Had a Eureka moment When debayering in Nebulosity i was not adjusting pixel size correctly.
20 5min subs, no darks ,flats or bias, will do later.
WO FLT110 + TMB flattener, Sequence Generator Pro (love this ) Nebulosity , PS CS6
Could somebody please explain why i am still getting egg shaped stars on the edges when using the flattener, i thought it would be corrected.
I am extremely pleased with the result so far.
Any critique would be welcome.
Cheers
George
_Whoops, don't know how i put this up twice _________________
looks like you've got real colour in there now! excellent, i knew it would be something to do with your settings must be a relief (I was going to suggest trying DSS). to the image, the blue channel is clipped and also the red in i think in one of the images. its good to have a look at levels and curves, and select the drop down box and change it from RGB, to the individual channel and do each one separate - rather than stretching all 3 at once.
if you are feeling really adventuress and want to have a go at the stars, go to EDIT, then TRANSFORM, then WARP to alter the edges, you'll need to crop it afterwards (you may have to SELECT ALL first. But i would have a crack at the data again and concentrate on the levels and curves and deal with one channel at a time.
looks like you've got real colour in there now! excellent, i knew it would be something to do with your settings must be a relief (I was going to suggest trying DSS). to the image, the blue channel is clipped and also the red in i think in one of the images. its good to have a look at levels and curves, and select the drop down box and change it from RGB, to the individual channel and do each one separate - rather than stretching all 3 at once.
if you are feeling really adventuress and want to have a go at the stars, go to EDIT, then TRANSFORM, then WARP to alter the edges, you'll need to crop it afterwards (you may have to SELECT ALL first. But i would have a crack at the data again and concentrate on the levels and curves and deal with one channel at a time.
But you've made some good progress
Cheers
Russ
Thanks Russ,
Your input is very welcome, i will try your suggestions and repost in a day or two. When you say have a go at the stars i'm not sure what you mean, are you talking about colour or elongation.
Also, how do i determine the correct distance from the sensor to the flattener.
George
another processing attempt
trying to control stars is difficult
not sure what is happening in the bottom right hand corner ??? amp glow ??
Hi George,
Colour looks great!
well done, must be satisfying to get there in the end
I can't see what you're referring to on the uploaded image probably because its compressed so much.
I have been using this subject as a way to learn how to process in ps.
This is about the best i can achieve with my limited knowledge, but learning all the time.
This hobby is so much fun and incredibly stimulating, not enough hours in a night.
11x 10 min subs, darks, flats minus bias. SGP, Nebulosity, PHD2, PSCS6
WO Flt 110, Atik 383+ osc, AZEQ6
Well done George,
Coming along nicely. learning from another thread, maybe that colour in the bottom right is due to the shutter on the 383+ when doing your flats.
If your flat exposures are too brief, the shutter casts a shadow, and then it gets added when subracting the flat.
Check your flats against your lights and see if it is in there in both, or just one.
Well done George,
Coming along nicely. learning from another thread, maybe that colour in the bottom right is due to the shutter on the 383+ when doing your flats.
If your flat exposures are too brief, the shutter casts a shadow, and then it gets added when subracting the flat.
Check your flats against your lights and see if it is in there in both, or just one.
Goran.
Hi Goran, i'm pretty sure it is from the shutter, what is an appropriate exposure time, if i becomes too long do i have to take flat darks?
Hi Goran, i'm pretty sure it is from the shutter, what is an appropriate exposure time, if i becomes too long do i have to take flat darks?
I personally wouldnt, take flat darks. The exposures are pretty short. Make a master bias and subtract that from your flat though. I have the same issue with the qhy9, i have been told ~2-3 secs would work. Of course that would require a fairly dim light source as you don't want to wash the exposure out. I haven't actually tried it yet though.
Hi George. Hope you don't mind me joining in. Just like to say that I prefer the colour that you ended up with on your earlier image - with more blue.
I've been going through exactly the same agonies with my image of eta C.
Robert
Hi George. Hope you don't mind me joining in. Just like to say that I prefer the colour that you ended up with on your earlier image - with more blue.
I've been going through exactly the same agonies with my image of eta C.
Robert
Thanks Robert, i know colour is subjective but i am wondering, is there an accurate colour, what it would really look like if we could actually see it.
In the lat image i tried to treat the colours equally in the histogram and that is what i ended up with
Hi George. I do agree there is a high degree of subjectivity in deciding colour rendering. However olours do depend on the nature of the processes causing them. Blue nebuale as I understand it (and I could be entirely wrong!) are reflection nebulae arising from reflection of light from of a nearby star by small dust particles as these latter have a size range similar to the wavelength of blue light thus these wavelengths are reflected more strongly.
That be as it may, what we get on our pics I'm sure also relates to conditions at the time down here on Terra-firma, hence we get different results not only between ourselves but within our own photos that we take from time to time.
Whatever, in the end, they're our pics. and we have the right to to have them however we like best. I like mine with some blue, you prefer your red. That's fine.
Incidentally, this is the histogram of my latest effort. Shows a pretty good RGB balance - I think. http://cdn.astrobin.com/images/thumb..._histogram.png
Wouldn't it be wonderful if our eyes responded to colour as well as they do to white light. Image how spectacular the night skies would be without having to resort to cameras.
Three really good results George, gotta be happy with that!
The second and third with the reduced star size/glare (leaving Diffraction Spikes aside for now) are very good.
Well done.
Thanks Trevor,
i had better polar alignment with the last images, i agree about the spikes, should have left them out.
Robert, it would be awesome if we could see what our cameras see.
i had look at your eta, the different colours do look good, what camera are you using? I took some more with a modded 500d with a cls filter , looks different to the atik
George, I'm using a Nikon D90 un-modded. Yes, I'm sure different cameras will have different colour responses. Modding the camera affects the red end too.
Robert
When debayering in Nebulosity i was not adjusting pixel size correctly. 
Thanks Russ, 
difficult
