Відео

First don't over expose, then it is just saturation or vibrance

this follow on video may answer your question ua-cam.com/video/IudhLAjqD8E/v-deo.html the short version is the more narrow the bandwidth the more signal loss you will have at lower f/. If the bandwidth of your filter is large ( maybe greater than 6 nm) then no problem, if the bandwidth is smaller, then you are throwing away (filtering) the signal you want.

thanks very much Brent.@@BrentMantooth

I don't know all the differences, but would bet it is pretty similar. There may be a few different bolts, but it has to be assembled somehow - and I would think they make it serviceable if someone ships it back.

if you lay it down like I did in the video it can be done, it just takes a bit of work. good luck.

I used a ball end hex for everything. It has been a while, but I think they were all metric, maybe?

I mount my control computer on top, and if using a hyperstar I also have a guide scope on top of the OTA. I also have a dove tail handle that I attach on top when lifting or moving to OTA.

Hi I have Celestron CPC 9.25 StarBright XLT Are you saying is no way I can de fork mine when you say is permanent attached? Now you scared me .

There were a few snug connections to get loose and it did take some leverage to get the side clamps to disengage. I found the trick of laying it out like I did in the video let me use a lot more force without worrying about dropping the scope.

The bandwidth and what makes MaxFR special are two different things. Bandwidth is the characteristic of what wavelengths will be transmitted. 12 nm is 12 nm, and they will follow the same transmission trends based on f/ that I presented. MaxFR is about the manufacturing process that Astronomik uses to produce the filter. I would assume it to be the specific materials, thicknesses, layering, and coatings applied to the filter to reduce glare, reflections, and protect the coating.

Thanks. I think the NBZ design is a little different since it’s a flat top transmission so it can reach out the maximum value at different f-ratios. Astronomik seems to have a different approach. In the end, no matter the design, what is important is the performance and these Astronomik seem to be quite good

no problem. I had a hard time finding some of the details so figured it may help others too.

I don't have evidence of this, but I think part of the premium price of maxfr filters is the quality control astronomiks provides. Also, the qc matters way more for ultra narrowband where very slight error is catastrophic. At 12 nm bandwidth, the qc doesn't have to be as stringent to still work great.

If you don't have halos or issues, I don't think upgrading to maxfr will do anything for you.

Thanks very much for both replies, I really appreciate it. 👍

if budget is no object - go 6 nm. if you want all the signal you can get, go 12 nm. at f3.45 incident angle is ~8.2 degrees - so look at the chart at a time stamp of 35:00 and compare transmittance at ~8 degrees. The 6 nm will have a little attenuation at the higher angles (down to ~80% transmittance). without doing the simulation... the 6 nm filter on your Quattro will probably make its light collection closer to f/4 ish. on my hyper star the 6 nm filter was giving a response closer to f/2.5 so maybe it won't be so bad for you? the 12 nm filter would give you your full f/3.45 signal. My testing was in a bortle 5/6 zone, and some of the comments indicate the benefit of the narrower filter may be more significant in higher light pollution conditions. some drawbacks on the 6 nm are that you may need longer exposures for you AF runs (I was doing ~8 second exposures to get confident and reproducible focus runs) the 6 nm filter will not give you better resolution... it will provide better signal to noise at f/5, and somewhat better signal to noise at f/3.45 compared to the 12 nm filter. Do these differences justify the difference in cost for you? that is up to you. depending on the currency conversion rates it can be cheaper to buy directly from astronomiks in Germany than to buy elsewhere. you may find my updated video of a little more help: ua-cam.com/video/IudhLAjqD8E/v-deo.html

and remember for the chart at 35:00, it is the area under the transmittance curve from where the photons are coming from on your scope - not just the transmittance at the highest angle - your quattro will be somewhat like my hyperstar. if you really want to know, download the python code and put in your scope parameters. my other video gets into this in more detail.

@@BrentMantooth I also have a similar backyard sky of about Bortle 5/6.

@@astrocrypto8438 after all of my filter adventures, I came to appreciate the importance of parfocal filters. on fast systems backfocus is critical, and if your filters are not parfocal, you may need different spacers for each filter. I now use only Astronomic filters for everything. this is also very important if you do OAG. for your Bortle zone... and scopes... I would say go for the 12 nm and spend the cost difference on other things.

The down sides to narrower band are cost and you may need longer exposures for auto focus runs. Otherwise it seems like 3 nm would be awesome for those focal ratios. Keep an eye out for reviews on halos

Good threads on cloudy nights about all the filters

That’s something to keep in mind. I’ve seen some threads in CN about halos with even the most premium brands. And definitely those can come from a lot of sources as you have shown. I’ll have to inspect some of my images to check where those halos were produced

Look for another video on my channel called "Bandwidth choices for narrowband imaging with fast optics" at the 6:53 marker I talk a lot more about how to figure out where the halo is originating from. The size of the halo tells you this distance from the sensor that is generating your reflection. In my case it was optics in the camera, not the filters. And the strength of some reflections may be very wavelength dependent.

youtube tends to filter out links, see if this works ua-cam.com/video/rtFX92dZE_w/v-deo.html

Post your results, love to see what you did!

Thanks. I have thought a bit since I posted this. 1. I am in Bortle ~5.3 (according to some app), after talking with a few other people, the differences would be much more apparent if there was more light pollution. 2. The real definition of contrast does not use the background subtraction that I used, so yes, there is probably some benefit to using the 6 nm, especially if there is more light pollution. However, if you are using fast optics (< f/2.5) you may be losing more signal than just reducing background. To go to 3 nm filter, you probably need to be > f/4 ish? to not have so much band shift that you are cutting a lot of signal (guessing, not running a calculation) I did a few other videos with some corrections to this video.

I am not sure what you mean. if you are using the 6 nm filter, you could set the lens to f/2.6 as that is about what the filter will pass, and maybe it will give you a little extra depth of field for good focus? if you are using the 12 nm filter, you can set the lens to f/2 and get most of the light through the filter.

That is a great question. I think it comes back to the statistics of signal of interest and sky glow, and that you just need 'more data' (more subs) to help remove the sky glow. I don't have a quantitative answer right now, but I think stopping down the scope does more damage to the signal than the narrower filter benefits the signal. The rate of real signal accumulation is the most important (so 12 nm) seems to be the key factor, and being above the read and shot noise of your detector. I provided links in the description for a paper from Abby Road Observatory (see the link for karmalimbo) Some of Jim's other papers on that that server get into simulating sky glow, but not in the context of exactly this question. Look up a video with the title "Deep Sky Astrophotography With CMOS Cameras by Dr Robin Glover" around the 50 min mark is a table based on f/ and bortle that gets at these concepts. I will think on it and see if I can do another video on these topics. I think Cuiv the lazy geek channel has a video about light pollution in Tokyo and signal as well.

hm, I bet you are stopping down your lens to f/2.5 with the 6 nm, and even more with the 4 nm, probably down to f/2.8. I may do a follow up looking at smaller bandwidth filters and for lenses. I think I also want to refine my index of refraction estimate, I thought of a way to get that a bit more accurate. What I learned was that the narrower filter was rejecting more real signal, than it was rejecting background for a net loss in quality.

I will see if I can setup and run the simulations to see what that would look like, hope to post it soon.

First pass is that the 6 nm will work fine on most 2.8 lenses up to full frame sensors

I will see if I can setup and run the simulations to see what that would look like, hope to post it soon.

@@BrentMantooth Awesome!! Thank you!

Have you run the simulation? I am very interested to know!!

@@tempusfugit6820 Just posted the Samyang calculations on my channel

Glad it was helpful!

these testing nights are educational. I may do some more comparisons but it is twice the work... and not as ideal for image workup. for your current filters - you have them and they actually get f3 that isn't bad, and it is a big investment in more filters for what is less than a full stop difference. Are the antlia filters blue shifted for fast optics? It would seem they would need a specific shift for that narrow of a bandwidth and a particular f stop.

@@BrentMantooth The Antlia website says? "Blue-shift data show that Antlia 3nm Pro filters can be used with nearly all systems as fast as f/3 with minimal loss in emission signal and meets the requirements of fast optics like Hyperstar and RASA.". I have the filters for normal imaging F5.6 on my refractor. I haven't used them on the SCT yet as I am waiting for my Celestron OAG to arrive (tomorrow) and then I will see what they look like at F7. There is a significant difference between the Antlia Ha 3 nm and the Optolong Ha 7 nm filter. I really want to try my Antlia 3 nm on Alnitak but the weather has been against me for months. I am mulling over getting the Hyperstar, but as it is 90 mm in diameter, I am a bit concerned that it will impact the amount of data going into it. So much to consider with AP!!

@@stephen2615 haven't analyzed signal yet, but reflections are very different from f/7 to f/2. I mean there is one less mirror in f/2, and we are talking about reflections...

I am in the process of analyzing the HyperStar data. Like you suggest, I think I am going to need that 15 sub data to make sense of what I am currently seeing. I was hoping to wrap up an analysis, but, like many science projects, I keep finding more questions. I will post part 2 soon.

Great question, I have a few other images from a different target, will take a look.

@@BrentMantooth Did a test on 12nm 1X300” and Ha and Sii showed halos on them imaging Alnitak Star at f1.9

soon, switching the scope over to hyperstar tonight so I can image tomorrow. [spoiler alert] At least at f/7 the OIII MaxFR was showing halos for both 6 and 12 nm. Talked with @deepspacedad and he didn't see reflections, at least with HyperStar.

@@BrentMantooth I have a QHY 268M (and other cameras, way too many cameras) and I am interested in a Hyperstar for my EdgeHD 9.25. Unfortunately, Starizona hasn't responded to my emails about whether I can use it with the Hyperstar. None of the QHY cameras on the website list the 268M or the 600M but they list the ZWO 6200.

I know they can support full frame 35 mm sensors (probably with vignetting) - I have the adapters for my Canon R5 but haven't tried that yet. You should just need the right back spacing.

Thank you! Cheers!

You noticed that? I didn't quite get the three fold symmetry.