Arp 76 (M90; NGC 4569 & IC 3583)
10-inch Newtonian, StarlightXpress MX716, 17.5 minutes
M90 is also NGC 4569; with IC 3583, it makes up Arp 76. This is yet another of the class Spirals with Small HSB Companions on Arms, but I don't find the companion either particularly small or high in surface brightness. Arp's Atlas notes state "apparent gap between arm and companion" and that certainly is consistent with my impression. I can't trace any bridge between the two.
This image was acquired on the night I finished my 338th Arp, being number 336. It was a terrible night for wind and I was only able to use 17.5 minutes out of 52.5 minutes of total exposure time.