Sample Selection We selected a sample of AM CVn targets from the collection of G. Ramsay et al. (2018) [4]. The NAVOO Project: photometry for AM CVn candidates Fig. 3. BinaPhot results for an observation night of ASASSN-14mv in Open filter. AM CVn Cataclismic Binary Systems AM Canum Venaticorum (AM CVn) systems are a unique subclass of cataclysmic variables where two DB white dwarfs exchange hydrogen-depleted material (Figure 1). They are characterized by their short orbital periods ranging from 5 to 65 minutes. These systems display superhump periodicities, resulting in a broad range of photometric variability. The number of known AM CVn systems has significantly increased from just 4 in the 1990s [1] to 70 today [2]. Despite this growth, Roelofs et al. (2007) predicted a much larger galactic population of 3x105 - 3x106 AM CVn systems [3]. Furthermore, only about 60 of the currently catalogued candidates have well- determined orbital periods, highlighting the importance of each new characterization. The Nice AM CVn Optical PrOject (NAVOO) was created for revisiting known AM CVn targets to obtain or refine their physical parameters. This project has already been granted observation time: four nights of photometry with the small-size telescopes at the Observatorio del Teide (the IAC80 and Carlos Sánchez Telescopes), and one night of spectroscopy with the Isaac Newton Telescope (INT) at the Observatorio del Roque de los Muchachos. Source Period (mins) Outbursts? Mag. Range (filter) ASASSN-14mv 41:(sh) Yes 11.8(V)-18.1(V) ASASSN-14fv ? Yes 14.6(V)-20.5(B) PU Aqr (SDSS J2047+0008) ? Yes 17.0-24 Gaia16all ? Yes 16.2-20.6(G) PTF1 J1523+1845 ? Yes 17.6-23.5 CRTS j0844-0128 ? Yes 17.4-20.3 DGMetrix DGMetriX is a set of user-friendly PyRAF scripts [6] for image reduction and photometric analysis of eclipsing systems. They all have been designed to fit any telescope and set of filters, thus providing a uniform way of obtaining differential photometry for diferent observations. • PhotoRed: Script to perform the reduction process, based on bias and overscan substraction, and flatfield correction. • AstroNet: The astrometrization process is done using Astrometry.net [7]. The script automatically detects the stars of the image and saves the astrometrization results in the images headers. • BinaPhot: The core of the script uses daophot to perform differential photometry. Some important corrections (i.e. airmass calculation, mean-FWHM computation) are applied to obtain small photometric variations. First BinaPhot results for ASSAN-14mv are shown in Figure 3. More observations are required in order to refine the period. Fig. 1. Artistical representation of a standard AM CVn system. Fig. 2. Average spectrum of ASASSN-14mv from WHT. Spectral Data Spectra for ASASSN-14mv were already taken and will be soon reduced and compared with those acquired by J. Green et al. (2020) [5] (Figure 2). References [1] Ulla, A. (1994). The AM CVn systems: A bibliographic search for clues to their cataclysmic nature. Space science reviews, 67(3), 241-362. [2] Pichardo Marcano, M., Rivera Sandoval, L. E., Maccarone, T. J., & Scaringi, S. (2021). TACOS: TESS AM CVn Outbursts Survey. Monthly Notices of the Royal Astronomical Society, 508(3), 3275-3289. [3] Roelofs, G. H. A., Nelemans, G., & Groot, P. J. (2007). The population of AM CVn stars from the Sloan Digital Sky Survey. Monthly Notices of the Royal Astronomical Society, 382(2), 685-692. [4] Ramsay, G., Green, M. J., Marsh, T. R., Kupfer, T., Breedt, E., Korol, V., ... & Aungwerojwit, A. (2018). Physical properties of AM CVn stars: New insights from Gaia DR2. Astronomy & Astrophysics, 620, A141. [5] Green, M. J., Marsh, T. R., Carter, P. J., Steeghs, D., Breedt, E., Dhillon, V. S., ... & Wild, J. (2020). Spectroscopic and photometric periods of six ultracompact accreting binaries. Monthly Notices of the Royal Astronomical Society, 496(2), 1243-1261. [6] Science Software Branch at STScI. PyRAF: Python alternative