Eta

casstony · #1 07-04-2019, 02:26 PM

12x5 minutes of Carina while I was waiting for conditions to improve last night. Carina is in the best part of my sky while Markarians, etc are low in the murk to the north.
Nice to see something big and colourful after peering at those little galaxies

Icearcher (Chris) · #2 07-04-2019, 03:59 PM

It might be better weather tonight, Adelaide last night was crystal clear.

Love the colour and the detail.

Its a bit crazy to think that we were both imagining about the same bit of sky at about the same time.

RyanJones · #3 07-04-2019, 04:30 PM

What a beautiful rendition of Eta Tony. Well done. The colour and balance is exceptional !

casstony · #4 07-04-2019, 05:18 PM

Thanks Chris and Ryan. It's easy to take the obvious targets for granted, but it really is a special area of the sky.

Out of curiosity I tried working on a single 5 minute frame and it looks sharper than the stack; the stack takes enlargement better though.

RyanJones · #5 07-04-2019, 05:21 PM

Out of interest Tony, what ISO are you using. Your dynamic range is really impressive !

casstony · #6 07-04-2019, 05:42 PM

I generally use ISO 400, though I should remember to drop it to 200 for bright targets to get more dynamic range.

I also want to try higher ISO, maybe 1600 on dim targets but keep forgetting. The Antennae galaxy tails might be better at high ISO.

ISO200 or 400 seems to be recommended for the Nikon D5600/5300.

The camera is not modded and I boost red/yellow in PS.

glend (Glen) · #7 07-04-2019, 06:15 PM

I am going the other way, reducing ISO from 1600 to 200 to get better dynamic range. If you have a combination of bright objects and dim in the same field, a high ISO is going to burn those bright objects. Is it not better to shoot more subs at a lower ISO to get the dim data built up without sacrificing DR on the bright?

Sunfish (Ray) · #8 07-04-2019, 06:19 PM

Very nice Eta. I like 400iso too for those bright objects. Much less noise and better colour as you show. Maybe a camera with a bigger more sensitive sensor than APSC 20mp could take 1600 or more but I think 800 is my limit. One good shot with in-camera dark frame removal turned on can be almost as good as a stack at 400.

mynameiscd (Andy) · #9 07-04-2019, 10:34 PM

Fantastic image of Eta you have caught here Tony.
A lot going on with plenty of colour and a real 3d look to it.
A real pleasure to view.
Cheers
Andy

casstony · #10 08-04-2019, 12:02 AM

Quote:

Originally Posted by glend

. Is it not better to shoot more subs at a lower ISO to get the dim data built up without sacrificing DR on the bright?

That sounds right Glen, though if I'm having trouble getting the dim object then it might be worth raising the ISO. Anyway I'm testing out different ISO's tonight since it turned out clear instead of the cloud that was forecast yesterday.

Thanks for the kind comments guys.

RyanJones · #11 08-04-2019, 10:42 AM

My 350d has a claimed " sweet spot " of 800 however a little bit of recent research and actually looking at the noise vs signal graph shows that the noise and signal increase equally from 400 to 800. Obviously the gain with 400 is better dynamic range. From experience with playing with shorter subs is that the more feint stuff will come out, it just requires a lot more intergration time. If the result is a cleaner, more colorful image, then I think that's the way to go. I used to be restricted to 22 sec subs on my alt az mount so taking 100s of subs is not unusual to me and I achieved a lot given what I was dealing with. It's just now it's going to be 100s of minutes subs. If that's what it takes to get great images, that's what I'll do.

casstony · #12 08-04-2019, 10:53 AM

I just left a comment in the Leo thread Ryan - looks like 400 is best with the D5600 after testing.

Atmos (Colin) · #13 08-04-2019, 11:16 AM

That’s a really nice Carina Tony, very nice colour tone variation throughout the nebulosity

I cannot speak for Canons but the older Nikon’s has their best at ISO800/1600 like the D700; this I found out through my own testing.

The newer ones like the D7200 and D810 have their peak at ISO400 but are still exceptional at ISO100. I’ve tested both cameras and found that after ISO400 the dynamic range drops away faster than the read noise and after ISO800 the RN virtually stops dropping while the dynamic range plummets.

So for every day photography I rarely go past ISO800 in any light because the read noise doesn’t improve so the dark areas are no better.

casstony · #14 08-04-2019, 12:45 PM

Thanks Colin. Between what you and others here have said, CN wisdom and my own wasting a few hours last night I'm confident ISO400 is about right

xelasnave · #15 08-04-2019, 06:13 PM

Perfect in my book.
So many great images coming in at the moment I cant get time to comment...busy busy must go.

alex

Paulyman (Paul) · #16 08-04-2019, 07:32 PM

Saw the single sub you posted on CN Tony. Looks amazing the colour is beautiful.