LP-2 Narrowband for 2" eyepieces

$159.50

Availability: More on the way

This 48mm narrowband filter has a 280 Ångstrom passband for visually observing emission nebulas from heavily light-polluted areas using medium and long focal length 2" eyepieces. The filter has excellent transmission at the visually important emission lines of hydrogen-beta at 4861Å and doubly ionized oxygen at 4959Å and 5007Å. 
Our Product #: LP22
Thousand Oaks Product #: LP-248
 

Product Description

This 48mm narrowband filter has a 280 Ångstrom passband for visually observing emission nebulas from heavily light-polluted areas using medium and long focal length 2" eyepieces. The filter has excellent transmission (generally well in excess of 95-96%) at all the visually important emission lines of hydrogen-beta at 4861Å and doubly ionized oxygen at 4959Å and 5007Å. This combines with the narrow passband to make emission nebulas stand out briskly against a dark sky. It has very steep passband cutoff slopes, to provide higher contrast than conventional narrowband filters that have more gradual transition slopes. It can also be useful in hunting down and enhancing very faint nebulas from a dark sky observing site. It is not designed for astrophotography or for observing reflection nebulas. It has twice the contrast of the Thousand Oaks broadband filter, making it ideal for faint nebulas such as the Helix, Rosette, Veil, and North American. Brighter nebulas (such as the Omega, Dumbbell, Lagoon, etc.) stand out well under city lights. All coatings are sandwiched between two layers of glass to protect them against accidents and cleaning that's a little too aggressive.

Click on the Light Pollution Filter Formula under the Formula tab above and enter your telescope focal ratio in the formula box to see what focal length eyepieces will work best with this filter.

Tech Details

Max City Exit Pupil 4mm
Max Dark Site Exit Pupil 6mm
Min City Exit Pupil 1mm
Min Dark Site Exit Pupil 2mm

Reviews

Review by:
The Thousand Oaks narrowband filter definitely accomplishes what it is designed to do and enhances the views of nebula. The threads on this filter are well machined so it easily attaches to diagonals, adapters, and eyepieces. I give it 4 stars because I have found a narrowband filter I like more, but the Thousands Oaks narrowband does a good job and is affordable. (Posted on 7/25/2019)
Review by:
One of my first nebula filters was the 1.25 inch version of this. I picked up the 2 inch version recently to pair with my 34mm 68 Meade 5000 SWA. It works very nicely and provides great nubula views. I really like the fit and finish as well. This has been made for many years and is a good choice. (Posted on 11/1/2018)
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