Jupiter and Ganymede - this morning 15th Feb

[iceman]

I took 17 avi's this morning, with a ganymede shadow transit underway, followed by the GRS beginning it's transit. Ganymede was also in view the whole time.

I've only processed the LAST avi (after the shadow transit had finished), and this is the result. There may be better avi's in the other 16 :) The seeing was fairly consistent across all captures, so I can feel an animated gif coming on, once I've processed all the data.

Quite happy with the result for this 1 avi - detail on ganymede as well as lots of features on Jupiter itself. Once I finish with all the data i'll present the image properly.

350 frames stacked, 15fps. 12" newt on EQ6, DMK21AF04 + 5x powermate.

Thanks for looking.

[Chrissyo]

Great shot! So much lovely detail:D Looking forward to when you finish all the data!:thumbsup:

[ving]

so did you write down all your settings from last year, remember them or did you have to relearn imaging jupiter?
thats v/good image :)

[matt]

Nice image, Mike:thumbsup:

Pretty exciting, actually, to be getting detail like that on Ganymede this early in the season.

You'd have to take that as a sign you're in for something special over the next few months?

[RB]

Awesome Mike, great detail indeed.
Hope your anim turns out, looking forward to that too!

[DobDobDob]

Freaky

[swannies1983]

Great shot! I'm in awe at how much detail you can get given the magnification.

I have been trying to image Saturn using my TAL 200K with the toucam at f/20 (2X barlow) but the seeing has been absolutely terrible the last week.

Question: is it better to image something at a lower f-ratio (i.e. no barlow/powermate) and then resize the picture or always try and use a barlow/powermate? I guess it all depends on the atmospheric conditions.

[sheeny]

Great shot Mike! I imagine it's just that bit easier to get detail on Ganymede with the 12" than the 10... it looks like it's very capable!

Swannies: generally its' better to capture the detail at as high a magnification as the seeing allows. Resizing, does not add any detail...

Al.

[bird]

Nice work Mike!

Bird

[Lester]

Thats a good one.

[davidpretorius]

pick of the season so far. I just had to comne back for another look!

Well done

[iceman]

Thanks guys, i'm very pleased with this one, and looking forward to processing the rest of the data.

This was the last avi in the session with the scope pointed quite high and dew was forming on the mirror (I had the fan off) making the image more grainy. Hopefully there's some better data earlier on.

Swannie: Definitely native image scale is always preferred. As Al pointed out, you get no more data by resizing.

Ving, there's not much to really remember with the DMK. The fps dictates the exposure, and it's either 15 or 30, depending on how much light I want coming in (exposure will be 1/15s or 1/30s). Gain will be near maximum, and that's all there is to it.

Processing takes some time to remember from last year, there's probably more I can get out of the data when I take some more care in processing.

[swannies1983]

Cool thanks for that. Could you perhaps post a raw single image so that I can get an idea what you were "actually" viewing on the monitor as you were recording.

I have been reading up that you should resist putting the gain up too high as it introduces noise??

[davidpretorius]

do not be too afraid of gain or gamma or how it appears on screen....up to a certain point.


stacking lotsa images will reduce the noise you introduce at capture time.
As Bird told me, "you can always reduce detail gained by higher gamma , but you can't introduce the detail after the event"I am convinced that over the last few years, the first lot of captures were done trying to have the video look like the finished product. Ie too dark, so it showed up the contrast etc. Recently, Damian Peach suggested higher gain so that you could pick up more detail, and any noise would be "stacked" out!

Bird has advocated higher gamma as well. This tends to bring out the details near the limb or near the edge.

This is translated into a reading of 200+ in K3ccd. For me and remember it is in the dark at the time, I try and get the video looking like a washed out object. Paul Haese even advocates having a light on behind you so you don't underexpose your image at night due to your eyes being night adjusted.

I tend to have brightness up around 60%, gamma at 20%, gain at 80%

Here are two images.

the first being a frame from David Tyler's night of great seeing back in 2005(http://www.david-tyler.com/jupiter.asp). i have downloaded the movie and broken it up into bmps.

Compared with a recent one of mine. Obviously, the seeing was no where near the same, but the capture settings are very different.

Post capture, you are then able to adjust up / down to get a final image. BUT, if the image was too dark to start with, then being a digital process, you can't add the detail in later, but you can adjust it back!

Hope this helps

[swannies1983]

dddooohhh, I wrote a long reply and accidently pressed back and now my reply has disappeared. Ok, I'll it again.

My set up:
Tal 200K FL=20000, f/10
Toucam is like a 6mm eyepiece (so I have been told?)
Therefore, toucam alone yields ~333X magnification while the introduction of my 2x barlow brings that up to ~666X magnification. Seeing will determine whether I can use the barlow and also the fact that my scope has a "maximum" useful magnification of ~400X.

My usual camera settings (no barlow):
shutter speed 1/25sec (slowest speed as it's not modded)
brightness ~50%
gain ~10% (reasons why so low due to my "noisey" belief)
don't really touch the gamma

with 2x barlow
shutter 1/25sec
brightness near max
gain 50%
and introduce some gamma as it's still quite faint

Dave, you said you have brightness around 60%, gamma 20% and gain at 80%. Is that for imaging Jupiter? Is this when using your 10" Dob? What magnification are these settings for?

Now, if the image is still to faint, what do you adjust? Is there a particular preference i.e. gain, or brightness or gamma? Or is it a combination of them?

Thanks

Daniel

[RB]

Makes very good sense David, it's so easy to fall into the trap of trying to get it looking perfect onscreen while capturing, when you're a nu-be.

[Dennis]

Just keeps on getting better and better Mike - terrific image with heaps of detail; both on Jupiter AND Ganymede.

Cheers

Dennis

[davidpretorius]

looking with eyeball is different to capturing lotsa bmps (ie a movie) and then trying to process the "seeing" conditions out.

400x is probably max for any eyepiece and telescope although on those rare occassions, you may push past this.

For my toucam acting as a 6mm eyepice in my 1250 focal length newt, 1250 / 6 = 208 x 7.7 (5x powrmate with 100mm extension) = 1600x.

another way to measure is 1250 x 7.7 = 9625mm. You will here most planetary imagers talk about focal length needing to be up around 10,000mm. Different cameras will change the physical size of the image depending on the size of the pixel area, so magnification is not really used as a term.

I would be keeping 1/25, setting the brightness to 50 - 60%, then upping the gain until you start to burn out the image, ie the white bands all become white. once you have focussed and about to image, then up the gain a little 10%, 20% etc.

The longer the focal length ie barlows and extension tube, the less light comes in and you have to up the gain or brightness.

I am at the limit of a toucam at 1600x with a 10" mirror etc. Mike here has a 12" mirror, hence more light and can push the mag further

I basically have to back the magnification off or have perfect transparency to do Saturn due to the relative dimness.

(Hey Mike, please feel free to split this thread if needed)

[swannies1983]

Yeah, sorry this thread went a bit off track....i didn't mean it to! :whistle:. We can continue to talk about this is another thread (once/if it's split) as we should just be inspired by Mike's image.

Thanks for your advice though. I will up the gain in future when I use the barlow. I think it will take a bit of time to sink in when you start talking about magnifications of 1600x or focal lengths of around 10,000mm. I just didn't think the atmosphere would allow you to magnify so much!! With those sort of numbers, jupiter or saturn must look like a fuzzy blob in the actual AVI, even in scopes with an aperature of 10" or 12"?? How do you get any detailed frames from an AVI with figures like that? I would greatly appreciate it if I could see some single raw AVI frames with a focal length that high.

Thanks

Daniel

[davidpretorius]

http://www.iceinspace.com.au/forum/showpost.php?p=193972&postcount=14

the two images in post 14 below are single frames from an avi from focal lengths that high.

On absolutely great nights and we are talking "seeing" of 9/10, then image simply sits there, does not wobble or go out of focus. From memory, I can think of 3 occassions. 26th April 2006 for me, bird had an experience with saturn just recently and Mike had one patch last year when he nailed it and dominated all major websites around the world for a few weeks

Here is a link http://www.iceinspace.com.au/forum/attachment.php?attachmentid=11941&d=1146136106 showing some raw images from the 26th.

These nights come along maybe once a year.

There are many things to contend with at high magnification. Mike has written a great article on it ( http://www.iceinspace.com.au/index.php?id=63,306,0,0,1,0 ) . We are all following Bird et al and imaging in separate colours and actively cooling our mirrors so there are no heat shimmers coming off the mirror.

It is a huge learning curve, but so worth while when it all comes together

[swannies1983]

Thanks Dave. All very helpful tips. I look forward to giving them a ago and posting my results :thumbsup:....just need the clouds to go away :D

[acropolite]

Stunning image Mike. Looks like the extra couple of inches of aperture are being put to good use. :thumbsup: