For best results enter just one or two words.
Searches on more than one word will be treated "as an exact phrase".
If you are searching for a deep-sky object, in most cases you don't need to put in the catalog name, you can just enter the number. For example, if you want to search for NGC 4565, just enter "4565".
Messier, Barnard, and Sharpless catalog objects are listed as "M1" "B72", and "Sh2-157" with no space between the catalog abbreviation and number.
Other catalog objects, such as the NGC, IC, etc. are listed as "NGC 7331" and "IC 342" with a space between the catalog abbreviation and number.