codemanwa When I try shooting with the any of the narrowband filters I don't see the object.

Is the object that you are imaging an emission nebula?

If it is a reflection nebula, you are likely going to see nothing through one of the standard "narrowband filters" -- the passbands of the filter and the reflection nebula simply don't overlap.

If you are imaging a galaxy or stars with a narrowband filter, expect to need an exposure time that is equal to about 300/W times longer, where W is the passband (in nm) of your narrowband filter.

In short, never use a narrowband filter with anything but emission nebulas, unless you want to add some particular regions (e.g. H-alpha) to an existing LRGB image.

With good filters, expect about an extra 10% of exposure time with the emission nebulas. If you are using the ZWO filters, expect to expose for at least an extra 20%. (You should have checked the specs before buying it. Caveat Emptor.)

Just remember that a narrowband filter does not make a nebula brighter, it simply makes what is not an emission line dimmer; and that produces the better signal to noise ratio for the emission lines. And it almost always makes a star much dimmer.

Chen

codemanwa I haven't had any luck with them.

Did you postprocess and stack your images?

First, remember that the filter wil not make the nebula any brighter, it simply makes the background sky and stars dimmer, while the good narrowband filters will only attenuate the nebula by a little (cheap narrowband filters will attenuate more, and require longer exposures). A narrowband filter basically makes something like a Bortle 7 picture look like Bortle 4 to 5 picturer, depending on how narrow band it is -- the narrower the passbands, the darker the sky. And they only work with emission nebulas.

A single frame with a slow OTA will still show very little brightness, even for something as bright as NGC7000. They just need to be properly histogrammed (stretched) with post processing.

Here is a single ASI2600MC 180 second, gain 100 image of NGC7000 on an FSQ-85 with a 0.73x reducer (330 mm focal length @ f/3.8), and a Radian Quad filter):

If you have an f/5.6 OTA, expect to expose an ASI2600 with gain 100 for 360 seconds to get the above, and with an f/8 OTA, expect to expose for 720 seconds to get the same brightness. With gain 0 (10 dB less gain), and a f/8 OTA, until histogrammed properly, the single frame would show almost nothing with a 300 second exposure.

Next is a stack of just 6 of the above captured images, and postprocessed with AstroPixelProcessor, Affinity Photo, and macOS Preview (equivalent to a 1000 second exposure at f/3.8 and 10 dB of camera gain):

Remember too that nebulas are extended sources; so, fast f-numbers help, no matter whether you are undersampled or oversampled for stars. The above images are basically a little faster than f/4. With a f/5.6 scope, you would need to double the exposure time to get the same image, with an f/8 OTA, you would need 4x more exposure time (total integration time of 4000 seconds, with ASI2600 at gain 100) to get the second image.

Avoid cheap filters; you get what you pay for. I know it is too late for you. Get at least Antlia or Optolong quality class. If you can afford it, get Astrodons and Chromas. You will eventually get disgusted with the cheap filters, and end up in total paying more when you end up upgrading the filter (this is how the poor becomes poorer). Cared for properly, filters last a loooong time; treat them as a long term investment. Thay will outlast many, many cameras as long as the size is suitable for future cameras.

With NGC7000, for example, look at the bright star Cyg Xi -- the bright star near the bottom right of center in the above images. Cheap filters will show bright halos and other aberrations. With the Horsehead Nebula, the Orion belt star Alnitak is a good star to judge quality of a filter.

I did notice that on NGC 7000 when I tried with the Luminance filter

With respect to your comment about Luminance filter -- with a good narrowband filter and the same exposure settings, (1) the brightness of NGC7000 nebula itself with the H-alpha filter should be really close to the brightness with the Luminance fiter, and (2) the background sky with the narrowband filter should be virtually black compared to sky background with the Luminance filter. If both cases are not true, return the narrowband filters, since those are the bare minimum of what basic narrowband filters are supposed to deliver.

By the way, I notice you are also using a ZWO filter wheel. Those wheels have terrible light leaks right around the white stepper motor. Make sure you use black electrical tape and tape off the gaps between the motor and the metal body of the wheel. Be sure not to tape over the shaft and bearing (there is no leak there).

Chen

codemanwa I thought on my next attempt I would try the out of the box live stacking on the ASI Air Plus device.

Don't do that. Use proper tools. AstroPixelProcessor is well worth the money and works well even if you just let it use its well thought out default settings.

If you have any field rotation at all, the ASIAIR live stacker will not give sharp corner-to-corner stars. With large enough field rotation over a long session, it may not even stack. ZWO's free software is not worth wasting time on either; you get what you pay for.

Chen

codemanwa I am still confused why I don't see anything

Are you seeing nothing after stacking? If so, the passband of your narrowband filter may be in the wrong place.

If you can see the nebula with a Luminance filter, a real Hydrogen alpha filter should give virtually the same brightness (with same gain and exposure time), but with much darker sky background. If your exposure time and gain with the Luminance filter shows the nebula, but a narrowband filter does not when using the same camera gain and exposure, there is something seriously wrong with the filter.

The Bubble nebula will be dim with a visual magnitude of +11. The Heart and Soul Nebulas are a quite a bit brighter at M+6.5. And of course NGC7000 is horribly bright, at M+4.0. So, for starters, I would focus [sic] on North America first before you get things sorted out.

With NGC7000, try the narrowband Hydrogen Alpha filter -- as you see from my NGC7000 image, it is much more abundant that Hydrogen-Beta or Oxygen III (the part that contributes only a slight bluish tint when it is combined with the deep red of the Hydrogen Alpha).

Since it is not that far away in the sky from NGC7000, and has even lower declination (so it is higher in the sky for most people in the northern hemisphere), you could try the nebulas in the Cygnus Loop. The Western Veil (NGC6960) is actually quite bright (M+5.0) and has very strong O-III/Hydrogen-beta in the filaments.

Likewise, the Eastern Veil is equally bright, and also has a lot of OIII/H-beta.

Both veil images above are cropped from a single large frame of the Cygnus Loop at 330 mm focal length taken in the Autumn of 2020 -- if you have a longer focal length OTA, just go to each one of the above separately. They are not as bright as NGC7000, but is a good test of both H-alpha and O-III filters. The uncropped Cygnus Loop at 330 mm focal length and an APS-C camera looks like this:

Before stacking and proper stretching of the 56 three-minute sub frames, one sub frame looks like this:

So, don't be discouraged if you only see a very dim image, especially if you have a slower OTA. Just postprocess it with a decent program to stack a couple of hours worth of images. May take more than a night's worth of image collection for the dimmer stuff. Just do not use software from ZWO to stack.

This is the Heart and Soul together, using a 200 mm focal length OTA and the cheaper Optolong L-eNhanced filter:

But since they are dimmer (requiring 4 times longer exposure, all else being equal, than the nebulas in the Cygnus Loop) I would also do a pass on them and just use NGC7000 and the Cygnus Loop to test with. NGC7000 is blindingly bright, and shouldn't take more than an hour worth of exposures to get some results, but the Veils are higher in the sky and may be more convienient (and able to test the O-III filter too).

Chen