Addendum to ATel 5304
ATel #5310; U. Munari (INAF Padova-Asiago), S. Dallaporta, G. Cherini, P. Valisa, G. Cetrulo, A. Milani, L. Ghirotto (ANS Collaboration)
on 22 Aug 2013; 17:24 UT
Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it)
The following information was missing from ATel #5304, and it is provided here following a request from ATel Editors.
We are collecting photometry of Nova Del 2013 every night since its discovery was posted to TOCP web page (http://www.cbat.eps.harvard.edu/unconf/tocp.xml). Given the large brightness of the nova, we are forced to use as local standards the bright stars HR 7811, HD 194841, HD 194113, HD 194631 and HD 194072 with their Cousins Ic magnitude taken from the Hipparcos Input Catalog and the B,V magnitudes from Tycho-2 catalog transformed to Johnson following Bessell (2000, PASP 112, 961). These five standard stars span a wide range in color to assure a good determinations of the coefficients of the instantaneous color equations transforming to the standard system. These preliminary B,V,Ic magnitudes are being checked against Landolt (2009) equatorial standards, and we are also deriving the magnitude of the standard stars in the Johnson U, Cousins Rc and Stromgren b,y bands in which we are also monitoring the nova. The high brightness of the nova and the large distance of the standard stars from it, force us to use short focal length refractors with their apertures reduced to a few cm in diameter, so that the exposure times are long enough with respect to CCD camera shutter opening/closing times. In addition, photoelectric photometry in the Johnson B,V bands is obtained with an Optec SSP-5 photometer attached to a 35cm telescope, using the same standards as for the CCD photometry.
We are also obtaining every night spectroscopy of the nova with four different telescopes located in northern Italy (cf ATel #5297). The Varese 0.61m telescopes, equipped with the Multi Mode Spectrograph, is used to record both Echelle (res.pow. 18000, range 3900-8600 Ang, 30 orders) and low resolution spectra (dispersion 2.1 Ang/pix, range 3900-8600 Ang). The Asiago 1.22m telescope + B&C spectrograph obtains low resolution spectra (dispersion 2.3 Ang/pix, range 3200-7700 Ang) while the Asiago 1.82m telescope + Echelle spectrograph secures high resolution ones (res.pow. 22000, range 3400-7300 Ang, 32 orders). Finally, low resolution spectra are also obtained in the far red with the Polse di Cougnes 0.70m telescope (1.1 Ang/pix, range 6500-9700 Ang, Schott 2mm OG5 2nd order cutting filter). At all sites the spectra are absolutely fluxed against the spectrophotometric standard stars HR 8004 (A1V) and HR 7596 (A0III), which have an energy distribution similar to that of the nova and are observed every night along with it.