Hot Saturday Night feb 5 Eta

[h0ughy]

I am resigned to the fact that deep sky DSLR work from the burbs is difficult enough but on a night when it was 33 for most of the night - horrible. With the light pollution filter the colours of objects are pretty hard to get. i have to work out how to get some better colour balance in the images i have taken, but for now here is the image - wear your sunnys also a shot of the noise.....

127ed f7.5 cooled canon40D iso800

[Peter Ward]

I chose to shelter inside with the Aircon going flat-out (bugger the power bill) with several cold ones and watched re-runs..

You were imaging that evening? ...what?! ...was it heat stroke? :)

[CoolhandJo]

Thats an impressive image. Loads of detail. Trade off for imaging in light polluted skies is colour variance - but PS Selective Colour helps a lot. Otherwise its pack up the entire kit and travel far far away!

[spearo]

That's come out quite nicely
I understand, these days if its clear...we image!
frank

[atalas]

Houghy,quite nice....though,your letting your basics get away from you mate.

Go back and make sure you don't clip your shadows and check my tutorial out on balancing color bias....It will help.

[h0ughy]

:rofl: yes heat stroke:P

[John Hothersall]

Thats a lovely result of a beautiful area. Don't know how you guys cope with 30+ deg at night, at 25deg at night in Bris I suffer coming from cold UK.

John.

[h0ughy]

thats what Qld astrofest is for - those that now me know what i take to it;)

yes every photon is sacred:lol::thumbsup:



mmmm Louie (careful not to call you Louise ;)) i have attached the histogram for the image not sure where i clipped the image:question: But then i dont use photoshop much - however the same principles apply;)

[h0ughy]

you dont really cope:D

[Octane]

David,

Apart from the colour, that has come out superb.

You have /got/ to be happy with how tight your stars are. I miss that focal length. :(

Well done.

H

[atalas]

Yep,not clipped according to that histogram mate...but It does look like color bias needs balancing....this is why I won't let go of PS.

Still like I said mate,a nice image!

[h0ughy]

yeah must fix the colour cast. I love my scope

[h0ughy]

i would love to fix the colour bias

[gregbradley]

Nice tight shot Houghy.

Modded DSLRs are always super red biased.

Colour bias is handled usually with levels/curves and an eye on the expanded histogram. Perhaps also easier with colour balance tool in PS.

Or you can do a custom white balance using an 18% Photographic grey card shot at midday as the reference for the custom white balance saved in the camera itself. Every shot after it is setup is adjusted using that custom white balance.
Then your colour downloads will be closer to usual colours with still a hint of too much red. But then it is far easier to correct.

Greg.

[h0ughy]

i have tried to do that a few months ago - with a lot of rain in between so will have to redo again. LOL its only art:question:

my biggest problem is the CLS filter giving a huge colour shift:shrug:

[DavidTrap]

I wouldn't be complaining if I could achieve that from the 'burbs...

I've been processing my modded 350D shots (well, the last data was 6 months ago) using Maxim. I set the colour conversion / debayering to R100% G110% B120% (or even140%). It certainly helped to boost the blues in my image of M20.

I read a tutorial by Michael Covington that suggested this as a way of preserving colour balance.

DT

[hotspur]

Image in post 15 looks good,I like the colours in this one.Well done.

[h0ughy]

i might have to read that and see how that will apply to my processing in PixInsight?

[h0ughy]

thanks Chris

[multiweb]

Great shot. The region around the keyhole is very well defined. Nice one. :thumbsup:

[jjjnettie]

good on you for getting out there Dave.
Lovely work.

[danielsun]

Nice one Houghy. Other than the colour, that is still very nice with huge detail!:thumbsup:
Just wondering, with being a cooled camera and such a hot night, what were your exposure lengths and how many?

Cheers Daniel.

[DavidTrap]

From memory, the original article from Covington was regarding a UNmodded DSLR. It suggested colour conversion with Red ~150% to compensate for lack of red response of the UnModdded sensor.

I think the ratios I have used were based on what gave me a reasonable colour, compared to other imagers results. You could do some experimenting and achieve a more scientific result.

Maxim saves the image as an unconverted FITS file. Flats & Darks are applied before colour conversion. Not sure how PixInsight works.

DT

[h0ughy]

Thanks Marc – it surprised me as the guiding was all over the shop with scintillating stars.

Thanks JJJ – you know how nuts I really must be LOL

The image is made up of 20 x 30 sec, 20 x 60seconds, 1 x 300sec, 6 x 605sec – would have been a lot longer but for the cloud that drifted over (very quickly), ISO 800



I might have to do a lot of experimenting David – I am far from happy and I have no star colours – that may be due to the stars being overexposed to get the nebulosity? But I did think the shorter shots may help put that back into the image?