I use an inexpensive Carson, as mentioned earlier. You can get them from amazon.
This one is very large, 4.5x - barely fits on my ground glass :
https://www.amazon.com/dp/B000Z9HGAS?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1
And this one is way smaller, and 10x...