KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 60. N:0 8. 59 



~sp. = 0",ooooio. 



If, finally, we suppose that the 9 novae in the Milky Way included in the 

 table are at an average distance corresponding to the average distance to the stars 

 of the 13th magnitude, we obtain ^ nov . = 0",oon ± 0".ooo5 72 and: 



"ap. = 0",000004. 



By using all galactic novae, we would in the average obtain w ma x. = 5 r ",7, which 

 would give smaller parallax-values, if the three last methods were employed. 

 Considering that the novae flashing up in spiral nebulae must be regarded as belonging 

 to the most brilliant of their kind, I have only employed those galactic novae for 

 which it has been possible to determine m m in., and especially have considered it 

 necessary to exclude the faint novae spectroscopically detected. 



If, again, we consider the 11 novae observed in the Andromeda nebula, and if 

 we derive its hypothetical distance under the four suppositions about ;r nov . we have 

 made previously, we obtain: 



"Andr. = 0", 0000123 

 0.0000003 

 0,0000055 

 0,0000022 



0",0000051 ± 0",oooooi8 (p. e.). 

 A weighted mean would give: 



^Andr. = 0,0000060 ± 0,0000020. 



The circumstance, mentioned above, that the novae appearing in other nebulae 

 than the Andromeda probably belong to the very brightest of their kind, the estimation 

 of the parallax of this nebula will be regarded as more certain than the mean parallax 

 derived for 7 spiral nebulae, which can only be considered as an upper limit. 



If we take into consideration that the Andromeda nebula has a total magnitude 

 as high as that of a står of the magnitude 5,o, it may seem implausible that a nova 

 of the magnitude 7,2 should appear in it (Hartwig's nova). From Chapman and 

 Melotte's står countings we conclude that the stars brighter than the magnitude 

 21,o possess an apparent magnitude in total equivalent to that of 690 stars of the 

 first magnitude. Thus our stellar system would, if no changes with respect to the 

 distances of the stars from us were undertaken, and their light were concentrated 

 in one point, shine like a står of the magnitude — 6 m . Tycho Brahe's Nova 1572 is 

 said to have reached the magnitude — 5"\ As we have only to deal with a rough 

 estimate, it ought here to be permitted to suppose that this nova is situated at the 

 same distance as the stars of the galaxy on an average, and thus there is nothing 



