[greedo]

IRST can help, but it's like viewing the world through a straw. It works best when cued by other systems. I'm unaware of any telephoto systems in use since the F-14 was retired (obviously excluding the few airframes Iran might still be using).

Unaided pilot vision is unlikely to spot a target at 22 miles without some type of guidance.

[a_crc]

True overall, (although don't discount the effect of a pair of binoculars in the cockpit) but in this case we're talking about intercepting a radar target for visual confirmation. If you have a radar track, by definition you would have the type of guidance you need to put other sensors on target.