OSC - What a unexpected disappointment

[Mark72]

Sara,

I think you used wrong debayer pattern - it should be BGGR in PI.

Your data is good, lots of color.

[ianaiken]

That's the spirit

[swag72]

Thanks for that Mark - I will make a note of the bayer matrix pattern. That has certainly added some colour.

Not wishing to be beaten, the OSC is on again now. IDAS removed and 300s subs rolling out. I hope to make sure that I have some colour left in the stars as the detail I am hoping will come from my Ha data from a few weeks ago.

Maybe I was rather quick to rant?!! We shall see!!!

[ollypenrice]

Interesting that Harry says OSC is not great on galaxies. That's exactly what I find as well.

Olly

[Jessun]

Sara, I use a OSC and find it just fine to work with. But my IDASv4 is in a drawer...

[swag72]

I have to say that last nights data, without the IDAS was better, but the OSC is a strange beast that's for sure. I thought that going from using a mono it would be far easier, but no ....... I think I shall persevere for now, but I'm still not hugely convinced as to it's worth compared to the mono.

Here's a HaRGB combination of the mono Ha data and the OSC.

IC1396 in HaRGB by swag72, on Flickr

[ncjunk]

Your rant made me laugh, its how i feel about my osc. I find rgb much easier than osc. rgb seems logical to me...osc is just witchcraft!

nice image that last one.

[swag72]

Ahh, witchcraft ...... Yes, that's what it is!

[ianaiken]

Having just processed my first image from a mono camera (Ha) I can now say how much easier that was compared to OSC processing. However, I feel having an OSC has made my skills stronger, maybe something I would not have got if I went straight for mono in the first instance.

Sara - looking good!

[r3i]

Latest pic is very good Sara - looks like you've got it all worked out.

[ollypenrice]

Ahh, witchcraft ...... Yes, that's what it is!

Well then, you should be fine, Sara! :D

I do agree with Senor Junk's point, though. OSC is sometimes funny and elusive to process. I've always warned people on 'what camera' threads not to imagine that OSC is easier to process.

Do you know the Lab colour boost trick which I learned from MartinB?

Convert to Lab colour mode, split channels and increase the saturation by 30 points (yes!!!!!!) on a and b channels before recombining.

You should also process a synthetic L layer separately, as you would a luminance. You can, for example, make a greyscale version, do an L processing job on it, and re-apply it as a luminance layer.

You do need to learn your way around OSC. It doesn't just follow directly from mono processing.

Olly

[PortableAstronomer]

Well, it was this old post with a OSC that convinced me that I must get one of those (at the time)...

http://stargazerslounge.com/showthread.php?t=79020

I've since tried Atik 314L mono (lovely camera) and also borrowed an 8300 mono once (which was a disappointment in terms of sensitivity), but I still use the QHY8 OSC most.

[swag72]

I have got that trick up my sleeve Olly. It is interesting that based on my DSLR and mono CCD experieince, I would always have suggested that people get a OSC as it is surely the best of both worlds. However, having used one I would definitely say that I prefer mono, and also that it is easier to process - I never thought I'd be saying that.

[reddoss]

As I also implied in my AN article, finding out what to do with OSC data is, at first, a bit daunting. Once you get the right routine it's a lot easier. The single flat and the lack of aligning are the perks. But is OSC easier? Nope! Not once you're inside the house.

Olly / Anyone,

I have just got hold of a 2nd hand SXVR M25C OSC. I will not be able to use it until the end of July due to having to go to Japan with work. I have bought Nebulosity as the capture software and am thinking about getting AA5 for processing.

Can someone recommend some good reading/websites which explains how to process OSC images?

Cheers,

Justyn

[Jessun]

You should be OK with your usual DSLR routines, but you will probably find that darks can be replaced by a defect map in AA.

Also you'll enjoy the longer subs you can do without increasing noise as much as a DSLR does.

It's a fine camera :-)

[ollypenrice]

Yes, and my OSCs like long subs. Worth a try.

Olly

[swag72]

How long Olly? I know that you are graced with nice dark skies. The mono is firmly on the Pentax now as I await some cloudless skies, I think they're all gone to England at the moment!!

[ollypenrice]

I go for round numnbers for the sake of darks and often go for 15 mins at around F5 with the OSC, Sara.

Olly

[swag72]

Cheers Olly - I think I am going to have to do some testing with this camera. Firstly, why does the maximum ADU figure only go to 55900, when with my other CCD it goes to 65556 (or something very close!) - This means that I am getting full saturation sooner - Is this a OSC norm?

I have an IDAS filter, so can manage the longer subs (I went to 10 mins before), but the stars were just blown out, hence my thinking of a star layer. When I did 300s without the IDAS, there was definitely less detail in the nebula.

I have found with mono RGB I tend to be at about 600s. I need to experiemnt more with the OSC, but I fear it's in it's box now and will remain there for a while!!

[dmahon]

Can someone recommend some good reading/websites which explains how to process OSC images?

It's the same as mono, isn't it?

If mono processing were best, surely OSC owners would just separate their pictures into individual (L)RGB frames and process that way, before recombining channels. Similarly, if OSC were best for processing, mono owners would combine their images into (L)RGB before processing. So the processing should be the same.

Or am I missing something?

[ollypenrice]

It's the same as mono, isn't it?

If mono processing were best, surely OSC owners would just separate their pictures into individual (L)RGB frames and process that way, before recombining channels. Similarly, if OSC were best for processing, mono owners would combine their images into (L)RGB before processing. So the processing should be the same.

Or am I missing something?

Maybe. You can improve image quality by processing RGB very differently from L. In the L you can process for detail, sharpness where desired, and contrast. In the RGB the priority is good saturation and low noise with no need for detail.

With OSC you can follow this principle by separating a synthetic L channel.

Where colour saturation is low you can iteratively apply the L in small doses, boosting contrast and noise reducing at each iteration.

Harry Page has good info on OSC processing on his Harry"s Astro Shed site.

Olly

[ncjunk]

I have found with mono RGB I tend to be at about 600s. I need to experiemnt more with the OSC, but I fear it's in it's box now and will remain there for a while!!

Don´t give up on it just yet! everythings a compromise and I plan on using mine for widefield at the same time the mono is doing close up.

I just tried my OSC again and found that it worked wonderfully last night at -20 deg c. No idea what the problem was but its now sorted so I just have to look at processing now. (I did remove a qhy6 driver that was causing conflits with the qhy8l cooling so I wonder if that made any difference..)

[ianaiken]

I agree with Neil don't give up on it yet. I've attached an M42 pic I did recently, its 18x60s subs. M42 is a hard target due to its position so it's only visible for a short period of time. It pops above the house, then goes behing the chimney, then there is a meridian flip, then it goes below the house. Hopefully you can see what the OSC can do for these types of targets. This is based upon the assumption that the pic is half decent

[ollypenrice]

This is based upon the assumption that the pic is half decent

But it isn't! It's way more than half...

Olly

[swag72]

Great image Ian. I think the OSC is just in the box until I suss out the smaller Pentax 75SDHF, which I am embarassed to say I've not yet used since getting it in March. The mono is on there at the minue, I'm sure the OSC will come out again!