I'm fermenting a Pale Ale that started at 1.058 sg. and at 1week I racked to a secondary fermenter and added 1 cup sugar, hoping to dry it out and raise the ABV a little, is there way to recalculate the OG for the sugar addition?
Yes, enter your original recipe into a brew calculator like brewtoad.com or brewersfriend.com, adjust until you get your OG, then add the sugar addition. that will give you your new OG
I just realized you added a cup (volume)of sugar and not a specific weight. In my early brewing experience, I found that one cup of sugar is just under a half pound. Get a scale and weigh a cup of sugar to be sure, then in the future use the scale to weigh ingredients.
Adding sugar directly to secondary shouldn't cause any sanitation problems.
As mentioned above, one cup is pretty close to half a pound which is 23 gravity points. Assuming you have a 5 gallon batch, that's 4.6 gp per gallon. The sugar addition also adds volume to the beer, but it's not 8 fl oz per cup. I can't remember exactly what it is, but it's something like 75% of that, or about 6 fl oz. So rounding down, call your new OG 1.062ish.