Combining the H-alpha and SII channels to create a third channel which one colours blue is quite legal artistically.
Scott is speaking artistically when he mentions a "pseudo-OIII".
However, for the folks who aren't sure, you cannot really infer the amount of OIII from the amounts of H-alpha and SII.
If you know the latitude and longitude of a boat, you can't reliably work out from that how much fuel it has.
The whole idea of three very expensive narrowband filters is that they provide three quite independent pieces of information, and you can't (in general) work out the third from the first two.
Nice image Scott, I will use it as a reference when making a mosaic of the Carina one beautiful night day when skies will be clear, possibly in a distant future by the look at the weather...
You wrote that you used 15-minute subs for Halpha, I have found 2-minute subs sufficient with this bright nebula for h-alpha (pixels in my camera are tiny comparing to yours - surface area of an individual pixel is about 6 times smaller - so am I right assuming your camera should be more sensitive?) Maybe shorter subs would make it easier for guiding and would allow you to collect better Oxygen data?
Thanks Slawomir. Your kind comments are greatly appreciated
I took the OIII several months ago when I first got the AZEQ6 when carina was rising at about 2 or 3 am. Since then I have balanced the scope nicely and can regularly pull good 30 minute subs (please don't think I am bragging as I am not). Just haven't got around to reshooting the OIII. And as you said, the clouds do not look like disappearing any time soon. Having said that, looking at the national radar loop, http://www.bom.gov.au/products/natio...sat.loop.shtml, I do hold some slight hope maybe late tonight or tomorrow night... We will have to wait and see.
In regards to the camera pixels and sensitivity, unfortunately I have no idea. There are surely some very smart people out there who will be able to shed some light on that... ANYONE!!!
All I know is the pixels are 9micro-meters on the 11000
The rocessing is perhaps a little rough (not bad) and an unusual colour scheme Scott but after looking at your image several times since you posted before commenting (as I often do) it has certainly grown on me and it has a certain appeal about it, so given this is the most imaged nebula in the southern sky I recon you have done alright. Playing with NB data mixing can be really fun and can produce great results so keep at it
Thanks Slawomir. Your kind comments are greatly appreciated
I took the OIII several months ago when I first got the AZEQ6 when carina was rising at about 2 or 3 am. Since then I have balanced the scope nicely and can regularly pull good 30 minute subs (please don't think I am bragging as I am not). Just haven't got around to reshooting the OIII. And as you said, the clouds do not look like disappearing any time soon. Having said that, looking at the national radar loop, http://www.bom.gov.au/products/natio...sat.loop.shtml, I do hold some slight hope maybe late tonight or tomorrow night... We will have to wait and see.
In regards to the camera pixels and sensitivity, unfortunately I have no idea. There are surely some very smart people out there who will be able to shed some light on that... ANYONE!!!
All I know is the pixels are 9micro-meters on the 11000
Once again, thanks very much for your comments.
No worries Scott
I am looking at upgrading my HEQ5 in the future; it is good to know that AZEQ6 works very well for you
Given that my maths is correct...pixels in my camera are 3.69microns, thus have about 1/6 surface area of pixels on your CCD, theoretically giving you 6 times higher sensitivity. Even if we take into account about 30% lower QE and 40% smaller light bucket (80mm vs 102mm), I strongly feel you can go with much shorter subs when shooting the Carina nebula and still have sufficient detail. Might be worth testing...let's hope the skies will allow for experimenting...
I have to admit, I like my long subs. But having said that, the detail that you were able to pull with your Carina image with, what, 2 minute subs if my memory serves me right is outstanding. Might be worth while experimenting with.
I started with the HEQ5. It is good. BUT the AZEQ6 is something else all together. The polar alignment function is something to behold. I can be setup and accurately Polar Aligned and imaging in an hour. Also, the 20kg weight capacity is so much better than the 15 of the HEQ5. I would strongly recommend to get it. Also, not sure if this is the forum for this, but go and see Astropetes at Mt Gravatt when you get it. Very nice guy and excellent after sales service.
I have to admit, I like my long subs. But having said that, the detail that you were able to pull with your Carina image with, what, 2 minute subs if my memory serves me right is outstanding. Might be worth while experimenting with.
I started with the HEQ5. It is good. BUT the AZEQ6 is something else all together. The polar alignment function is something to behold. I can be setup and accurately Polar Aligned and imaging in an hour. Also, the 20kg weight capacity is so much better than the 15 of the HEQ5. I would strongly recommend to get it. Also, not sure if this is the forum for this, but go and see Astropetes at Mt Gravatt when you get it. Very nice guy and excellent after sales service.
Thank you for the hint, I really appreciate your advice.
Also, thank you Scott for your kind comment regarding the degree of detail on my 7th, or maybe 8th attempt at the Carina
There is always another level that one can reach with the astro-gear you have, each attempt is a valuable lesson, that's why I do not mind shooting over and over the same popular targets. Thats also why I love astrophotography; it is challenging, there are always others that consistently take amazing photos that you can learn from and it helps me a bit to better comprehend our insignificant yet unique place on the Cosmic map.
