L-Extreme first light - does this look right?

[scotty38]

I have been using gain 200 and offset 30 for a little while now and I have dropped my exposure down from 300 seconds to 180. The Veil image I posted in the Deep Sky section is the last one I've taken and is 32 frames and to be perfectly honest is possibly the image I am most happy with in my "just over" a year of doing this. Of course all my calibration files are the same gain, offset and temperature...

 

[iantaylor2uk]

Maybe not, but my approach is to go with as short an exposure as possible since it is the total integration time that matters, not the length of the individual subs. Using the excel spreadsheet for sub exposure, the minimum sub time decreases as the gain goes up. With a UV/IR filter I usually image at 30-60 secs, and use 2 mins for the L-enhance filter. I may go to even shorter subs  if I'm using the f/4.5 Newtonian.

[Budgie1]

Exposure wise, I haven't really reduced it after changing from gain 120/offset 8 to gain 200/offset 30. This past week I've been imaging with 240s & 300s exposures using the Askar Duo-band filter on the ASI294 MC and have got some good images out of it.

As @Adam J mentioned, make sure the flats are the same gain & offset as the lights, I know on APT I sometimes forget that the Flats Assistant uses the Bulb gain setting, which I normally leave set to 300 because I use it for finding the target & plate solving. I also make sure the flats & flat-darks are shot at the same temps as the lights and I aim for ADU of 26,000 +/- 500.

Edited March 28, 2022 by Budgie1

[Adam J]

11 hours ago, scitmon said:

 

No, but should that matter as long as I don't saturate pixels?  It should still calibrate out should it not?

Honestly at gain 200 there is no need to go for 5min subs. 2 min should work fine. 

Adam 

[scitmon]

I will defo drop the exposure time next time then and see how that works out.  I still would like to get to the bottom of why I can't get above 14k ADU on Nina's flat wizard though.

[Richard_]

1 hour ago, scitmon said:

I will defo drop the exposure time next time then and see how that works out.  I still would like to get to the bottom of why I can't get above 14k ADU on Nina's flat wizard though.

Which drop down item are you selecting in the wizard? There's three to choose from which are: sky flats, dynamic exposure and dynamic brightness (if memory serves). 

[scitmon]

7 minutes ago, Richard_ said:

Which drop down item are you selecting in the wizard? There's three to choose from which are: sky flats, dynamic exposure and dynamic brightness (if memory serves). 

I'm not familiar with that drop down?  I see no mention of it in https://nighttime-imaging.eu/docs/master/site/tabs/flatwizard/ either.  Is it a feature of an older version?

[scotty38]

20 minutes ago, scitmon said:

I'm not familiar with that drop down?  I see no mention of it in https://nighttime-imaging.eu/docs/master/site/tabs/flatwizard/ either.  Is it a feature of an older version?

That's an old version you're looking at. Try the beta (that's not a beta 🙂 )

[Richard_]

19 minutes ago, scitmon said:

I'm not familiar with that drop down?  I see no mention of it in https://nighttime-imaging.eu/docs/master/site/tabs/flatwizard/ either.  Is it a feature of an older version?

Ah my bad! I'm using a beta version of NINA and I didn't realise that this feature was not available in the stable release of NINA. Here's the documentation:

https://nighttime-imaging.eu/docs/develop/site/tabs/flatwizard/

[scotty38]

But for the avoidance of any doubt every single NINA developer considers the Beta the stable version.....

[scitmon]

Ok, I'll check out the latest version.  I'm presuming that Dynamic Exposure is the one to go for with my LED light panel method.  It does sounds like the method I've been using anyway so I have my doubts anything will be different, but I'll try and report back.

[Stuart1971]

13 minutes ago, scitmon said:

Ok, I'll check out the latest version.  I'm presuming that Dynamic Exposure is the one to go for with my LED light panel method.  It does sounds like the method I've been using anyway so I have my doubts anything will be different, but I'll try and report back.

Dynamic exposure will alter the exposure length to suit the light panel, and ADU you choose

Dynamic brightness will alter the panel brightness to suit the exposure and ADU you choose, so this will not work unless it’s a panel that can be controlled via the software..👍🏼

Edited March 29, 2022 by Stuart1971

[scitmon]

Installed the beta version of NINA and had a look at the flat wizard page:

Notice the ADU of 100% Histogram Mean Target?  Why is it only 16384 when others here see higher?

[Richard_]

11 minutes ago, scitmon said:

Installed the beta version of NINA and had a look at the flat wizard page:

Notice the ADU of 100% Histogram Mean Target?  Why is it only 16384 when others here see higher?

Under Options > Camera what bit level have you set your camera too? A 14-bit image results in 16,384 ADU whilst 16-bit image results in 65,536 ADU.

[scitmon]

Yes I had it set to 14 which I thought was correct.  I see that they recommend 16 though so I will give that a try (it is showing higher ADUs with 16 in)

Edited March 29, 2022 by scitmon

[scitmon]

Does this mean all my lights have been adversley effected?  Not sure what the implications of having the wrong bit depth set are?

[Richard_]

1 minute ago, scitmon said:

Yes I had it set to 14 which I thought was correct.  I see that they recommend 16 though so I will give that a try (it is showing higher ADUs with 16 in)

The recommendation of shooting flats at 30,000 ADU is on the assumption that ADU scale is for a 16-bit image, which is about 50%. The number of ADUs for a given bit image can be calculated by raising 2 to the power of the bit (e.g. for 16-bit image, the total ADU is calculated as 2^16 = 65,536).

2 minutes ago, scitmon said:

Does this mean all my lights have been adversley effected?  Not sure what the implications of having the wrong bit depth set are?

Your camera will only record data in 14-bits but by setting the software to a bit depth of 16 will alter the scale at which everything is set at. I use an ASI533MC and I have it set to 16-bit which works fine

[Adam J]

On 29/03/2022 at 19:32, scitmon said:

Yes I had it set to 14 which I thought was correct.  I see that they recommend 16 though so I will give that a try (it is showing higher ADUs with 16 in)

just reading through this old thread, that will indeed be your problem. 

Adam