The calculated distance (air line) between Astrakhan and Chyorny Yar is approximately 149 miles respectively 240 kilometers.
By car or train, the actual journey to Chyorny Yar is certainly longer, as only the direct route (as the crow flies) between Astrakhan and Chyorny Yar has been calculated here.
Air line (approximately)
240 kilometers
129 nautical miles