Skymax 127 with a Canon EOS 1100D ?

[JamesF]

I've had rubbish images with my Phillips. The seeing is crucial. You can do exactly the same thing on two nights, on one you get lovely detail and on another it's a formless blob. I've never been able to get the kind of images that James posted. I guess I've been unlucky. Planetary is strangely hard! As has been said, just keep plugging on.

Hopefully you have indeed just been unlucky.  Seeing does make a huge difference.  A while back I posted at least one animation that really showed the changes in seeing over the course of a few hours.  The detail in the final image drifts in and out very noticeably.   My best images generally seem to have come when I've spent four or five hours capturing data and was lucky enough to get some decent seeing in that time.

James

[Cloengaa]

Ahhh so when you image you might do 4 hours but only use 2 hours of data ?

Where I live which is a pretty good dark site, 25km south of Gothenburg, it seems at around 2am I have really stable atmospheric conditions, the stars don't blink so much. I just moved here so will be fun to see the results. Just have to be awake at that time ( I am old haha) and need to get a longer usb cable so I can connect my webcam to my desktop pc.

[Astrosurf]

Yep, a large amount of data is important. I've never captured nearly enough, but then I'm aware of Jupiter's rotation. How do you manage to get hours of data without blurring??

[Cloengaa]

I was wondering that too...as Jupiter rotates the red spot moves......so I would think after getting 1 hour of data the spot has moved so much that stacking the movie would blur out the spot ?

[JamesF]

For Jupiter I generally capture two- to three-minute runs over a period of several hours, so I might have fifty or more files of captured data depending on how much I've tinkered with things between capture runs.  Then I stack all of those and pick out the ones that look decent to process first.

James

[Cloengaa]

But James if you take these videoes....over a period of time the great red spot have moved. How do you get that sharp when stacking if it has moved ?

[JamesF]

Each of the videos Is processed completely separately.  Other than for animations, I just pick the best ones captured over the course of the night.  If I have eighty capture runs from a period of three or four hours on a night where the seeing looks ok, the chances are that there'll be a few where it came together pretty well.

James

[Cloengaa]

Ahh ok. So how long can you capture on Jupiter in one take without messing up the great red spot ?.

[Astrosurf]

Each of the videos Is processed completely separately.  Other than for animations, I just pick the best ones captured over the course of the night.  If I have eighty capture runs from a period of three or four hours on a night where the seeing looks ok, the chances are that there'll be a few where it came together pretty well.

James

I get yer!

[JamesF]

Ahh ok. So how long can you capture on Jupiter in one take without messing up the great red spot ?.

With the 127 Mak and a colour camera I'd probably draw the line at three minutes unless you're going to get into playing with WinJupos to do derotation.  Now I'm using a C9.25 and mono camera I tend not to go over two minutes.  I've not experimented with WinJupos yet myself.

James

[Cloengaa]

Ahh well James you have just been added to my new personal Jupiter Teacher haha....and I see you have imaged the other planets too soooo. Congratulations hahaha.

[Cloengaa]

Btw James. If I use the Skymax 127, do I need a flattener or comacorrector ? I think that is for DSO photoes but that could be an interesting challenge also.

[JamesF]

You don't need one for planetary imaging, no.  I've done some imaging of globs and planetary nebulae with the Mak and didn't use one then either.  It's possible that some further optical correction would help however, as you can see from the image of M13 below.  The entire process is quite awkward -- you really need an EQ mount and guiding to be able to do it.  Unguided I was throwing away a huge number of subs.

James

[Cloengaa]

But the synscan mount can be guided can it not ?? even though only guided in alt/az.

[JamesF]

You need something that will track in RA to get the necessary exposure times for the subs for DSO captures (from memory the above images used exposure times of small numbers of minutes for a single frame).  With an alt-az mount you'd see trailing due to field rotation in those kinds of exposures.

James

[Cloengaa]

True but I was thinking if I could use guiding for planets also...I take it guiding on Jupiter would keep the planet more stable in view than the mount just normal tracking Jupiter ?

[JamesF]

It's easier just to get your alignment well sorted and tweak the mount manually if the planet starts to drift off the sensor, I think.  A bit of drift or "wobble" in a planetary capture sequence is probably fairly useful anyhow.  AS!2 relies on it for debayering raw colour images whilst stacking I believe.

James

[Cloengaa]

aha ok hehe