Jupiter through an undriven Dob

[cathalferris]

March 17th, about 9pm.

I had the 12" Flextube set up in the back yard, finally reached some sort of thermal equilibrium and out of sheer curiosity I attached the 600D to the scope just to see what I could get with an undriven dob. This is with about 18 seconds of video, in relatively poor seeing even for low altitude Ireland.

305mm f/4.9 Skywatcher flextube dobsonian, undriven, 2x TV 1.25" Barlow, Canon 600D movie mode, 3x digital crop. 6300K colour balance with Magic Lantern. Effective focal length about 3000mm

WinFF to convert the Canon .MOV to rawvideo .AVI

Astrostakkert to align and stack.

Registax 6 for wavelet processing.

Real quick and dirty, nothing further done.

It's noisy, and not well colour balanced. I know I need to be able to get ~2 min of data, so this is nothing more than a proof of concept. It shows nearly as much detail as I was able to see with binoviewers a little later on. Reasonable result for undriven I think.

I have an EzCBP EQ table kit en route from the States at the moment, and that'll give me the ability to get a lot more data to play with.

[mitchelln]

Very good for undriven! You should be able to back off the ISO with such a large mirror and such a bright object. That should improve the noise. I never go above 1600 with my 7D. Or perhaps the wavelets were overcooked a bit?

All in all a good job though. Interestingly, I've never found >1 minute of capture makes any difference to the result at 30fps.

[Grotemobile]

Very good. Loads of detail. Very difficult

with a un driven mount..

Steve

[cathalferris]

Thanks!

I thought I had the ISO set at 800, as I've seen some interesting tests done that show that this is the best for dynamic range capture - at least in the RAW photo files. As it is, the ISO is nothing more than in-camera gain control. I always capture at ISO800 unless trying to work with the moon.

There was an awful lot of noise in the final stack that the lower wavelet sliders were showing. No increase in visible detail, just more pronounced noise. I tried to reach a balance with the wavelets.

Looking back at the raw video, it appears that the seeing was a lot worse than I remember it with large undulations and general fuzziness, and that never helps for planetary imaging. It is of course also possible that my focus was a little out, and that's something that I will make more sure of to get right with my next opportunity. I don't remember the seeing being that bad when I was actually looking through the eyepiece later on that evening..

When I get the table built and running, I'll see what happens witth a 1.6x barlow (nosepiece from WO binoviewers) added to the image train as I know I'm still short in focal length to get the best detail possible.

More practice required I think!

[Pete Presland]

Fantastic effort!

[cathalferris]

Handguided (!) and stacking as above. Almost getting detail on Io...

1/94 sec exposures on iso800, 1m22 video, AS!2 auto frame selection.

[cathalferris]

seeing disimproved as the evening wore on..

Plus I started to get dew forming on all surfaces, including the primary! That didn't help matters at all.

Still quite impressed with the pic from earlier tonight. Now to sleep..

[Owmuchonomy]

March 17th, about 9pm.

I had the 12" Flextube set up in the back yard, finally reached some sort of thermal equilibrium and out of sheer curiosity I attached the 600D to the scope just to see what I could get with an undriven dob. This is with about 18 seconds of video, in relatively poor seeing even for low altitude Ireland.

305mm f/4.9 Skywatcher flextube dobsonian, undriven, 2x TV 1.25" Barlow, Canon 600D movie mode, 3x digital crop. 6300K colour balance with Magic Lantern. Effective focal length about 3000mm

WinFF to convert the Canon .MOV to rawvideo .AVI

Astrostakkert to align and stack.

Registax 6 for wavelet processing.

Real quick and dirty, nothing further done.

It's noisy, and not well colour balanced. I know I need to be able to get ~2 min of data, so this is nothing more than a proof of concept. It shows nearly as much detail as I was able to see with binoviewers a little later on. Reasonable result for undriven I think.

I have an EzCBP EQ table kit en route from the States at the moment, and that'll give me the ability to get a lot more data to play with.

Very good. I have the same kit so now you have inspired me to have a go. Did you have to provide balancing weight to the mirror end?

[cathalferris]

I have a stack of hard drive magnets that I wrap in a cloth and stick to the tube, that works some bit for balance. I've yet to find the right place and mass to have good balance for all angles. I can get it close enough though.

It is kind of amusing to watch Jupiter bounce around the screen so much when hand nudging, I was very surprised with the end result given the video.

Always worth a try anyway. I took some 20 clips and most were not good, these were the best of them.

Typed on a handheld screen.