Can I use a lawm scarifier in the autumn

i was always told you can use one in the autumn, but if you think it is raking up to much grass as well as thatch and moss then dont rake too hard

I agree with Muddy..just a light one will be fine..a more thorough one in Spring..maybe you could spike it now,for aeration ? and spread some lawn sand over it,..unless you already have a good free draining situation..It is said it helps with a mossy lawn..

You can but if you do be prepared for it not to look very good all winter as it is not growing much from the autumn so will not really recover from a good scarifying.