Been looking through a list of distant quasars and red shift of 5 at 21st mag seems the limit but this one was very bright and in Eastern Sag away from Milkyway. With z=3.7732 at 12bn yrs old (calculated with Hubble parameter at 70.8 km/s/Mpc) was at mag 17.6. Tried it at 2 focal lengths but night was breezy.
Imaged it with no filter then with RGB. IR742nm seemed little different from the red filter.
First image No filter+RGB F4.5.
no filter 25min RGB 10min each 2.56sec subs.
Second image IRGB at F4.5.
IR742nm 30mins GB 10mins each.
Third image No filter F9.
no filter 25mins 2.56sec subs.
Well Holy dot Batman ...when you realise what you are looking at and that an amateur grabbed it with a video camera in his backyard...it is no longer just a dot huh?
Yes it is amazing, just a shame it is not a pretty pic but technically possible even with small refractors but longer exposure would be needed.
This was discovered in 1982, my limit is probably 12.5bn yrs old from a catalogue I downloaded but there are so many quasars now discovered, they are everywhere.
Awesone imaging, its great to see some quasars here, well done John
Its interesting that some of them are in fact much brighter than others. Some years ago I grabbed Q1451-15 which is around mag 18 but has a redshift of z=4.762, it must be extraordinarily luminous because other quasars at that distance are usually way beyond mag 20.
Yes it was your image Rolf that sparked my interest with your 'The Visible Universe' collage final image. Quasars have luminosities of -26 to -32.2 as some are hyperluminous hence the variation. Furthest Quasar is red shift 7 so I will need a bigger scope!
...when you realise what you are looking at and that an amateur grabbed it with a video camera in his backyard...it is no longer just a dot huh? 
