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Inexpensive flat field panel

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#1 Taylor

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Posted 17 October 2019 - 01:26 AM

Not wanting to pay $200 or more for a flat field panel, I took a look on Amazon. It fits perfectly on my AT115EDT. 

 

I found something called "Hercules flat field panel". 

It came from China, seems reasonably well built. The site where the DC wire goes into the panel itself looks like it needs to be watched carefully, but I've read this about more premium panels as well so I can't hold it against it. 

 

Used it tonight with great results. APT flats guide had no problems creating a good set of flats for my first astrophoto tonight. 

 

If you're looking for a reasonably priced panel, I suggest looking into this. 

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#2 Midnight Dan

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Posted 17 October 2019 - 09:30 AM

How "white" is the light?  I bought a cheap panel and made my own several years ago, but over time the light has drifted from a pinkish cast originally, to a strong bluish color now.  It is especially bad when the weather is cold.  

 

Would it be possible to run a test by putting yours in the freezer for a half hour, then turn it on and see if the color is still somewhat neutral?  Thanks!

 

-Dan



#3 Taylor

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Posted 17 October 2019 - 07:55 PM

Dan, it is slightly blue. 

However, when I take the images from it into DeepSkyStacker, they're converted to grayscale anyways.

My first imaging run with it (my first real imaging run, ever, really), the final product seemed decent to me. I didnt have issues with color in post processing. I'm a newbie though so I could be wrong. 

 

From this discussion, it seems like color shouldn't be the end of the world. So far, in my limited experience, they seem to be right. 

https://www.cloudyni...t-color-matter/



#4 View2

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Posted 17 October 2019 - 08:45 PM

True I have heard of people using Blue Sky Flats in the evening. And I wish I hadn't seen this because a couple years ago I bought a spike a flat which works perfectly of course but it cost a lot. One of these might be cool for a grab-and-go setup. Depending on how bright it is though a narrowband flat could take some time?

Edited by View2, 17 October 2019 - 08:46 PM.


#5 Midnight Dan

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Posted 17 October 2019 - 08:46 PM

A little color cast is no big deal.  But a strong color cast means the peaks in the histogram are spread far apart.  That makes it hard to get a good mid-range exposure in all three channels without clipping. With mine, I have to underexpose more than I'd like to be sure that the strong blue color won't cause a problem.

 

-Dan


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#6 Kendahl

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Posted 17 October 2019 - 09:04 PM

Have you tested it for flatness? If not, set your DSLR lens down on the panel, find a combination of settings that gives you a reasonable histogram, and measure the average brightness at the center and several positions around the edge. What makes Spike-A-Flat so expensive is the engineering to guarantee flatness within 1%.




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