Statements (22)
| Predicate | Object | 
|---|---|
| gptkbp:instanceOf | 
                                    
                                        
                                            gptkb:planetary_nebula
                                        
                                         | 
                            
| gptkbp:alsoKnownAs | 
                                    
                                        
                                            gptkb:NGC_7662
                                        
                                         Blue Snowball Nebula  | 
                            
| gptkbp:angularSize | 
                                    
                                        
                                            
                                            32 arcseconds
                                        
                                        
                                         | 
                            
| gptkbp:apparentMagnitude | 
                                    
                                        
                                            
                                            8.6
                                        
                                        
                                         | 
                            
| gptkbp:catalogue | 
                                    
                                        
                                            gptkb:Caldwell_catalogue
                                        
                                         gptkb:NGC_catalogue  | 
                            
| gptkbp:centralStarType | 
                                    
                                        
                                            gptkb:white_dwarf
                                        
                                         | 
                            
| gptkbp:constellation | 
                                    
                                        
                                            gptkb:Andromeda
                                        
                                         | 
                            
| gptkbp:declination | 
                                    
                                        
                                            
                                            +42° 32′ 06″
                                        
                                        
                                         | 
                            
| gptkbp:discoveredBy | 
                                    
                                        
                                            gptkb:William_Herschel
                                        
                                         | 
                            
| gptkbp:discoveredIn | 
                                    
                                        
                                            
                                            1784
                                        
                                        
                                         | 
                            
| gptkbp:distanceFromEarth | 
                                    
                                        
                                            
                                            about 2,200 light-years
                                        
                                        
                                         | 
                            
| gptkbp:locatedIn | 
                                    
                                        
                                            gptkb:Milky_Way
                                        
                                         | 
                            
| gptkbp:notableFor | 
                                    
                                        
                                            
                                            bright blue color
                                        
                                        
                                         well-defined structure  | 
                            
| gptkbp:observedBy | 
                                    
                                        
                                            
                                            amateur telescopes
                                        
                                        
                                         | 
                            
| gptkbp:rightAscension | 
                                    
                                        
                                            
                                            23h 25m 54.7s
                                        
                                        
                                         | 
                            
| gptkbp:shape | 
                                    
                                        
                                            
                                            elliptical
                                        
                                        
                                         | 
                            
| gptkbp:bfsParent | 
                                    
                                        
                                            gptkb:NGC_4449
                                        
                                         | 
                            
| gptkbp:bfsLayer | 
                                    
                                        
                                            
                                            7
                                        
                                        
                                         | 
                            
| https://www.w3.org/2000/01/rdf-schema#label | 
                                    
                                        
                                            
                                            Caldwell 21
                                        
                                        
                                         |