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Calzune

Convince me going MONO....

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Convince me going MONO....

First I wanted to buy a zwo asi 294mc pro, but since the production has stopped because corona virus the stores will not get it until late mars or april, Im thinking on maybe a mono cam will be a better choice in the long run?

The price difference is 1000USD more with a complete mono kit with everything I need. (asi 1600pro, filterwheel, LRGB filters + 7nm Ha,OII,SII).

My skies so far have not been good the last months, only 1 clear night every 10 days or so. And because of that I think a OSC cam will give me pictures each night I image,

However I have read that a Mono cam is more sensitive that OSC cams and requires less imaging time per filter because it uses the whole sensor in each filter so it produces a stronger signal in less time.

A mono cam is also better if I have light pollution and neighbors that have many lights in their yard..

I have also looked at zwo asi 071, but thats "only" 3-500 usd less than 1600mm pro kit..

help...:D

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Edited by Calzune
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It really depends on what interests you have today and where you think you will be in the future. Today's One shot colour cameras take great pictures and Software allows you to do live stacking so you can watch the image improve frame by frame. But for faint galaxies monochrome is the way to go.

With Mono, collecting the images is only part of the story. You have a couple of hours processing time before the final image is available.

I started with a OSC camera and have taken satisfactory images with it. Today, except for lunar and planetary, I am exclusively Mono.

Atik Cameras do live YouTube videos demonstrating their infinity OSC cameras and I think there is a live broadcast next week. Check out their website for more info.

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With mono you have more options. You can do narrowband. You can image for detail when seeing is good, and colour when seeing is bad. RGB filters generally have a stopband at the Na/Hg wavelength. Mono is not slower than osc. With an electric filter wheel, you can alternate filters to shoot all colours during one session.

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I made the transition from a DSLR to mono last year and was initially apprehensive especially with what a lot say  “I can’t be doing with all the faff” but does require an initial outlay of some more £££ 
It genuinely isn’t a faff and with your filters in an EFW this and your camera just connect to the scope and that’s the difference in setup. 
Image acquisition is just a case of setting a plan up in your software and away you go pretty much the same as an OSC.
Processing is more in-depth but the way I see it is there are so many crappy nights that I can’t get out due to weather that there is plenty of time to learn new/practice processing skills.
As @wimvb has said you can shoot all filters in one night so as a rough example LLLRGB and just repeat this over and over again ....no need to capture Lum one night Red another etc. 
Not the most technical post but these were some of my initial concerns before I made the decision to go mono and I’m more than happy with my choice.

Edited by Danjc
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Why I use mono:

Mono allows you to shoot luminance (all colours at once) so that stage means you work about three times faster than OSC where the chip is always trapped behind RGB filters. It is therefore about 20% faster - at least.

Some targets are best shot in RGB plus narrowband. For example, 

Narrowband is obviously best shot in mono because all the pixels will receive light through the filter. Only the red filtered pixels (1 in 4) receive light through an OSC Bayer Matrix.

Narrowband beats light pollution (though I don't have any.)

Ha can be shot in moonlight on all pixels, not 1 in 4.

Processing mono images: does it take longer? I found it very hard to get to the standard I wanted using OSC. I don't know why exactly. At the stacking, calibrating and combining stage it adds no more then ten minutes, probably less. Do you need to refocus between filters? If they are the same make and decent ones, no, but you can. In OSC you can't - and the need to refocus is not driven by the filters but by the optics. If you focus in Luminance then RGB will be OK.  Do you need flats per filter? Once in a blue moon you might but 95% of my images use a luminance flat for all channels.

In mono you can shoot just what you want to shoot based on the target. This might mean lots of L and little RGB. Or no L and just RGB. Or either of these combinations plus narrowband. You are not stuck with all those RGB filters blocking the light when not wanted and getting in your way. 

Olly

Edit: Carole, below, mentions the ability to bin 2X2 for colour. I'd forgotten that. You can also bin 2x2 (or 3x3) to avoid being over sampled in all filters. With CMOS cameras now having such tiny pixels this might be an advantage at even quite modest focal lengths- though the gain from binning with CMOS is not as great as with CCD.

 

 

 

Edited by ollypenrice
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OSC for me, have used the Atik Infinity for 3 yr now have ZWOasi533 pro on order with FLO, Mono obviously gives fine detail image & produces better results, so its a case of how much do you want from an image, a reasonable photo in quick time does for me.

Short subs on alt/az or eq ,with optolong l-enhance filter subduing a lot of LP from bortle 7/8 backyards as well as bringing colour out on Emission Nebula.

3 or 4 DSO's a night is easy and the final image looks ok.

regards

eric

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I have never looked back since I went Mono.  The sensitivity is far better than a colour camera showing much more detail. 

OK it costs more initially with all the filters and filter wheel and takes a bit more learning, but I'd never go back to a colour camera after using mono. 

I generally set up a sequence of all filters that are parfocal (I check them all before I start (not all are but most) and simply run a sequence so if I get a clear night I can get a complete image in one evening, capturing the data that is not parfocal of course separately, usually at the beginning so once that is done I can go away and leave the rest chugging away as a sequence. 

You also get the option to bin data with Mono cameras, and I use this all the time for the colour component  cutting the time down greatly.  If I had copious clear skies then I might not feel the need to do that, but it certainly seems to work for me with the cloudy UK skies.   

The option to use narrowband in my LP location is another big plus, I know some people say they can use narrowband with a colour camera, but I can't imagine they can get so much detail and must take far longer.

Finally, there are some targets that just don't show off their potential in RGB.

HTH

Carole 

 

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Some brilliant advice above and I am not really experienced enough to add anything really. I was asking the same question just over a year ago and eventually went the mono route and I really do not regret it.

I think it really does come down to what you want to do and what targets maybe you want to image.

I have no experience of dedicated OSC as I went from DSLR to dedicated mono but I would think whatever image you can get in a night with OSC you can achieve with a mono. Yes you may have to take 3 or 4 images to the one OSC but the total exposure time need not be any more due to the extra sensitivity, and as Carole says if your filters are parfocal then no more fuss either as you can use session software such as APT to do it all automatically without your intervention. Yes it takes a bit more work in the processing but the end result may be worth it. 

I think the biggest factor to rule OSC out maybe if you want to go Narrowband, do you want to capture some images that really require NB whether due to their intensity, emission wavelength,  or whether due to you being in a light polluted area. And imaging in a near full moon NB also comes into its own. 

Steve

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A few nights ago there was a gap in the clouds and I started an imaging sequence. Guiding was good, seeing ok, so I started a sequence with 25 x 2 min L, then 10 x 4 min R, G, B. Mid into G, clouds moved in and I had to abort the sequence. Would OSC have been better? At least I would have had data for a complete image, right? Not in my opinion. That image would not have been good by any means. I would still need to collect more data in order to get anything presentable. 1 1/2 hours just isn't enough time, whatever technology you use. Even if clouds had moved in after a complete LRGB cycle, that wouldn't have been enough. I know that with my cmos camera, I need at least 100 L subs and some 30 RGB subs for an image that I can process the way I want it. But  with the L that I collected, I have the beginning of what can become a good image. And I can probably use the R, and maybe even the G in the final image. OSC wouldn't have been any faster.

And processing mono isn't any more complicated than osc. PixInsight takes care of the subs being calibrated correctly, and with subfame selector, I can choose exactly which frames to use of each filter. This gives me more freedom than osc.

Edited by wimvb
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I can’t comment on the ZWO filters but when I started with mono I couldn’t afford everything in one go so just bought my camera and a Baader Ha filter just to get me going. 
The camera (if ZWO)should come with an adapter to accept a single filter so not essential for an EFW straight away (for me anyway). 
One thing I will say as it was also mentioned to me was do you plan on going narrowband and broadband  ? If so a 7/8 position wheel will be better from the off. I did go 5 position but got a used one for a £100 but will need a larger wheel in the near future. 
May be worth mentioning your choice of camera as slightly bigger filters work better with certain sensor sizes.....but someone with more knowledge than me will be able to advise better than me on this. 
 

 

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