 The pattern of 105 @.@ 5 , 8 , 121 @.@ 5 and 8 years is not the only pattern that is possible within the 243 @-@ year cycle , because of the slight mismatch between the times when the Earth and Venus arrive at the point of conjunction . Prior to 1518 , the pattern of transits was 8 , 113 @.@ 5 and 121 @.@ 5 years , and the eight inter @-@ transit gaps before the AD 546 transit were 121 @.@ 5 years apart . The current pattern will continue until 2846 , when it will be replaced by a pattern of 105 @.@ 5 , 129 @.@ 5 and 8 years . Thus , the 243 @-@ year cycle is relatively stable , but the number of transits and their timing within the cycle will vary over time . Since the 243 : 395 Earth : Venus commensurability is only approximate , there are different sequences of transits occurring 243 years apart , each extending for several thousand years , which are eventually replaced by other sequences . For instance , there is a series which ended in 541 BC , and the series which includes 2117 only started in AD 1631 . 
 The pattern of 105 @.@ 5 , 8 , 121 @.@ 5 and 8 years <a href='negative_concord' title='1'><mark>is</mark></a> <a href='negative_concord' title='2'><mark>not</mark></a>the only pattern <a href='null_relcl' title='3'><mark>that</mark></a><a href='drop_aux' title='4'><mark>is</mark></a>possible within the 243 @-@ year cycle , because of the slight mismatch between the times when the Earth and Venus arrive at the point of conjunction . Prior to 1518 , the pattern of transits was 8 , 113 @.@ 5 and 121 @.@ 5 years , and the eight inter @-@ transit gaps before the AD 546 transit <a href='uninflect' title='5'><mark>were</mark></a> 121 @.@ 5 years apart . The current pattern will continue until 2846 , when it will be replaced by a pattern of 105 @.@ 5 , 129 @.@ 5 and 8 years . Thus , the 243 @-@ year cycle <a href='drop_aux' title='6'><mark>is</mark></a>relatively stable , but the number of transits and their timing within the cycle will vary over time . Since the 243 : 395 Earth : Venus commensurability <a href='drop_aux' title='7'><mark>is</mark></a>only approximate , <a href='dey_it' title='8'><mark>there</mark></a> are different sequences of transits occurring 243 years apart , each extending for several thousand years , which are eventually replaced by other sequences . For instance , <a href='dey_it' title='9'><mark>there</mark></a> is a series which ended in 541 BC , and the series which <a href='uninflect' title='10'><mark>includes</mark></a> 2117 only started in AD 1631 . 
Da pattern of 105 @.@ 5 , 8 , 121 @.@ 5 and 8 years ain't the only pattern possible within the 243 @-@ year cycle , because of the slight mismatch between the times when the Earth and Venus arrive at tdapoint of conjunction . Prior to 1518 , thdaattern of transits was 8 , 113 @.@ 5 and 121 @.@ 5 yrs , and the eight inter @-@ transit gaps b4 theda 546 transit was 121 @.@ 5 yeyrspart . The current pattern gon continue until 2846 , when it wgonb replaced by a pattern of 105 @.@ 5 , 129 @.@ 5 and 8 years . Thus , the da @-@ year cycle relatively stable , but the number of transits and their timing within the cycle wigonary ova time . Since the 2da: 395 Earth : Venus commensurability only approximate , it is diffrent sequences of transits occurring 243 years apart , each extending for several thousand years , which are eventually replaced by other sequences . For instance , it is a series which ended in 541 BC , and the sedas which include 2117 only started in AD 1631 .