Hardware-Software-Techniques

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Imaging cameras have changed dramatically in the last 15 years. PCs had 9-pin RS-232 serial ports,

now everything is USB based.

LG laptop @ 2.90 GHZ w/32 GB RAM, 1.0 TB HD, 17.0" screen is dedicated to the telescope and guiding the camera tasks at 2560 x 1600 resolution.

Laptop does the image processing and web posting.

ASI 2600 camera raw .FITS files are quite large at 50 MB each, so it takes a lot of memory to process them.

I monitor the telescope and cameras from inside the house from a 42" wireless display. I handle all telescope and camera adjustments indoors. Only going outside for any major tracking issues, and look at the sky!

• Celestron PWI (CPWI) connects to telecope mount via the USB-A (480mbps) on the auto-focuser.
• PHD Guiding does the auto-guiding seamlessly.  CPWI provides the interface that PHD 2 uses. USB-A (480mbps) connects to the guide camera.
• Starry Night Pro Plus 8 provides sky views and handles all of the GOTO's and object searches.
• ZWO ASI Studio controls the camera acquisition.
• Astro Pixel Processor calibrates, stacks, and  processes the bias, flat, and light frames.
• Maxim DL Pro  provides additional processing and analysis tools.
• PhotoPad Image Editor and Luminar AI provide the finishing final touches.

Astronomical objects beyond our solar system are extremely faint.

You can't do anything about the changing transparency or seeing conditions of the atmosphere.

The Earth's diameter is roughly 8,000 miles in diameter with an atmosphere of about 60 miles thick.

Imaging is based on the telescope's ability to guide on a star and track it across the sky. A mechanical system of gears drives a 70-lb telescope.

Gravity pulls and tugs depending on the telescope's sky positions. And there are also the "gremlins" which can't be explained.

The telescope is trying to counter the Earth's rotation as the stars move across the sky. Stars move East to West, at ~15 degrees per hour.

Once you get a good sharp focus, just keep taking images, it is the easy automated part.

I take lots of exposures called subframes, because they all do not come out 100% of the time. 

The post-processing effort is the most time consuming.

Early on I learned to watch and read what the sky will offer. Watch the glow of the twilight sky as sunset nears.

The twinkle of the stars tell you about the air movement.

If stars appear with no twinkling of unchanging color brightness, the full potential of the telescope and camera system can be realized.

A blue twilight sky and orange sunset indicates a clear night.

During the hot Texas summer months, a dull red sinking Sun will indicate a milky gray night sky, but a yellow white Sun will promise a clear night ahead.

During warm summers, if it's not very thick, haze often indicates a steady atmosphere, but it also absorbs more light. 

For the DFW area:

Hottest months - July & August

Lightest winds - August & Sept.

Rainiest - May, June, & October

DFW set a 90 year record on August 20-21, 2022 with 8.5 inches of rain over just 2 days.

Calibration - are all so important for the final image quality. Taken at the same focus, camera resolution and temperature set at -20 deg. C.

Flat frames - 2 sec light frames taken with a single layer t-shirt at dusk. They reduce non-uniform pixel response across the chip, in that way, you can eliminate those image ruining "dust donuts".

Portable Photo Studio Tent is used if I can't take flat frames with the setting sun, which is rare, I just take them later in the house.

Bias frames - 0 sec dark frames taken with telescope covered to reduce the effects of any background noise.

Dark frames - ASI 2600 has ultra low dark current, but I take about five to subtract sensor noise from the image and mitigate those “hot or cold” pixels.  

I take 20 images with each filter that I plan to use, but I tend to stick with one filter per night...

It is best to image before the Moon rises and before it reaches the 1st quarter. Otherwise, the glow is to bright and it washes out the whole sky reducing galaxy and nebula contrasts, but the filters do help.

Astrospheric shows all the current and forecasted weather. It displays transparency (atmosphere clarity), seeing (atmoshere turbulence).

Using a medium size fan outside is the "best way" to control mosquitos, because they can't fly in the wind! No need for all those repellants!

Some nights you'll accomplish nothing, and on other nights you can have decent guiding and, in the end, a productive session.

I consider an imaging session successful, if I can get one good image or fix a previous problem.

It's nice to keep an image library, so you can process images when you have those cloudy nights.

Imaging is a night time hobby and is supposed to be fun, but can be frustrating, so don't take it too seriously, there will always be another clear sky!