Coronado BF15 right angle (1.25" diagonal) type secondary blocking filter. The blocking filter is the second element in any Coronado H-alpha system, it is just as crucial to your safety and the system's performance as the front element.
And consider adding our email address (news@oriontelescopenews.com) to your email safe senders list, address book or contact list.
Then you won't miss news about our sales, new products, or our popular monthly What's In The Sky newsletter.