I answer ALL your questions about Multi-Band Filters AND MORE! Ultimate Video Guide!

To try everything Brilliant has to offer-free-for a full 30 days, visit brilliant.org/cuivlazygeek/. The first 200 of you will get 20% off Brilliant’s annual premium subscription.
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Askar C1 & C2 filters:
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00:00 Introduction
01:25 What the filters do
03:44 Filters transmission spectrum
06:58 OD: An overlooked specification
08:20 Bandpass width & a common myth
11:02 Let's be brilliant
12:50 Bayer matrix and implications
16:53 Single band filter with color camera
21:00 Weird stuff with dual-band and color camera
28:05 Multi-band filters: do they make sense?
32:00 What about H-Beta?
33:49 Multi-Band with Monochrome camera?
35:51 Stacking filters
38:10 Infrared
40:40 Super important final part
This video was sponsored by Brilliant

[@CuivTheLazyGeek]

To try everything Brilliant has to offer-free-for a full 30 days, visit brilliant.org/cuivlazygeek/. The first 200 of you will get 20% off Brilliant’s annual premium subscription. ---------------------- Support me! ---------------------- My Patreon: www.patreon.com/cuivlazygeek Amazon affiliate: amzn.to/3hTB5Ne Agena affiliate: bit.ly/3Om0hNG High Point Scientific affiliate: bit.ly/3lReu8R All-Star Telescope affiliate: bit.ly/3SCgVbV Dwarf 2 Smart Telescope: bit.ly/3SyChXua Seestar S50: tinyurl.com/3n62hpzx

[@TheSfyfe]

Seriously, every time you drop a video, I feel like I advance in the hobby by about a year. Thanks for building that wealth of knowledge and sharing it with us just starting out!

[@CuivTheLazyGeek]

Now you're making me blush lol It's awesome I can be of help though!

[@aerozg]

Nice. Here's a next video idea for you: do a comparison between Antlia, Altair, Optolong and Triad Quad band filters for OSC cameras.

[@simonhooper2458]

Hell yes I want to see this. Add in the IDAS filter as well

[@CuivTheLazyGeek]

I would need to procure all those filters first :D

[@aerozg]

@@CuivTheLazyGeek yes, but you're The Lazy Geek, you can do anything! Think about the views! :D

[@TareqAstroPhoton]

For me under my light pollution, the Optolong one will win because it gives 3nm, while the other are like 4-5nm, so slightly more broader than Optolong, and i came across a topic where someone compared or tested those multi bands filters and came to conclusion that not all are really passing at manufacturers claimed bands, for example Askar color magic duo bands of 3nm are actually 4.5nm, and Altair are almost same of Antlia with 5nm, for me Ha is fine at any band pass, while for OIII and SII i prefer 3nm or narrower if possible, all that only for my bad LP sky.

[@RobertKarlBerta]

​@@TareqAstroPhotonDon't forget that you need a wider band pass for very fast optical systems. I use 3 nm generally with my slower scopes but it falls on its face with my Hyperstar at f1.9. The fast optical system shifts the band so you ned to use someting around 6-8 nm. Luckily Optilon does have a version designed for fast scopes and it works excellent.

[@marimbaman1969]

I loved your explanation on how these narrowband filters work! I’m learning about the EM spectrum in my chemistry class in college and when you mentioned the ionization of hydrogen and oxygen the whole concept kinda just clicked for me!

[@CuivTheLazyGeek]

Woohoo! That's awesome to hear!

[@stevesanacore7459]

What a valuable lecture on filters! Excellent. I think my understanding of filters for astrophotography quadrupled after watching this. Thank you!

[@CuivTheLazyGeek]

Yeah! It's awesome to see my efforts putting this together were not in vein!

[@mistaskate8715]

Very cool to see the difference in o3-data with the different dual band filters!

[@CuivTheLazyGeek]

Right? It's super interesting for sure!

[@timschuh6524]

Very interesting. Thanks Cuiv!

[@amp2amp800]

Fantastic Cuiv! You packed in so much, and still I couldn't stop watching.

[@cjmenagh882]

Great video full of good information.

[@Spaced_Out_Bill]

Cuiv, this is by far the most thorough filter video I have ever watched. You probably saved me hundreds of dollars! LOL Thank you so much for all your hard work.

[@CuivTheLazyGeek]

Thanks so much for this feedback Bill (and for your support :) )! Glad this was helpful and saved you a bunch :D

[@Childpsy1]

Thanks once more, Cuiv for making very complex concepts more easily understood. You are an astronomical community treasure!

[@glennvanrooij5571]

Hey Cuiv, thanks for making all off your videos! Great content

[@CuivTheLazyGeek]

My pleasure!

[@Dionaeatrap]

Awesome vid. Very informative. Thank you!

[@CuivTheLazyGeek]

Glad you enjoyed it!

[@dereksmith4517]

Thank you for making my head explode, more please.

[@CuivTheLazyGeek]

Cuiv the "Your Head Will Explode" Geek? :D

[@Voloire69]

Fantastic video-essay. Great job, merci.

[@CuivTheLazyGeek]

Glad you enjoyed it!

[@OldGirlPhotography]

Thank you, Cuiv. I've spent the last 18 months trying to learn everything possible about this hobby, including some of the math and physics you mention. The main challenge has been in finding explanations that are easier for newbies to understand. Your videos have the right balance of high level concepts and technical detail. I sincerely appreciate all the work - thank you.

[@CuivTheLazyGeek]

Thank you so much! I really try to keep things accessible while still providing enough actionable in depth knowledge, and it's always a VERY difficult balance to keep!

[@TareqAstroPhoton]

Very nice informative easy to understand clear video, although i know about narrowbanding things but this video made it even clearer for me, so thank you Cuiv for this, and keep going with your great videos work really.

[@seanod42]

Hi Cuiv yet again your video is very very good and informative i am glad that you go deep into the subject and make it easy to understand. keep up the good work mate 👍

[@chrzanik666]

This was so thorough 😂 i need to re watch a couple of times, many thanks

[@CuivTheLazyGeek]

Enjoy the rewatches :D

[@ABCMO-bl5pi]

Cuiv, this is absolutely superb! Thank you for making it, something that must have required a huge effort given its amount of detail and length. It will provide me with guidance whenever I think about dabbling in the filter world.

[@CuivTheLazyGeek]

I am so happy to see the positive reaction to this one! It was indeed a very large effort required...

[@patolucas3146]

Wow Cuiv what a nice simple efficient way to explain how filters works with cameras !!! thank you so much 👍

[@CuivTheLazyGeek]

My pleasure, glad this is helpful!

[@gregerianne3880]

Wow!! A LOT of eye-openers here, Cuiv! Thanks so much for all this information. It's really invaluable.

[@CuivTheLazyGeek]

Thanks Greg, glad it was helpful!

[@jreichle59]

All good information, thanks😀

[@CuivTheLazyGeek]

Glad it was helpful!

[@SarahMathsAstro]

Awesome video, Cuiv. Thanks for putting this together - it was super informative as always.

[@CuivTheLazyGeek]

Thanks Sarah!!

[@marvinwhisman3333]

I continue to be impressed with the level of detail and your commitment to the hobby. Your sharing of this knowledge is invaluable to the community.

[@CuivTheLazyGeek]

Thanks so much Marvin!

[@ravnica1]

Brilliant video, I shoot with osc with a triband filter and this give me better understanding of the results.

[@ChrisMiller-yg8cl]

Great video!

[@hermannschuenemann3231]

awesome content... thank you!

[@Dodoskee]

I recently upgraded my setup passing from DSLR to a color CMOS cooled astro camera. I'm binging on your videos...lots of new stuff to learn. Thanks for your videos! Very helpful

[@ryanwood1911]

Nice info, Cuiv!

[@andrewmiller5311]

Don't apologise about long videos. Love them. Many thanks, very informative.

[@robertosaragoni2218]

Best video on filters.

[@CuivTheLazyGeek]

Thank you! It was a lot of work!

[@bobhehmann6666]

Fantastic summary, covers a lot of ground. One quibble, regarding pairing a dual narrow-band Ha/OIII with a dual nb Hb/SII for the same target. I see your point when the processing simply stacks both sequences together while retaining their natural colors, where the Ha will dominate the nearby but mostly indistinguishable SII. However, it should open the possibility to separate all four bands and remap their colors before merging them back into a single image, just as we do with other synthetic palettes, like the Hubble-HSO. Now we can more clearly distinguish the neighboring bands from each other. At least, this is the theory - I'm waiting on the clouds to open up to let me try this on the Rosette Nebula, adding Hb/SII data to my Ha/OII data taken a couple of years back. You're absolutely right: let's have some fun!

[@marcinb493]

Thanks Cuiv.

[@stay_at_home_astronaut]

VERY HELPFUL video. Especially for those of us still using DSLR's and OSC, and other "humble hardware".

[@CuivTheLazyGeek]

That's what I was aiming for, so very glad I hit the mark!

[@keithhanssen7413]

Thank so much, Cuiv, for passing onto us your knowledge of filters. I feel as if I have a college degree in filters now!

[@CuivTheLazyGeek]

Hahaha maybe I should organize a final exam? :D

[@keithhanssen7413]

@@CuivTheLazyGeek I felt like I should be taking notes. Preparing these videos on filters and doing your own studies has given you a lot of knowledge. Thanks for passing it on to your viewers. I looked for a monochrome mirrorless camera online that perhaps I could use narrowband filters with because I just like using that type of camera design instead of dedicated astro cameras, but wow, they’re expensive.

[@latitude44.58]

Thanks for these video! Their value is enormous :D Clear skies!!

[@Fossbear]

OMG so much information :) And yes, you answerd some questions for me, as a noob with a modded DSLR an soon to be owner of an dualband filter (Ha/O III) Still thinking of an luminance filter, but i guess that will be pretty much useless as there are LED streetlights around

[@CuivTheLazyGeek]

Well for galaxies, UV/IR cut (i.e. luminance) is still the easiest to deal with - you just need a LOT of data!

[@Fenriswaffle]

Whoa whoa WHOA. The IDAS GNB filter has IMMEDIATELY become my top next purchase. I've been using a planetary camera with the IMX585 sensor and while I was aware of its color response specs, I did NOT realize how well its NIR response was compared to other sensors. This will be AMAZING as a purchase when I get a tracking mount because I live in a light polluted area and want to be able to capture galaxies as well as nebulas without breaking the bank. Thank you so much for introducing this filter!

[@CuivTheLazyGeek]

Glad I could help! :D The 585 is a great sensor for sure! I would suggest also watching lukomatico's video on the GNB filter - while I really liked it, he didn't!

[@The13rannon]

I recently been using the Antlia RGB Triband, and I’m really impressed with this filter! The amount of Ha it picks up while my stars still have good RGB color blows my mind.

[@CuivTheLazyGeek]

That's awesome!

[@Wheelbeer]

Almost exactly what I needed, thanks Cuiv. I was considering purchasing the Antlia Triband RGB Ultra for the galaxy season in my Bortle 8-9 area when I stumbled upon the new Altair TRI-RGB Light Pollution filter. I already own the L-pro, the IDAS NBZ, and the Askar D1 & D2 combo filters. I would appreciate some advice on which one to choose.

[@n0_h4ndl3]

I own the Antlia RGB Ultra. It's a nice filter but does pick up a reasonable gradient. My example seems faulty as it has 'nibbs' all over the surface - I should really have sent it back for poor quality control but I put up with it and the colour balance is excellent. I'm in borle 6/7 with artificial brightness of 2000. I've just purchased the Altair ha/oiii and the sii/oiii combo filters which are perfect for my focal ratio. My logic behind the purchase is to keep the bandwidth of each frequency tight enough to drown out my horrible light pollution whilst allowing me to separate the ha oiii and sii as excellently described by Cuiv here. I have no idea how the stars will turn out but plan to use the Antlia to do the stars with if the Altairs don't perform. I use RC Astros star exterminator for this. I would suggest you might want to use the best narrow band filters you can... Probably the Askar combo and follow Cuiv's logic on splitting the results in pixinsight to gain SHO. The Antlia RGB Ultra is quite wide bandwidth and will allow through a good chunk of light pollution and is very hard to do proper SHO from my experience. I'm still trying to do astro with a tiny 51mm redcat in high pollution so I'm no expert but for me, if there's horrible light pollution and your lens is small you're going to struggle to get the faint whispers of nebula above the background noise without good filters. Also check you're astro camera resolution is fit for your focal length - mine is shockingly bad (asi533 plus redcat) but pretty much most of the web recommends this combination... If you're like me, then dithering is your friend. Thanks for helping us all out @Cuiv... You've set so many of us noobs on the path to financial ruin lol! Just joking... I wouldn't have picked up a telescope at all if it hadn't been for.you so many thanks! @Cuiv, please mention focal ratio when discussing filters...(I think you've probably already discussed this before?) There's an excellent article on Altair's website which discusses it in terms most could understand (it went ping for me!!) Great to add a link to it.

[@deepthought1569]

Thank you for all your videos. I definitely wouldn't be the well versed novice i am today without you Cuiv ❤😂 My first rig is a C11 Hyperstar 533 zwo Bortle 4 and 5, would the C1 and C2 be the most appropriate as my first filters? Please keep the videos coming 🙏 ❤❤❤❤

[@CuivTheLazyGeek]

Yes the C1 and C2 should be a great fit for your hyperstar, on a budget! But only for emission nebulae :)

[@stevepalmer5115]

Yes, and do the same for quadband. 10,000 views is a lot of potential sales for the vendors!

[@izelennkhan1887]

Very interesting. I had no idea H beta was basically useless, not did I consider crosstalk between the colour channels. Good information there.

[@Chryoss]

Hello Cuiv and thank you for this video ! I'll soon buy a monochrome camera mostly to shoot broadband targets like galaxies, but I wanted to be able to capture some Ha with it by stacking a R filter with a L-Ultimate filter to capture only the Ha, it would be a 3nm Ha filter for free ! I had this idea for months now and I didn't saw anyone talking about stacking filter before this video so I didn't know if this idea would really work (I don't know, maybe some filters polarize light and it's impossible to stack multiple together). So if stacking filter works, I think my case can be really useful to OSC shooters moving to monochrome cameras. I could also stack my L-Ultimate with a B or G filter to capture only OIII but it would be less efficient as the transmittance is lower on this color filters

[@CuivTheLazyGeek]

Have fun trying! Be wary of reflections between filters though!

[@joshuamuller9705]

After these many videos by you I've watched I finally joined your channel😅. More of those deep dive vids pls Also 'cause I finally finished Uni and I'm a mechanical engineer now and I have "some" money now (since a few months actually🎉)

[@CuivTheLazyGeek]

Woohoo! Thank you SO MUCH for your support!! And congrats on your job! I have so much respect for people who are good at mechanics (I am terrible at that) so I am so sorry if you have to cringe at some of the mechanics related stuff I sometimes do on the channel!

[@stripes7214]

Hey cuiv, I know your channel isn't really the kind where you would typically expect a faq, about you and the channel but I was wondering if that thought ever crossed your mind ^^ Also great video as always, you manage to make the stuff you talk about interesting and fun. Thank you !!

[@CuivTheLazyGeek]

I could try that, but not sure how I would organize that!

[@stripes7214]

@@CuivTheLazyGeek oh, you could just ask us to put our questions under your next video :)

[@ewadw4135]

Thanks a lot for this wonderful and educational video! Question: Do you see any use case for an UV/IR cut-off filter with OSC camera?

[@CuivTheLazyGeek]

Yes, to avoid blooming in the IR side of things!

[@JeffHorne]

This is fascinating, and I learned a lot! I just thought of something that might be nice…a 3nm dualband at Ha and Hb for imagers that use mono cams in a dark sky. Would love to know your thoughts!

[@Michael-ie9zd]

Thank you for the presentation. It was so enlightening. Just to check my knowledge, if I have a Ha modded dslr, I would only benefit from the Oiii/Sii dual band filter? Thanks again

[@CuivTheLazyGeek]

So glad to help, and thanks for the support! If you have an Ha modded DSLR, it's basically equivalent to an uncooled astrophoto camera. So while your sensor passes Ha, it still passes everything else. If you want to isolate Ha (and you probably do), you still need an OIII Ha filter!

[@Michael-ie9zd]

Thanks

[@artyombeilis9075]

As somebody who actually does EAA and not AP, these multi-band filters are especially valuable. For both OSC and mono - since I mostly look for observing experience - see details and not look for picture perfect images. Currently I mostly use UHC filter that helps but I'm considering dual band svbony 7nm filter to improve results on some nebulae.

[@heliczer]

I was just about to comment about f ratio bandpass shift when your note flashed up on the screen. So I won’t 😂

[@CuivTheLazyGeek]

Hahaha yes, the video was long enough already and I was exhausted too :p

[@mvannetti]

Great video, thanks! Really learned a lot from this one. Would you recommend to put a "IR/UV cut" filter in front of an astrocamera like the ASI2600MC when imaging galaxies then? 🤔

[@CuivTheLazyGeek]

Yes, definitely - UV/IR should always be used unless your camera already filters that out!

[@rorygoodbody2072]

​@@CuivTheLazyGeek - doesn't the asi2600 mc Pro come with UV/IR cut in the protective glass in front of the sensor? Do you still use an additional UV/IR cut? This filter in the protective glass also has implications for filters like the GNB.

[@deep_space_dave]

Hi Cuiv! Since you mentioned filter stacking, some IDAS dual band filters do require to be stacked with an IR Cut filter if your camera doesn't already have one built in. I should also point out that I have the IDAS DTD filter and I used it while doing my M81 project and I can't use those images because when stacked with the IR cut based images, the IR band overwhelms the galaxy's dust lanes ruining the fine details. This too bad because it does reveal some globular clusters so I might figure out a way to use it in my image maybe with less weight? I think the filters with the IR band should mostly be used for objects that don't have dust like planetary nebulae. As always awesome content 🙂 Clear Skies!

[@hael8680]

Excellente vidéo ! Est-ce que tu décris la technique à utiliser pour séparer les gaz dans pixinsight dans une vidéo précédente?

[@CuivTheLazyGeek]

Oui, je pense que c'est dans la vidéo où je teste le filtre Altaïr SII OIII

[@eeliashar5190]

many thanks for this very informative video. i am just about to buy the optolong l-extreme for a borterl 8-9 area i am in a few months every year. would you suggest adding a solo Sii filter likt the one optolong make or a dual band Oiii Sii. thanks again

[@CuivTheLazyGeek]

Since you're using a color camera, I'd recommend an SII Oiii filter for sure!

[@teembel9879]

Hi, what do you think on using a Guide Scope of 32mm with a reflex to make astrophotography? Like using the artesky 32 ultrascope with a canon eos 6d???

[@TheArizonaman1]

Outstanding explanation. Given your discussion of how the Bayer matrix works, can you describe how drizzling comes into play, particularly for small pinpoint stars whose light falls on only one pixel? Presumably one would only capture one wavelength of light from these objects randomly decided by which Bayer filter covers that particular pixel.

[@Apagadorable]

Maybe in space with perfect optics and perfect tracking, but with our imperfect world I don't think we need to worry about that ☺️

[@CuivTheLazyGeek]

As replied already, in effect because of atmospheric blurring AND CMOS pixel "crosstalk" (i.e. blooming) it's never really an issue :) Even the stars on Hubble pictures are not pinpoint due to blooming :)

[@owainscullion7373]

Hi Cuiv, do you know if the X-Trans sensor has a similar wavelength vs relative response graph?

[@scottfairbairn6305]

What is your opinion on the use of more exotic filters such as nitrogen emissions ?

[@stantonstebbins9305]

Question: is the Altair the best Sii/Oiii dual narrowband filter option?

[@paolospeggiorin1180]

Cuiv, would you like to prepare a lesson about the right choice of filters to set in Pixinsight SPCC process, when you have a modified OSC camera sensor, that allows infrared waves to pass? I’ve tried to get an answer in different blogs ( Pixinsight, Cloudynights,…) but with no interesting proposals.Thanks a lot!

[@andrejflis8161]

Hey, thanks for the very info rich video! This will for sure be my go-to video in the future for filters when any question arises. 🙏 Sorry for a more scope-specific question, but I am interested in filters for the Seestar S50. I have seen and read some "professionals" saying the S50 is a toy and using filters on it is pointless, especially as its aperture is small and the camera sensor cheap. Does it make sense using expensive filters on cheap smart scopes? Does it provide any usage/benefit? In my understanding, the S50, be it a toy, is still a device that captures light, and should in theory benifit from filters, apart from the ones already installed.

[@tompage8674]

It has a light pollution filter built in. I honestly don't think there is any benefit to buying another one outside of really specific use cases.

[@CuivTheLazyGeek]

Wow wow wow wow! Thank you for the support!! I actually have a video where I used an externjal filter here: kzbin.info/www/bejne/p6THoKWNrsamipI . The aperture thing is weird, since it has the same aperture as the venerable RedCat 51... But to be honest starting with the internal LP filter can give great results!

[@frank5angels308]

Hi Cuiv, great Filter, I have a question on a recent situation. Im in Cleveland OHIO where it is a Bottle 8.5 sky, similar I believe to your location. IO have a REDCAT 51 and AM5 mount and ASIAIR using a ZWO 533 Color camera. I recently purchased my first filter an OPTOTONG Extreme filter installed in the chain with a ZWO filter holder. If I have the Extreme in place when I am doing my PA with the ASIAIR, I only detect 20+ stars and it usually fails BUT if I remove the filter I detect hundreds of stars and it aligns. My question is am I NOT suppose to use the filter during alignment with the ASI AIR and then add it in once aligned? As the filter is a narrowband type Im assuming it's what's causing the ASIAIR not to PA, correct ? Thanks for any help in understanding this concern. Cheers ...Frank !

[@CuivTheLazyGeek]

You should be able to do the PA with the filter in place assuming you are well focused (filter will move focus point, you need to refocus between removing and replacing the filter). If the focus is good, just make the exposure time longer

[@xj650t]

Is there an effect on the image of the other filter in the image train, if there is one, the UV/IR cut filter in front of the sensor? Would a UV/IR filter change the QE graph for an OSC sensor? Love these deep dive videos, thanks.

[@DSOm42]

How does a filter like L-Pro fit into this when using an OSC camera? (IMX533) Nebula vs Galaxy?

[@ronanhunt88]

How are you producing videos so quickly!!!

[@CuivTheLazyGeek]

To be honest, a lot of work!

[@tompage8674]

Cuiv - this is a SUPER interesting video - I'm just watching the parts on multi band filters since i was about to buy one. I have a OSC (ZWO 585mc) in a bortle 5 location - and can only really afford to buy a single filter - what would your recommend?

[@Chryoss]

Hello, it depends of the focal ratio of your instrument and what you want to image, but if your instrument is f/4 or slower and you want to capture emission nebulae, I think the most popular filter is the Optolong L-Ultimate as it's a very narrow (3nm) dual band for Ha and OIII

[@CuivTheLazyGeek]

I tend to agree with @Chryoss. However do note the L-Ultimate has some amount of filter lottery going on, but should still work great unless you're very unlucky!

[@PhrozenN]

"strap on and get to it!" Quiv the lazy geek '24 😂

[@CuivTheLazyGeek]

mwahahaha :D

[@eeliashar5190]

ONe more question please. when using a filter in a OSC do i aim to increase subs duration, or is it better to increase the number of same duration subs? if i usually take 30 sec shots with my ASI533MC at 100Gain what's my best approach to plan a shot with a NB filter? many thanks

[@mikebennett1301]

Very useful as always. Explains why separating Ha OIII from my one filter does not give as good results as images I see that were taken in mono.

[@CuivTheLazyGeek]

Happy it was useful :)

[@simonhooper2458]

I know that it is generally frowned upon to stack filters. However if you had an IDAS filter for capturing galaxies & then stacked an ir cut filter behind it for half of the session, could this be used to increase the dust lanes?

[@CuivTheLazyGeek]

To be honest I would just replace the IDAS with the UV/IR cut, then you have both a natural color image and the GNB image that you can merge judiciously

[@andrewweller5119]

off to buy an Air Riffle to take out all the local LED street lights

[@CuivTheLazyGeek]

Sounds like a good plan lol

[@JeffSmithbureau13]

So I guess I'm confused about what sort of filters you would recommend for OSC cameras? I've seen fairly positive reviews of tri-band and quad-band filters, but if you don't like them, what is the alternative, especially in a high-light-pollution environment?

[@CuivTheLazyGeek]

Two filters: Ha OIII and SII OIII are my current recommendation (Altair, Askar, and other brands offer those sets)

[@JeffSmithbureau13]

@@CuivTheLazyGeek Ahh, OK. Thanks!

[@Brians_Astro-Adventures]

Thanks again for your video…🔭

[@andynowlen]

This is my favorite kind of video. Now I need to know how to process tri-band quad band data for the best results

[@CuivTheLazyGeek]

I basically treat tri-band or quad-band data as Ha OIII and do a fake SHO palette using Bill Blanshan's narrowband normalization!

[@xaviergonzalez4800]

Can you use the dual narrowband filter on a monochrome camera and separate the 2 bands using a picture of the same image but taken with only an Oiii filter? Like using Photoshop and adding the Oiii with the mode to subtract. Whatever is left would be the band that is not Oiii, right? Or stack the filter with a red filter that should give you only Ha or Sii, but if you use a blue filter, you will get only the Oiii in a monochrome camera. What is your thoughts on that idea?

[@CuivTheLazyGeek]

In theory, yes, that should work - far less than ideal, but it could be fun to try!

[@sarahjanereilly9335]

I have an Antlia dual narrowband (Ha, Oiii) and interested in adding Sii, I know you are not keen on the Antlia Hb/Sii, so how about mixing in another brand with Sii/Oiii - does that work?

[@CuivTheLazyGeek]

That works!

[@sarahjanereilly9335]

@@CuivTheLazyGeek thanks Cuiv - so I am guessing you might recommend the Altair! Hello from the French Alps, BTW. We were promised a clear sky tonight but someone was fibbing - so it’s bon nuit from me!

[@floriantreisch-6832]

Hi, do you have experience with ultra narrowband filters? They have a halfwidth of for example 4nm. Do you see a difference compared to a not so narrow filter because of the optical doppler effect? The expansion speed of M1 is 1500km/s. That makes a blueshift of 3nm. Or am i wrong?... very good video!

[@CuivTheLazyGeek]

Huh, I hadn't thought of that, but you're right there should be a shift of 3.3nm or so! That could be a cool video idea though! Trying to measure the redshift of objects via ultra narrowband vs narrowband filters!

[@fabio9811]

Would it make sense to have an luminance pixel instead of an second green pixel ?

[@CuivTheLazyGeek]

It could - but it would require new debayering algos, etc.

[@stevejones7830]

Is there a point for filters like the optolong l pro if you're in a bortle 4 area with a osc camera with no intention of using multiple filters, conditions have been bad enough that I don't think I've hit 15 hours yet since October, so I've got time for 1 set of exposures per session. Using an FRA400 and a 2600mc pro.

[@CuivTheLazyGeek]

I'm personally not a big fan of filters like the L-Pro - I prefer then to just have a UV/IR cut filter

[@williamdelaire9908]

Pretty much a noob here, I've only taken pictures of the Orion nebula a few times with a Nikon D5000, but are there any DSOs that can't really be seen (or are barely visible) with just a DSLR because of outside factors (like light pollution) where a filter would help isolate the emitted wavelength(s) and make the DSO come through?

[@CuivTheLazyGeek]

You'll need to first look up on modded DSLRs! Sorry this is a broad topic that is difficult to answer in a comment!

[@lee-van-cleef]

I read somewhere that the Bayer matrix actually blocks NIR. Wouldn’t this render filters like the GNB useless for galaxies?

[@CuivTheLazyGeek]

It's the opposite, the Bayer matrix basically becomes half-transparent in NIR!

[@abhijitjuvekar]

I seen Optolong L-Pro filter kind of kills the galaxy details overall... I image using ZWO 1600MMPro and bottle 6-7 sky using GSO 6 inch RC. I also found as you mentioned in last part IR Pass filter like Astronomik ProPlanet allow high contrast and better images of galaxies and also helps in some nebulae.

[@RetiredMillennial]

I noticed you are still don't have any svbony ones there? Is there a reason for that? I bought those but couldn't use them yet so can't really say if they are any good or not even with my limited knowledge of AP.

[@CuivTheLazyGeek]

I simply don't have an SvBony filter :D

[@RetiredMillennial]

oh ok@@CuivTheLazyGeek Btw after I bought Ha OIII and an SII, I realised I also had an OIII standalone. Is thee a way I can use that one or it's just not necessary?

[@pirlouit44]

my filter band of brother

[@TheCosmicGuy0111]

Cool

[@j.s.3407]

Since you have the transmission percentages of RGB bayer filters (as shown in your graph), can't you use some kind of math to recover the "real/true" values OII, SII, and Ha by comparing ratios of the RGB pixel values against the transmission percentages in the camera specification?

[@CuivTheLazyGeek]

You absolutely can! But you probably don't want to because Ha overpowers everything. We intentionally bring the brightness of OIII and SII up to compete with Ha so we can get nice Hubble palette colors for instance :)

[@j.s.3407]

@@CuivTheLazyGeek Checkout what what the Dark Sky Geek has to say about Ha OIII extraction. But as robyx mentions in the PixInsight forum on this topic the Dark Sky Geek forgot to subtract the backgrounds from each channel before performing the linear algebra. Quoting from robyx on PixInsight forum (can't link here because KZbin won't publish this comment if I do): These are my adjustments. Let defines the backgrounds with a _b postfix, like R_b for Red, G_b for Green and B_b for Blue I would use (minute 1:29) R' = R - R_b G' = G - G_b B' = B - B_b O3'(B', R') = (B' - 0.0625*R')/0.498 + O3_b O3'(G', R') = (G' - 0.2*R')/0.914 + O3_b The pedestal term O3_b is needed since in the areas of the sky where there is no significant O3 emission the signal is so low that it can be clipped. Then you may find the proper combination of the two: O3 =k*O3'(B', R') + (1-k)*O3'(G', R') where k is [0,1] is the weight that maximise the SNR(O3 - O3_b). Now that you have O3 you can extract Ha (note that again you need to remove the pedestal in O3 since you want the real O3 signal in the equation): Ha = (R' - 0.03*(O3 - O3_b))/0.8 + Ha_b where Ha_b is a pedestal to avoid clipping since in the areas where there is no Ha the signal may be clipped to zero. I think this is the right way.

[@j.s.3407]

It would be interesting to see if this technique can make your two OIII images look similar. Also, if you make your two master frames available (one for each filter), I could check it out myself.

[@bradtem]

Thanks, but you didn't answer the one question I came for -- comparing the narrower band (4nm) dual-band set you hold up (ie. Altair) with the wider one like the C1/C2. Clearly the wider one is going to capture more light pollution and skyglow, but what happens in practice? How much worse is it, to justify the cost of the Altair, or Askar's $440 6nm version of the C1/C2?

[@CuivTheLazyGeek]

You can see a comparison between 7nm and 5nm here: kzbin.info/www/bejne/on7XZ2aFlryZjrMsi=a2LZehSA80eM_AXx Obviously, C1 and C2 vs Altair would be a far larger difference (assuming use at F4-F5)

[@bradtem]

@@CuivTheLazyGeek Thanks. I think many people will be debating the question of mono camera + HSORGB filter set + 8-wheel and OSC + pair of dualband + 5-wheel or just drawer. The latter is going to be a lot cheaper --and possibly easier, and I know you have moved this way while I am still shooting mono+narrowbands but with an old camera and considering the switch. So what people want to know is just how good it can get, and what you get for your money with different dualband sets, ranging from the Askar C1/C2, the Askar Super D, the L-Extreme and the pricey Antila. Even the high end is cheaper than Mono+HSORGB because of the "mono tax" it seems.

[@RedmanObservatory]

🖖This is great TV

[@thebst6408]

like 797 ❤

[@alpsalish]

That thumbnail is terrifying. Otherwise, great content.

[@CuivTheLazyGeek]

Thank you? Is the thumbnail that terrifying??

[@alpsalish]

Has some Golem energy to it. I look at the photo and see you saying, "These are my precious!" With your arm wrapping up the astro filters and the smirk on your face I can tell you're sharing your knowledge, not your filters! It's probably mostly imagination 😅 and as I was saying, great video!

[@photonqopt]

Minor nit: emission line is broadened for various reasons although for the sake of the topic at hand, it doesn't matter. See en.m.wikipedia.org/wiki/Spectral_line#Natural_broadening

[@CuivTheLazyGeek]

Actually there's a more valid nitpick in the same category: redshift! Something like M1 has a redshift of around 3.3nm as far as I can tell! I need to test that stuff out :)