Post by Dragon Man on Jan 16, 2024 6:57:11 GMT
Although I have been imaging for over 20 years, I have always been a OSC imager with Webcams, Analogue Video Cameras, and DSLR's, I am only new to this FLI PL16803 Mono camera and Filter wheel.
Mono Cameras and Filter Wheels are all new to me.
After a fairly dismal attempt for my first image I followed it up with a big improvement on my second image.
But on closer examination when Zoomed way in I see thousands of ugly dots that Darks will not remove.
It doesn't resemble noise.
I will show you what I mean:
I am using an:
- FLI PL16803 Camera,
- FLI ten position filter wheel CFW-3-10 with Astrodon E series 50mm square filters,
- FLI Atlas Electronic Focuser,
- Officina Stellare RH200 Telescope.
To check if it is Ice Crystals forming when the sensor drops below Zero Degrees Celsius (Freezing Point) I spent a couple of hours today capturing LRGB's, Flats, and Darks.
All the lights and the Dark were taken at 120 seconds and the Flat at 20 seconds, in an ambient temperature of 20c.
The camera sensor temp was 24c.
I could not get the weird white dots to appear again as in my images above.
So, after reading the Internet and searching for help, It was suggested I turn the cooler on and set it to -20c.
BINGO, there they were!
So the problem may be using the Cooler on our hot nights. We are in Summer and we get some fairly warm humid nights. Condensation loves warm air!
As a test, I turned the Cooler on and and worked my way down until the dots appeared. Then back up a few degrees.
Working my way down, the dots appeared as I approached Zero. I found the sweet spot in an Ambient temperature of 20c to be 4c.
________________________________________
And now as a preventative measure:
In an attempt to dry out the sensor a bit, I opened the observatory and exposed the equipment to the hot Australian sun on a day of 29c degrees (84F) for a few hours, and simultaneously ran the camera for about 1 hour with the sensor temperature set at 37c (98F).
All in a hope that any moisture has evaporated out through any leakage that it used to get in.
At the end of the few hours of hot sun, cloud was building which means I would lose the heat from the sun. I then sealed gaps around the Camera and Filter Wheel with absorbent cloth, then wrapped the whole Imaging train completely in 2 layers of Mylar Thermal Insulation Blanket to keep dew of all parts behind the Telescope.
So it can still cool the back of the camera, the only exposed part is the Cooling Fan at the back of the Heatsink behind the camera.
The Focuser, Filter Wheel and Camera are completely sealed against any moist air.
I hope it works.
I will get some test shots on the next night it's not cloudy
Mono Cameras and Filter Wheels are all new to me.
After a fairly dismal attempt for my first image I followed it up with a big improvement on my second image.
But on closer examination when Zoomed way in I see thousands of ugly dots that Darks will not remove.
It doesn't resemble noise.
I will show you what I mean:
I am using an:
- FLI PL16803 Camera,
- FLI ten position filter wheel CFW-3-10 with Astrodon E series 50mm square filters,
- FLI Atlas Electronic Focuser,
- Officina Stellare RH200 Telescope.
To check if it is Ice Crystals forming when the sensor drops below Zero Degrees Celsius (Freezing Point) I spent a couple of hours today capturing LRGB's, Flats, and Darks.
All the lights and the Dark were taken at 120 seconds and the Flat at 20 seconds, in an ambient temperature of 20c.
The camera sensor temp was 24c.
I could not get the weird white dots to appear again as in my images above.
So, after reading the Internet and searching for help, It was suggested I turn the cooler on and set it to -20c.
BINGO, there they were!
So the problem may be using the Cooler on our hot nights. We are in Summer and we get some fairly warm humid nights. Condensation loves warm air!
As a test, I turned the Cooler on and and worked my way down until the dots appeared. Then back up a few degrees.
Working my way down, the dots appeared as I approached Zero. I found the sweet spot in an Ambient temperature of 20c to be 4c.
________________________________________
And now as a preventative measure:
In an attempt to dry out the sensor a bit, I opened the observatory and exposed the equipment to the hot Australian sun on a day of 29c degrees (84F) for a few hours, and simultaneously ran the camera for about 1 hour with the sensor temperature set at 37c (98F).
All in a hope that any moisture has evaporated out through any leakage that it used to get in.
At the end of the few hours of hot sun, cloud was building which means I would lose the heat from the sun. I then sealed gaps around the Camera and Filter Wheel with absorbent cloth, then wrapped the whole Imaging train completely in 2 layers of Mylar Thermal Insulation Blanket to keep dew of all parts behind the Telescope.
So it can still cool the back of the camera, the only exposed part is the Cooling Fan at the back of the Heatsink behind the camera.
The Focuser, Filter Wheel and Camera are completely sealed against any moist air.
I hope it works.
I will get some test shots on the next night it's not cloudy