NGC6820 in narrowband

[Carole]

My 3rd and final image from Cairds October DSC

Dual Rig

Atik314L/WOZS71
Atik460EX/ED80
Both with x0.8 focal reducer
HEQ5
Ha 29 x 600 = 4 hours 50mins
Oiii 17 x 600 binned + 5 x 300 = 3 hours 15 mins

Total imaging time = 8 hours 5mins
Mapped HOO

Oiii taken with Atik460/ED80 and Ha taken from both cameras.
There is some blue signal in there, but it seems to be swamped by the stronger Ha signal

Despite over 8 hours imaging time it is STILL very noisy. 



Toned down colour version as per conversation below.

[MarkS]

Very interesting object.  You've got some good data there.

However, recalling our conversation from DSC you are presenting some very saturated colours in this image - especially the strong blue background.  Is this how you intended it to appear?

Mark

[Carole]

I was thinking the blue was some Oiii signal rather than the sky background as it is not all over, I was stretching the blue hoping that the Oiii in the middle of the nebula might appear.  I just checked the oiii data and there is an area of Oiii nebulosity on the right side, but not quite as large as the area showing in blue.

But I take your point on the red - following our conversation.  I will do another version.

Carole

[The Thing]

Hi Carole, as Mark says, looks like someone dropped the ketchup... There's some interesting stuff going on in the sauce though.

A little less red saturation may reveal more detail and subtlety I think. As to the noise, what temp do you set your cameras to? I try for -20C (-35C delta with my camera) and get almost no noise on darks, just hot, cold and warm pixels.

[Carole]

I do -15 Duncan.

As to the noise

I have come to the conclusion that some of the images I have been doing of late are not imaged very often and I think the reason why is because they are very faint and need a lot more data than the average target.  Probably why I am getting a lot more noise than usual.  I must stop trying to be so ambitious.

I had a conversation with Mark about my recent visit to the optician -  I am slowly developing cataracts worse in the right eye, not that I can sense any problem, but apparently it can also affect colour perception, so I asked Mark to give me a nudge if my images got too bright, which he has done very tactfully.  I do like strong colours, but maybe my eyesight is making them too far OTT.

Just working on another version, but it looks so anaemic to me.  Will have to rely on you guys to tell me if it is OK.

Carole

[Carole]

See my last post and the revised colour version which I have inserted in the top post together with the original for comparison.  (at least for now).

Carole

[The Thing]

That is much more pleasant on the eye Carole, the Ha is a better red and shows more tonal gradation.

Sorry to hear about your oncoming cataracts. Our French french teacher just had hers done, all over very quickly over two weeks and she was able to come into teach us the same day after each eye. She said that her distance vision is now superb and she is amazed at the difference in colours, she is getting rid of some clothes she can't believe she bought as a result!

[Carole]

Thanks for that Duncan, I never realised colour was part of the cataract problem.  I think its going to be some time (maybe even a few years before they will do them), but in the meantime I will have to be guided by every-one as to colour intensity. 

To be honest, to me, the 2nd image looks quite dull in comparison, but therein lies the problem.

Once I have eventually had them done I will have to look back on these images and see what I think then. 

Carole

[NoelC]

Very good image.
I actually like the bolder colour; it  is after all only a representation of the data and it sells the content slightly better in my view (but then what do I know).  I agree there is a slight dominance of Ha.
I took a look at this one:-
https://apod.nasa.gov/apod/ap041004.html
If yours is overcooked then they must be on drugs!
Keep up the good work.
Noel

[Carole]

Blimey, can't believe that was an APOD. 

Yes I prefer the top one, but I can't trust my eye sight at the moment.

Thanks Noel

Carole