Light source for flats

[CaptainShiznit]

Hey,

So my first attempt at flats didn't work out (muslin cloth over scope pointed at white laptop screen) as my image still had vignetting.

I bought an LED tracing pad off Amazon: https://smile.amazon.co.uk/dp/B078JN5B86/ref=cm_sw_r_em_apa_i_aDCnEb0BG0BWD

What would be the best method to use this for flats? Balanced on top of the scope by itself? Diffused with a T shirt? Build a box?

Cheers.

[geordie85]

I use a similar light pad, on the dimmest setting and still diffuse with a couple of sheets of paper

[CaptainShiznit]

18 minutes ago, geordie85 said:

I use a similar light pad, on the dimmest setting and still diffuse with a couple of sheets of paper

The brightness isn't adjustable on this one unfortunately. So you just stack sheets of A4 directly onto the scope with the light pad on top of that?

[Xsubmariner]

One of my lightpads is an artist pad used for tracing, coupled with some paper sheets then balanced on the scope it works well.

[Yawning Angel]

I dimmed one further with Neutral Density film, which is inexpensive from you favourite online auction site

[Anthony1979]

Do you face your telescope up and place your light on top of the scope

[Hughsie]

I have something similar but the brightness is adjustable. 
 

Point the scope straight up. As you have no brightness adjustment it’s a bit of trial and error with sheets of paper or a white t-shirt (handkerchiefs or something similar also help) over the front of the scope and between the light panel. Aim for a stretched histogram between 30/50% from the left hand side.

[CaptainShiznit]

9 minutes ago, Hughsie said:

I have something similar but the brightness is adjustable. 
 

Point the scope straight up. As you have no brightness adjustment it’s a bit of trial and error with sheets of paper or a white t-shirt (handkerchiefs or something similar also help) over the front of the scope and between the light panel. Aim for a stretched histogram between 30/50% from the left hand side.

Excellent info, thank you. I just found some neutral density film on the old auction site as Yawning Angel suggested as that seems like a good idea. Grabbed a 0.3 and 0.6 density sheet (50% and 25% transmission) for a couple of quid for a bit of trial and error.

[Aramcheck]

I've been using two sheets of white acrylic & artists LED tracing pad. Early days, but seems to be working ok. I have found though that I get better results extracting the luminance from the Master Flat & using that when calibrating my lights.