  We report long-termed UBVRIRcIc photometry of the highly eccentric 12.04 day
detached eclipsing binary V490 Sct (V =13.1, B9.5+A0, e = 0.40), which we use
to determine its relative and absolute parameters. The absolute masses, radii,
and temperatures are Ma = 2.33+/-0.1 Msun, Ra = 1.91+/-0.04 Rsun, and Ta =
9960+/-60 K for the primary and Mb = 2.24+/-0.1 Msun, Rb = 1.86+/-0.04 Rsun,
and Tb = 9700+/-80 K for the secondary. The system displays a slow periastron
advance that is dominated by general relativity (GR). Our measurement, dw/dt =
0.86 deg/century, is 32% less then the expected rate, dw/dt = 1.24 deg/century,
which has an 83% contribution from GR. A comparison with current stellar
evolution models shows a good match to the measured properties at an age of
about 130 mln. years and Solar abundance. The photometrical parallax of the
system pi = 0.77 +/- 0.02 mas, matches quite well the GAIA DR2 value, pi = 0.76
+/- 0.04 mas.
