New strange pattern appearing on ALL my Master Lights High rejection in PixInsight?

[oymd]

I've noticed recently that ALL of my Master Light HIGH rejection images, when stretched, show a new strange pattern.

Does anyone know why this is happening, and does it have any relevance?

Here's a stretched HIGH REJECTION master light to show the pattern.

I always stretch the Master Light High rejection image as a habit, before looking at the actual Master Light image, and never saw this pattern before. This pattern started appearing only in the past couple of weeks on ALL my processed master lights?

Previously, it would only show RGB pixels scattered quite homogenously across the image.

 

[Adam J]

20 hours ago, oymd said:

I've noticed recently that ALL of my Master Light HIGH rejection images, when stretched, show a new strange pattern.

Does anyone know why this is happening, and does it have any relevance?

Here's a stretched HIGH REJECTION master light to show the pattern.

I always stretch the Master Light High rejection image as a habit, before looking at the actual Master Light image, and never saw this pattern before. This pattern started appearing only in the past couple of weeks on ALL my processed master lights?

Previously, it would only show RGB pixels scattered quite homogenously across the image.

 

Possibly frost on the sensor.

[wimvb]

How did you integrate? Pixel rejection settings, etc. It looks to me that the issue lies there.

[oymd]

I use DEFAULT settings of WBPP. 

Just add the lights, flats and dark flats, in addition to darks from my library. 
 

I’ve spent some time on this today and did some investigative work. 
 

It seems that the issue was with a NEW set of flats and dark flats I took last week. 
 

I redid all my WBPP with my second last eat batch of Fs and DFs that I took last month and the issue disappeared. 
 

Looking back now at all my Master Lights I took over the last week with this set of new flats and dark flats, there is indeed some kind of a bluish gradient in the center of the image corresponding to the to this same pattern?

 

Having said all that, I had indeed a frost issue build up on my sensor 2 weeks ago, which I THINK is now sorted, after I’ve added a dew heater strap wrapped around the camera and filter drawer. 

[Adam J]

13 hours ago, oymd said:

I use DEFAULT settings of WBPP. 

Just add the lights, flats and dark flats, in addition to darks from my library. 
 

I’ve spent some time on this today and did some investigative work. 
 

It seems that the issue was with a NEW set of flats and dark flats I took last week. 
 

I redid all my WBPP with my second last eat batch of Fs and DFs that I took last month and the issue disappeared. 
 

Looking back now at all my Master Lights I took over the last week with this set of new flats and dark flats, there is indeed some kind of a bluish gradient in the center of the image corresponding to the to this same pattern?

 

Having said all that, I had indeed a frost issue build up on my sensor 2 weeks ago, which I THINK is now sorted, after I’ve added a dew heater strap wrapped around the camera and filter drawer. 

You don't say what camera it is. I still feel it's frost. 

[oymd]

35 minutes ago, Adam J said:

You don't say what camera it is. I still feel it's frost. 

Sorry. It’s the 294MC Pro

[GoldTop57]

I have the 294MC Pro too - possibly frost or dew.

[PadrePeace]

What temperatures/humidity are your shooting in?

What temperature are you cooling the sensor down too?

Do you use dew straps on the scope and guide scope?

how good was your polar alignment? 

I ask because I’m seeing stars which are all badly trailing in the same direction which could be bad polar alignment and a lack of corrective guiding. If both your guide and main scope have Dew then that might give the trailing stars which are not guided out effectively added to the issue in the middle of the frame and maybe add this thought to your diagnosis.

Edited October 9, 2021 by PadrePeace

[oymd]

46 minutes ago, PadrePeace said:

What temperatures/humidity are your shooting in?

What temperature are you cooling the sensor down too?

Do you use dew straps on the scope and guide scope?

how good was your polar alignment? 

I ask because I’m seeing stars which are all badly trailing in the same direction which could be bad polar alignment and a lack of corrective guiding. If both your guide and main scope have Dew then that might give the trailing stars which are not guided out effectively added to the issue in the middle of the frame and maybe add this thought to your diagnosis.

 

6 hours ago, GoldTop57 said:

I have the 294MC Pro too - possibly frost or dew.

 

6 hours ago, Adam J said:

You don't say what camera it is. I still feel it's frost. 

Further details:

PA routine is always the same: I PA with IOptron iPolar and double check with SharpCap. Always reach excellent. 
 

I’ve been abroad the past few months. 
 

Ambient temperatures at night were LOW 30s back in August and now MID 20s. 
 

Sensor temp is always at -5C

Last month i imaged over several night NGC 6960, and I noticed a circular gradient bang in the middle of the master image which became very visible after applying Starnet. 
 

I posted the issue here, and was advised it’s FROST on the sensor. Humidity is obviously high here. 
 

Since this issue arose, I’ve now wrapped the camera and filter drawer in a dew heater, and the circular gradient has gone. 
 

I suspect this pattern is indeed frost, as the flats I’ve been using were taken at the END of an imaging session back in early September, BEFORE I started wrapping the camera with a dew heater. 
 

I’ve reviewed those sold flats, and indeed on closer inspection there is a circular bluish white blown out area in the Center of the flats. When really zoomed in they appear as tiny blue pixels

 

[PadrePeace]

So it’s the flats adding the gradient. Hope you can resurrect your work and get a good image out. 

[Adam J]

4 hours ago, oymd said:

 

 

Further details:

PA routine is always the same: I PA with IOptron iPolar and double check with SharpCap. Always reach excellent. 
 

I’ve been abroad the past few months. 
 

Ambient temperatures at night were LOW 30s back in August and now MID 20s. 
 

Sensor temp is always at -5C

Last month i imaged over several night NGC 6960, and I noticed a circular gradient bang in the middle of the master image which became very visible after applying Starnet. 
 

I posted the issue here, and was advised it’s FROST on the sensor. Humidity is obviously high here. 
 

Since this issue arose, I’ve now wrapped the camera and filter drawer in a dew heater, and the circular gradient has gone. 
 

I suspect this pattern is indeed frost, as the flats I’ve been using were taken at the END of an imaging session back in early September, BEFORE I started wrapping the camera with a dew heater. 
 

I’ve reviewed those sold flats, and indeed on closer inspection there is a circular bluish white blown out area in the Center of the flats. When really zoomed in they appear as tiny blue pixels

 

The solution to frost is to open the camera and replace the descant not wrap a heater around it. You can either recharge it or you can buy new tablets. But heaters are not going to help you. 

I described the process here. 

same for your camera. 

Adam

 

Edited October 9, 2021 by Adam J

[oymd]

2 hours ago, Adam J said:

The solution to frost is to open the camera and replace the descant not wrap a heater around it. You can either recharge it or you can buy new tablets. But heaters are not going to help you. 

I described the process here. 

same for your camera. 

Adam

 

Thanks Adam

I'll give that a go as well.

I'm currently abroad, and cannot order the FLO desiccant pack here.

I'll just have to go for the microwave option.

I think it was 50% for 2 minutes?

Also, whilst I have the camera open, is it OK to very gently clean the actual sensor with a cotton bud and 70% alcohol?

I've always had an annoying dust moat on my images and flats? The flats do calibrate it out, but there's always a faint prescience in the final image?

 

[wimvb]

18 hours ago, oymd said:

blown out area in the Center of the flats

Not blown out I hope, because that would mean you're in the non linear region of your sensor's response, and may very well be the reason why flats won't work and leave a pattern in your images.