Deep sky camera for planetary imaging

[Eruliaf]

Good evening,

For the first of my two stupid questions tonight - I already know the correct answer  (which is buy a dedicated planetary camera), but I can't help think that I must be able to get a better image of Jupiter than the pixelated dot that I currently achieve with my ZWO071MC colour camera. I have been taking a video file, approx. 1 minute passing through Autostakkert and saving the resulting image. The issue I have is that irrespective of the resolution (lower resolution provides a larger image, but obviously of a lower quality) the stacked image is appalling - example below. When previously doing this via my DSLR, I am sure Autostakkert took significantly longer to process than the 15 seconds it has been taking for my latest 1+Gb files!

So, starting with the basics - what are the first school boy errors that typically trip people up, or is the answer simply that the camera is not designed for this and a pixelated dot is the best that can be achieved with a dedicated deep sky camera.

As always, thank you in advance for any response/guidance issued!

[vlaiv]

While ASI071 is not the best choice for planetary - it can actually work quite ok if you set things up properly.

Main issue with that camera is that it has relatively high read noise (compared to proper planetary cameras).

First things first, ASI071 has large pixel size of 4.78µm. This means that you need to barlow your scope to certain F/ratio to get image your scope is capable of. In this case, you need about F/18.7 or round that up/down to nearest whole number - so F/19 or F/18.

What scope are you using? From your signature, I see that you have 130PDS and 200P - both are F/5 scopes? You'll need at least x3 barlow or even x4 barlow to get to wanted F/ratio

Next is reducing read noise as much as possible. For this you need to use gain value of 200+ - which will give you around 2.2e - 2.3e of read noise. Not ideal, but far from useless.

Following step is to ensure you can capture enough frames. Use ROI of say 640x480 - that will give you something like 70fps. Again - not ideal, but not bad either.

It seems that this camera does not have 8bit mode - which is shame, but if it does - use that as it will give you another small boost for FPS.

Set exposure length at say 5ms (don't look at histogram, image might be dark but that is ok - it will be fine after stacking).

There you go, above should be enough to get you started in right direction with this camera.

Here is another tip - if you are interested in planetary and you already image, why don't you consider adding guiding to your setup? Most planetary cameras can double as excellent guide cameras.

 

[licho52]

Before I sold it I was able to use 533MC as both planetary and deep sky.  I would definitely use a barlow to reduce pixelation and drizzle in postprocessing to further enhance resolution.