Astrophotography: OSC vs Mono!!!
ฝัง
- เผยแพร่เมื่อ 13 ก.ค. 2024
- In this video I will discuss the pro's and con's of each camera.. plus dispel a persistent myth about astrophotography with a mono camera.
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#astrophotography
#monochrome
#astronomy
#narrowband
#oneshotcolor - วิทยาศาสตร์และเทคโนโลยี
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Excellent presentation by someone who sounds like a real instructor, not some fumbling, bumbling time-wasting "influencer" who is sharing their inexperience with us.
I shoot with OSC not because the camera is less expensive, nor because I am not seeking the highest quality I can, but because when I've looked at the very best mono images and the very best OSC images, I don't see a lot of difference. Quality of optics, focusing, tracking and guiding and sky conditions contribute greatly to the quality of the data, mono or OSC. And much of what makes an image "pop" with color, detail and sharpness has to do with total integration time and processing and post-processing as much as data acquisition. With our current evolution of software, there is so much we can do to control the balance, hue, contrast, saturation and brightness of individual colors. Though it makes sense that shooting in mono may not take much more time that shooting OSC, with processing that's not true. It requires more flats, more integration time and more processing time. It's also possible that OSC cameras will continue to get better and close the gap even more between OSC and mono. People are getting great images with both OSC and mono, and there are poor images being created with both types of cameras as well. www.youtube.com/@astromusicvideo
Thanks Jerry! Wonderful shots and music on your channel. CS!
Hi! I am just starting out with this hobby and got a rig together around March 2024. I was able to get a nice small refractor, guide scope, strain wave mount, Windows mini computer to run N.I.N.A., EAF, and I had two small uncooled cameras to start off with. I live outside of Toronto and wasn’t expecting much in the beginning. I was going to try OSC on broadband galaxies and try Ha on the mono camera. I expected very little in Bortle 8/9 skies. I was blown away by being able to image some nice galaxies and it completely changed my expectations. I decided to continue with OSC and bought a nice 533 cooled color camera. I just have to learn how to properly process the images but it is all seemingly coming together. Never thought I’d be able get a rig working overnight from my backyard and allowing me to sleep while the rig is working hard all night so quickly. Many thanks to all the great resources on TH-cam. Thank you for your insight on OSC vs mono it now makes more sense as I discover what is possible.
You're welcome. This is an amazing hobby. Good to hear of your progress. :)
The cost of the scope could also be a consideration. For OSC you need a good quality APO to get all colors in focus at the same time and to not suffer from chromatic abberation. With mono you can focus closer to the wavelengths of your filter.
Another point: luminance vs. color. If you have a good luminance grey image you can colorize it with much lower resolution color data and still get stunning results. I like to shoot luminance mosaics and then use a shorter focal length scope that fits the whole mosaic in a single frame and get the color data for the project insanely fast. At the end i have an incredible high resolution image with great colors.
While watching your video there came an idea to my mind. I like to use the HA-filter as a luminance filter because it contains the most information of emission nebulae and blocks so much light pollution and i get great SNR with it. But what if i would use something like an Optolong L-Ultimate on a mono. It still blocks the light pollution but lets through more signal from space so the SNR would be even better? (O3 & HA wouldn´t be separated as a downside)
Good points!
Yes, you can get away with a lesser scope and mono. Great tip on Mosaics! I have found LRGB mosiacs to be a pain.. but using a wider fov for the color data is a good idea.
I think maybe using a dual band filter on a mono as a lum channel for broadband data sounds intriguing. For NB images.. I don't think anything would be gained. Thanks for your comments. CS!
Nicely Explained James and having moved to mono not that long ago I would say you nailed the points, the main one being people confuse thinking you need MORE data with mono just being more work. Like you I still find it refreshing now and again to use my OSC, it's like what ! No filters, flats ....
Thanks Ollie! If you ever have a bad run with your mono rig.. pull out that OSC out and point it at a bright target for an easy win. HHmm.. might make a good topic for another song :)
Very nice presentation. Watched half of it this morning and finished it now. Living in a Bortle 8/9 location, OSC was my first choice, given that I was a newbie and the so-called misconception about time taken to finish the images. Now I think I did not make any mistake by buying ASI533MC Pro with L-Pro as well as L-eXtreme filters. I have extensively used my ASI533MC Pro for more than a dozen narrowband targets in the past 6 months. But even after gathering 0ver 10 hours of data, the image quality is not up to the mark.
After watching all your processing videos and finally this one, I think mono is the way to go and should be my next step. The only consideration is the cost factor, which makes me wait at least six months before spending any dollars on astro equipment & accessories like, filters and filter wheel, etc.
Thank you very much for sharing your knowledge. I hope we will keep learning from you for a long time. God bless you!!!
Thank you so much. I'm really glad you've taken the time to watch my videos. Your videos are very good too, I enjoy watching each of them and seeing your progress. :)
This is a great video James. Very well explained. I couldn't agree with you more about the "fear " going into mono. Once i found out that there was a program where I could program my night, that was the best thing for me. Once I found and saw how mono data compared to color, I just never want to go back lol clear skies
Thanks Isaac! Automation does take a lot of the anxiety out of it :) CS!
Nice explanation, thank you for the video. When I finally got my RASA 8, I decided to only go with OSC over mono, the main reason being that I cannot use a filter wheel. Second reason, I live near Chicago and the weather is very unpredictable. I do have a filter drawer so I will shoot broadband then "season" my images with Ha, Sii, and Oiii as weather permits. Yes I can only capture 1/4th the signal using narrow band with a OSC but this is the RASA we are talking about here so what I loose in data I make up for in speed so I just expose longer. Heck I tried imaging Orion and with the RASA it was like imaging the sun LOL. But yes if I have a scope where the camera is mounted on the back, I would definitely say mono with filter wheel is the best way to go as with the automation we have now makes that setup a lot easier. CS!
Thanks Dave! That F2 speed does help a lot. OSC with RASA sounds like it would be a awesome setup for broadband mosaics :)
When you address the "misconception" at the beginning, you don't take into account the fact that it (mostly; I'll return to this) doesn't matter to SNR if you have a Bayer matrix. The interpolation that takes place during demosaicing retains the SNR of the set of pixels that do receive light in each channel. So it is the case that the parallelism you get from OSC is faster than the serial capture required of mono for a given SNR. What makes mono better than demosaic OSC data is that interpolation (or really the fact of the matrix itself) loses high-frequency detail, not SNR. The visual difference gets interpreted as "lower SNR" but it's really just not as sharp. There is a slight edge to SNR that does comes from a degree of efficiency loss due to the physical interference of the matrix on the sensor (as you mentioned), not from the fact that it's "25% red" etc. On the other hand, even that is counterbalanced with the fact that the transmissions overlap a lot more than most mono RGB filter sets. All that said, one should never be using interpolated demosic algorithms on OSC data. You should *always* use CFA Drizzle 1x. This will maintain the high-frequency detail and produce a result that rivals mono RGB. However, you also lose the speed from the parallelism and the excuse about time. There's also the advantage mono has for narrowband (where it clearly is more efficient since you aren't starting with any parallelism advantage) and using LRGB techniques.
Thank you for the detailed explanation. Good information here.
In the end is it still pretty much a wash between the two in broadband in regards to total integration time.
But you could run the similar algorithm (or bin 2x) on mono data which increase the SNR with a loss of resolution , so your argument doesn’t make sense to me , isn’t SNR about how much Signal data get detected at the sensor , OSC losses photons at the sensor due to the Bayer matrix so therefore I think there is a loss of SNR for OSC.
man I am definitely in a predicament I currently own a OSC camera but I am a fan of more processing work not necessarily the flat frames I have to carry my Skywatcher EQM 35 with an 8 inch reflector up and down 3 flights of stairs so lighter weight is a necessity lol. I absolutely love the mono data Ive been seeing but I'll have to stick with OSC for a while especially with time is not really on my side. Great video and comparison between the two!
Thanks!
Taking your rig out, up and down stairs each time takes some dedication. I salute you :)
If you'd like to try your hand at some mono I date, I have a couple of sets out there. Look for my video titled "Channel Update". In the description is a google drive link to SHO data for the pacman nebula. Also, if you check out my community tab, the last update I put in there includes a google drive link to SHO data for the Eagle nebula.
great discussion James!! should help a lot of people. I'm OSC maybe until spring..little too cold to mess about now. the redact is perched and ready!!
Thanks Chad! Hope it doesn't get too cold. CS!
One more thing to mention is that you will usually get the next step OSC Cam for the same price as the lower monochrome Version plus all the additional stuff. Example: QHY533 with filterweel bundle is about 1500€ (here). Good Filterset (L-RGB) is roughly 300-500, NB-Filters of quality are easily another 500 ore much more if you like. Plus all the threading, adapting, cabeling. In summary you reach 2500€ for 11Mpix with no effort. But what do you get for this money in the OSC Range? Right, an 268C. And that are more than twice the pixels of the 533. So the Ha-gap is shrinked to 30% if you like or by doing some non academic math you can claim to gather more than twice the light for the same money.
Of course this do not take focal length and FOW aspects into account but its a point to think about probably.
And by the way: I am going heavy with the idea of having both running in parallel for HaRGB a while ;-) Price should be still the same or below the full mono kit.
Good points. HaRGB produces some awesome images :)
Very interesting James for me it's all down to cost most of my kit is second hand & some stuff I bought really cheap to, maybe I'll dip my toes into mono one day but I'm pretty happy with what I'm getting now. I have to admit sometimes I'm processing then reprocessing images again & again to try & get better colour as sometimes that [art can be a struggle at times.
Great video as always clear skies!!
Thanks Tich! It's no hurry.. the most important thing is that you enjoy what you're doing. :)
Fantastic. Thank you.
Thanks Robert!
Great video James! I only shoot in mono. The only OSC I ever tried was my unmodded dslr. I think it's great to see the comparison and I agree with you about the myth. I see it in many places as well and it seems that you really can't change most people's minds once they believe it. Also, Freudian slip at 26:27? Hahahaha!
I swear.. I said shot, not 💩. lol. I think I was just speaking fast and that's how the mic picked it up. :)
Back in the days of film, mono images were quite popular. When I started out, it was film - black and white. Then on to CCD's but strictly mono as the costs were very high just for a simple camera, let alone an expensive filter wheel (used) with very expensive filters which have been eclipsed by the current batch of filters on the market today. Now I have multiple scopes, multiple cameras, both color an finally get some filters for my new mono cameras. Thank you for the basic timing for taking RGB mono images, as my old numbers were a total guesstimate in the first place.
Thanks Robert! I didn't know astrophotgraphy was a thing until late 2016. I heard about doing long exposure with film... so cool. If I knew about that back in the 90s.. I probably would have gotten into it :)
Excellent advice. The one thing I think you could have emphasized more is the value of the Optolong L-Pro with OSC for beating light pollution (I'm in Bortle 6). Like you, I went from DSLR to mono, but have recently bought a cooled OSC camera, and I've found the L-Pro is fantastic with that and with my DSLR (which I still use on my portable rig). I still mostly shoot mono, but the L-Pro makes OSC possible when I travel or just don't want to mess with multiple filters.
Thanks Dave! I have heard a lot of good things about the L-Pro but I don't have personal experience with one. Maybe I should get my hands on one for some testing at some point. :)
Great explanation and myth busting.
Thanks Hogarth!
Great information!! I do have a question. If I invest in the filters for the one shot camera, do they carry over to the monochrome if I upgrade at some point? Or are they completely unnecessary when doing a monochrome camera?
Duel/Tri/Quad and similar filters are not needed with mono. For example, a dual band filter that passes Ha and O3.. with OSC you can separate the data (red= Ha, Blue/green = O3). With mono, all that data is grey scale.. so no way to split ha from o3. You can use it.. some people have experimented by using such filters to act as sort of a lum layer for narrowband data.. but I don't think there is much gained verse running single band filters with the mono sensor.
Thanks, very helpful
Glad it was helpful!
Pretty Nice Overview. As a beginner I've never tried a Monochrome Camera. Not because I feel It takes too long. But if i want color Images i need to buy some Filters and a filter wheel and offcourse you need To deal with more data. I might look into One sometime in the Future Though! Found this Intresting, Thanks For sharing James! 👏
Yea, the expense for going mono is high. In due time, no rush. :)
OSC for galaxies. Mono for Nebulas.
If you use dual-band filters, OSC is similar to Mono minus some absorption in the color coating of the matrix.
True, but the limited amount of red light that is passed by the bayer matrix means you're getting much less Ha or Sii signal. On bright targets the impact is limited, but on fainter targets.. I have found that mono with an Ha or Sii filter pulls in a lot more "red" signal than the dual band filter with OSC.
I started on the monochrome route from the beginning, and found LRGB or RGB imaging with hydrogen alpha and the red data spliced together works very well from a light polluted area.
Nice! Halrgb is a winning combination, especially in light pollution
@@DSOImager It certainly is. The next step is to add O-III into the mix.
“I don’t have time to get 4 frames” was biggest misconception preventing my permanent switch to mono camera. Now, I have no OSC camera.
Superiority of mono camera in every aspect is absolutely massive.
Agreed, although i think i will always have a OSC my arsenal. I found targets like comets to be much easier with OSC. I think mono is capable of doing a better job on the comet, but i find processing them to be a pain in the arse, so ill take the OSC shortcut for those, lol.
@@DSOImager Exactly! Taking pictures of bright comments are very problematic. Processing is even more difficult.
The "mono takes 3-4 times as long" myth is propagated by a lot of people. When I first started AP, I thought the same thing... well, I need to use 3 or 4 filters, so that means 3 or 4 times the integration. It's very easy to think that way... and very hard to convince people, once they've started that line of thinking, that it isn't the case. Like you, I went from DSLR to mono. When I was making my purchase decision, I didn't think OSC made sense. I _knew_ I wanted to target emission nebulae. I also didn't feel (justified or not) that OSC was enough of a step up from my existing DSLR.
Most tri-band filters I've seen are Ha, O3 and Hb. I don't recall seeing any SHO tri-bands. Only filters I know that include S2 are the Radian Triad Ultra (absurdly expensive) and a dual band S2/O3 (IDAS used to make, but stopped... Askar has their Colour Magic line currently). You make a very valid point about the cost benefit being greatly diminished when you start including various filters and wheel for that OSC.
I thought I saw one out there that included SHO.. I don't recall who it was.. maybe it was stc. I knew about the idas filter but didn't know they stopped making it, interesting. I think at some point I am going to want a full frame camera. Given the extreme costs of filters.. I was thinking maybe going OSC for broadband mosaics.. and maybe something like the two askar filters.. would be a lot cheaper than 7 2" filters, lol. We'll see.. that's still down the road a bits. I don't even have a scope that can handle a FF sensor. Thanks for commenting Jonny!
In the first section, I thing tou are confusing time with space, ie picel space. All of the color pixels are delivering the same xposure as mono pixels are in the same time, you are just getting about 1/3 ad much pixel space for each color.
Yea, I agree with that. The point I was trying to make is that it's a wash between them in regards to total integration. The misconception I was addressing was this idea that OSC needed less total integration time vs Mono. I don't see that claim as much as I did a year ago when this video was published thankfully.
585 came today...
C11 still waiting patiently to be used ... :)
mono is definitely in the cards but Id rather have the university loan Mr one than having to buy it ... especially now that we know the allocated budgets for next year.... uvir filter comes in handy for NEO detection and yes, it works a treat with mono while synthetic tracking
I went for the 585 to go along with the 135 F2 for mosaic work and plain EAA fun ... also binned makes for a killer planetary camera
The 585 is an awesome camera. @lukomatico has put out a number of awesome images with the 585 he'd been running for awhile. :)
Osc is the only way when you have limited clear nights per month or year.
For me it was the price reason.And its still faster than mono.Not 3-4 times but still.
Price is certainly a legit reason.
In regards to speed, what makes you say osc is faster?
@@DSOImager I think he means easier lol you don't have to combine the lrgb data like you do with mono you get a full color image right out the box as well as no need for a filter wheel or planning the night out for each filter. Just my guess though I use a osc I get pretty good images with it and having to carry a rig down 3 flights of stairs I would prefer to have as little weight as possible added on 😅
@@theenergeticturtle94893 flights of stair! That's dedication. :)
Yea.. I agree its easier.
@@DSOImager I blame the smart scopes love them for the light weight stuff but wasn't happy with how limited they were definitely makes a difference with the cooled camera and no field rotation it's worth the back aches in my opinion
@@theenergeticturtle9489Agreed. The smart telescopes have their place.. I see them as a more casual experience. The type of imaging I do is not possible with today's smart telescopes.
The part about the exposure time is somewhat misleading.... In an OSC you have e.g. only 25% red pixels but each red pixel collects the same amount of light as a pixel on a mono camera with a red filter. Only difference is the transmission of the red filter (mono) vs. the red filter on the bayer matrix. During Debayering the exposure value of the "few" red pixels is kind of duplicated (in fact interpolated) to the green and blue pixels. This way every pixel gets R, G and B values.
The consequence of this is: The Image from an OSC has the same "brightness" as an image with a mono camera. The difference is the resolution as 75% of the red/blue pixels are only "guessed" by the DeBayering algorithm. 50% for the green.
In normal (daytime) photography usually the loss of resolution is specified with about 30%. A DeBayered image has approx. 70% of the nominal sensor resolution (a little more resolution in the green channel, a little less in red/blue). With astrophotography i expect similar values for larger structures (like Nebulae) and a little more resolution loss with very tiny structures like very dim stars (worst case: Only 1 bright pixel) as there just are no plausible values in the neighborhood to get good values for the interpolation. Because of the small pixel size of current CMOS sensors (most astrophotographers use sensors that lead to slight oversampling) this is not a problem for most setups.
In theory there is a way to use the full resolution even with OSC sensors. I am not sure if any stacking software is capable of this (maybe PixInsight?): Instead of DeBayering the OSC-Image you can just stack e.g. the red pixels and ignore the "missing red" on the green/blue positions. If you have enough exposures this would "touch" every pixel in the resulting image due to slightly different positions and dithering resulting from the image registration. This way the stated "only 25% of light" would be correct. But as far as i know most of the stacking softwares are working with "classical DeBayering".
I don't think that part is misleading. The green and blue portions of the bayer matrix block red light. Sure, the algorithm is filling in some of the blanks.. but that's still not the same as every pixel receiving red light. The issue is most noticeable if you test with a narrowband filter. If you put an Ha filter in front of a OSC camera.. and collect an hours worth of data.. and then compare that to an hours worth of Ha on a mono camera.. the difference is significant. The Debayering process isn't making up for the significantly less data captured in that case.
I believe on bright/common objects the difference between the two isn't much.. but on dimmer objects.. the difference becomes noticeable. Ironically, you'd need more integration time with the OSC vs Mono.
I think the alternative method of stacking you are talking about is called "Bayer Drizzle". I've not experimented with this way of stacking.. so I could be wrong here.. but if it works like drizzling the data, then you do take a SNR hit.
@@DSOImager The Algorithm duplicates e.g. the red pixels - more or less depending on the surrounding pixel values. That means instead of one red pixel with 5000 ADU you get 4 pixels with 5000 ADU in a 2x2 matrix (with some variations depending on the algorithm and surrounding). This is nearly the same as with the mono camera - except that the pixels that are produced by the debayering are just guessed where the mono really has collected photons on those pixels. Some loss can be explained by the bayer matrix in front of the sensor. Those bayer filters have a significant worse transmission than good RGB-Filters - resulting in less signal collected by the OSC. Maths do not lie ;-)
@@ubit64 Thanks for explaining this Udo. It is a clearer explanation than I have read elsewhere in regards to how the bayer matrix is used. CS!
With monochrome you don't need more time, but you have to be luckier
Well said
If not price and cost of filters, nobody will be talking about OSC.
It's amazing how much the filters cost.
@@DSOImager I wanted H-gamma 1.25” filter from Chroma. They quoted $2750!
@@anata5127 😮
What target did you have in mind for H-gamma?
@@DSOImager I do pictures of galaxies with S2-Ha-O3-Hb-AT435/20 (includes Hgamma)-Sloan/i (NIR). It is impossible to predict outcome. So far I have tried m31 and m33. Very different results. M31 have almost no Hb and Hg and well weaker NIR. Boring galaxy. M33 is reach in NIR and narrow-band spots. There is even spots with a lot of O3-Hb, but weak Ha. M33 is truly terrific galaxy. It also has a lot infrared dots. Clusters? Stars? Don’t have resolution to tell.
This is inaccurate information, collecting more photons with mono is not faster than OSC, You get a slight bump in resolution with mono but the one red pixel is still collecting the same number of photons, so you definitely need more time to shoot 7 different filters and then process 7 sets of data… OSC is massively faster, it’s just not as flexible and has slightly less resolution, but is also much less expensive… Mono is also NOT more sensitive, once you include the 10% to 70% light drop of the filter in front of that mono camera they are equivalent and most OSC will be more sensitive unless you’re using extremely expensive filters…
I didn't say that mono was faster. I said it wasn't slower. I said that its wrong to think one needs to gather 3 to 4 times the integration time when compared to OSC. I said for a given time (1 hour was my example) its a wash between the two. OSC is most certainly not faster. That is the very misconception I tried to dispel with this video.
Mono data being a bit more work in post processing? Yes.. I covered that in the video. Mono with its assorted filters are more expensive? Yes, also covered in the video... although now you can buy multiple dual band NB filters for OSC. Add in a light pollution filter and possibly an in between filter like the L-Enhance and the price gap between the two starts to narrow.
And speaking of NB, OSC simply can not match the efficiency of a mono sensor when it come to NB data.. again.. due to the bayer matrix. As stated in the video.. I have both. I have used Ha filters with my OSC. I have also used the L-Extreme with my OSC. While they work.. and open up OSC users to the world of narrow band.. Pure Ha subs from a mono camera are superior. It's not even debatable.
If you still think OSC is way faster than mono.. then we can respectfully agree to disagree :)
@@DSOImager I own several sets of both and I assure you mono takes far more time to complete a project than OSC or DSLR... The quality can be better though. My mono rigs have been sitting idle for this very reason, weather has been poor and time is limited for processing. I understand what your saying, but the overall experience with mono especially shooting all 7 filters is going to beyond the average person that is still involved in a career... Just running the scripts and noise reduction on the mono data along with stacking and shooting the flats is is many many hours more time that working one set of color data... So it's the entire workflow experience in total that's very different...
@@robertw1871 Okay, so you are talking about the entire time on a single project. Sure, I agree it's more work with mono.. but how much more work depends on each of our circumstances. I typically shoot 20+ hours on a single target. Doesn't matter if I'm using OSC or Mono so acquisition time is the same. I am able to leave my rigs out in my backyard for stretches at a time under covers. I don't have to reshoot flats for several weeks normally. If I had to shoot flats and tear down every night.. then yes.. that is a big deal and can even be a hobby killer for some. When it comes to processing.. LRGB is a little more involved than OSC.. but its not a significant difference IMHO (except for mosaics).
I did cover all these points in the video. I felt I provided an objective comparison and did not declare one better over the other. It's dependent on circumstances and which way is more fun for each astrophotographer. Also, I do have a day job. I would love to do AP full time but that won't be until I retire.. which is a long time off. CS!
@@DSOImager Yeah I’m just speaking from my own experience on OSC vs Mono… Mono is wonderful, especially when the moon is up or just to grab that extra detail, but mostly I’m just going with the 2600MC or the full frame DSLR depending on the FOV… When summer hits and hopefully there’s more clear skies I’ll switch back to mono… Spring around here will be 90% rain, and so far late fall and winter have brought rain and 100% overcast except a few hours one or two days a the last month… So for a 2 or 4 hour window, more than 1000mm and Mono are both shelved for me… It’s looking like wide field 200mm f/2.8 and 480mm with OSC…