Moving from stock DSLR to dedicated astro camera, need some help

Paolo:
the million dollars question: mono or OSC? I have to say that I'm very intrigued by mono imaging, but I'm also afraid about the additional complexity (e.g. dealing with filters, flats, etc) and higher costs associated with it. And we all know that more complexity means more risks that something can go wrong.

Struggled with this recently myself.  I am no means an expert and I implore more experienced members to correct me but:

As far as I know everything else being equal, mono will beat OSC every time in terms of SNR and detail. Mono cameras do not have to fight the bayer grid that OSC's have.  I'll let others go into the more detail in terms of acquisition and processing mono vs OSC since all I do is OSC so instead I will focus on the cost. Let's go head to head; ASI 2600MC vs ASI 2600MM just to give you an idea of the cost difference. I hope you don't mind if I use Canadian dollars because, ya know, I'm Canadian.

First, the 2600 MC and accessories:
ASI 2600 MC: $2,589.99 (You'll need the camera, obviously)
Filter Drawer: $109.99 (Somewhere to swap out filters makes things much easier)
2" Dual Band Filter:  $384.99 (A nice duo band filter for emission and planetary nebula, given your bortle 7 situation)
Light Pollution Filter 2": $269.99 (For those broadband targets in bortle 7)
UV-IR Cut Filter 2": $84.99 (The 2600MC doesn't have a built in UV/IR filter so this is the "base" filter you'd need if you are not using any other)
All in all the cost for this OSC setup is $3,439.95 CDN and outside of the UV/IR filter the other ones are debatable. I just used them for examples.

Now, lets go mono! The most basic setup would be the following
ASI 2600 MM: $3,199.99 (Yeah, you'll still need the camera)
5x2" Electronic Filter Wheel: $389.99 (Gotta put your LRBG filters somewhere!)
2" LRGB Filters: $389.99 (The filters to get a nice colour image)
So, this most basic of mono setups is $3,979.97 CDN, only 500 dollars more right? Well with this set up all you will able to do is color images, not any narrowband palettes such as the much adored Hubble SHO palette. Also, there is no electronic focuser here. With mono, every time you change filters you will have to refocus. In this set up that means you have to physically get out there and refocus the imaging train whenever you change filters. Maybe this is a problem for you, maybe it is not; but it will be very costly in terms of efficient imaging time.

So the first thing we tack on to this set up is an electronic focuser for $259.99. We are now at 4,239.96 CDN. If you want to do narrowband, we have to tack on some 2" SHO filters for $916. This brings the cost up to $5,155.96 CDN. Now, maybe you don't want to be swapping filters out of your filter wheel all the time, so lets trade that 5x2" filter wheel for a 7x2" filter wheel for$ 519.99. The total cost of our mono set up is $5,285.96. That is about two thousand more than the full OSC set up. The cost comparison can change wildly based on the filters you choose. I used the fairly cheap ZWO filters for mono costing, but the higher end ones start to get up there.

The mono set up can also get cheaper if you go with 36mm filters, however with an APS-C framed camera like the ASI 2600 MM, from what I read on the ZWO website, 36mm filters are only good for F ratios 5.5ish and slower or else you will be fighting vignetting which might be bad news for your fast f/5 scope. But just for kicks, with 36mm filters and a 36mm filter wheel it would be like $4,726.96 CDN which is 1300 dollars more than the OSC set up. Again, depending on the filters you go with, the price difference can go up or down.

So is it worth the extra cost and effort? Well that is your call. You have a lot of pictures you can compare here on astrobin. This is entirely subjective on my part, but I think as an astrophotographer's skill increases they have no choice but to move to mono to really push things to the limit. For me, the cost did me in and I am now expecting a 2600 MC since I already have the filters from my ASI 533 MC. But even I know that the more I dive into this hobby, all roads will eventually lead to mono; even mine. Just when I am not a starving university student!

When all is said and done (and there will be a LOT to disagree with) if you want a simpler, easier life go OSC (with LP filters). If you want to squeeze out every single photon out of your kit and don't mind the cost and added headaches go mono+filters. I imaged for over ten years with mono cameras in my Bortle 6/7 skies and then decided to go OSC. I am NOT looking back.  As for the cameras, I am very pleased with ASI. I reckon QHY had issues with software/drivers in the past but I'm not sure it does today. If you can return the camera if not satified go for the cheaper option.

Hi Paolo,

I think you should use the search function and see what other galaxy people are using, especially those imaging from light polluted areas and generally skies with less-than-observatory grade. My impression is it's mostly focal lengths around 1000mm (maybe 1500mm, maybe 700), apertures between 5 and 10 inches (usually 6 to and cameras with sensor size smaller than APS-C. In my opinion there is no way you'll be able to utilise the focal length of the 12 inch RC in city skies (it will probably prove unworkable) and the 2600 is too large a sensor for all but a handful of galaxies. 

So you can reduce your camera and scope budget significantly which will give you much better results for what you want to do and leave you with enough extra $$ to go mono, which I highly recommend. 

Cheers,
Dimitris

@dkamen thanks! good point about using the astrobin advanced search function to gather data and make some stats out of it

@Björn Arnold  that's true about resolution when using, for example, 12" RC. But I could, for example, bin 2x2 right? This way I could resample the data and increase the SNR by ~x2. And also get a nice close up of the galaxy, which I wouldn't have at, for example, 1000mm. Or am I missing something here?

There indeed is a road behind me i had lots of fun with my SkyGuider Pro, and pushing that little beast to the max has taught me quite some stuff!
I'm not really afraid of mono per se, I'm afraid about myself being too lazy sometimes and mono requires more effort than OSC, but it also gives so much flexibility...

BTW, thank you all guys for your feedback(s)!

I disagree with some of the comments regarding mono vs, OSC.  As for a ease of use, once all is set up it does not take long to click on a few buttons an set up the imaging sequence for the night.  There  will be  more work in stacking/calibrating each channel. The cost will be more and some filters such as Astrodon are expensive. BUT, because you live in an light polluted area, you will find the mono image easier to post process. That will be due to being able to take advantage of narrow band filters.

I live in a bortle 6/7 skies and I personally think OSC is very limited to short exposures and bright objects.  For me galaxies or out,  except the very brightest.  Planetary nebula can be bright and done only using Red/Green/Blue filters.  Since the detail is small, one needs all the resolution you can get.  I would do a search on a few planetary nebula and see what equipment is being used for the best results.

Flats will be necessary with both mono & OSC under bortle 7 skies.  You might get away with out them using narrow band.  The lighter the background, the more necessary flats are.

One thing I have learned, your sky is the last determining factor.  You will not be able to achieve more detail that the seeing will allow.   Consider that when you determine your camera/scope arc/sec per pixel ratio.  Also, LRGB will not go deeper or brighter that the sky glow will allow.  You will need narrow band filters to do that.  I have no experience with the new Tri-Narrow Band filter for OSC.  But they will not work on galaxies, because it will be filtering out most of the galaxy star light.

Invest in the mount.  

I'm a Sony CCD imager and have no experience with the CMOS cameras. However, I see very impressive results with them.

I will end with this comment.  I have been imaging under light polluted skies for 15 years and have concluded that mono narrow band imaging is the only way one can achieve good to very good images.  Also, one is limited to mainly nebula.  If I want galaxies, I have to travel 5 hours.  I prefer fast refractors such as the Tak FSQ106ED at F3.64.  But other less expensive brands have shown great results. When I have done planetary nebula I use a C9.25 or C11 at F10 using RGB binned 2x2.  But I must confess my result have been limited.

Lynn

haaa…I'm starting to finally understand all this binning thing. Basically, taking into consideration the sony imx571 sensor and a 2032mm tube (e.g. 10" RC) vs a 1200mm tube (apo/newton) :

6248x4176 px, 3.76 um
    -> 2032mm, bin 2x2, no crop: 0.76 "/pixel
        -> 3124x2088 image size

    -> 1200mm, bin 1x1, 50% crop: 0.65 "/pixel
        -> 3124x2088 image size

So yep, it seems that a big RC might not be a good idea after all

BTW, I have no idea how to measure my seeing. I usually just look at how much stars are twinkling, but that's all! Is there a way to get a number?

I'm more and more convinced by the mono route.
Now I only have to decide which camera (or, better, which sensor)

About mono, I was thinking I could buy these filters:

• LRGB => Baader planetarium parafocal
• H-alpha => Antlia PRO 3nm
• SII, OIII => Chroma

This way I can buy this year LRGB+Ha, and next year SII and OIII.

What's your take on those filters?

When you get the 1600, don't forget that you are buying yourself some nice micro lensing artifacts.

@Michael Caligiuri  not sure I understand your argument here why you would want to use wider filters for more light polluted skies. Intuitively I would go even narrower to get better snr by removing more unwanted light pollution.

D. Jung:
@Michael Caligiuri  not sure I understand your argument here why you would want to use wider filters for more light polluted skies. Intuitively I would go even narrower to get better snr by removing more unwanted light pollution

The argument is based on integration time not so much light pollution (my bad).  Assuming shorter subs and less overall integration time from typical backyard/urban suburban conditions the wider bandwidth filter lets more light (i.e. nebulosity) in than a 3nm filter would for the same integration time.  Also, the wider bandwidth permits easier framing with shorter exposure times.  Just based on experience.