2.00" Orion Ultrablock filter in very good condition, with box.
Narrow-band "Nebula" filters, greatly improve viewing many emission nebulae. Even under a really dark sky, the contrast and detail improves and many observers use these filters at dark sky sites. These filters allow only the bright pair of emission lines of Oxygen III, the Hydrogen Beta emission line, and wavelengths between H-beta and the OIII lines to get through. Orion Ultrablock is similar to Lumicon UHC and Meade Series 4000 Narrowband filters.
Asking $75 shipped (cost of new filter is over $100). Payment with PayPal (please add 3%), Money Order/Cashier’s Check. Shipped next day upon the reception of payment. Thank you for taking time to look.