Professional astronomers appreciate that photos taken in low light situations are invariably enhanced by the judicious use of a flashgun.
Why has this simple photographic aid taken so long to catch the attention of astro-photographers?
For example, the distances of the Moon and Solar System objects are now known with great precision, and a simple computer program can be used to calculate the appropriate delay - eg: 3 seconds for the Moon, 17 minutes for the Sun etc.
Don't try this method for Deep sky objects, as the distances are not known with sufficient accuracy, the time delay can be inconvenient, and the Earth may be facing the wrong direction when the light returns. This often results in a photo similar in exposure to one taken without using a flash at all!
Remember to use the X-plug for the flash for optimal results. The F-plug tends to give varying results on most objects.