Very good.. sharp as a razor.
However. with a little more aggressive processing (to get rid of LP), you could have end up with this :-) Or even better ..
Rob was over. We did drift align just fine...then I didn't set the park position correctly so we couldn't do a mount star alignment. I don't have an EQ6 myself but I managed to get it all wrong like a seasoned pro!
Then I forgot to do up the AZ bolt under the mount head...so after the drift align...the first pic...."Star drift"!. Instead of fixing it we just took some quick'n dirty subs.
We also had troubles with his 12V PSU...it had the unfortunate ability to slip partly out of the EQ6's power connector & re-set the handset at the most in-opportune times!
Anyway we pointed the scope at a few quick targets & did some reduced length subs...around 15 seconds x 20 or so for each.
I'm actually surprised by the light gathering ability of Robs 8" F4 scope...damn it's quick in getting light to the image plane...maketh for short bright exposures! It has some field curvature for the short FL but this could be fixed with a baader MPCC...or image crops.
It's a learning curve! Next time we will nail it.
But I do like that OTA!
We will do it all again soon Rob
Edit:
Lets send the Tiffs to Bojan for photo manipulation...I suck at this!
Just tried to find the thread where I described my way of getting rid of LP background, but it seems it disappeared..
Anyway, I am using only DPP (that came with camera, most likely)
Forgot to say...no dorks (errrr I meant to say "no darks") subs on any pics.
We didn't have time & they were short subs stacked in DSS.
Edit:
I've just got Noel Carboni's photoshop actions (now Prodigital Astronomy tools) but am still struggling with it. I didn't use the tools on these original DSS stacks.
I also need a de-convolution routine but...that really costs or is imbeded in software just do not have...or that cost too much ATM.
Maybe I should just try fiddling more in photoshop.
Last edited by wasyoungonce; 16-03-2010 at 09:14 PM.
Can I just get some clarification here - these great shots were 20 x 15sec shots stacked in DSS? What was the ISO on these shots?
There's hope for me yet, since the best I can manage with my Pentax Km is a maximum exposure of 30 seconds without the Pentax IR remote control..... I've just got to get drift aligning sorted!!
Can I just get some clarification here - these great shots were 20 x 15sec shots stacked in DSS? What was the ISO on these shots?
There's hope for me yet, since the best I can manage with my Pentax Km is a maximum exposure of 30 seconds without the Pentax IR remote control..... I've just got to get drift aligning sorted!!
Cheers,
Mario
Mario...why don't you get a cable shutter release & put the camera into "bulb" mode. That way you can take any length exposure you want. I'm sure you could make your own.
My camera, the Pentax Km, does have a bulb setting but it requires the actual Pentax IR remote control F to work. It does not have the option for a standard cable release. The model before mine, the K200D, used the Canon cable release, which I have from an old film Canon, but the Km went "hi-tech" and dispensed with this!!
The other issue with the IR remote is that you need to keep the button pressed for as long as you want the exposure to last. I've bought 2 "cheapies" from Hong Kong, but both will only activate the shutter release and not keep it open. Hence I'm only able to do a maximum of 30s exposures until I get the official Pentax IR remote.
The description of the procedure is below (using Digital Photo Professional that comes with Canon camera on disk):
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.
My camera, the Pentax Km, does have a bulb setting but it requires the actual Pentax IR remote control F to work. It does not have the option for a standard cable release. The model before mine, the K200D, used the Canon cable release, which I have from an old film Canon, but the Km went "hi-tech" and dispensed with this!!
The other issue with the IR remote is that you need to keep the button pressed for as long as you want the exposure to last. I've bought 2 "cheapies" from Hong Kong, but both will only activate the shutter release and not keep it open. Hence I'm only able to do a maximum of 30s exposures until I get the official Pentax IR remote.
Cheers,
Mario
Damn...that sucks.
I was on the pentax site and they indicated that there was a cable shutter release for the K-m. I looked up the specs & they do not mention a cable release socket...so they appear to be giving mixed signals.
Damn.
is there anyway to use the USB to control the camera?
Bojan - I have been looking for this for a while thanks for writing up the procedure. I'm using a LP filter and I'm assuming a similar process will help with color correction?
. Instead of fixing it we just took some quick'n dirty subs.
...I suck at this!
