Do Astrophoto Filter manufacturers LIE TO YOU? You CAN find out!

[@TheNarrowbandChannel]

Happy to see you back! Your info is always valuable to use and you cover things no other channel does.

[@operatingprincipals9606]

Cuiv’s content probably has the most lasting value. Some of the other channels are interesting at first, stirring interest, but offer little and are not worth continued viewing.

[@ApoorvaIyer]

Cuiv has uploaded a new video. Birds are singing again, the flowers are in bloom, the sound of happy children fills the earth. Everything is right again! Welcome back!

[@CuivTheLazyGeek]

Don't make me laugh out loud like that!

[@threethirdsnerd6118]

I’m so happy to see you back, Cuiv! There’s no one like you nor any one that teaches this complex material as clearly as you do.

[@thomasbrooks644]

Welcome back !!

[@im1bigfish]

Welcome back Cuiv! I was pretty worried about you, but glad to see you're back making amazing videos for our small community. Keep up the great work and please know there are a ton of people that support what you do.

[@alangoldberg5577]

I’m just catching up with your channel, and think it’s great to see such rigor and fun. As a sensor system specifier in my day job, I was curious about the asymmetric response you mention at about 50:40 - the tail toward the blue. I followed up with some questions to Goyalab. They confirmed my suspicion: the angular acceptance of the spectrometer internal collimator is wide at f/1.8. The illuminator is wide and diffuse (not collimated), which means that oblique light in a cone corresponding to f/1.8 is getting into the spectrometer through the filter under test. That oblique light is shorter wavelength (bluer) than the design bandpass of the filter. This is not a defect in the spectrometer or the filter, just the way they work. The maximum theoretical spectral shift of a filter at f/1.8 is ~1.6% of normal wavelength. That is how far light can be “leaked” into the apparent blue tail. The blue shift goes a little slower than cosine of the maximum oblique accepted illuminated angle. At hydrogen alpha (656.28 nm) that amounts to about 10.5 nm. See the very good but technical recent white paper by Baader Planetarium on the topic of transmission shift through interference filters It isn’t possible to calculate the amplitude of this measurement “leak” precisely without knowing a bunch of stuff about the angular spread of the illuminator, the angular response of the spectrometer, the manner in which the slit is integrated across the detector chip, etc. Also probably not worth the effort. There are ways it can be calibrated and removed by calculation from the raw spectral transmission curve. The phenomenon could be reduced simply by using a mask on the illuminator that reduces its diameter. A condenser lens between the filter and slit would theoretically help a lot, but would introduce other complications. I expect that the same phenomenon is shifting the apparent transmission peak a bit toward the blue. This is something that should be calibrated and bounded. Given the relatively small size of the obvious shape asymmetry, this effect should also be small, but it needs to be considered when using this type spectrometer with interference filters, and pushing the device to its limits. The watchword is: It is easy to make mistakes in spectroscopy. Probably easiest to just understand that the blue tail is a measurement artifact and not something to worry about. I love the idea of this easy and relatively cheap spectrometer, and appreciate Cuiv bringing it to our attention. I’m recommending it for my home astronomy club, NOVAC, as a test resource for our many narrow-band astrophotographers. Now, what about connecting it to the telescope? Thanks, Cuiv.

[@salomon1639]

Welcome back. As you can see a lot of people missed you. As I said before, this is the best astro channel. Take it easy as we want to see you but also don't want you to burn yourself out. You look great and well rested and excited that you are back.

[@therealremo]

Welcome back! Thank you for returning to helping me (and others) understand these 'things'!

[@msimmonsmcse]

THIS MADE MY WEEK! - Not just the content, but to see CUIV IS BACK!

[@williamhouse5081]

It's sad that we are literally playing the lotto when it comes to filters that are extremely expensive, I've been lucky with mine, I think. Thank you for spending your own money and time to test these filters and share the results, it may just push the manufactures to do better. Now don't burn yourself out, we don't need a video every week. Welcome back!

[@jiffijoff9780]

Well said - all aspects 👍

[@flexable9256]

Unfortunately, it's likely the same for everything. On my Camera (Nikon Z6), I have a 20mm f/1.8 S lens, and a 35mm f/1.8 S also. I can tell you the 35mm is phenomenal, and trasmits significantly more light than the 20mm, despite being both new, from the same manufacturer with the same specs (ok, f number, not T, but they are from the same line).

[@prnzssLuna]

You're back!! And your first blessing is a >50 minute long video too? Good to see you back!

[@nxu5107]

Hi Cuiv, good to have you back!!!!!!!!! . Hope you are well and hope to see you more here again. Thanks as ever.

[@TubenStefan]

Danke!

[@frigateaviation5047]

Great to have you back Cuiv, and enjoying what you do, as much as we enjoy what you share with us.

[@davidmcneel1987]

Cuiv! Welcome back! Hope you are doing well.... glad to see you back!

[@asht.9857]

Happy to see you back my friend. Your videos are much needed in this hobby.

[@paulmcgougan]

So excited to see you back! Hope you’re feeling better.

[@monsyschuller3561]

So happy you re back! Missed your videos, always a great inspiration for me! Hope you are doing well! Best regards from Germany!

[@tjeyko40]

So glad to see you are back! Thanks for putting this together!

[@timmc83]

Welcome back!! Have been waiting for your return!

[@derekderek2570]

Welcome back to us? Welcome back to you!!! Missed your content and happy you're healthy and looking good!

[@PatriotAstro]

Welcome Back Cuiv!!! I see 53 minute video and immediately start thinking of all the video editing time you put into this! Great video and thanks for all of the hard work!

[@CuivTheLazyGeek]

Hahaha, you would know! :-)

[@AnakChan]

Welcome back :D! So glad to see you again!!

[@philipgelsheimer5705]

Great to see you back Cuiv! Over the years you have been instrumental in enhancing my addiction to astrophotography!

[@inferno760]

Welcome back! We’ve missed your videos. Hope you’re well!

[@lwizzit]

You’re attention to detail is mind bending. How did you even know that the kettle has a neon lamp as opposed to a LED as one would expect?

[@stevekuzmic3911]

Cuiv . Made my day glad to see you back hope all is good

[@JoesAstrophoto]

Nice to see you creating content again! Very interesting and informative video man, hope all is well with you.

[@lukomatico]

Hey Cuiv! - It's awesome to see you back my friend, I hope you have been keeping well 🙂Superb, in-depth analysis here - just what the astronomy world needs! that spectrometer looks like an incredible tool, even with the small drawbacks you mention. Great work, as always man!

[@CuivTheLazyGeek]

Thanks!! I'm really happy having that spectrometer for sure!

[@OtziVideo]

Welcome BACK Cuiv! ... VERRY NICE to see You !!! I am HAPPYYYYY !!!!

[@juergenehnes8152]

Welcome back Cuiv, nice to see you again. Missed your videos.

[@jim3029]

Great to see you back and what a great return video!

[@TheFranqd]

Welcome back !!! It's nice to see you again !!!

[@rbrbrts]

I'm in awe of you taking the time to do such a thorough analysis. Thank you so much for this. I'm so tempted to set up to do this, but I'm not sure I have the patience.

[@DB2023Space]

He's baaaack 👏Cuiv, glad to see you here buddy and hope you're doing well!

[@AKohler_Photo]

So glad to saw a video of Cuiv, The Lazy Geek when I clicked on my notifications 😀 Great to see you back! And thanks for the interesting video!

[@Neilus001]

Yes!! Welcome back!! So good to see you again.

[@RazorChrist]

Welcome back, Cuiv! We definitely missed you!

[@thomasbrooks644]

Welcome back, perfect timing with my moving from one shot color to mono !

[@tmrdarkstar85]

Welcome Back Cuiv, I have been waiting for this video

[@Deep_Astro]

Welcome back Cuiv ! Happy to learn again from you !

[@vinoner1]

The Cuiv is BACK!!! Good to see you again.

[@deep_space_dave]

Cuiv welcome back, we missed you. :-) Happy you are making videos again as you have been a great inspiration. I now have my baby RASA (C6 with Hyperstar) and now can autofocus. Plate solving with Hyperstar is amazing, especially being near Chicago (Bortle 9+++). I had no idea there were so many stars that could be seen from here! I am also now a big user of NINA. Being a Linux geek / admin , I love opensource! I really appreciate you testing these filters as now that my kit is mostly complete, buying filters is all that is left and they could double my costs easily. Thank you for the video!

[@WindyCityAstrophotography]

Cuiv! Welcome back! Wow, excellent work on this one!

[@ldipenti]

Great to see you back, Cuiv! Thanks for this detailed video.

[@PagyBio]

So glad to see you back here, Cuiv! Nice!

[@richardkelsch3840]

What a great way to come back! A very rigorous scientific look at the various filters. I am pleased that your assessment of the NBZ filter matches the results that I have been getting with it in images taken with my RASA 8 under Bortle 5 skies in Arizona. I have yet to try it with my C-14 Hyperstar in Ontario, also under Bortle 5 skies, due to weather considerations. Hopefully it will do just as well. Also, glad that you will be one of the judges in our Starfest Imaging Contest in August. Hope all is well with you and yours. I look forward to your next video, whenever it may be. Rick Kelsch

[@benc7102]

G’day & Welcome back Cuiv Great to see you back Been watching all your videos on repeat for awhile Cheers mate

[@astrocampernsw]

Great to see you back Cuiv, hope all's well. Thanks for your efforts.

[@josephluciani5531]

So glad you’re back. When you announced that you were taking a break, I found it a bit disturbing that you (your videos) were not going to be part of my morning coffee. As always, I want to thank you for your energy and enthusiasm. You bring a lot to this hobby and hopefully you’ll find a way to continue to produce your wonderful videos.

[@Apagadorable]

Absolutely fantastic to have you back! ❤️

[@Matty7272]

Awesome vid Cuiv and glad to have you back! Always enjoy your videos

[@gazer63]

Welcome back! You were missed. Wonderful video. Thanks for spending the time and money on doing this analysis. It was very informative. 👍🏻👍🏻👍🏻

[@celestromel]

Hi Cuiv, welcome back! You really have been missed! Particularly from Sydney 😁

[@philleng480]

Yay, good to see you back Cuiv. Missed your informative, technical, challenging, and entertaining videos. Cheers!

[@elmikol2443]

Welcome back! Thanks for sharing this buddy!

[@perrydouglas7944]

Welcome back Cuiv. Good to see your latest posting and hope all is good with you.

[@DeanLouviere]

Yay!! Your back!!! I have been waiting for a video in months!!!

[@johndoedro]

Wow! Happy to have you share some Astro information to us again! Welcome back, cuiv!!!

[@jean-clauderoussil6830]

Is a real pleasure to see you back lazy geek, merci de ta presence dans ce champ de specifiter de l'astrophotographie, you make the difference!!!

[@PopeAstro]

Welcome back.. nice to see you alive and well!!!!

[@AstroOnBudget]

Welcome back indeed! We missed you

[@chrisjames5223]

wow. This is above and beyond. Very well done. I would love to see a larger sample size on the most popular ones like the L-extreme. thank you for doing this

[@CuivTheLazyGeek]

I'd love to have a larger sample as well, but I'm limited by what I have on hand... A dealer would have access to that kind of sample size...

[@youky6383]

@@CuivTheLazyGeek Maybe some people here could send you there filter. I am sure many people would be happy to know that their filter works as desired, and that would provide you a wider range of filters, from different batches.

[@captgbakos1291]

As a member of the Order of the Lazy Geeks I'm so happy to welcome you back. And what a way to come back!! Who else would put themselves through this level of effort to keep the filter manufacturers honest?!! Thinking of The Emperor has no Clothes... well done.

[@marklewis9265]

you're back! mate i drank many beers in your absence, took astrophotos, froze my butt off (cause it's winter here in australia) and well you know, watched every other youtube astrochannel i could. cheers and beers!

[@CuivTheLazyGeek]

Beers!

[@syberand]

Good to have you back! Great and informative video as always.

[@Sanctimonial]

So glad to see you’re back now 😊 is it possible for you to test the antlia 3nm and 4.5nm filters?

[@CuivTheLazyGeek]

Only if someone sends me a sample :)

[@Sanctimonial]

@@CuivTheLazyGeek I maybe willing to lend you my 4.5nm ones when I buy them

[@bmur56]

My favourite geek is back ! I'm nowhere near advanced enough to be using most of the filters you mention but I still found the presentation super interesting. Whenever you are ready for another video, I'll be happy to view it. Take care.

[@WRX2001]

Welcome back , I finally got all my equipment due to covid and shipping problems . I will soon be attempting to build an automated telescope using your instructions.

[@balacv02]

Cuiv, that was an excellent video. Lot of efforts on your side, both in terms of money and time. I have this one question though. Have you quantitavely compared the Goya lab, spectrometer with one of those expensive ones used in labs, just to get an idea, how close or far away the results are?

[@CuivTheLazyGeek]

Yes I have, as mentioned at some point in the video :-)

[@stevenickolls8016]

Oh, welcome back home Cuiv we have all missed you.

[@BarryWilliams0]

So great to have you back. There's been a Cuiv-shaped hole in KZbin for too long! 😊

[@jonathanr2830]

Awesome video! Awesome hoodie! Great to see you, again, sir!

[@PetterAstrom]

Welcome back! I’ve been waiting for this moment!

[@martinsastrophotography]

Hi Cuiv. So great to see you back! Respect for taking time out when you needed it. I’m the guy that had just bought the f/1.8 Baader Ultra high speed narrowband filter set when you published the video reporting that they were no good! You have gone to great lengths to do this…respect for that too. I have two questions I would really appreciate you answering…. 1) How do you know what the mean incident angle at the filter is in your setup? For example, I use a C11 EdgeHD with Hyperstar v4. 2) How do you convert that angle to a shift in nanometres? Is there an equation you can share? Thanks again and I look forward to seeing more videos from you as and when you want to make them.

[@ScrapYardDog64]

Glad to see you back, I missed your posts, excellent research on the filters.

[@GallusInsuber]

Hi Cuiv, so glad to see you back with your great smile!!!

[@jinx0192]

Thank you for yet another great video Cuiv! You were missed greatly!

[@kkename737]

Well come back and it's great to see you

[@georgalbrecht8029]

Nice seeing you back and interesting information 👍

[@massimo541]

Welcome back! Fantastic review 👏👏👏

[@thelovin71]

Great to have you back Cuiv!

[@BryonStice]

So happy to see you back! I've been loving my hyperstar c6! Any plans to review the new 533 mono cams?

[@hbmike47]

Wonderful video. Keep getting technical. I find your explanations really helpful. One thought was to rig up a tilt adjuster and actually measure the shift of these filters. That's the missing piece in connecting your spectrometer results to performance. Very good point about fast scopes with central obstruction and those without. Perhaps with a fast refractor is better to have a slightly broader band where with a Hyperstar or RASA it's better to have a correctly shifted but still narrow band. 8

[@olly7248]

Welcome Back Cuiv… we missed you 😀

[@nn1982in]

Welcome back! Good to see you.

[@beatsntoons]

welcome back, Cuiv, we've missed you!

[@gazza9839]

Welcome back Cuiv, good to see you're ok. Fantastic content 👍🏻

[@astrofromhome]

Great to see you back Cuiv! Just got into this amazing hobby recently and I have been afraid that one of the best astro photography channels would never come back. Your videos are so amazing! I have learned so much from your channel already. Thanks for all efforts that yo have put into you videos! 🙏🙏🙏

[@ricklaird2218]

Great information. So welcome to hear your voice again. You mentioned you have simplified your setup to only use an OSC. Is that the 533MC? Are you using the Optolong L-extreme? , What are you thoughts on using an Sii filter in conjunction with the Extreme To get all of SHO. The dual band handles the Ha and Oiii and move to a Sii filter the Sulphur II. This would allow a true SHO image. Thanks so much for all your help.

[@psuaero100]

First, glad to see your back! I definitely missed your videos the last few months. Second, excellent video. I'm an engineer and love this type of analysis. Unfortunately, $2k is a little out of my league to scratch that itch. Third, now that you've got the equipment and taken the care to calibrate it. Would you consider measuring other filters and posting results on a web page or providing them to others so we can see how other filters compare and also how multiple copies of the same filter compare? If you're interested, PM me and we can discuss details like shipping, turn around time, compensation (for you), etc. Unless I'm mistaken, the gathering of the data for each filter doesn't look like a particularly labor intensive process for you. Some, like me, might even find this sort of analysis therapeutic. LOL.

[@psuaero100]

PS: What software are you using to display the bandpass data? I really like how quickly you can add/subtract the filters as well as see the cursor data points. Very smooth!

[@jackelrdhdhd4534]

GLAD YOU'RE BACK !!

[@johnday2676]

Welcome back, this is data I would have never investigated unless for you. Thank you very much!

[@Oamaruastro]

So happy to have you back!

[@danboulton2128]

Welcome back Cuiv. Its great to see you back.

[@JavierLopez-zj9yc]

Great to see you again. Welcome back and greetings from Spain!

[@joell8433]

salut Cuiv, content de te voir de retour. Comme d"hab toujours top tes vidéos.

[@squirrelsrus1]

Glad to see you back and thanks for putting in all of the work to do this analysis.

[@derekregan6926]

A fantastic video for us viewers to watch, there's always been that stigma around the baader, especially the O111 filters, that pretty much confirms the doubts Great to have you back Cuiv, hope there's more to come

[@phmasampaio]

Welcome back Cuiv! Always good to see your videos again!!

[@BTurner.]

Welcome back, I’ve missed you! 😊