ADC - Will it make any significant improvement

[Allan3026 (Allan)]

I will start with my setup.
Mount: AZ EQ5 in EQ mode
Scope: Skymax 150 mak
Camera: ASI482MC
Software: Sharpcap (full version)

I've been trying to image saturn with poor results. I get an image swimming with focus rapidly changing, signs of blue and red on opposite sides of planet disc coming and going. It seems impossible to focus as the image is swimming so badly. Is this just "poor seeing" or collimation or something else? Will an ADC make any difference? Not sure if I can attach the video ser file from sharpcap here.

[iborg (Philip)]

Hi Allen


My first question is - how high above the horizon is Saturn? I would suggest wait for it to above 45deg, others with more experience will be able to give you a better angle.


Are you focusing over a roof top or some other possible hot object? This can also increase the shimmering.


If these are OK, then it could just be poor seeing that you are experiencing.


In addition, I have always found that focus is shifting, which is why the trick is to take many 'stills' (ie say 10,000 video frames) and stack the good ones to get a nice image.


I have produced reasonable images from what seemed poor video, including plenty of swimming and moving around the frame.


If you haven't processed your video as yet, give it go, you may be pleasantly surprised.


Good luck


Philip

[Startrek (Martin)]

Hi Allan,
I mainly image DSO but do planetary imaging from time to time with my Newts , DSLR and Televue Powermates. I’m by no means an expert but have done it now for 6 years.
Personally I’d opt for a minimum of 60 degrees Alt to achieve a more stable capture video. Less atmosphere at higher altitudes.
Most Planetary imaging video capture will bounce around a bit obviously the amount is dependant on atmospheric stability / conditions ( and your altitude)
The red slither or disc on the bottom and blue on the top is usually caused by imaging at low altitudes ( it’s an optical phenomenon or artefact )
I use Autostakkert to stack my video frames and Registax 6 to post process.
These have been around for a while now but work well.
Registax 6 will help remove those red and blue discs too.

Good luck with everything

Cheers
Martin

PS: I noticed the other night Saturn only just peaked around 65degrees Alt so that would have been the opportune time to capture it ( not down amongst the trees )

[Allan3026 (Allan)]

OK so I just checked and it was at 29 deg alt. (thought it was higher). I will try again much later (higher alt).
Also it was over the roof of my shed so may have been giving off heat. Thanks for that suggestion.
Is the 482 an OK planetary camera? It has large pixels but I read that is OK with long FL (mine is 1800mm).
I have the ASI2600MC duo for DSO. I might try it on Saturn with ROI setting.
I tried stacking in Autostakkert. My underwhelming image is attached.

[Startrek (Martin)]

Allan,
Imaging at that low altitude of 29 degrees is generally a waist of time if you want reasonable results , I don’t even DSO image below 35deg Alt as your trying to punch through so much atmosphere.
As far as cameras are concerned you use just about anything ( I use a crappy old Canon 600D with pixel size of 4.3uM ) but smaller pixels are preferable. Probably the most important thing to have is a focal ratio between f15 and f30 which you can achieve by using a Barlow or Powermate.

General rule of thumb to determine the “best focal ratio” of your image train for Lunar and Planetary imaging is -
Poor night of seeing 3.5 x pixel size of your camera
Average night of seeing 5 x pixel size of your camera
Good night of seeing 7 x pixel size of your camera

That’s great your using Autostakkert but most folk ( me included) only use it to stack only ( no sharpening etc.. )
We leave to fine tuning or post processing to Registax 6 which is excellent !!!

I’ll attach my procedures for both Autostakkert 3 and Registax 6 for you to have a look. Strongly recommend Registax 6 to finish off your image.
Also attached is some of my planetary work with my crappy old Canon 600D DSLR , 8” Newt and Televue Powermates
All the images were captured at 60 degrees Altitude or above !!

Hope all the above and attached is useful

Cheers
Martin