Great Effort Mitchel.. A very lovely area of sky, well imaged.
To use the background offset in nebulosity, just open the image in nebulosity and click on the backgroung offset menu item. When the chart comes up do not adjust it just close the chart and save your image. Do NOT ADJUST THE SLIDERS.
Coming along very nicely for light poluted Sydney and short exposures.
Well Done.
Ok then, oh that turned out better!! Thanks!
I would still like to bring more colour out. Any ideas anyone, or should I just take more shots?
Last edited by Lumen Miner; 14-08-2009 at 07:34 PM.
I would still like to bring more colour out. Any ideas anyone, or should I just take more shots?
If you have Photoshop or similar program. Image Adjust, Hue and Saturation, and lift the saturation slider a bit until you are happy with the colour.
Your next big step is to start calibrating your images with Flats, Darks and Biaas frames. This will lift the dark region on the right of your image which I suspect is vignetting and even up the whole image quite a lot. Just remember to get the best out of Flats you really need to take Bias or darks of some kind.
Good luck and keep at it. (Start Saving, your hooked)
If you have Photoshop or similar program. Image Adjust, Hue and Saturation, and lift the saturation slider a bit until you are happy with the colour.
Your next big step is to start calibrating your images with Flats, Darks and Biaas frames. This will lift the dark region on the right of your image which I suspect is vignetting and even up the whole image quite a lot. Just remember to get the best out of Flats you really need to take Bias or darks of some kind.
Good luck and keep at it. (Start Saving, your hooked)
Thanks, I am using gimp and have had lil' play with hue and saturation. Just stabbing in the dark though.... I'll give it another go, after work tonight. I also want to try and take alot more exposures....
If I was to take say 100 20 second shots, would I therefore need to take 100 20 second dark frames to be successful?
"Good luck and keep at it. (Start Saving, your hooked)"
Oh!! I was wondering what that sharp pain, in the back of my shoulder was!!!
If I was to take say 100 20 second shots, would I therefore need to take 100 20 second dark frames to be successful?
I think there is not much benefit in taking that many shots.. from my experience, 10-20 is more than enough to (almost) remove the sensor noise. Especially if you are close to the city. The same number of darks should be adequate.
The real improvement (in terms of the number of objects recorded) will be imaging from the dark site and with longer exposures (and this will depend on the tracking performance of your mount).
EDIT:
Keep in mind that the shutter has a finite life time, ~30-50.000 shots.. Mine went faulty after 3500 only and that set me back by $250 (normally this is $500, I was lucky because people from Canon service were very kind to me !!)
EDIT2:
I am using Digital Photo Professional for curves and background light pollution removal (this came with my Canon) and it is more than adequate.
To give you an example, have a look at those two images. The second one is made from RAW file, the first one is a stack from 15 exposures, 45 sec (on eq mount) with 135mm lens (Tair-11A), stacked in DSS and processed with DPP.
The LP in Melbourne is pretty terrible, as it is visible on the unprocessed image.
If you are interested in how exactly the image is processed, I can post my method, it is pretty straight forward.
EDIT:
I played a bit with DPP on your image, the result is also here. Not much better than what you have done... I only managed to stretch it a bit more, but the colour balance is similar
Wrong part of the anatomy....right pain. It's in the hip pocket where you'll be feeling it!!!!
Ten or 20 are more than adequate with such short exposures but the real impact will be made by taking flats and using them in your calibration process..
The pain you are experiencing is probably a stab wound from wife of girl friend.
If you give up astrophotography you will feel a warming hand on your head and a voice echoing "Good boy".
Well done Mitchell. Are you the guy who built the one sided Dob?
What's DSS Bojan. How can I use it to take care of field rotation due to a slow RA drive on an EQ5? Hopefully it is a moot point because I'll have a HEQ6P before Christmas.
Well done Mitchell. Are you the guy who built the one sided Dob?
What's DSS Bojan. How can I use it to take care of field rotation due to a slow RA drive on an EQ5? Hopefully it is a moot point because I'll have a HEQ6P before Christmas.
DSS is Deep Sky Stacker .. and it is freeware. Sorry for not having been more clear
Well done Mitchell. Are you the guy who built the one sided Dob?
What's DSS Bojan. How can I use it to take care of field rotation due to a slow RA drive on an EQ5? Hopefully it is a moot point because I'll have a HEQ6P before Christmas.
To give you an example, have a look at those two images. The second one is made from RAW file, the first one is a stack from 15 exposures, 45 sec (on eq mount) with 135mm lens (Tair-11A), stacked in DSS and processed with DPP.
The LP in Melbourne is pretty terrible, as it is visible on the unprocessed image.
If you are interested in how exactly the image is processed, I can post my method, it is pretty straight forward.
EDIT:
I played a bit with DPP on your image, the result is also here. Not much better than what you have done... I only managed to stretch it a bit more, but the colour balance is similar
Yup my images were not too good, very light polluted. you can barly see the milky way in them, basically black....... I'm not shooting in RAW yet either, just JPEG.... I will try soon though.
Yes, I would appreciate hearing your method... I am not one, to turn down free knowledge... Thanks..
Yup my images were not too good, very light polluted. you can barly see the milky way in them, basically black....... I'm not shooting in RAW yet either, just JPEG.... I will try soon though.
Yes, I would appreciate hearing your method... I am not one, to turn down free knowledge... Thanks..
Well, your image is quite good, considering from where it was taken :-)
The method I developed to remove LP background is illustrated below: they are all screenshots from Digital Photo Professional Tool Palette, that I am sure came with your Canon.
1) After opening stacked image from DSS (in Tiff format, darks and flats are applied as well as part of DSS processing), you have the histogram looking like (1).
2) In RGB tab, you form the curve like it is shown on image 2, by clicking and dragging the curve to the desired position. I usually start with lower left side and add 2 or 3 points more.
3) Adjust the individual thresholds for each colour channel (by right-clicking and dragging the left-most edge of the histogram frame in appropriate tab), such that the histograms for colours are more or less aligned, like shown on 3 for Red.
For images from light polluted sites, you will have to do it for Red and Green only.. the Blue one will usually remain as it was. The result is shown on image 4.
4) Then, go back to RGB tab and adjust thresholds as shown on 6.
5) repeat the procedure once more from 3), until you have histogram as shown on image 6.
6) Finally adjust upper threshold like shown on 7.
And this is it.. 5 minutes of work or even less (not counting here the time for stacking, this may take longer, depending on number of images and the speed of your computer). All done without additional expensive software, not a single additional cent spent.. (you should already have DPP, since it comes with each Canon DSLR). You can upgrade it on Canon official site to the latest version for free.
The method also works for dark sites, but then you may have to play with Blue channel as well, and the first RGB curve may not need to be so "curvy".. because there will be much less LP background.
WoW!! I will try this exact method tonight. I want to capture a few more frames and try again.
Thanks for the effort in the post with pictures especially.... That should almost be its own topic, great for all us learning.
You are most welcome
I am always glad to help, especially when my advice does not have any hidden costs attached
We should always try to use what we have... and usually it is almost always possible to obtain decent results
