Beginners, monochrome is fastest and easiest!

[Alien 13]

12 minutes ago, John78 said:

This point is one I don't really get - if you're going to fork out a grand plus on a astronomy specific cooled camera why would you even consider a OSC version, who buys them and then why??  How is it even a marketable proposition?

 

 

I expect colour cameras are used in other imaging applications like microscopy as well as machine monitoring.

Alan

[Ouroboros]

19 minutes ago, John78 said:

This point is one I don't really get - if you're going to fork out a grand plus on a astronomy specific cooled camera why would you even consider a OSC version, who buys them and then why??  How is it even a marketable proposition?

Fully agree people use DSLRs because most people that would consider this hobby already have one, so its logical to use it while dipping ones toe so to speak.

I probably would have moved on from my cranky old DSLR and bought an OSC if I hadn't been put off by all the negative comments about them. In the absence of such negativity I would have thought to myself: ah an OSC looks like a modded DSLR with the advantage of being cooled ..... and I can buy one for about the same price as a decent DSLR without all the expense of a filter wheel and filters ..... and since I only get a few hours imaging a month if I'm lucky, and have to set up and tear down my kit each time so simple is best, I might well get better results than I do now.    But ... as I say, because of the negative press, and my reluctance to fork out for a mono CCD, filter wheel, filters etc plus the added learning curve, I end up ..... doing nothing. 

[Knight of Clear Skies]

Don't suppose you could post up your red channel please Olly? Would be interesting to see how it compares to the Ha.

[ollypenrice]

1 hour ago, Knight of Clear Skies said:

Don't suppose you could post up your red channel please Olly? Would be interesting to see how it compares to the Ha.

Sure. I'll post the RGB-only as well. I applied the Ha solely to the red channel in blend mode lighten. It could also, maybe, go in as luminance but only very slightly. More would be heresy!!

RGB

 

Red

 

Olly

PS The full 25 hour monty is a lot better. Jointly done with Mr and Mrs Gnomus and looking a bit rough posted directly onto here. I normally link from my Smugmug gallery site. However, the difference between 2 hours and 25 hours might be described as 'sobering.' What a game!!

 

[geoflewis]

Wow...!!!

[steppenwolf]

3 hours ago, John78 said:

This point is one I don't really get - if you're going to fork out a grand plus on a astronomy specific cooled camera why would you even consider a OSC version, who buys them and then why??  How is it even a marketable proposition?

Well, me for one!  A full RGB image in a series of single shots under fickle UK skies - what's not to like? Sadly, I don't have an image of the Heart Nebula but I have plenty of OSC images on my website and still use an SXVF-M25C when I'm after an RGB image even though I have an excellent mono CCD camera. The most recent OSC image I have captured is the one shown below captured with an ATIK 4120EX. Maybe not a prize-winner but surely not too shabby for JUST 1 HOUR of data?

[ollypenrice]

55 minutes ago, steppenwolf said:

Well, me for one!  A full RGB image in a series of single shots under fickle UK skies - what's not to like? Sadly, I don't have an image of the Heart Nebula but I have plenty of OSC images on my website and still use an SXVF-M25C when I'm after an RGB image even though I have an excellent mono CCD camera. The most recent OSC image I have captured is the one shown below captured with an ATIK 4120EX. Maybe not a prize-winner but surely not too shabby for JUST 1 HOUR of data?

Far from shabby!

I had a spell with parallel OSC and mono Atik 4000s. My thinking was that if I was going to be running two cameras at once I'd give myself a break and have one of them easier to manage on the capture side. In the end, though, I found I could get more done with two monos.

I'm not bashing OSC or DSLR here. My point is just to say that mono and filters is not a slow system, as so many people believe.

Olly

[Alien 13]

9 minutes ago, ollypenrice said:

I'm not bashing OSC or DSLR here. My point is just to say that mono and filters is not a slow system, as so many people believe.

Olly

I am still finding it difficult to understand why a mono camera without filters isn't better, it must be faster as it captures everything in one go, narrow band isn't a real representation of an object unless you include microwave/radio waves and every other available spectrum.

Alan

[steppenwolf]

Quote

I'm not bashing OSC or DSLR here. My point is just to say that mono and filters is not a slow system, as so many people believe.

One day, I must put this OSC v Mono + LRGB filters to the test myself but I tend to concentrate on narrowband these days although that may change this winter!

Worry not, Olly I know you're not knocking OSC per se, I was more interested in answering the question posed by John who seemed incredulous that anyone would buy a OSC camera, suggesting that they were not a realistic proposition for anyone - I think I have shown that they are a realistic proposition and indeed a marketable proposition at that in the right conditions and with the right subject.

[Macavity]

I have learned something OSC = One Shot Colour!
http://www.atik-cameras.com/news/mono-colour/
I admit to some residual confusion. Towards the end:
 

Quote

Another factor to consider is, though we hate to say it, cost. Although there is little
to no difference  between a mono and OSC version of the same camera model...

But there are only two basic camera technologies - MONO and "Colour"?
which differ re. presence of a Bayer Matrix? Though manufacturers may
indeed use a totally different CHIP in their mono and colour versions.

That there may not be a simple (e.g. numerical) relationship between
the two is a common enough feature of many things Astronomical...

[John78]

14 minutes ago, steppenwolf said:One day, I must put this OSC v Mono + LRGB filters to the test myself but I tend to concentrate on narrowband these days although that may change this winter!

Worry not, Olly I know you're not knocking OSC per se, I was more interested in answering the question posed by John who seemed incredulous that anyone would buy a OSC camera, suggesting that they were not a realistic proposition for anyone - I think I have shown that they are a realistic proposition and indeed a marketable proposition at that in the right conditions and with the right subject.

Incredulous maybe ?, the point being if you can deliver that great result with 1 hour, and if what Olly is saying is true (and I think we all agree it is) then an equivalent mono camera will deliver faster results than its colour counterpart.

Im also fairly sure the reason colour cameras especially the new CMOS ones exist is simply parts availability is huge, thus prices are low.

I guess my final point of baulking at a OSC would be narrow band imaging, sure if you only ever want an RGB image it's a reasonable solution, if you want a narrowband image, an OSC is tying your hands and poking you in both eyes with pointy sticks ??

[ChrisLX200]

Remember that for RGB (and thus OSC cameras) you really want a dark, moonless sky. If you have any light pollution it plays havoc with your raw data and can be very difficult to process effectively - colour bias/gradient is common and an utter pain to remove. The Moon only adds to your woes and reduces the number of possible nights you could be imaging (at its best anyway). Think about your local conditions before deciding..

ChrisH

[ollypenrice]

10 hours ago, Alien 13 said:

I am still finding it difficult to understand why a mono camera without filters isn't better, it must be faster as it captures everything in one go, narrow band isn't a real representation of an object unless you include microwave/radio waves and every other available spectrum.

Alan

If you want to capture the maximum amount of light from a source then an unfiltered mono camera is the way to do it. However, the image will be visually incoherent because lots of photons from outside the visible spectrum will flood the sensor. I don't think anybody would want this. A luminance filter restricts the incident light to that of the full visible spectrum and captures all of it at once so it is the fastest way to record all the incident visible light. However, it cannot, of course, distinguish colour.

Do you want colour? I do. The colours in broadband images are real in the sense that the distribution of incident wavelengths is preserved in the final image, properly attributed to their colours as perceived by the eye. If it were possible to make a telescope which could direct sufficient object photons into our eye to trigger our colour vision than the colours in well made LRGB or OSC images would be what we would see. (Such a telescope cannot be made at present and perhaps never will be made.)

Does narrowband represent the object? It most certainly does represent the object when we define the object as the source of the photons in question. That is not the same as representing the entire field of view with its multiple sources of photons. The charm of a NB filter is that it selects just ionized hydrogen, or just doubly ionized oxygen, and allows us to see structures in those gasses which are otherwise drowned out by light from other sources. As long as the filtration is declared I think it's both attractive and informative.

SPEED.

Let's be optimistic and say that a colour filter blocks 2/3 of the light. (I think it's nearer to 3/4 but not to worry.) Any given pixel of an OSC is, therefore, catching 1/3 of the light throughout the shoot. A mono camera is doing exactly that during the colour acquisition but the moment the L filter goes in it is racing away from the OSC by catching 3/3 of the light. I cannot see any flaw in this argument but I'm happy to listen.

EASIER?

We've given the 'faster' football a good kick around but are you really going to let me get away unchallenged on the 'easier' side of my claim? That doesn't sound like SGL to me!!!! There is a perfectly understandable perception that OSC must be easier than multiple filter mono imaging. I don't believe it is, though.

Firstly let's look at what you do to make an RGB image. You shoot a set of red, a set of green and a set of blue and stack-calibrate them. You are now two clicks away from an RGB image. Click 1 aligns the images together. Click 2 blends them into a single colour image. Now that cannot be difficult!  It really is that simple. However, that simplicity doesn't, of itself, make it easier. Here's what does make it easier.

-You capture the right amount of each colour. An OSC captures twice as much green as red and blue. Given that green is a 'problem colour' in AP (hence the-plug in Hasta La Vista Green or PI's SCNR Green) this green excess is not at all helpful. With experience you will find that you may need to shoot more of one colour than another to get a balance which works best in your LP situation, with your LP filter, etc. From my dark site I just shoot equal amounts but the flexibility is there. I've just processed two guest DSLR images from an LP site and they clearly need considerably more blue. This would be easy to arrange with a mono camera.

- If your optics are not perfectly corrected you can refocus for each filter. An OSC focus is a cross-spectrum compromise.

- If your fourth filter is Ha, as in my example of the Heart, you have a highly structured, sharp, contrasty layer to inject those qualities into the final picture. 

- If your fourth filter is luminance then you have a lot more signal to play with than you'd have in an RGB image and you'll find this makes the processing much easier. More signal is always easier to process than less.

Olly

[Gina]

Very well put Olly

[AKB]

50 minutes ago, ollypenrice said:

EASIER?

We've given the 'faster' football a good kick around but are you really going to let me get away unchallenged on the 'easier' side of my claim? That doesn't sound like SGL to me!!!! There is a perfectly understandable perception that OSC must be easier than multiple filter mono imaging. I don't believe it is, though.

Firstly let's look at what you do to make an RGB image. You shoot a set of red, a set of green and a set of blue and stack-calibrate them. You are now two clicks away from an RGB image. 

No, can't let you get away with that.

You seem to have overlooked the complexity (and cost) of a set of filters, a filter wheel, and switching between them manually (or automatically having set up the right software to do all that.)

One reason that people use OSCs is that it IS a lot easier in terms of hardware setup.

 

 

[ollypenrice]

1 minute ago, AKB said:

No, can't let you get away with that.

You seem to have overlooked the complexity (and cost) of a set of filters, a filter wheel, and switching between them manually (or automatically having set up the right software to do all that.)

One reason that people use OSCs is that it IS a lot easier in terms of hardware setup.

 

 

I've acknowledged the cost at the outset and am confining my comments to speed and ease. But, yes, filters can be expensive of course.

An electric wheel is a luxury and would add to the complexity of setup in a mobile rig. Operating one is a total non issue, though. You just plug in a sequence and press go.

Can we really call a manual filter wheel complicated? You put your thumb on the wheel and turn it. It's as easy as falling off a unicycle. You have to rename the files, too, on a manual wheel but, again, not difficult. An electric sequencer will name the files for you and put the filter in the FITS header so you can't go wrong.

In the scheme of imaging complexity I'd call it pretty tame, no?

Olly

 

[RayD]

20 minutes ago, AKB said:

No, can't let you get away with that.

You seem to have overlooked the complexity (and cost) of a set of filters, a filter wheel, and switching between them manually (or automatically having set up the right software to do all that.)

One reason that people use OSCs is that it IS a lot easier in terms of hardware setup.

 

 

I tend to agree.

I use mono almost exclusively, and couldn't agree more with the OP that the results are far better than with either DSLR or OSC for a given time and conditions, and I think that point has been very adequately demonstrated.  However, whilst I do indeed find mono "easy", and use an automatic filer wheel and sequencer etc. I don't think there can possibly be any argument for it being easier than OSC.

If you took a total novice and gave them the 2 options to adopt from scratch, I suspect they would undoubtedly be imaging (note above re. quality) quicker and with less head scratching with OSC than mono, which in my eyes make OSC easier?

Easy......yes, definitely once you are used to it.  Easier......nope, afraid not.

[Gina]

Imaging might be easier though IMO there is little difference once you have set things up, processing is far more difficult with an OSC.  As has been said the over preponderance of green and deficit in blue means you have to adjust curves on the three colours to make the histograms match and of course, you are throwing away loads of unwanted photons you struggled to capture.

[ollypenrice]

9 minutes ago, RayD said:

I tend to agree.

I use mono almost exclusively, and couldn't agree more with the OP that the results are far better than with either DSLR or OSC for a given time and conditions, and I think that point has been very adequately demonstrated.  However, whilst I do indeed find mono "easy", and use an automatic filer wheel and sequencer etc. I don't think there can possibly be any argument for it being easier than OSC.

If you took a total novice and gave them the 2 options to adopt from scratch, I suspect they would undoubtedly be imaging (note above re. quality) quicker and with less head scratching with OSC than mono, which in my eyes make OSC easier?

Easy......yes, definitely once you are used to it.  Easier......nope, afraid not.

How about post-processing though? I always found OSC quite hard to process. It was OK on bright objects but was somehow sluggish to respond to post processing input. It just didn't seem to give much back. When I had both versions of the Atik 4000 I tended to use the OSC in conjunction with Ha captured in the mono. If I factor in this experience I still conclude that for a given result mono is easier.

Olly

Gina posted the same point as I was typing.

 

[RayD]

1 minute ago, Gina said:

Imaging might be easier though IMO there is little difference once you have set things up, processing is far more difficult with an OSC.  As has been said the over preponderance of green and deficit in blue means you have to adjust curves on the three colours to make the histograms match and of course, you are throwing away loads of unwanted photons you struggled to capture.

Agreed Gina, but this is all referring to the quality of the resulting images, which I agree is far superior.

Note the OP refers to "Beginners" who won't know a curve from a bend, or histogram from histamine.  A OSC will give you a colour image with absolutely no processing at all, mono won't.

[Macavity]

Of importance (imo) is number of binary BITS used to represent the image.
What is the inherent "resolution" of the chip? How do the ADCs convert it into 
digital format? How is the information packed into "standard" data format etc.

If you are using colour (to some approximation) the available intensity levels
are divided by THREE. On the other hand, MONO data may only mean 12/14
bits (e.g. not 24!) Be aware of difference between "RAW" format and others?
How does YOUR software process the abvailable data e.g. 16 or 8-bit etc. 

If you need to S-T-R-E-T-C-H image, the more BITS available the better!
But later, you can process in 8-bits and (likely) present the data as .jpg's.
I think it worthwhile spending a little time understanding the above ideas?

For THAT reason, you are "safer" with MONO cameras. Though you should
take care not to *waste* DATA along the processing chain? 
Once it's gone... it's GONE! 

For Deep Sky, I use a filter SLIDE. The big advantage is that I can SEE the
label of the filter I am using! I use a colour Camera for "Planetary" 'cos I'm
not that nimble in changing filters? (And I sense it is sufficient for me!)

There are a host of other things that come up. Newtons Rings in H-Alpha
Mono. Moire Patterns in colour planetary images? Thing sent to try us.

[RayD]

1 minute ago, ollypenrice said:

How about post-processing though? I always found OSC quite hard to process. It was OK on bright objects but was somehow sluggish to respond to post processing input. It just didn't seem to give much back. When I had both versions of the Atik 4000 I tended to use the OSC in conjunction with Ha captured in the mono. If I factor in this experience I still conclude that for a given result mono is easier.

Olly

Agreed, and I'm sure those using OSC once they understand how mono really works will no doubt make the switch as undoubtedly (and you have demonstrated excellently) the results are far superior.  However, your OP refers to "beginners" and that mono would be easier for them, but as they can get a (limited quality) colour image with no processing at all, I don't think it can be easier.

Btw nice image with limited time 

[ollypenrice]

1 minute ago, RayD said:

 A OSC will give you a colour image with absolutely no processing at all, mono won't.

Surely not! Precisely the same post processing techniques are needed to turn the linear image into a stretched one. The only difference in getting to the post processing stage is in the two clicks needed to turn R and G and B into RGB and the one click needed to debayer an OSC (once you've identified the correct Bayer pattern to do so.)

Olly

[RayD]

2 minutes ago, ollypenrice said:

Surely not!

??

Ok maybe "OSC" was not a good example, but certainly I can take a JPEG image straight from my DSLR and open it in all it's colourful glory so how can mono therefore be easier?

[Gina]

I guess if you're prepared to put up with a thoroughly rotten image you could get away without processing by using JPG capture (sorry for swearing!!!) but I'm sure nobody would leave an astro photo unprocessed - the result would be so disappointing that it would put the majority of people off bothering to go any further.  Maybe it's a case of "beginners" or "absolute beginners" but absolute beginners would be better off forgetting about a telescope and just using the camera lens for widefield shots.