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Messages - vpcirc

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General / Re: Eliminate Satellite Streak
« on: 2015 April 02 13:33:35 »
Why does this have to be so complicated? I have to calculate formulas for pixel math? I love PI, but this is it's greatest weakness. One frame in a stack of 15 has a trail and it appears in the final stack? In CCDStack i could simply paint that area out and the data would be filled in from the average of all the other values in the frames. Things like pixel math, while great if you're an math expert, are confusing as it gets many new users discouraged from using PI. This would be the greatest program in the world for astroimaging if they'd just fix the broken UI

General / Re: error in batch preprocessing
« on: 2015 January 19 01:18:30 »
Are you checking "use master xxx" when no master yet exists?

General / Re: Maximizing SNR in a stack
« on: 2014 December 22 10:46:17 »
In reading the documentation, I can already see things I'm doing incorrectly for the best results. I was using registered images but not cropped

"In the Target Subframes section, add all target subframes. Subframes may be raw, calibrated or registered, but all should be the same type, have their overscan regions (if any) applied and cropped, be compatible for registration (if unregistered) and be compatible for integration. Measurements are typically most accurate on calibrated but unregistered subframes."

That would make sense has a registered image would have areas needed for cropping.

I did not create a PSF model either as described below which would further corrupt the model

"Select a Point spread function (PSF). The PSF functions are defined in the DynamicPSF process documentation. Star images will be fit to the selected PSF model. The quality of the fit on each subframe is provided by the StarResidual and StarResidualMeanDev properties once the measurement process has completed. A map of residuals for each fitted star in each subframe may also be generated by clicking the Output Maps button."

At this point I'm wondering if the small improvement I saw in normalization is worth the amount of work required compared to just using a reference image? The further you read, the more complex it becomes

General / Re: Maximizing SNR in a stack
« on: 2014 December 22 08:31:58 »
The results you get will depend on which images you reject from the stack and understanding what most of the meanings of the terms are. For example I think I understood that the SNR graph isn't a good example to use for rejection since thin clouds can make it appear better than it is in the graph.  FWHM and Elasticity seem to be the best but I'm learning as I go. Blink is a good secondary check, but hopefully this complex script will do a better job than our eyes in getting the best result. Of course I'd like to just push a button and the script says yea-ney!  I recall going to Adam's class and him saying any image with less xx percent weight he excludes. There is some heavy duty math going on here, so I think once I can figure out what to reject and what to accept, it will be as Juan said in another post "my best friend"

General / Re: Maximizing SNR in a stack
« on: 2014 December 21 15:40:26 »
I'm saying if you weight the images, then use fits keyword weight in normalization, then choosing the reference image doesn't seem to matter. This is not so much about noise reduction, and more about getting a proper normalization.

General / Re: Maximizing SNR in a stack
« on: 2014 December 21 14:52:57 »
In the final test, I took the best reference image, then used the key word weight. Changing the reference image did not seem to make any difference from what I can see

General / Re: Maximizing SNR in a stack
« on: 2014 December 21 14:48:05 »
Well here's some results
I used the same bad reference image and stacks. The files had all been weighted in the sub frame selector. In the first integration I used noise evaluation. In the second integration I used fits keyword "weight"
The weighted stack from what I can see is a better quality master. It appears to not place nearly as much value on the reference image if the weight in the fits header applied by the script Screen shots and links to actual masters are posted below

General / Re: Maximizing SNR in a stack
« on: 2014 December 21 14:21:05 »
I'm testing that Warren!!

General / Re: Mosaic processing - can't get backgrounds even
« on: 2014 December 15 18:41:29 »
On my latest, I eyeballed the histograms of all 4 panels to get them close as possible, then a light DBE and finally a gradient exterminator in the forbidden program. Worked wonderful

General / Re: Problem using SHO Script
« on: 2014 December 14 18:02:44 »
Here's a screen shot

General / Re: Problem using SHO Script
« on: 2014 December 12 07:41:00 »
I'll post a screen shot later

If I use the subframeselector script, then after measuring and rejecting I save the files with the fits keyword weight, then choose keyword in image integration and type "weight" will I get a better weighted result? I assume since the image has a values assigned to it at that point, a reference image would be unnecessary. Is this correct?

General / Re: Mosaic processing - can't get backgrounds even
« on: 2014 December 10 15:04:24 »
I think it's better to apply DBE etc and stretch them as equally as possible first. There's a great video showing how to use select points to remove any gradients on the PI resources page.

General / Re: Problem using SHO Script
« on: 2014 December 10 14:56:23 »
You need to check the boxes for auto stf. It's a representation only. Also you'll need to select new image each time or you'll overwrite the the one you just did. Personally I found better results by transferring and a STF stretched image in all 3 channels. Warren Keller has an extensive tutorial on this in his PI series 3 on narrowband which I helped him test different procedures since there's not a lot of documentation. 

General / Best method to remove bright star reflections
« on: 2014 December 03 20:36:38 »
I'm sure there's a way to do this in pixel math, as DBE sure doesn't work. I'm trying to build a mosaic and of course the darn reflection moves based on which panel. That tells me I may need to combat it before building the mosaic. Any help would be greatly appreciated. A link to a master fits is here:

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