Flats Failing Me?

[fatboy1271]

Disregard what I said above. I downloaded your flat. The brightness on it is perfect, it might even be a little bright.
For 14 bit scale I get Red 8135, Green 10065.8, Blue 11834.0

Wow, sorry once again, but I don't know why I can't get the same readings that you get when looking at the Mean... With that said, I'm extremely happy to hear that I got a good Flat!!!

Thanks Stuart!
fat

[fatboy1271]

Hey Jim,

I'll send you a message with my email address because I'd love a copy of the script! I'm definitely going to try out APT. I think you're right about the beta downloads. If it works for me then I'll pay for it. It's a pretty small amount of money compared to the rest of the stuff I've purchased for this hobby.

It sounds like you're having a great time with this and I love how much help you're offering

I love my Geno! You'll see a good picture of him in my email signature

[JayTee]

Of all the paid for software I own, APT is by far and away the best value for the dollar spent. It is my image acquisition software. For me, it is at least as good as N.I.N.A so I have no real desire to switch to N.I.N.A..

Cheers,
JT

[fatboy1271]

Of all the paid for software I own, APT is by far and away the best value for the dollar spent. It is my image acquisition software. For me, it is at least as good as N.I.N.A so I have no real desire to switch to N.I.N.A..

Cheers,
JT

Thanks JT! I'm excited to give it a try. Of course, we have clouds right now and then our family has a busy weekend coming up. Who knows when I'll actually get out again, but I will definitely set up all my equipment one of these nights before.

[Stuart]

Here is a screenshot
As I said, the ADU is a bit too bright, but I wouldn't decrease the time. At 0.18 seconds that's pretty fast. What I would do is put a couple of sheets of white paper in between the light source and the scope and increase the time if necessary. You don't want to have shutter shadow, so I recommend a shutter time of 0.5 seconds.

[fatboy1271]

Here is a screenshot
As I said, the ADU is a bit too bright, but I wouldn't decrease the time. At 0.18 seconds that's pretty fast. What I would do is put a couple of sheets of white paper in between the light source and the scope and increase the time if necessary. You don't want to have shutter shadow, so I recommend a shutter time of 0.5 seconds.

Hey Stuart,

What's different in my PI that I'm not seeing the same things you are? Mine is K and yours is RGB...

[Stuart]

I don't even know what "K" is and I don't see an option for it on my statistics process.

[fatboy1271]

Hey Stuart,

More frustration on reading the Flats in PI; however, I'd love for you to please check my latest. NINA is happy with how my Flats are coming out so if you check one and say it's good then I will just have to trust NINA.

_FLAT_0.15s_1600.00iso_2019-09-18__0(45).cr2:

As to my PI vs your PI Statistics readings, this if from the PI forum: Statistics RBG vs K...?

"they have their RAW module set to debayer CR2 files and you don't. therefore you get a greyscale CFA image (one channel) and they get 3 channel RGB.

if you want to see what they are seeing you can just use the Debayer module to debayer your flat. then when you look at the stats of the debayered flat you'll see RGB.

rob"

I went into RAW Format and changed my settings from Create raw CFA image to Create raw RGB image just to see what would happen. Still not seeing the readings I expect to see; however, maybe you'll tell me I reading it right and the Flat isn't good...?

Thanks to anyone still following along with me

fat

[Stuart]

To my measurement it's a tad bright. I'd go way down on the ISO with the goal of having an exposure time of about 0.5 seconds. (It's okay not to have the same ISO on the flats as you do on the lights)

[Stuart]

Now, I have to add that I haven't used a DSLR in years so I could be completely wrong.

[fatboy1271]

Someone on NINA's Discord channel said that ISO doesn't have to be the same too. Should I go as low as 100 or something like 400?

Thanks for looking! Oh, would you mind posting a screenshot of your RAW settings in PI? Just curious to see what you have there.

fat

[Stuart]

Hm....I'll try. Not sure where to find it. Where is it?

Oh, and in answer to your other question, it doesn't matter what the ISO settings are. The purpose of the flat field is to remove vignetting and dust donuts, which you will see in any ISO setting. The problem with fast shutter speeds is you run the risk of shutter shadow or flicker if you're using an LED panel.

[Stuart]

Wait I think I found it. Is this what you're asking for? I've literally never seen this menu before.

[fatboy1271]

That's what I was looking for! You probably don't care about that page since it looks like you don't use a DSLR...

Thanks!

[fatboy1271]

Alright Stuart, I set my RAW to what you have and now I'm getting the same results. Good news, right? Well, I'm still confused... From what I've read I need to use the Pure RAW setting since I'm using a DSLR; therefore, are you getting the correct results or do those settings not matter as to the Flat Statistics?

If you are confident that my Flats that you said were good, but maybe a little bright, are actually good then I can just check what that reading is in Pure RAW and use that as a gauge going forward.

[Stuart]

Hey, remember that I haven't done DSLR imaging in nearly 7 years, and I wasn't using PI at the time (I was using CCDStack). But from what I know it's fine with the caveats I wrote above. (lower ISO, increase shutter speed, decrease brightness a tad, consider dampening the light source with a couple of sheets of white paper, etc.)

Another thought--you might want to download a free trial of SGP. That program has an ADU measurement in it if you want to double check your results.

The most important thing is do your flats work in removing vignetting and dust motes.

[fatboy1271]

Awesome, thanks Stuart!

[yobbo89]

how are things traveling on your flats fatboy, i sometimes do find problems with my flats and i take 3-4 different exposures at different settings and then find the best one. it's a bit of trial and error, i sometimes do see people have problems when they do the punch in the correct numbers but it's not working correctly.

[fatboy1271]

Hey yobbo, thanks for checking in on my Flats; that's very awesome of you!

I'm using the Flat Wizard in NINA and I seem to be on the right track...? I just ran some this morning for last night's session and I didn't have any issues getting them run. Analyzing them is a whole different confusing mess, but I do think they are working.

[Stuart]

Hey Fat,
I figured out why we're getting different values. I was measuring your debayered frame and you seem to be measuring a nondebayered frame. In another thread I extracted the lightness from a flat and got a single value (see the last flat thread)
Stu