Looking for advice on planetary lucky imaging

I'm glad you asked this. Now that Jupiter is getting a bit higher in the sky I'm going to try it with my Edge 9.25 (focal length 2350mm). It has a Dawes Limit of 0.49

If imaging at 1/3 of the Dawes limit is the recommendation, then I think that means using only a 2x Barlow with my 3.76um chip (since that would give a scale of 0.17"/px. Going to a 3x Barlow would probably be pushing it too far, right?

Stuart Taylor:
I'm glad you asked this. Now that Jupiter is getting a bit higher in the sky I'm going to try it with my Edge 9.25 (focal length 2350mm). It has a Dawes Limit of 0.49

If imaging at 1/3 of the Dawes limit is the recommendation, then I think that means using only a 2x Barlow with my 3.76um chip (since that would give a scale of 0.17"/px. Going to a 3x Barlow would probably be pushing it too far, right?

That depends very much on the seeing. I wouldn't push it for starters and then see how it goes. BTW, Jupiter is pretty low for us in the UK. Try Mars instead and you can push image scale a bit further.

andrea tasselli:
BTW, Jupiter is pretty low for us in the UK

Thanks. I was under the impression that Jupiter was fairly high at the moment (38 degrees), but I don't know much about planets. I now see that it will be higher next year. 

Jupiter Ephemeris Generator 3.0 (seti.org) for those who want to create their own ephemeris.

Clear skies
Wolfgang

Indeed, Saturn raises more slowly over the upcoming years. I look at it this way: When Jupiter starts to decline rapidly from his peak in 2026, Saturn is about to become decent and constantly getting better until 2034 in the northern part of the sky. So for the next 10+ years you will have either Jupiter or Saturn on a reasonable altitude.

By the way, a better ephemeris calculator than what I postet above is Horizons System (nasa.gov).

Clear skies
Wolfgang

If you are using a color cam, you can push it a bit higher with my experience.

I found somewhere a rule of thumb using pixel size in micron multiplied by 5 to 7 gives the most desireble resulting focal ratio.

With my 10“ F5 Newton with an ASI 290MC with 2,9mu pixels would result in roughly F15 to F20.

With my imaging train I reach F19,6 and it works well.

Please mind that barlows will provide different multiplication factors depending on the distance of the chip. The farther away the higher the factor.

In Firecapture there is an option to display the actual focal length taking pixel size and planet size. This is fully automated, you only habe to click one button and the live result will be displayed.

Stephan

Andy Wray:

andrea tasselli:
That's correct, for a perfect scope of that aperture. So, yes, aim at that pixel scale of 0.2"/px, take or leave. As the image is bright enough that should do for starters.

Thank you!  I'll now try and match the Barlow and camera to get roughly there.  My wife asked me for ideas for Christmas, so lots of options here.  She likes to buy me bits for the telescope.

Never calculated by Dawes limit, but I just did now it seems to be 0.77.

That being said, I have been imaging Jupiter using a 3.75 pixel camera with a decent 3x Barlow which gives a 0.17, with good result.

From my limited experience these numbers are general guidelines, they aren’t set in stone. 

the general rule is about 5x your pixel size so in my case that would be F18 at about 0.27 , but I’ve managed to go to 0.17

Mind you the seeing plays a huge role it what you can ultimately achieve, you should give it a try and see what’s best for you.

In my case my 3x Barlow is much better than my 2x that’s why I use it, and the seeing is good. I do need to crank up the gain when using the 3x, which made the images grainy but when I used winjupos it kinda fixed that.

I use an asi224mc and a Celestron C6 sct and a Celestron x-cell 3x Barlow.

you can check out my images of Jupiter and estimate how much more details you can achieve based on the size of your scope.

Regards,
xee