This is my first Keyhole nebula from the DSI. I think my eyes are playing up or that im gonna need glasses really soon but i can't tell which one is better?
Here are the two pics im having troubles with adjusting in PS.
your images are getting better Ezy, nice neb but your tracking is still not right and that detracts from both images. You nail the tracking you will get the money shot! I must say you have come light years in using the DSI!
I agree with the comments about tracking. You're focus "looks" pretty good, but a bit hard to tell until you get the tracking sorted.
A question for you regarding PS. What features are you using to adjust your images? Levels, curves, brightness, contrast? Do you use the histogram at all? The reason I'm asking is that your brighter stars are all sigma clipped which tends to indicate you white point has been set to low. Would you mind posting an unprocessed original bmp (assuming it's not over 150KB then use a Jpeg) so we can see how the original stars looked?
your images are getting better Ezy, nice neb but your tracking is still not right and that detracts from both images. You nail the tracking you will get the money shot! I must say you have come light years in using the DSI!
Thanks h0ughy and everyoe. still not sure about the tracking. the polar scope showing the octan's are on the bottom but the octan's should be facing up. the way i managed polar align is to unscrew the polar scope so that octans looking through it is facing up which makes the scope loose therefore not an accurate polar alignment.
hey paul, ive used all sorts of settings in PS. curves, noise pro mainly all the options you'll find in adjustments under image in PS. attached is a straight shot off the DSI.
The image was taken roughly as my powerpack ran out in the middle of exposure.
Do a bit of a search through the site for techniques for polar aligning using the drift method. It will be much more accurate than using the polar finder scope.
Re your polar scope. Does the etch of octans appear to rotate in the pfs if you loosen RA and rotate the mount in RA?
I had a quick look at your original in PS particularly the histogram. You image has severly clipped white and black points. The first histogram below is yours and the second is roughly what you should be trying to achieve, initially anyway, in your processing. If your image is arriving at PS clipped then you need to make some sort of adjustment in possibly exposure, gain, etc.
Then check your histogram in Autostar and see if it's clipping. If it's fine then save your images as FITS files (I can't remember if AS will save as Tiff) rather than bmps. At least that way you'll keep your image as 16 bit rather than having it converted to 8 bit when saved as a bmp. If you save as a bmp in Autostar Suite you don't have any control over how the 16 bit is converted to 8 bit and valuable information can be lost. (as is seen in your histogram)
There is a FITS to TIFF conversion on the net somewhere (I think Eddie T did one. Check his site http://www.astroshed.com/software.html) as well Nasa has a FITS plugin for PS I think.
Do a bit of a search through the site for techniques for polar aligning using the drift method. It will be much more accurate than using the polar finder scope.
Re your polar scope. Does the etch of octans appear to rotate in the pfs if you loosen RA and rotate the mount in RA?
just checked. The polar scope rotates with the RA axis! so i guess i have to rotate the RA when doing polar alignment.
I had a quick look at your original in PS particularly the histogram. You image has severly clipped white and black points. The first histogram below is yours and the second is roughly what you should be trying to achieve, initially anyway, in your processing. If your image is arriving at PS clipped then you need to make some sort of adjustment in possibly exposure, gain, etc.
Then check your histogram in Autostar and see if it's clipping. If it's fine then save your images as FITS files (I can't remember if AS will save as Tiff) rather than bmps. At least that way you'll keep your image as 16 bit rather than having it converted to 8 bit when saved as a bmp. If you save as a bmp in Autostar Suite you don't have any control over how the 16 bit is converted to 8 bit and valuable information can be lost. (as is seen in your histogram)
There is a FITS to TIFF conversion on the net somewhere (I think Eddie T did one. Check his site http://www.astroshed.com/software.html) as well
Nasa has a FITS plugin for PS I think.
thanks for your informed post paul. thats weird as i normally save my pics in .tiff format but haven't try fits.
Here's an example of one of my very first Eta Carinas using the DSLR, along with the images histogram.
Looks very similar to yours. But notice the histogram. There is a little bit of white clipping at the right hand side and the full white range has information in it, but the left hand (black point) end isn't clipped, though there is information right to the end. It's not the perfect example but gives you some idea of what to aim for. A better exposure would have had the bulk of the tonal range more towards the middle of the histogram, though that would have probably led to more clipping at the white end. BTW this is the unprocessed image.
The thumbnail versions look great! Good result and plenty of focal length there. Maybe you should try a shorter focal length which will help hide the tracking errors.
Your imaging is coming ahead in real leaps and bounds, may I be so bold as to suggest now is the time to learn how to drift align, you will see a huge difference.
Check to see if the TIFFS you saving are 8 bit or 16 bit
i was actually saving them as 8bit.
Quote:
Originally Posted by iceman
The thumbnail versions look great! Good result and plenty of focal length there. Maybe you should try a shorter focal length which will help hide the tracking errors.
thanks mike. still dont get focal lengths etc. do i simply get a focal reducer to shorten the focal length?
still need to learn how to drift align. arggh information overload
lol at dave, will do mate will do.
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