Dave, Stacking of flat frames is intended to eliminate random noise. Pixel-to-pixel variation is an actual (non-random, repeatable) difference between pixels...
No, Flat field removes the effect of individual pixel response to light. Each pixels QE is different. You take more than one flat to make a master to zero in...
I think that I have seen this on my sky flats too. It happens on my ASA system N12 with steep vignetting at the corners. It is only visible on an extreme...
Paul, yes, I am subtracting bias from non-dark subtracted flats. The over correction problem appears with either ELP or a large white board as the light...
Max/Ron I see what you are saying...oh well.Scratch another idea. And I always remember my favorite bumper sticker; (presumably by a marketing board) "Eat...
I've used this method many times over the years of having an RGB image, in this case a galaxy, and a finished luminance layer that was aligned and added as a...
Hi Dennis. I had this same problem with my SXVF-M25C color ccd camera if I shot my flats with a light box to achieve a mean adu value of 20,000. I was told to...
Hi, Can we divide an actual flat by some value, a mathematical division, to bring it to the desired value ? Jean Guy Moreau To: ccd-newastro@yahoogroups.com ...
Thanks. Then the answer is no, that will not help. The problem with high values was not that they were high. It was that with high values, the chip response...
In "HAIP", it is recommended that a 'dark calibrated' and 'average stacked' set of Flats - at this stage just a 'MasterFlat' - should then be 'normalised' such...
Scaling doesn't change the data. If someone wants to scale to a median of 1.0, that is for their convenience. It has no actual impact on the math whatsoever....
Hi Niall, "Are you definitely 'pre-calibrating' your Flats with either a MasterBias or MasterFlatDark? If not, your Flats will still include 'bias offset'...
Hi Tom, I used the animation palette in PhotoShop (introduced around CS2?). There are some good tutorials at the Adobe site showing how to use this palette. ...
Hello I have a well matched CCD Imager (Atik 314L) and Scope (80mm refractor), thanks to Mr. Wodaski's book - 2.66 arcses/pixel. I'm most interested in...
Q1: The only reason to buy 2" filters if you need them now, or plan to require them in the future, in order to avoid vignetting due to the size of your chip....
Does anyone have or know where I can find the exact layout of the Le Sueur Astro Pier J bolt template? I need the radius from center and the bolt/thread sizes....
Hello. I am looking for a product called RealSky DSS Northern Hemisphere. This was released on CD many years ago. It seems that my #9 image disc has been...
Software Bisque used to sell that product - have you contacted them? I may have a set of these around somewhere in new Mexico, but I won't be there for a month...
I'm wondering what folks are doing with this issue: I have a nicely deconvolved luminance file, nice resolution etc; now I have a LOT of color data which is...
This really depends on the quality of the data you have in hand. Even if the color is unbinned, do you have enough data, to get to low enough noise, to even be...
The Cap Locks turns the brush to high precision and makes the small X appear. Bill I had similar issues before with the brush not showing anything but a very...
A couple of questions and a statement on this... Questions: Ron, you said, "Since the color data is filtered, you might need 3x the color data relative to...
Hi group, Traveling to the Winter Star Party was worth the effort. I carried my CCD camera on the plane along with my 4" refractor and a 2 pound netbook as...
