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Anyone using LED or EL tracing tablet for flats? Even illumination?

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#1 rms40

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Posted 06 December 2019 - 09:26 AM

I tried an LED tracing tablet a couple of years ago. I found that the illumination was not even across the panel. There were lighter/darker stripes.

 

Recently, I have read about people using the newer EL type panels. Anyone having success with these?

 

I have a really nice smaller Altinak Flip Flat for my refractors. Works great. But,  I need a large panel now for my 14". An EL panel would be much less expensive.

 

Randall



#2 Dynan

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Posted 06 December 2019 - 09:52 AM

I use regular printer paper to even out the light from my panel. It would also blend and color variations from the panel. I believe some panels may not emit true white light, so a white buffer may help.

 

Another couple ideas, in front of the panel, I have seen are a sheet of white plexiglas, multiple layers of white cloth.

 

I used a panel with great success with my C11.

 

Here is a sample of a flat analysis. This one was a bit higher than 50% of scale, but the histogram looked good, so I used it with good success:

 

flat analysis.jpg

 

I standardized my flat process by using a known setting on the panel (lowest, highest, or a preset level [some panels lighten in steps]) and make note of the number of sheets of paper I used.

 

Makes chasing those little 'dust bunnies' pretty easy.


Edited by Dynan, 06 December 2019 - 09:53 AM.


#3 bobzeq25

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Posted 06 December 2019 - 11:39 AM

I tried an LED tracing tablet a couple of years ago. I found that the illumination was not even across the panel. There were lighter/darker stripes.

 

Recently, I have read about people using the newer EL type panels. Anyone having success with these?

 

I have a really nice smaller Altinak Flip Flat for my refractors. Works great. But,  I need a large panel now for my 14". An EL panel would be much less expensive.

 

Randall

At the risk of being offensive.

 

Some cheap panels work, some don't.  I chose to avoid fuss, and got a Spike-A-Flat.  My t-shirts have retired.  <smile>  No need for paper.  Set it on top of the scope or point the scope at it, and shoot.

 

The big model is $380.  Compare that to the cost of your other equipment.

 

http://www.spike-a.com/flatfielders/

 

As they say about good equipment.   It.      Just.       Works.



#4 xiando

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Posted 06 December 2019 - 12:02 PM

I use an Ebay-grade EL panel that cost me around $100 five years ago. It has a pretty even profile and I've had no issues with it whatsoever. If I were really worried, I'd create a group of flats in which I rotate the panel 90 degrees  every N lights to compose an averaged 4xN master. There are no point-hotspots when using EL panels like one *might get from an LED panel. I do not use any diffusers. Just the panel inserted into a simple ~$20 Walmart picture frame.

 

At least for the smaller apertures, (6" or less") they work great.



#5 rms40

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Posted 06 December 2019 - 01:39 PM

Believe me, I would go with the Altinak or Spike-a-flat if I could afford them. They work well and are no fuss. I also like to support our vendors. It is the money thing right now.

 

The EL panels look like they should work better than led types. I would like something to hang on the wall that is plenty large and would work without modification. Anyone else using these?

 

Randall



#6 wal20

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Posted 07 December 2019 - 08:15 AM

I found a 5-inch panel at Ellumiglow: https://www.ellumigl...-5in-circle-kit. It includes  9v batterypack/controller. They also have a 14-inch version. It's just the panel so I made an enclosure with interchangeable collars for my ST80, Canon EF300 and WO RedCat 51. I posted it on Thingiverse: https://www.thingiverse.com/thing:3629917. Works well.

 

Bill


Edited by wal20, 07 December 2019 - 08:45 AM.

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#7 AhBok

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Posted 08 December 2019 - 09:07 AM

I have the 14” Ellumiglow panel and it is very flat and evenly illuminated. I tried tracing tablets, but the Ellumiglow panels are far better and still rather cost effective.

#8 rms40

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Posted 08 December 2019 - 09:59 AM

Thanks for all the info. Has anyone used their camera to measure the ADU count across an EL panel? I think it would be best to point the camera on axis at different points from the middle to sides and see if the counts are roughly the same. When I did that with my LED type panel, there were bands of higher/lower ADU areas. I use those panels for work lighting in the observatory. They are actually really nice for that.

 

I wonder what makes the Ellumiglow brand different from others. The color of the light spectrum? The evenness of illumination?

 

 

Randall


Edited by rms40, 08 December 2019 - 10:09 AM.



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