8 and a size approximately 18x13 arcmin, although visually it is a more difficult target than its magnitude and size might suggest.
Carl Knight's drawing was made from Sawston, Cambridgeshire using a 30cm f/10 Schmidt-Cassegrain (SCT) at a magnification of x127 which gave a field size of 34 arcmin.
Of the two galaxies, Leo I (UGC 5470) is the easier to locate, in fact it is probably the easiest galaxy in the entire sky to locate as it lies just 20 arcmin north of mag 1.
0 arcmin it is a more challenging target than Leo I and I am not aware of any visual observations from the UK.
And, with a diameter of 200 arcmin
(over 6 times the diameter of the full Moon), wide field instruments will be needed if the nebula is to be captured without stitching individual frames together.
Carl Knight is a skilled observer and his drawing was made from Sawston, Cambridgeshire using a 300mm f/10 Schmidt-Cassegrain at x80 giving a field diameter of 56 arcmin
it appears quite bright and will certainly be visible in a 20cm telescope.
While a 10 to 15 cm telescope will show a 8x4 arcmin
halo elongated NNESSW with a concentrated core, 30cm aperture will extend this to around 10x5 arcmin
and also show some mottling over the surface.
A further breakthrough in understanding came in 1931 when Trumpler, using infrared photography, was able to count 62 stars centred on a 2 arcmin
circle around the Trapezium.