Skip to main content

prob nova in the field of FN Aql

ctia's picture
ctia
Offline
Joined: 2010-07-24

 On 9th of July during an observation of FN Aql I observed a prob Nova indicated on the picture at link http://imageshack.us/photo/my-images/21/novaaql.png/

On JD 2456118.3861 mag V = 9.520 + 0.007 and B = 10.34 + 0.04

On 10th of July it didn't move from the day before position.

 

CTIA

Tiziano Colombo

t_colombo@alice.it

Coordinates? ...and other information
KTC's picture
KTC
Offline
Joined: 2010-12-08

Coordinates?

Image:  north arrow?  east arrow?  image scale?  field of view size?

FITS image?  (instead of compressed/lossy jpeg)

Without that information it is very difficult to compare your image to a star chart or image...or plate solve it.

Thank you in advance.

A visual quadruple
Sebastian Otero's picture
Sebastian Otero
Offline
Joined: 2010-09-19

Hi, Tiziano,

I had to rotate and flip your image to compare it against the real sky and I found that this is not a nova but the already known multiple star ADS 12092 = HD 179019 = BD+3 3929.
The main components are two stars of V-mags 10.45 and 10.55 separated by 8".5 and there are other two stars of mags 12.2 V and 12.9 V-mag. separated by 6 and 11" from the 10.45 mag. primary (mags derived from CMC14 and UCAC3)
The ASAS-3 combined magnitude is V= 9.58, consistent with the blend of these 4 stars and with your measure.

No variabilty and no nova here.

Best wishes,
Sebastian

HD 179019
HQA's picture
HQA
Offline
Joined: 2010-05-10

I checked the APASS archive, and this field was observed on several occasions.  The star in question was always there at about the same brightness.  I think the problem here is that UCAC3 does not contain this object, so if you do a VSP plot of the field, there is a missing star.  This is because it is a close double, and the astrometric solution probably failed, so they left it out of UCAC3.  In cases like this, always plot a DSS chart to guard against such missing stars.

BTW - the Simbad coordinates for this object are wrong.  The APASS coordinates are 19:10:41.4 +03:25:47 (J2000), which matches other catalogs.

When you image as faint as APASS, this is a very pretty field with lots of stars.

Arne

HD 179019
HQA's picture
HQA
Offline
Joined: 2010-05-10

BTW - I've put a 30x30arcmin cutout of a V-band APASS image of the field (north up, east left) at:

http://www.aavso.org/tmp3/20244_120709_v.jpg

Arne

UCAC3 and VSP
Sebastian Otero's picture
Sebastian Otero
Offline
Joined: 2010-09-19

Hi, Arne,

Both components of the main pair are in UCAC3, only the 12.2 mag. companion is missing (and the 12.9 mag. star is missing from CMC14). They should plot, although at mag. 10.49 and 10.57 (f-mags). The a-mags are wrong (11.09 and 11.24) so if VSP uses those, that could be a reason. What magnitudes does VSP use?

Cheers,
Sebastian

FN Aql suspect
HQA's picture
HQA
Offline
Joined: 2010-05-10

here is a BSM light curve of the suspect.  As you can see, it is basically constant, with perhaps a long-term trend of a few hundredths of a magnitude.

http://www.aavso.org/tmp3/fnaql_suspect.png

Arne

UCAC3
HQA's picture
HQA
Offline
Joined: 2010-05-10

Those stars may be in the official release of UCAC3, but do not appear in VSP.  I know at one time we were using a pre-release copy of the catalog, and I'd have to track down what release we are currently using.  I'd prefer to just wait for UCAC4.:)

Arne

Sorry, The field is about
ctia's picture
ctia
Offline
Joined: 2010-07-24

Sorry,

The field is about 1.5°, north up and east right.

Tiziano

CTIA

suspected nova in AQL
ctia's picture
ctia
Offline
Joined: 2010-07-24

Hi,

in fact I didn't find it in the VSP, that's the reason of my alert,

sorry,

 

Tiziano

Checkings
Sebastian Otero's picture
Sebastian Otero
Offline
Joined: 2010-09-19

Hi, Tiziano,
Don't be sorry. The moral is: never trust charts for new/missing objects. Although the current charts are great, they have some limitations as Arne said, coming from the source catalogues used for plotting.
So, always get an approximate position, check your planetarium software and if you still don't see anything, then go to VizieR to see what's around that position:

http://vizier.u-strasbg.fr/viz-bin/VizieR

Good luck next time!

Cheers,
Sebastian

 

Image plate solve - results
KTC's picture
KTC
Offline
Joined: 2010-12-08

The field is about 1.5°, north up and east right.

Please see attached jpeg image...a screen capture of your image (converted to FITS, with annotations removed) which is overlayed/superimposed on the Virtual Sky in TheSky6Pro.  (This helps verify that the image is a correct match to the star pattern in that part of the sky.)

North is rotated about 31.5 degrees from 'up', and the image is reversed.  Field of view is approximately 48 x 46 arc minutes.

The image is centered at approximately (J2000) 19 11 22.26 +03 27 53.06.

Image scale is 4.64 arcseconds per pixel.

The 'object in question' in your image is at approx. J2000 19 10 41.43 +03 25 51.77.

Modern astrometric software tools are available to analyze your images, and provide precise information as to location, image scale, orientation, etc...and help remove doubt and questions.  (And if you make a FITS image available, it's even easier to analyze than a website/png/jpeg image.)

I am happy to help you improve your rig and software suite.  We can continue this discussion publicly in this forum, or in private.

another tip
FRF's picture
FRF
Offline
Joined: 2010-08-09

In case VSP doesn't plot anyting with the built-in catalog setting, use the DSLR image plotter function of VSP! Sometimes it helps.

prob nova Aql
ctia's picture
ctia
Offline
Joined: 2010-07-24

Thanks to all of you for your suggestions,

Tiziano

CTIA

DSLR image plotter in VSP
Mark Blackford's picture
Mark Blackford
Offline
Joined: 2011-01-15

Hi All,

I just looked for the DSLR imager plotter function in VSP but could not find it. Could you describe how to access it. Cheers,

Mark

Oops, I wanted to say: "DSS"
FRF's picture
FRF
Offline
Joined: 2010-08-09

Oops, I wanted to say: "DSS" images. It is in the Advanced Option section:

"WOULD YOU LIKE TO DISPLAY A DSS IMAGE ON THE CHART?
If Yes, retrieves and displays an image from the Digitized Sky Survey"

o NO              x YES

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484