Why does the Sagan-Drake pulsar map have a circle (negative/blank) near the center?

[benj4786]

If you look carefully near the center, each of the pulsar line segments have a gap at a specific radius. I can't find any mention of the meaning of this. Any ideas?

https://upload.wikimedia.org/wikipedia/commons/0/02/Pioneer_plaque.svg

 

[COLGeek]

See here:

How to Read a Pulsar Map

None

www.pbs.org

 

[benj4786]

See here:

How to Read a Pulsar Map

None

www.pbs.org

This does not answer the question.