Does anyone here use a light panel for flats?

[Trippelforge]

I have come across a few videos of people using them to get even lighting for flats. However when I searched around I noticed many had mixed reviews. So I was curious if anyone who uses one could give me a suggestion on which one to buy. 

Thanks!

[Roy Foreman]

The ones I use are 'Photolux' sold by Wex Photographic here in the UK. They are designed for viewing photo transparencies and so have white LED illumination which is very even, and supposedly colour balanced. They come in various sizes - I use the A4 and A3 ones, and are way cheaper than specialised units for taking flats. They are USB powered but come with their own power supply too.  Obviously you have to balance them on the top of the scope tube, which needs to be vertical, and are very light. There are 3 brightness levels, the dimmest being most appropriate for our use,  I use mine with scopes up to 11" SCT and find they work really well, but I do monochrome flats, not colour.

Hope this helps.

[Trippelforge]

9 minutes ago, Roy Foreman said:

The ones I use are 'Photolux' sold by Wex Photographic here in the UK. They are designed for viewing photo transparencies and so have white LED illumination which is very even, and supposedly colour balanced. They come in various sizes - I use the A4 and A3 ones, and are way cheaper than specialised units for taking flats. They are USB powered but come with their own power supply too.  Obviously you have to balance them on the top of the scope tube, which needs to be vertical, and are very light. There are 3 brightness levels, the dimmest being most appropriate for our use,  I use mine with scopes up to 11" SCT and find they work really well, but I do monochrome flats, not colour.

Hope this helps.

Thank you. I haven't heard of people taking monochrome flats? What is the reasoning behind that, are you not shooting in color?

[Elp]

I've got two of the cheap dimmable LED tracing panels off Amazon, both work perfectly fine, I've used with all sorts of optics, in fact my last session I didn't even balance on top of the dew shield (as I couldn't), just held it by hand as nearest I could and the flats were fine. I do however dim the light with a few perspex sheets for a more even tone.

Calibration files are usually treated as monochrome initially when you're processing (even if taken in colour), the images when stacked change to colour once you do a debayer operation.

 

[Jim Franklin]

I bought something like this a few years back and put it in a frame with a 8" outer diamter, the side with the LEDs was covered by a 5mm white acrylic cover to give a spread out light. It worked fine until it stopped working. I keep meaning to build another. 

https://www.ebay.co.uk/itm/266498378265?chn=ps&_ul=GB&mkevt=1&mkcid=28&var=566288847457&google_free_listing_action=view_item

Edited November 27 by Jim Franklin
Forgot to add link

[ONIKKINEN]

I have used LED tracing panels in the past, both A4 and A3 sized. They can work but have quality and durability issues as they are basically plastic toys. One developed a fault in some of the LED strips and another had a terrible USB socket that would only work if i hold the cable in. However they are so cheap that i can recommend them, at least the A4 models.

I had enough of these however and bought a proper flat panel that works reliably and has perfect illumination, but of course this was many times the price of a tracing panel. The panel i got is this one: https://www.astroshop.eu/flatfield-masks/lacerta-flat-field-mask-283mm/p,67325

[Elp]

5 hours ago, ONIKKINEN said:

terrible USB socket that would only work if i hold the cable

I've had something similar with one, but mine I think it's the cable at fault. My A5 and A4 are still going strong after three odd years, for the price they've done the work.

[TiffsAndAstro]

I use a very broken tablet but have a tracing panel as back up 

The panel works but feels cheap. Luckily it was cheap,  but i doubt it will last too long

Edited November 27 by TiffsAndAstro

[Roy Foreman]

12 hours ago, Trippelforge said:

Thank you. I haven't heard of people taking monochrome flats? What is the reasoning behind that, are you not shooting in color?

I shoot in colour and the flats are taken in colour but treated as monochrome for the purpose of compensating for vignetting and dust motes.

I notice from some of the replies that some people are using tracing panels. These generally are not as well balanced in terms of light output as those intended for photographic use, for looking at transparencies. 

[Fegato]

I use one of Gerd Neumann's Aurora panels. I upgraded to this from a cheap tracing panel when I got an 11 inch RASA. It works really well. Simple (but expensive), the light is not adjustable, but you buy filters to dim the light as required.

The electrical connection to the panel itself is with very thin wires, and some do complain that these fail. You do need to be careful with this, but I've had mine over 3 years now with no issues.

[Xilman]

I use one, very successfully, but can't tell you its make.  First it is in La Palma and I am not. Second it is not mine but belongs to the guy who has a robotic observatory on my land; because I didn't purchase it I can't tell you where to get one.

What I can say is that it is big enough to cover the front of Kevin's 50cm reflector and my 40cm. It might be a little large for your use. However, if you can wait until late January I can try to find out the details.

Paul

[michael8554]

I use a cheap A3 Light Box/Light Panel for my 8" SCT, hanging on the wall of the dome.

The only problem was getting a flicker-free output.

The lowest power setting had flicker only noticeable on the Flats.

So I added ND filter sheets to give an output low enough to require at least 1 sec exposures with my DSLR.

To avoid shutter and mirror artefacts.

Michael

[PhilB61]

I use a 10" Samsung tablet, seems to work really well with NINA flats wizard. I just have to remember to turn off auto dimming. I also do worry it will slide of though as the screen is very slick and totally flat

[ONIKKINEN]

20 hours ago, Elp said:

I've had something similar with one, but mine I think it's the cable at fault. My A5 and A4 are still going strong after three odd years, for the price they've done the work.

They are indeed great value. My first one lasted almost 2 years, second one a year or so and the third (the A3 for my 10") i didnt use but twice. These 3 are still half the price of the dedicated flat panel i bought so i could have just bought more tracing panels and hoped to not get unlucky. But flats are essential so bit the bullet, hopefully this one lasts longer.

[Elp]

Indeed, flats can make or break a session.

[Trippelforge]

On 27/11/2024 at 10:20, Elp said:

I've got two of the cheap dimmable LED tracing panels off Amazon, both work perfectly fine, I've used with all sorts of optics, in fact my last session I didn't even balance on top of the dew shield (as I couldn't), just held it by hand as nearest I could and the flats were fine. I do however dim the light with a few perspex sheets for a more even tone.

Calibration files are usually treated as monochrome initially when you're processing (even if taken in colour), the images when stacked change to colour once you do a debayer operation.

 

I came across those and due to the price almost just bought one. But then I was worried about how even the light would be across the panel. Does adding sheets help even it out?

[Elp]

40 minutes ago, Trippelforge said:

I came across those and due to the price almost just bought one. But then I was worried about how even the light would be across the panel. Does adding sheets help even it out?

The light is even on both of mine, the issue is (well my long fight against flats) I've learned to dim my light down so the flats are a few seconds as opposed to sub 1s and since doing this I havent had an issue with flats. The other reason to diffuse the light from these is that the surface has a sort of dot matrix pattern on it and I didn't want that in the flats (if even possible at long bright exposure) so a few sheets of perspex spreads out the light. Paper/white t-shirt I'd expect a similar result, I didn't use paper however as it can contain a grain within (and durability is an issue, my perspex has lasted years and is easily cleanable though you do have to watch for dust sticking to it due to static). I've also tried ND film which helps with weight especially when putting on top of a collapsible dew shield but it's difficult to keep flat without creasing (you have to layer a few sheets/wrap around the panel), and the static problem also applies, it's easier to clean a sturdy flat object in separate layers than a piece of film.

Edited 57 minutes ago by Elp