First Galaxy - NGC 253

leinad (Dan) · #1 27-12-2008, 09:48 AM

350D(modded) with ED80; Guided ST80/DBK21
4 x 300secs ISO800
Flats, Darks, Bias.
Stacked DSS, tweaked in PS CS3.'

I'm a little worried that I may have taken bad Bias frames? or used wrong master combine routine? For some reason there seems to be a vertical granulation after processing, also the corner brightness Im not sure if its light pollution, nearby laptop light or error in the stacking process.
Still alot more to learn(though I learnt alot from tonights 6hr session of to do's and not to-do's

).
All comments welcome.

P.S I'm already wanting more aperture

batema (Mark) · #2 27-12-2008, 10:16 AM

It is a thrill when you shoot your first galaxy. I can not help you with the processing side of things but your focus looks good as does the tracking. Well done and keep them coming. Maybe try for 7 - 8 min shots on this one and take more shots as this will improve you signal to noise ratio which then improves the image quality. I think?

Mark

JohnG (John) · #3 27-12-2008, 11:48 AM

Firstly, may I say, you have done very well for your 1st Galaxy shot

.

The glow on the right hand side of the image is normally associated with Amplifier Glow, it takes on a deep red appearance although it is normally confined to the lower right on the 350D. I suspect that the ambient temp was fairly high when you took the shot. As far as the banding is concerned, could be any number of causes, possible bad darks, could be a data lead running over a power source, banding is known to occure when a USB mouse is used on a laptop, could be a lot of things although I am leaning towards high ambient temp.

Were your Darks taken at the same temp and ISO as your Lights, how many did you take........ I would suggest around 15-20 is a good number. Your BIAS shots, if you use them, should be taken at the shortest possible exposure on your camera and at the same ISO as your Lights and Darks, once again, around 15 or 20 should be enough.

With your Flats, the camera must be in the same oreintation and focus position as when you took your Lights, with the 350D, if you can keep the Histogram around 1/3 to 1/2 to the right of the left hand edge they will do the job, once again, I would suggest around 15 to 20 Flats.

And has been mentioned, I would go for around 10 or so Light Subs, depending on your light pollution, I would probably go for 300-360 seconds.

All in all, an excellent first galaxy, there is a lot to learn, keep at it.

Cheers

Jen · #4 27-12-2008, 01:01 PM

i would be jumping up and down with excitement with a first shot of a galaxy like that very cool

leinad (Dan) · #5 27-12-2008, 03:29 PM

JohnG:

Thanks for that advice . Now that I think back about the night, NGC 253 was the first imaging run of the night. I think I should have left the camera outside for a while even if not attached whilst drifting aligning/star alignment; to allow it to cool to outside ambient temp; then done at least 10 or more subs with good delays in between.

I check the one sub and it shows the banding and glow in the corner.
Thanks for the advice

Kevnool (Kev) · #6 27-12-2008, 04:28 PM

I was going to say it was small but when i clicked on it it was very good and theres alot of detail in there also.
Good work...cheers Kev.

jase (Jason) · #7 27-12-2008, 04:52 PM

Certainly a good effort for a first galaxy image. Pleasing detail present. I sense the data could be stretched a little more, but you'll need to get rid of the amp glow. Nothing a gradient removal algorithm cant remedy. Look forward to see more. Well done.

leinad (Dan) · #8 27-12-2008, 07:05 PM

Quote:

Originally Posted by Jen

i would be jumping up and down with excitement with a first shot of a galaxy like that very cool

Yes, very pleased Jen. Might have another try tonight.

Quote:

Originally Posted by Kevnool

I was going to say it was small but when i clicked on it it was very good and theres alot of detail in there also.
Good work...cheers Kev.

Thanks Kev. I had to crop it down a little from fullsize as it was much too noisy. Will need longer exposures and darks. I attached a larger crop; guess sometimes image scale and detail have limits? still more to learn here

Quote:

Originally Posted by jase

Certainly a good effort for a first galaxy image. Pleasing detail present. I sense the data could be stretched a little more, but you'll need to get rid of the amp glow. Nothing a gradient removal algorithm cant remedy. Look forward to see more. Well done.

Thanks Jase. How does one apply(get my hands on) this gradient algorithm?

RobF (Rob) · #9 28-12-2008, 02:57 PM

I think you've had a great first go there! Looks like you've actually got quite a bit of data to play with too - certainly plenty of detail to bring out in the centre and likely you can stretch our some more brightness in the periphery.

Processing is a whole new adventure after you've carefully collecting collected your subs. And its always tempting to go back and fiddle as you keep learning more!

I'm sure people here can direct you to some web tuts or give specific info if you want more help with processing - even to the extent of posting your stacked master and asking for someone to have a play.

Dylan (Dylan) · #10 01-01-2009, 01:41 AM

leinad,
eventhough the back drop is dark, the planet is visible even in a small size photo!