What looks like a double star in this image is actually a single, distant quasar which is behind a closer (but still distant) giant elliptical galaxy. The three insets show, from left to right, the double as imaged by the Hubble Space Telescope, imaged by the 8 meter Subaru  telescope in Hawaii using its Adaptive Optics system, and my image using a Meade 10" SCT, all at roughly the same scale. The lensed images are at Gaia G magnitude of 18.8 (roughly approximating a broad-band visual magnitude), and are separated by 3.03 arc seconds.  In the Hubble inset image, G0 is the lensing galaxy, A and B are the lensed quasar images, and you can also see an almost complete Einstein ring (G1) around the central galaxy.

Lensed double quasar SDSS 1206+4332 is one of a few dozen gravitationally lensed quasars which have been used by astronomers recently to obtain a measurement of the Hubble constant in a manner that is independent from the local distance ladder method. The method is called Time Delay Strong Lensing and it makes use of the fact that the lensed quasar is inherently variable on a timescale of days to months, and if you know the lensing geometry, it turns out that the brightness change in the lensed images isn't simultaneous. It depends on the path length difference, so if you measure that and know the lensing geometry, you have a measure of the distance scale.

The quasar itself varies by about 0.2 to 0.3 magnitudes randomly,  but multi-year observations of the pair show a delay of about 111 days between brightness changes in the two quasars. The redshift to the lensing galaxy is about z=0.75 and the quasar is z=1.79, which is a comoving distance of 16 billion light-years.

My image was acquired using a Meade 10" f/10 SCT, ZWO ASI6200 mono camera, no filters or focal reducers. The camera was binned 3x which produces about 0.9 arc seconds per pixel as the scale. Image profiles in Astrometrica produced a FWHM of 2.9" for field stars. The aperture-based SNR for stars of similar brightness is about 25, which means that it would be possible to see the variability in the quasar as a pair as an amateur, but a challenge to observe the difference (but not impossible). My colored inset image uses the SAO DS9 "heat" false color map to match to the Hubble inset image on the left.

Science image references are Rusu et.al. MNRAS 11 June 2021 (ArXiV 1506.05147v2) and Birrer et.al. MNRAS ( ArXiV:1809.01274v3)