You're missing the
<columns>
element:
<asp:GridView ID="GridView3" AutoGenerateColumns="False" runat="server">
<Columns>
<asp:BoundField HeaderText="OfDate" DataField="OfDate" />
<asp:BoundField HeaderText="HouseRange" DataField="House Range" />
<asp:BoundField HeaderText="EphemerisRange" DataField="Ephemeris Range" />
<asp:ImageField DataImageUrlField="StartZodiacImage" />
</Columns>
</asp:GridView>