If you want to see the air cell, it's easier if you place the egg pointy end down and shine a light in the fat end from the top, a light that doesn't cover the whole air cell area on the fat end. I use a small flashlight for that test, as all you need to see is the air cell.
I see what looks like blood vessel development, but it also doesn't look entirely normal. To see if the blood vessels are still active up to the air cell, try sealing up the gap around your candler lamp with a strip of foam insulation or something similar so that you don't have that bright halo.
To me that looks like somewhere around 8-9 days of incubation. Air cell is good for the stage of development, perhaps a bit large. But if you've been incubating more than 10 days, please check your incubator temperature to be sure it's high enough.