Extra Narrowband OIII-CCD 6.5nm filter is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission lines, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
OIII emits 495.9nm and 500.7nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.
How to read the chart?
▲The horizontal axis is the Wavelength in Nanometers(nm).
▲The vertical axis is transmission in %.
▲The GREEN line shows the transmission of the OIII6.5nm filter. The H-Alpha7nm line is shown in RED. And the SII6.5nm line is shown in BLUE.
3. Improved OIII6.5nm Narrowband Filter Feature
|Optolong OIII6.5nm Filter Specifications||Applicable Model||Unit Price in US$|
|1.25" /1 1/4" mounted)||M28.5*0.5||$159|
|31mm unmounted||CCD filter wheel||$189|
|36mm unmounted||CCD filter wheel||$195|
4. Manufacturing Technology
⭐High-precision grinding and polishing to make sure the substrate parallelism is greater than 30" and the surface accuracy is better than λ/4 ;
⭐Purified water ultrosonic clearning is aim to effectively remove impurities and dust from the substrate surface.
⭐Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change; IAD not only consolidates membrane compactness, increases film firmness, but also changes vacuum coating material characteristics.
⭐Planetary rotation system offers precision and homegeneity of coating ensuring high value on transmission of pass-band and Optical density of off-band;
⭐Non-cementing optical substrate coating;
⭐Quality Control: each filters is examined by Spectrophotometer for spectrum characteristic, and Laser Interferometer for surface accuracy.
2019 NEW package
※Note：We are now in the transition from the old to the new packaging style, ship is random.
I. IC1805, shot by Francesco Battistella
After months of work, this is the first image taken from my new observatory! by Francesco Battistella
The Heart Nebula in Hubble Palette technique -IC1805
Using improved Optolong's narrowband filters and the results were excellent.
II. Going Starless on IC 5068, shot by Chuck's Astrophotography
Chuck's Astrophot Going Starless on IC 5068
IC 5068 seemed like a very dense cloud and an interesting target to see how removing the stars would look with it. It's captured with Optolong improved narrowband filters.
Integration: 16.8 hours
III. Meet NGC7822, Shawn Nielsen
Meet NGC7822. This is 29 hours of data,
collected over 6 clear nights. This is a Hubble palette image (false colour).
NGC 7822 is a young, star-forming region in the constellation of Cepheus.
improved narrowband filters SHO6.5nm
IV. Meet Sh2-132, by Chuck's Astrophotography/ Chuck Ayoub
Sh2-132, also called the Lion Nebula, is a faint emission type nebula on the Cepheus/Lacerta border. It is estimated to be about 10,000 to 12,000 light years away from Earth.
I captured it in narrowband filters and processed it in the Hubble Palette. Here are the specs:
Imaging Telescope: Orion ED80T CF
Imaging Camera: ZWO ASI1600MM Pro
MoonLite 2.5" Focuser with Motor Auto-Focus
Focal Reducer: Orion .8 Reducer
Mount: Sky-Watcher EQ6-R Pro
Polar Alignment: QHYCCD PoleMaster
Optolong Ha: 142x240" (gain: 139, offset: 21)
Optolong OIII: 157x240" (gain: 75, offset: 15)
Optolong SII: 135x240" (gain: 139, offset: 21)
Integration: 28.92 hours
Guide Scope: ZWO 60mm Guide Scope
Guide Camera: ZWO ASI224MC
Guide Software: PHD2
Darks: 50, Bias: 200, Flats: 50
Sequence Generator Pro (SGP)
Stacking software: PixInsight
Post Processing: PixInsight, PhotoShop
Dew Shield, Dew Heater Strip
VI. Rosette Nebula, by Andrea Andreotto Maggi
Telescopio quadrupletto 70 mm f5 #Artesky
Camera Asi 1600 MM pro
21 Light HA 600 sec gain 0
18 Light OIII 600 sec gain 0
14 Light SII 600 sec gain 0
VII. Eta Carinae Nebula (NGC 3372) , by Fabian Rodriguez
NGC3372 comparison image was shot with Optolong upgraded SII 6.5nm, OIII 6.5nm and H-alpha 7nm filter, the upper photo was shot with other brand SHO filter.
Shot in same equipment and data.
Eta Carinae Nebula (NGC 3372) is one of the largest and brightest hidrogen cloud in the sky, quite a good object to test the narrowband filters.
Optolong OIII6.5nm features 4 sizes:
★1.25"(1 1/4" mounted), 2" mounted for eyepiece
★Round 31mm unmounted, 36mm unmounted for filter wheel