I wondered if i could image this close pair with the Esprit 100 (550 mm focal length)/ QHY16200 CCD combo. After test images i decided to use 120 seconds, shoot a lot of subs and use 2 x drizzle in APP. The Arcsinh stretch in pixinsight worked best followed by carefull curve adjustment. The inset upper-left is a 500% blow-up.
"The Twin Quasar (also known as Twin QSO, Double Quasar, SBS 0957+561, TXS 0957+561, Q0957+561 or QSO 0957+561 A/B), was discovered in 1979 and was the first identified gravitationally lensed object. It is a quasar that appears as two images, a result from gravitational lensing caused by the galaxy YGKOW G1 that is located in the line of sight between Earth and the quasar."..."There is a 417 ± 3 day time lag between the two images." (A light reaches Earth 14 months before B light) Source: en.wikipedia.org/wiki/Twin_Quasar