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Messages - jkmorse

Pages: 1 ... 59 60 [61]
901
General / Re: Synthetic Lums - One more time please
« on: 2013 September 28 04:44:24 »
 :embarassed: :embarassed:

Sorry folks, need to clarify that I do understand that Juan suggests using the ImageIntegration Tool to build the synlum which suggests that the only question for my first question below is whether to do DBE for each channel stack before creating the synlum.

Hope that clarifies.

Jim

902
General / Synthetic Lums - One more time please
« on: 2013 September 28 03:47:21 »
 :embarassed:
 
Ok, I am still trying to get my head around using unbinned RGB's and creating a synlum from them.  But that raises two questions:

First, exactly when in the workflow should you create the synlum?  It seems are two possibilities, (i) combining the "raw" RGB stacks WITHOUT performing DBE, background neutralization and color calibration to keep the RGB image "pure", or (ii) develop the RGBs normally, including performing DBE on each channel, then doing background neutralization and color calibration before creating the synlum so that the data for the synlum has been "cleaned up" first. 

Second, does this same theory apply to NB imaging under PI, namely, should I be creating a synlum from the combined Ha, OIII, and SII image.  Just shot new NB stacks of the Helix and NGC 7380 over the weekend.  I'm anxious do my first PI NB processing and want to get this right.

These are pretty basic questions, but I am new both to PI and the whole LRGB vs. synlum debate. 

Thanks,

Jim

903
Tutorials and Processing Examples / Re: Problems in image calibration
« on: 2013 September 25 06:57:19 »
Richard,

Had the same problem recently but it is just a function of how STF sometimes works with uncalibrated images as far as I can tell.  Way I dealt with it was to simply open all of the images, make sure the setting are right in STF, then load the files normally in Image Calibration.  Seemed to clear the issue right up for me.

Good luck,

Jim 

904
General / Re: LRBG v. RGB again
« on: 2013 September 24 04:23:12 »
Juan,

Thanks for setting me straight. 

Jim

905
General / Re: Selecting reference image for integration
« on: 2013 September 24 04:00:06 »
Juan,

In the typical workflow, ImageIntegration comes before applying DBE.  Would the same be true when creating a synthetic Lum from the RGB channels using ImageIntegration or should you first apply DBE to the RGB channels before running ImageIntegration to create the synthetic LUM to get the cleanest possible image without gradients?

Thanks,

Jim

906
General / Re: LRBG v. RGB again
« on: 2013 September 24 02:27:03 »
Geoff & Juan,

[/quote]
Glad to see this explanation.  I always thought that using the same data twice (synthetic lum from RGB) to get a free lunch seemed to good to be true.  Now I see that we still pay for the lunch, but its arrangement on the plate is different.
Geoff
[/quote]

I want to follow up the "something for nothing" thread Geoff raised above.  I am a lawyer (I know, I know, even worse, I work for big oil), not a numbers guy, though I try and am facinated by the theory.  Putting aside for the moment the synthetic lum issue, when I change my imaging workflow from LRGB with binned RGB stacks to RGB unbinned, I will likely shoot 3 hours of each.  When I was shooting 5 hours of Lums, even I could figure out that I was getting the benefit of 5 hours of lum data for SNR purposes.  But when I shoot three sets of unbinned RGBs at 3 hours each, am I getting 3 hours of imbedded Lum data for SNR purposes, or 9 hours, or something in between. 

Thanks,

Jim

907
General / Re: LRBG v. RGB again
« on: 2013 September 23 08:10:06 »
Geoff & Juan,

[/quote]
Well unfortunately there is always this tradeoff---save time, lose quality--spend (waste?) time, gain quality.  See these posts by Juan
http://pixinsight.com/forum/index.php?topic=1137.msg5592#msg5592
http://pixinsight.com/forum/index.php?topic=1636.msg9297#msg9297
[/quote]

Ok, I am willing to try since when I shoot NB I certainly don't need a separate Lum image, just the Ha, OIII and SII stacks.  And the posts you quote seem to support just ignoring the Lum all together and just working in RGB space.  But then why all the talk about the need to create a synLum.  That just seems to recreate all the problems that Juan was arguing against. 

Confused but willing to learn.

Jim

908
General / Re: LRBG v. RGB again
« on: 2013 September 22 00:45:30 »

In my case, the only drawback for separate Lum filter is it's terrible under heavy light pollution. I use Astrodon LRGB filters and there is a "hole" in RGB filters to filter out light pollution. I also image with Astrodon Ha filter and blend Ha with Red and make HaRGB images instead of LRGB. I am never successfull imaging with Lum filter under heavy light pollution.

I guess it depends on the environment in your area whether Lum filter works for you or not.

I feel your pain on the question of using a Lum filter in heavy light pollution.  I live in Dubai currently and in Houston when in the States and both are aweful.  My choice is to drive (4.5 hours in Dubai, 90 minutes in Houston) to a more suitable location.  In the light, your only real option for any kind of clarity is to shoot narrowband.  I have imaged using Ha, OIII and SII astrodon filters under a full moon with no problems.  Colors are "unnatural" though there are lots of articles about using two color NB images to build a final image with more natural colors.  You have my sympathies brother.

909
General / Re: Selecting reference image for integration
« on: 2013 September 19 01:17:50 »
Just a quick add that if you aren't using the SubFrameSelector (SFS) tool you owe it to yourself to try it out.  I probably get carried away, but when I run the ImageIntegration tool I create small incremental changes to the sigma clipping settings (one parameter at a time, of course) and then repeatedly test to results with the SFS to hone in on the best result.  Once I get one sigma setting set, I do the same with the other.  SFS is the way to go since it is right there in the PixInsight work environment and makes my workflow that much easier  :)

JIm

910
General / Re: LRBG v. RGB again
« on: 2013 September 19 01:02:16 »
I agree with papaf on this one.  The primary benefit of shooting a separate Lum is that I can do 4 or 5 hours of 15 minute Lums and a dozen 5 minute 2x2 binned RGBs each in a single evening.  Compare that to shooting 1x1 binned RGBs and I am down to 3 hours for each, if lucky.  Seems like the LRGB route is the way to go 

Jim 

911
Off-topic / Re: PixInsight a revelation
« on: 2013 September 19 00:55:06 »
Juan,

Another quick way to produce a Brightness Mask in PixInsight currently is to create an image clone, then simply do an Invert and adjust the inverted clone with HistogramTransform and apply the mask to the image when happy.  You can also blur through Convolution if required

At least that what I am using and it seems to work.

Regards,

Jim

912
Off-topic / Re: PixInsight a revelation
« on: 2013 September 17 04:48:36 »
Thanks for the quick and helpful response.  I will play with the resampling tool tonight.  As to waiting on the new Brightness Mask tool, well, just like Christmas, some things are worth waiting for.  Always a good day when I fire up PixInsight and it starts by loading a new routine.  ^-^

913
Off-topic / PixInsight a revelation
« on: 2013 September 17 00:58:00 »
Pixinsight World

Hello from a recent convert to PixInsight.  I have been imaging for several years but was stuck in the CCDStack/Photoshop routine which always felt so unintuituve and clumsy.  The tools, while usage, felt like trying to carve a block of stone with a pick and shedgehammer wearing ski mittens.  You can do it, but the frustrations are paramount (which makes me marvel all the more when looking at the work of true Photoshop aficionados).  And it's all hit or miss, no science, at least that I could really control (chainsaws to do ice sculptures is another metaphor that jumps to mind).

And then I read an article mentioning PixInsight.  I looked at it early on but it seemed so complicated for someone just getting their feet wet that I shied away.  But now (with the extremely helpful work of Harry's tutorials as a starting point, huge cudos there!!) it is like walking into a giant toystore for astroimagers!!  There is so much designed just for us and, while often complicated (sometimes VERY complicated) the processes just make sense.  And the experimentation that is possible when tweaking an image has, really for the first time, helped me realize all the fun of the processing side of imaging.  I happen to be working in the Middle East (imaging from a mountain in Oman on my weekends) and since I am on single status (my wife had enough of foreign assignments after our first 10 years stint) I have lots of time on my hands.  I literally spent the entire past weekend redoing several old images just to get a solid grounding in what Pixinsight has to offer.  I have a couple of new image sets from early September that I haven't even touched yet because I was shooting new Darks and Bias frames to work exclusively in the Pixinsight environment.

Anyway, I have blathered on long enough, but do have a couple of questions.  First, the mask building routine in ACDNR is so easy, is it available as a stand alone process to create masks for use with other processes?

Second, is there an easy way to crop images to a specific size?  I have my office walls lined with US sized 8.5 x 11 inch prints.  Cropping to size is easy in Photoshop but I am hoping there is an easy way to do that in Pixinsight as well.

Anyway, thansk again for an awesome product.

Clears Skies. . .

Jim Morse 

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