Just 1 hour of 2 min subs on the Rosette Nebula

[Stuart1971]

Quite happy with this for just 1 hour with my QHY268c and the Optolong L-Extreme filter..

Processed as Ha and OIII, although the RGB processed version looked pretty much identical…

 

 

Edited February 24, 2022 by Stuart1971

[StuartT]

Very nice! I assume that when you say ‘processed as Ha and O III you’re meaning some kind of pseudo-narrowband emulation using pixinsight from an OSC (rather than using a mini camera)?

[Stuart1971]

1 hour ago, StuartT said:

Very nice! I assume that when you say ‘processed as Ha and O III you’re meaning some kind of pseudo-narrowband emulation using pixinsight from an OSC (rather than using a mini camera)?

Well, the L-Etreme filter only passes Ha and OIII and is designed to use with OSC cameras, so in APP, you stack the data twice, ones too extract the Ha and again to extract the OIII, then you end up with two mono images which you combine and assign Ha and OIII, TBH the image comes out pretty much the same when processed as RGB, so it was not really worth the effort in the end…

[bottletopburly]

Lovely image Stuart 👍 amazing camera loads of detail and for just 1hr astounding really 

[StuartT]

1 hour ago, Stuart1971 said:

Well, the L-Etreme filter only passes Ha and OIII and is designed to use with OSC cameras, so in APP, you stack the data twice, ones too extract the Ha and again to extract the OIII, then you end up with two mono images which you combine and assign Ha and OIII, TBH the image comes out pretty much the same when processed as RGB, so it was not really worth the effort in the end…

Ok, I’ve not tried that (I just use all the default settings in APP as I don’t understand what it’s doing anyway! 🤣)

so could you assign the Ha and O III to blue and yellow to get something like a Hubble image?

[scotty38]

1 hour ago, Stuart1971 said:

Well, the L-Etreme filter only passes Ha and OIII and is designed to use with OSC cameras, so in APP, you stack the data twice, ones too extract the Ha and again to extract the OIII, then you end up with two mono images which you combine and assign Ha and OIII, TBH the image comes out pretty much the same when processed as RGB, so it was not really worth the effort in the end…

yep but I think the idea is you can process them separately before combining them so as to apply different things to Oiii and Ha accordingly.

[scotty38]

4 minutes ago, StuartT said:

Ok, I’ve not tried that (I just use all the default settings in APP as I don’t understand what it’s doing anyway! 🤣)

so could you assign the Ha and O III to blue and yellow to get something like a Hubble image?

Yeah you can then recombine assigning your Ha and Oiii as HOO or whatever to the RGB channels.....

Edited February 28, 2022 by scotty38

[StuartT]

17 minutes ago, scotty38 said:

yep but I think the idea is you can process them separately before combining them so as to apply different things to Oiii and Ha accordingly.

 

15 minutes ago, scotty38 said:

Yeah you can then recombine assigning your Ha and Oiii as HOO or whatever to the RGB channels.....

Ok. I should prob learn how to do that. Do you know of any videos showing how it's done?

[scotty38]

17 minutes ago, StuartT said:

 

Ok. I should prob learn how to do that. Do you know of any videos showing how it's done?

What software do you use, I tend to butcher mine mainly in PI 🙂

[StuartT]

6 minutes ago, scotty38 said:

What software do you use, I tend to butcher mine mainly in PI 🙂

I use Astropixel Processor or Siril

Pixinsight looks way too imtimidating

[scotty38]

Ah, I have APP too but videos are a bit thin on the ground. Not sure if Sara Wager has any on her site???? I have not really used Siril so not looked for videos either I'm afraid.

[Stuart1971]

46 minutes ago, scotty38 said:

yep but I think the idea is you can process them separately before combining them so as to apply different things to Oiii and Ha accordingly.

Interesting as I did not know how to process, so asked on the APP forum, and the mod on there sent me full instructions, and it did not include processing them separately, I had to put all the subs in and use the extract Ha tool, and then the same with the extract OIII, this then gave me two mono images, which I then had to put in the combine RGB tool, assign them to Ha and OIII, then it gave me a colour image which looked pretty much identical to the RGB processed image, so they then told me to increase one of the sliders on the OIII to 3x and this changed the colour from all red, to a blueish centre, OIII, with deeper red outer, Ha, not sure how to get other colours though….🤔🤔

so how would I process the two mono images separately or is there  another way I should be doing this..?? In the end I stuck with the RGB processed version

[Stuart1971]

53 minutes ago, StuartT said:

Ok, I’ve not tried that (I just use all the default settings in APP as I don’t understand what it’s doing anyway! 🤣)

so could you assign the Ha and O III to blue and yellow to get something like a Hubble image?

Me neither most of the time, I had to ask on the APP forum….😂

[scotty38]

To be honest I could never get my head round it in APP so didn't really try and it's no use pointing you to the hundreds of PI examples either. BTW if you separate the Oiii and HA and then just combine them then yeah that's just like doing it all combined in the first place hence they look the same.

For the colours you'd have to adjust the sliders differently but if memory serves me correctly you can choose from different palettes anyway. Just scroll down the panel on the left hand side and there's drop down where you can pick and then "apply" or something. I'm not in front of my machine with APP right now otherwise I'd take a screenshot but will do so later if you don't find it first....

[StuartT]

6 minutes ago, Stuart1971 said:

Me neither most of the time, I had to ask on the APP forum….😂

Ok, I've contacted Sara Wager. She's an APP expert so maybe she can shed some light on this. I'll report back if she does.

Or maybe it's simply not possible in APP and I'll have to take the plunge into Pixinsight! 😱

[Stuart1971]

1 minute ago, StuartT said:

Ok, I've contacted Sara Wager. She's an APP expert so maybe she can shed some light on this. I'll report back if she does.

Or maybe it's simply not possible in APP and I'll have to take the plunge into Pixinsight! 😱

Oh, it is deffo possible…just don’t know have….👍🏼

[Stuart1971]

5 minutes ago, scotty38 said:

To be honest I could never get my head round it in APP so didn't really try and it's no use pointing you to the hundreds of PI examples either. BTW if you separate the Oiii and HA and then just combine them then yeah that's just like doing it all combined in the first place hence they look the same.

For the colours you'd have to adjust the sliders differently but if memory serves me correctly you can choose from different palettes anyway. Just scroll down the panel on the left hand side and there's drop down where you can pick and then "apply" or something. I'm not in front of my machine with APP right now otherwise I'd take a screenshot but will do so later if you don't find it first....

Yes, you are correct, I just chose the HOO as I was directed too, will try some others and see what happens….👍🏼

[scotty38]

2 minutes ago, Stuart1971 said:

Yes, you are correct, I just chose the HOO as I was directed too, will try some others and see what happens….👍🏼

Ok nice one. I'd have to remind myself what it does but I think it takes what you have, in this case an Ha and an Oiii channel and applies them in whatever percentages you choose to the palette you choose ie SHO or HOO or whatever. Something like that anyway but it's ages since I looked at it....

[Anne S]

There's a topic under Imaging tips and techniques that describes using L'Enhance data being used to create a Hubble palate image. I'd put a link but I don't know how to.

You need to split the rgb image after stacking, Photoshop will do this, as well as Affinity Photo, but there's probably others. You use the red channel  which has hydrogen recorded and other the blue or green one, whichever is stronger, which has the Oiii. Just delete the one you don't use, probably blue as there's more green pixels. Make sure the remaining Oiii channel is called blue the create a synthetic green by combining a percentage of the remaining two channels, probably by layering and adjusting blends etc. Not an expert on Photoshop etc, I use Pixinsight!

Stretch the 3 channels so they look fairly similar then recombine as you want. I may have missed something but it explains it very clearly in the thread I've referred to above.

In any case, to process these multiband filter, at some point you really need to split the channels to you can stretch them appropriately to look like the images online. Here's my first attempt using this method below. The first one done without splitting the channels and looks like a RGB image and hardly shows the Oiii at all as the ha is so strong. Hope this helps. Camera was an Alik320e OSC which is not as sensitive as modern cameras.

I did reduce the star size on the second one!

[StuartT]

4 hours ago, Anne S said:

There's a topic under Imaging tips and techniques that describes using L'Enhance data being used to create a Hubble palate image. I'd put a link but I don't know how to.

 

Thanks Anne. I can only see this topic covering how to do this in pixinsight.

Did you mean there is a topic covering how to do it in Photoshop? 

Edited February 28, 2022 by StuartT

[Anne S]

I know you can see the separate colour channels in Photoshop. I think you can delete unwanted channels which, if you do it three times you'll get separate red, green and blue. I think. I do have a ASI533 OSC but I've only used it a couple of times because I do mono imaging at home.

You can stretch in Photoshop and you can recombine channels once you've stretched them. If you make the red mono image RGB you'll see three channels again, all the same Then you can paste the better of the blue and green channels onto the relevant channel, eg blue and green for HOO. I have a Photoshop astronomy book which shows a method for combining ha data into the red channel.

You ought to be able to make  synthetic green channel by layering blue onto red and trying blend levels and opacity.

This is a bit speculative as I haven't tried any of it. I have the odd OSC image so I can experiment but I've got to go out shortly. I'll try tomorrow. I don't use Photoshop much except for finishing off my processed images from Pixinsight. 
 

 

[StuartT]

4 hours ago, Anne S said:

I know you can see the separate colour channels in Photoshop. I think you can delete unwanted channels which, if you do it three times you'll get separate red, green and blue. I think. I do have a ASI533 OSC but I've only used it a couple of times because I do mono imaging at home.

You can stretch in Photoshop and you can recombine channels once you've stretched them. If you make the red mono image RGB you'll see three channels again, all the same Then you can paste the better of the blue and green channels onto the relevant channel, eg blue and green for HOO. I have a Photoshop astronomy book which shows a method for combining ha data into the red channel.

You ought to be able to make  synthetic green channel by layering blue onto red and trying blend levels and opacity.

This is a bit speculative as I haven't tried any of it. I have the odd OSC image so I can experiment but I've got to go out shortly. I'll try tomorrow. I don't use Photoshop much except for finishing off my processed images from Pixinsight. 
 

 

Thanks for this Anne.
 

I’m gradually coming the conclusion that I need to take the next step in my astrophotography journey and embrace filter wheels and mono cameras and finally become a grown up 🤣

 

[Anne S]

I started with a mono camera and manual filterwheel. That worked fine until I upgraded my camera and bought a StarlightXpress original filterwheel. I still use mono at home as I've an observatory so can leave it all set up.

I prefer a OSC for starparties on my mobile rig, less weight and complication. Last year I upgraded my second hand Atik 320e to a ZWO 533. Its giving me a chance to try a cmos camera as that seems to be the way things are moving. If my 11 year old SX694 dies a death it'll probably be replaced with a mono cmos camera. I like large objects so would like a larger sensor which is readily available with cmos and much more reasonable in price. My SX694 cost £2000 and is a 1 inch diagonal sensor.

Pre cmos it was usually quicker to get good data using mono due to the better sensitivity. True narrowband is possible. However the newest cmos cameras such as the 533, 2600 and others, when used with the new multiband filters, are proving to be just as good as the old mono ccds. You do need to process them correctly which is more tricky and time consuming.

I take it your camera is cmos, don't know the QHY model numbers. The main issue with mono is the extra filterwheel and filters which can be eyewateringly expensive, particularly if you need larger ones. I need 36mm ones for my 694 as I use it with a focal reducer. I had bad vignetting.

[StuartT]

1 hour ago, Anne S said:

I take it your camera is cmos, don't know the QHY model numbers. The main issue with mono is the extra filterwheel and filters which can be eyewateringly expensive, particularly if you need larger ones. I need 36mm ones for my 694 as I use it with a focal reducer. I had bad vignetting.

Yes, the camera I use for DSOs is a ZWO ASI2600MC CMOS colour camera. APS-C sensor with super low noise. It's an excellent camera. But at some point, I'll probably invest in its mono cousin (ASI2600MM).

But as you say, the idea of a filter wheel and all those expensive filters (not to mention the massively longer imaging time required) is quite a step!

[Stuart1971]

2 minutes ago, StuartT said:

Yes, the camera I use for DSOs is a ZWO ASI2600MC CMOS colour camera. APS-C sensor with super low noise. It's an excellent camera. But at some point, I'll probably invest in its mono cousin (ASI2600MM).

But as you say, the idea of a filter wheel and all those expensive filters (not to mention the massively longer imaging time required) is quite a step!

I think the gap between OSC and mono has definitely gotten smaller, gone are the days where people can say that mono is better, it may still slightly have the edge, but OSC CMOS is for sure catching up, you say longer imaging times for mono, but with modern CMOS MONO cameras these are far quicker than older CCD mono cameras, so what was a long job to get a good mono image with CCD, is now much much quicker…and easily doable to get a good image in one session, with three filters to get through…even here in the UK…

Like you, I have the 2600 sensor camera, and find it very good, now I have the hang of the gain and offset settings, as this was all new to me coming from a world of CCD, but I would consider the mono version too, when funds allow….😮👍🏼