Filters for AP

Hi all,

What filters do you recommend me to use for AP in general and DSO in particular/specific?

Also what good brand that give quality and price? i don't want to buy only high priced filters while some other brands can give same/similar quality with better/lower prices.

Not interested in filters for planetary or solar or even lunar, only astrophotography of DSO.

Heya,

None. I recommend you do not filter it. You want to capture all the light you can. I assume you're using an OSC sensor, like a dSLR or something, and not a monochrome system. If you're shooting mono, or a full spectrum modified OSC, then there are filter options. But really for an unmodified OSC sensor, I wouldn't use any filters at all. There are expensive "light pollution" filters but I would avoid them, you can do the same job in post-processing without sacrificing losing light to it (all filters reduce how much light will make it to your sensor).

Top shelf stuff includes Astrodon, and then good stuff with reasonable prices include Astronomiks and Baader. But again, I wouldn't get any filters at this time, unless you're shooting mono or modified OSC (to be full spectrum).

Are you using a tracker? (What's the longest duration exposure you can tolerate?)
What sensor are you using?
What is the focal-ratio of your system?
Shooting under dark skies? Or is it severe light pollution?
Do you currently process DSO and have experience, or is this all new?

Very best,

If you're using a DSLR to image then your camera has an internal filter which is blocking both UV and IR... but it's also trimming the visible spectrum wavelengths to match the sensitivity of your human eye.

Most of the normal matter in the universe is hydrogen. The most dominant wavelength of light emitted by excited hydrogen atoms is the hydrogen alpha wavelength at about 656nm. This is inside the visible spectrum, but it's near the long end and our eyes aren't particularly sensitive to it. The internal filter on your camera starts to trim the reds and ramps up the filtering gradually as it approaches the end of the visible spectrum (and it's 100% blocked by the time it gets to the 700nm wavelength which is the start of the IR.) But since the Ha is only 656, your camera is already blocking nearly 75-80% of the light at that wavelength.

Since it's the most common wavelength for deep-sky nebulae, this means you have to run longer exposures to collect more light to gather Ha information.

Many astrophotographers will modify their DSLRs (or buy pre-modded cameras) which allow the full visible spectrum to pass completely unfiltered. A "luminance" filter does this. That's a filter that blocks only the UV & IR but doesn't block visible wavelengths at all.

If you live in light polluted skies (like me) then imaging is pretty difficult to do without a broadband light pollution filter. These filters block the wavelengths associated with mercury and high-pressure sodium street lights but allow most other wavelengths through. This tends to do a fairly good job of improving sky conditions (although with cities switching to LED lighting things could get a lot more challenging.)

Anyway, here's an example of what I get using a Canon 60Da (that's an astrophotography DSLR made by Canon that ships with a filter that allows significantly more sensitivity in the Ha band)

Here's the natural light polluted sky:

I gave up on trying to add a 3rd image to the above post and will just add it here.

This next image was taken at the same observatory and using the same equipment (same Celestron C14 telescope) using the same Canon 60Da camera. Local light pollution would have been the same as well.

However, this time I'm using the Orion SkyGlow light pollution filter. This is a different object, it's M57 aka the Ring Nebula.

MalVeauX wrote in post #18331040
Heya,

None. I recommend you do not filter it. You want to capture all the light you can. I assume you're using an OSC sensor, like a dSLR or something, and not a monochrome system. If you're shooting mono, or a full spectrum modified OSC, then there are filter options. But really for an unmodified OSC sensor, I wouldn't use any filters at all. There are expensive "light pollution" filters but I would avoid them, you can do the same job in post-processing without sacrificing losing light to it (all filters reduce how much light will make it to your sensor).

Top shelf stuff includes Astrodon, and then good stuff with reasonable prices include Astronomiks and Baader. But again, I wouldn't get any filters at this time, unless you're shooting mono or modified OSC (to be full spectrum).

Are you using a tracker? (What's the longest duration exposure you can tolerate?)
What sensor are you using?
What is the focal-ratio of your system?
Shooting under dark skies? Or is it severe light pollution?
Do you currently process DSO and have experience, or is this all new?

Very best,

I don't use OSC, i am using DSLR, until one day later i may try to get that CCD camera used for AP, and i got recommendations if i will get CCD then to go with the mono one, still not any soon.

I ordered a tracker but i have to wait so long for my order to be processed and then shipped to me, so the mount is done almost.

Sensor is DSLR as i said, but i am planning to add CCD sooner or later.

Focal ration is F5 as starter, but i will use my DSLR and a lens too, mostly 300 f2.8, maybe Canon 135mm f2 and also Canon 100-400 f4.5-5.6 mk1, but the scope i ordered and waiting is non APO regardless it is F5, if i use some kind of filters it may change that focal ratio.

I shoot under severe light pollution, there is no dark sky in my country any close, i have to drive so very far which is out of my range or i won't do at all, so LP is heavy or bad so i have to find a way for that, and that is why i asked about filters for NB or LP specifically.

It is all new for me, didn't process DSO yet, but i did read a lot in another sites and watched videos, so all what i get is if i can get those multi exposures [flat, dark, bias,...etc] then stacking them i will get some results to play with, i have DSS but i couldn't do anything with my DSLR because no tracking so it is failure as i didn't track any star and i don't want do that manually, so i will wait the mount, but you asking me because you think i will give up due to no knowledge about DSO processing you think i don't know about stacking topic? i don't know how to stack perfectly because i don't have the files, but for sure i will give that a long time learning and experimenting so don't worry about processing, if i couldn't do it properly then i just let someone do it for me then i will ask him for the steps, are you meaning something else about process DSO rather than what i said?

TCampbell wrote in post #18331295
If you're using a DSLR to image then your camera has an internal filter which is blocking both UV and IR... but it's also trimming the visible spectrum wavelengths to match the sensitivity of your human eye.

Most of the normal matter in the universe is hydrogen. The most dominant wavelength of light emitted by excited hydrogen atoms is the hydrogen alpha wavelength at about 656nm. This is inside the visible spectrum, but it's near the long end and our eyes aren't particularly sensitive to it. The internal filter on your camera starts to trim the reds and ramps up the filtering gradually as it approaches the end of the visible spectrum (and it's 100% blocked by the time it gets to the 700nm wavelength which is the start of the IR.) But since the Ha is only 656, your camera is already blocking nearly 75-80% of the light at that wavelength.

Since it's the most common wavelength for deep-sky nebulae, this means you have to run longer exposures to collect more light to gather Ha information.

Many astrophotographers will modify their DSLRs (or buy pre-modded cameras) which allow the full visible spectrum to pass completely unfiltered. A "luminance" filter does this. That's a filter that blocks only the UV & IR but doesn't block visible wavelengths at all.

If you live in light polluted skies (like me) then imaging is pretty difficult to do without a broadband light pollution filter. These filters block the wavelengths associated with mercury and high-pressure sodium street lights but allow most other wavelengths through. This tends to do a fairly good job of improving sky conditions (although with cities switching to LED lighting things could get a lot more challenging.)

Anyway, here's an example of what I get using a Canon 60Da (that's an astrophotography DSLR made by Canon that ships with a filter that allows significantly more sensitivity in the Ha band)

Here's the natural light polluted sky:

Hosted photo: posted by TCampbell in
./showthread.php?p=183​31295&i=i21620677
forum: Astronomy & Celestial

You can see that's pretty muddy and you can barely make out the DSO (in this case it's M27 the dumbbell nebula)

Here's the same object, but this time I'm using a Lumicon Deep Sky filter (a broadband filter)

Hosted photo: posted by TCampbell in
./showthread.php?p=183​31295&i=i105176655
forum: Astronomy & Celestial

That's certainly "better" but you can see that I get this tremendous blue color cast. With a bit of work I can correct that in post processing (but it does take some work) and even then I feel the colors are a bit wonky. But you can certainly see how much more detail I get. The lobes near the top and bottom of the nebula don't show up at all in the version of this image that doesn't use a filter (these images were taken one after the other using the same scope. Everything is identical except for the filter being used in the 2nd image.

I'll see if I can add a third image... it was taken using an Orion SkyGlow filter. The forums normally only allow 2 uploaded images so maybe I can add it to my 'gallery' and imbed it that way.

Both of these were taken when M27 was starting to get low in the western sky (I really shouldn't have imaged them at that time) which means I was picking up a lot of atmospheric dispersion. If you look at the top image you can see the stars have a red fringe on one edge and a blue fringe on the other. That's not the optics of the scope - that's the sky acting like a prism due to the low angle. To fix it I had to split the RGB into separate images, do a star alignment, then re-combine them again (using PixInsight.)

I live in so bad light pollution urban for sure, so that i want a filter, i can't depends on taking millions exposures to stack them and get nothing, in fact so many DSO photos i saw are done with one type of filter or another, LP or HOS or LRGB, and i doubt they are shooting in light pollution sky, so even in dark skies they use filters, what i can say in my LP town?

How come my DSLR has a UV/IR layer? i never read about it before unless i passed it somewhere, so if that is true then why can't i catch anything in our LP urban while the sky is clear?

TCampbell wrote in post #18331305
I gave up on trying to add a 3rd image to the above post and will just add it here.

This next image was taken at the same observatory and using the same equipment (same Celestron C14 telescope) using the same Canon 60Da camera. Local light pollution would have been the same as well.

However, this time I'm using the Orion SkyGlow light pollution filter. This is a different object, it's M57 aka the Ring Nebula.

Hosted photo: posted by TCampbell in
./showthread.php?p=183​31305&i=i145689293
forum: Astronomy & Celestial

I want to add that other than converting the RAW to JPEG and scaling the image down to 800 pixels on the long edge, this image hasn't been processed. This is straight out of the camera.

Notice the strong blue color cast is gone (replaced with a weak green color cast) and how much the contrast is improved. This is a relatively inexpensive filter.

If you have good dark skies, don't use a filter UNLESS you're trying to collect more data in some specific narrowband. For example, some people will use an Ha (which blocks all light except Ha) so they can intensive the Ha areas of an object... or maybe a OIII filter or an SII filter, etc. But these are narrowband filters specifically used when you know the object glows at those wavelengths and you want to intensify the light gathered without continuing to gather more full-spectrum light (and possibly over-saturation and clipping data elsewhere.)

You never want to clip data... so if you just keep the shutter open longer and longer, you'll eventually hit a point where maybe your DSO is looking better... but the stars are clipped (hovering your mouse over those pixels in photoshop would read 255, 255, 255 (e.g. for 8-bit channels) which means the stars can't render in true color because the data is clipped. So the narrowband lets you collect more of what you want without continuing to collect more of everything you don't want. They are normally used to combine to the broadband data.

There are a few other brands that I haven't personally used but get good reviews. One is Astromik (e.g. the Astronomik CLS filter) ... there's another whose name escapes me right now, but I know a few of the imagers in my club swear by them. I'll see if I can get the name and update them.

I will get the mount and i already ordered a tube refractor to give it a try, so this will allow me for long exposure, but i live in heavy LP, how can i over or by pass that?

Tareq wrote in post #18331433
I don't use OSC, i am using DSLR, until one day later i may try to get that CCD camera used for AP, and i got recommendations if i will get CCD then to go with the mono one, still not any soon.

I ordered a tracker but i have to wait so long for my order to be processed and then shipped to me, so the mount is done almost.

Sensor is DSLR as i said, but i am planning to add CCD sooner or later.

Focal ration is F5 as starter, but i will use my DSLR and a lens too, mostly 300 f2.8, maybe Canon 135mm f2 and also Canon 100-400 f4.5-5.6 mk1, but the scope i ordered and waiting is non APO regardless it is F5, if i use some kind of filters it may change that focal ratio.

I shoot under severe light pollution, there is no dark sky in my country any close, i have to drive so very far which is out of my range or i won't do at all, so LP is heavy or bad so i have to find a way for that, and that is why i asked about filters for NB or LP specifically.

It is all new for me, didn't process DSO yet, but i did read a lot in another sites and watched videos, so all what i get is if i can get those multi exposures [flat, dark, bias,...etc] then stacking them i will get some results to play with, i have DSS but i couldn't do anything with my DSLR because no tracking so it is failure as i didn't track any star and i don't want do that manually, so i will wait the mount, but you asking me because you think i will give up due to no knowledge about DSO processing you think i don't know about stacking topic? i don't know how to stack perfectly because i don't have the files, but for sure i will give that a long time learning and experimenting so don't worry about processing, if i couldn't do it properly then i just let someone do it for me then i will ask him for the steps, are you meaning something else about process DSO rather than what i said?

Tareq wrote in post #18331436
I live in so bad light pollution urban for sure, so that i want a filter, i can't depends on taking millions exposures to stack them and get nothing, in fact so many DSO photos i saw are done with one type of filter or another, LP or HOS or LRGB, and i doubt they are shooting in light pollution sky, so even in dark skies they use filters, what i can say in my LP town?

How come my DSLR has a UV/IR layer? i never read about it before unless i passed it somewhere, so if that is true then why can't i catch anything in our LP urban while the sky is clear?

OSC is one-shot-color, and that's what your dSLR is, it's a bayer matrix sensor that has been filtered to block UV/IR and is not very sensitive. And there's nothing wrong with this, it's fine! It's very common to image with this. You cannot use narrowband imaging with a color sensor because it won't be sensitive to the wavelengths for the most part, and the lack of sensitivity will require extremely long exposure times. You cannot use narrowband filters with an unmodified dSLR sensor and get the results you're looking at on the web. The info linked above were imaged with a modified dSLR sensor to allow to be sensitive to full spectrum light, and not just some of it (and even then its still not as sensitive and useful for narrowband compared to a true monochrome sensor).

All unmodified dSLR sensors have UV/IR filters, and most of them have a low pass filter too. They're meant for terrestrial imaging. You need to change your mindset for astrophotograhpy, it's totally different. Exposure is different too. All traditional concepts other than composition are completely different and will not be even close to the same in astrophotography compared to terrestrial photography.

It's ok to shoot in light pollution, even without filters. Again I would still not bother with a light pollution filter on an unmodified dSLR sensor. Just get lots of exposures to stack and get a good high signal to noise ratio from that and you'll get rid of most of the noise and you can process out most light pollution just fine by having a high signal to noise ratio from lots of exposures. The price you would pay for a quality light pollution filter is far better put into a monochrom cmos sensor in your future and quality filters. By the way, you certainly do not need a CCD. Today's CMOS options are as good and in some cases better than CCD for the cost.

Once your tracker arrives, and you can get say, 2 hours of data on a subject and stack those exposures, you'll see a huge difference and you'll be able to easily process out light pollution without a filter. This is a common way to approach astrophotography. You do not need a light pollution filter. If you think you want to do narrowband imaging in the future, through light pollution, put all your pennies towards a monochrome CMOS camera and a few quality filters (HA, S3, O2), instead of light pollution filters and dSLR stuff.

+++++++++++++

Biggest Suggestions for your situation:

Start with your tracker, as you cannot do long exposure without one and keep tight stars.
From there, guiding is the next step in controlling tracking.
Don't spend any more money yet. No need to get a telescope. Lenses are fine! Don't waste money on some filters for a color dSLR sensor.
Shoot wide field with camera lenses. 400mm is wide field by the way!
Get experience with proper exposure for astrophotography and stacking and processing. It's not at all like terrestrial exposure and histograms.
A normal histogram target is often only seeing a single spike at 1/4th to 1/3rd fill on the histogram on the left side. That's it! And get LOTS of those to stack.
With lots of light pollution, it's common to go for 1/3rd to nearly 1/2 histogram, but no more. And to get as many hours of it as you can.
Getting data is all about increasing signal to noise ratio. I do a minimum of 2 hours on even bright targets, and some require close to 6 hours as a minimum!
There's lots of tutorials on how to process data from light pollution and deal with gradients, etc.
If you're gonna spend money, put it towards a monochrome cmos camera and quality narrowband filters.

Again, if you want to truly do DSO any day without clouds in severe light polluted skies, you want to get a monochrome sensor now, first and foremost, and you want active cooling. You can add narrowband filters later or one at a time (start with HA first, then add O3 and S2 as you can).

Start shopping for an ASI1600MM-Cool and then add HA/S3/O2 filters as you can over time. This is the best way to approach your situation, rather than trying to use a color sensor and a light pollution filter.

+++++++++++++++

I learned most of my processing techniques from "Astronomer's Do It In the Dark" tutorials.

Here's some examples from an unmodified dSLR color sensor with no filters, just lots of integration time (minimum 2 hours of exposure time):

IMAGE LINK: https://flic.kr/p/RgsU​H1

IMAGE LINK: https://flic.kr/p/QBWu​oz

IMAGE LINK: https://flic.kr/p/RBoC​1J

IMAGE LINK: https://flic.kr/p/RCyN​NC

IMAGE LINK: https://flic.kr/p/R2kw​Q5

IMAGE LINK: https://flic.kr/p/Srjm​E2

MalVeauX wrote in post #18331475
OSC is one-shot-color, and that's what your dSLR is, it's a bayer matrix sensor that has been filtered to block UV/IR and is not very sensitive. And there's nothing wrong with this, it's fine! It's very common to image with this. You cannot use narrowband imaging with a color sensor because it won't be sensitive to the wavelengths for the most part, and the lack of sensitivity will require extremely long exposure times. You cannot use narrowband filters with an unmodified dSLR sensor and get the results you're looking at on the web. The info linked above were imaged with a modified dSLR sensor to allow to be sensitive to full spectrum light, and not just some of it (and even then its still not as sensitive and useful for narrowband compared to a true monochrome sensor).

All unmodified dSLR sensors have UV/IR filters, and most of them have a low pass filter too. They're meant for terrestrial imaging. You need to change your mindset for astrophotograhpy, it's totally different. Exposure is different too. All traditional concepts other than composition are completely different and will not be even close to the same in astrophotography compared to terrestrial photography.

It's ok to shoot in light pollution, even without filters. Again I would still not bother with a light pollution filter on an unmodified dSLR sensor. Just get lots of exposures to stack and get a good high signal to noise ratio from that and you'll get rid of most of the noise and you can process out most light pollution just fine by having a high signal to noise ratio from lots of exposures. The price you would pay for a quality light pollution filter is far better put into a monochrom cmos sensor in your future and quality filters. By the way, you certainly do not need a CCD. Today's CMOS options are as good and in some cases better than CCD for the cost.

Once your tracker arrives, and you can get say, 2 hours of data on a subject and stack those exposures, you'll see a huge difference and you'll be able to easily process out light pollution without a filter. This is a common way to approach astrophotography. You do not need a light pollution filter. If you think you want to do narrowband imaging in the future, through light pollution, put all your pennies towards a monochrome CMOS camera and a few quality filters (HA, S3, O2), instead of light pollution filters and dSLR stuff.

+++++++++++++

Biggest Suggestions for your situation:

Start with your tracker, as you cannot do long exposure without one and keep tight stars.
From there, guiding is the next step in controlling tracking.
Don't spend any more money yet. No need to get a telescope. Lenses are fine! Don't waste money on some filters for a color dSLR sensor.
Shoot wide field with camera lenses. 400mm is wide field by the way!
Get experience with proper exposure for astrophotography and stacking and processing. It's not at all like terrestrial exposure and histograms.
A normal histogram target is often only seeing a single spike at 1/4th to 1/3rd fill on the histogram on the left side. That's it! And get LOTS of those to stack.
With lots of light pollution, it's common to go for 1/3rd to nearly 1/2 histogram, but no more. And to get as many hours of it as you can.
Getting data is all about increasing signal to noise ratio. I do a minimum of 2 hours on even bright targets, and some require close to 6 hours as a minimum!
There's lots of tutorials on how to process data from light pollution and deal with gradients, etc.
If you're gonna spend money, put it towards a monochrome cmos camera and quality narrowband filters.

Again, if you want to truly do DSO any day without clouds in severe light polluted skies, you want to get a monochrome sensor now, first and foremost, and you want active cooling. You can add narrowband filters later or one at a time (start with HA first, then add O3 and S2 as you can).

Start shopping for an ASI1600MM-Cool and then add HA/S3/O2 filters as you can over time. This is the best way to approach your situation, rather than trying to use a color sensor and a light pollution filter.

+++++++++++++++

I learned most of my processing techniques from "Astronomer's Do It In the Dark" tutorials.

Here's some examples from an unmodified dSLR color sensor with no filters, just lots of integration time (minimum 2 hours of exposure time):


Very best,

Thank you very much!

Actually getting a mono camera is a next or second step i will do after getting the mount and the scope, with the mount i can use either the DSLR with lenses or even DSLr with scope, so then i can simply add a mono camera, i didn't care if CCD mono or CMOS, actually i think i was looking at CMOS mono camera and i thought they are CCD cameras, so i will remember strictly to choose CMOS mono one then, and here is the thread about filters which i am definitely going to do NB once i get that mono camera, but i was curious to learn more about those LP filters, you answered me about them so i can simply pass them, why i asked then, if i didn't ask i may buy them and find out they are not much of use, but good you gave me the answer even before i order them, but just for experimenting i bought one filter not so expensive to try with the scope i ordered, just test and it is not a big deal.

Now if sooner or later i buy that Mono CMOS camera and i plan to do narrowbanding or even boardband, then i will definitely look at Ha-OIII-SII, but should i only get that expensive brand one? Astrondon is very expensive and also Astronomik, I found those filter from Baader at better prices, and they are coming with 7nm which is reasonable contrast to test, but do you think Baader is on par with Astro-brands? I can buy the 3 filters 1.25" 7nm at good price if from Baader, in fact i can order them next week or 2 months later if i need to regardless i don't have any mono camera yet.

Also by Mono camera, you swear by ASI ones? i mean it is an amazing one, but what about Atik or ZWO or QH and whatever? filters can be ordered before because they are cheaper than the mono camera, but i know you or others will tell me to get the camera first then filter, then i will wait very long because if i spend on filters now that will delay about 1-2 months in the future of my plan about mono camera, and the problem is that i was thinking to upgrade my not yet here scope because if i will use DSLR and lenses then scopes and mono camera is pointless here, but once i mention the scope then i have to mention that the one i ordered is very cheap and only for tests or learning, so if i buy another scope expensive and great for DSO then this will kill my saving for a mono camera anyway.

Sorry, ASI is from ZWO, i corrected myself.

Tareq wrote in post #18331505
Now if sooner or later i buy that Mono CMOS camera and i plan to do narrowbanding or even boardband, then i will definitely look at Ha-OIII-SII, but should i only get that expensive brand one? Astrondon is very expensive and also Astronomik, I found those filter from Baader at better prices, and they are coming with 7nm which is reasonable contrast to test, but do you think Baader is on par with Astro-brands? I can buy the 3 filters 1.25" 7nm at good price if from Baader, in fact i can order them next week or 2 months later if i need to regardless i don't have any mono camera yet.

Also by Mono camera, you swear by ASI ones? i mean it is an amazing one, but what about Atik or ZWO or QH and whatever? filters can be ordered before because they are cheaper than the mono camera, but i know you or others will tell me to get the camera first then filter, then i will wait very long because if i spend on filters now that will delay about 1-2 months in the future of my plan about mono camera, and the problem is that i was thinking to upgrade my not yet here scope because if i will use DSLR and lenses then scopes and mono camera is pointless here, but once i mention the scope then i have to mention that the one i ordered is very cheap and only for tests or learning, so if i buy another scope expensive and great for DSO then this will kill my saving for a mono camera anyway.

Astrodon is pretty much top shelf.

You can get Astronomik or Baader, if one is cheaper. Ideally, start with an HA filter. It's ok to get a 5nm or 7nm filter for HA, it's a very prolific wavelength so you will image a lot of it and you don't have to be strict with it compared to other wavelengths. For the S2 and O3, you may want to spend a little more and go for the 3nm spec, to ensure you're basically only getting that wavelength. This is why its cheaper to just start in HA and image in B&W and HA basically, then slowly add S3 and O2 to your set as funds allow, and going for the tighter higher quality filters in those two. You can get your luminance data now and learn to acquire data and process data without color first, you have to learn that anyways, so no need to wait. You can get filters as funds permit.

There are lots of manufacturers of current CMOS, like ZWO, Antik, QHY, etc, most of them use a Sony sensor anyways. Right now the sensor to look at is the 1600MM-Cool, no matter the manufacturer. It's a micro-4/3's sensor size with 16MP and is a real monochrome sensor with active cooling. It's one of the best imaging sensors you can get for the money right now for it's sensor size and with cooling. ZWO just happens to be dropping quality cameras for very competitive prices and are driving the market.

Very best,

MalVeauX wrote in post #18331533
Astrodon is pretty much top shelf.

You can get Astronomik or Baader, if one is cheaper. Ideally, start with an HA filter. It's ok to get a 5nm or 7nm filter for HA, it's a very prolific wavelength so you will image a lot of it and you don't have to be strict with it compared to other wavelengths. For the S3 and O2, you may want to spend a little more and go for the 3nm spec, to ensure you're basically only getting that wavelength. This is why its cheaper to just start in HA and image in B&W and HA basically, then slowly add S3 and O2 to your set as funds allow, and going for the tighter higher quality filters in those two. You can get your luminance data now and learn to acquire data and process data without color first, you have to learn that anyways, so no need to wait. You can get filters as funds permit.

There are lots of manufacturers of current CMOS, like ZWO, Antik, QHY, etc, most of them use a Sony sensor anyways. Right now the sensor to look at is the 1600MM-Cool, no matter the manufacturer. It's a micro-4/3's sensor size with 16MP and is a real monochrome sensor with active cooling. It's one of the best imaging sensors you can get for the money right now for it's sensor size and with cooling. ZWO just happens to be dropping quality cameras for very competitive prices and are driving the market.

Very best,

Thank you very much!