the POSS-I red plate) shows a star of about this brightness or slightly brighter at this location, so evidently this star has ordinary colors (not extremely red, for instance).

\Brian Skiff (bas@lowell.edu)

CCD image

(Please note there is a radiation event just at the center of the image)

Kato's comment

(vsnet 767)

I took last night a V-band image of the field of V337 Cyg. Unfortunately I couldn't make calibration using standard stars due to passing clouds.

The resultant chart gives a 14.8 mag star very close to the nominal position of V337 Cyg. This star seems to be identical with a 16 mag star pointed out by Brian Skiff (vsnet #762).


    19 59 53.6  +39 13 55     (UJ1.0)
    19 59 53.61 +39 13 54.3   (Ouda image)

It would be interesting to note the difference between the magnitudes. Whether the blue-sensitive J plate produced this difference, or the star actually varies should require further confirmation, which might lead to an identification of the "lost" V337 Cyg.

For readers' examination, I have placed a GIF file of the field in the VSNET Home Page. The V337 Cyg page is directly accesible at the URL:

Taichi Kato

Sumner's comment

(vsnet 772)

The DSS image of the suggested V337 Cyg candidate is, as you have no doubt noted, a close double. The positions of both stars (from DSS using FITSview) are as follows (2000):

        19 59 53.62  +39 13 54.5  ~15
        19 59 53.85  +39 13 51.0  ~17

Separation is about 4.5 arcsec @ ~140 degrees p.a.

I hope the "real" V337 Cyg soon jumps up and shows himself!!

Bruce Sumner

Manek's comment

(vsnet 775)


I would like to help with the V337 Cyg case. There really wasn't published any finding chart for this star and the situation is same for (almost) all other stars in the two fields covered by Baade (AN 232, 65, 1928).

However, as a part of my PICA Project (abbreviation for Precise Identification and Coordinate Adjustment) which should at the end give positions of about 7000 variable to at least 1" precision, I have triend (succesfully) to recover many of Baade's stars in Cygnus field during my visit on Sonneberg Observatory in 1994 (many thanks to the observatory staff and Peter Kroll !)

I have found V337 Cyg in at least 3 outbursts, being usually less than 5 days long and reaching about 15 mag in maximum on blue plates. In minimum it is belowthe plate limit (< 18 mag pg). Plate scans were made for both (maximum and minimum) states and hope to put them on VSNET WEB. The field size and orientation is approximately the same as present Ouda CCD frame on WEB.

The nearby star at 19 59 53.6 +39 13 55 (2000.0 - Skiff) stands almost on the Baade's position and was confusing during the identification process.

V337 Cyg position (not yet measured precisely) is

     19 59 53.0   +39 14 02  (2000.0)

On this position is a faint trace of possible object in the Digitised Sky Survey.


Jan Manek
Stefanik Observatory                Private :
Petrin 205                          Werichova 950
118 46  Praha 1                     152 00  Praha 5 - Barrandov     |_|_|
Czech Republic                      Czech Republic                  /   \
Internet : jmanek@mbox.vol.cz                                      |-O-O-|

Sumner's comment

(vsnet 780)

Hi all,

Regarding V337 Cyg.

I have had another look at the DSS image of V337 Cyg, taken 10 August 1950, to confirm Jan Manek's identification. As he comments, there is a faint image near his position. Using FITSview I obtain the following position (2000):

        19 59 53     +39 14 02    (Makek)
        19 59 52.95  +39 13 59.3  (DSS)

The DSS image is extremely faint, probably about 19.

There is also a possible trace on DSS of an even fainter star closer to Makek's position. The final identification of V337 Cyg in quiescence will await direct examination of the Palomar Sky Survey matched to outburst activity of the variable.

Bruce Sumner

Sonneberg images by Manek

(left) V337 Cyg (marked by two lines) in outburst. Original plate is GC8010 dated 46977.481 (JD) obtained on Sonneberg Observatory with 400mm astrograph.

(rigth) V337 Cyg field in quiescent. Compare with plate showing star in outburst. Original plate is GC9234 dated 47776.414 (JD) obtained on Sonneberg Observatory with 400mm astrograph.

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