Jupiter help please

[jambouk]

I've done some planetary before, so I'm not a total newbie with this, but....

Finally had a clear night last night to test stuff out. There was a fair amount of star twinkle, and there was a lot of moisture in the air, but the sky was crystal clear (never sure which is transparency and which is seeing).

Anyway, at about midnight when Jupiter was high, I had a go at capturing data.

180 Mak on equatorial mount. Flip mirror and on the back of that a 2x Powermate, and then the ASI ZWO 120MC CMOS camera, connected to my laptop. I was running SharpCap2 to capture (first time I've used v2 of it).

Went to Pollox to focus with a Bhatinov (same elevation as Jupiter and a few degrees to the north). Got what I thought was bang on focus. Went back to Jupiter, got it on the sensor.

Got the area of interest down to about 640x560, and the tracking was pretty good so it stayed in this area for ages. I was amazed at how clear the bands on Jupiter were. I also noticed loads of dust bunnies on my sensor. Anyway, dropped the exposure time down to about 0.02seconds and the gain to about 50%; all other settings were default (it only allowed RGB24). Did various runs of 1.5minutes, and some longer with a larger sensor area and did some 'dithering' to see if that would help with the dust bunnies during processing....

Anyway, ran it through registax (v5 and v6) and I just can't seem to get a sharp Jupiter. The only thing which seems to be sharp are the dust bunnies. I've also run the data through PIPP to get rid of the worse 50% and still no joy.

So, is this poor focus, bad seeing/transparency, dust bunny effect, or something else?

Thanks for any advice. Images attached are screen shot of sharpcap capturing, a screen shot mid raw video, and a screen shot of the stacked image (adjusting wavelets does nothing to Jupiter, only to the dust bunnies).

James

[Space Cowboy]

Image scale is your main problem James. Your scope is f15 and with the 2x barlow and flip mirror you must be running at over f40 which would be at the limits with a imaging source ccd cam sensor but the ASI cmos sensor produces images about 1.5x larger which means your scale is way too big. You could probably do without the 2x barlow and just use the flip mirror and see how you go with that.

Personally I would focus on Jupiter rather than a star. If there are moons near by they are the best focus aid. Get them pin sharp and you wont be far out. Also your image looks too dark. On sharpcap there is an exposure histogram which needs to be 60-70% full.

A cotton bud and lens cleaning fluid should clean off the dust bunnies. Maybe try a lens blower first.

[cgarry]

That looks you have used a bit to much focal length for the seeing conditions, hence the blurry planed combined with a lot of dust/dirt somewhere on your optics (probably the image sensor).

While capturing try rotating the camera and see if the dust bunnies stay in the same position, if they do they are on the sensor or a filter connected to the camera.

Cheers,

Chris

[michael.h.f.wilkinson]

The single shots do not look bad at all (as sharp as it will get at F/30 given the small pixel size of the ASI120). The stacking algorithm is probably latching onto the dust bunnies. Two things can help on the current data:

1. Acquire flats, which will show just the dust bunnies (remember to crop to the same size/offset as the capture). These will reduce the dust bunnies.

2. Manually select align points away from dust bunnies.

[Kokatha man]

No idea James - but the comments others have made re the f/l will affect outcomes, especially in poorer seeing.

I'm also sorry to say that this would be just about the worst case of dust on the sensor that I've ever seen   - taking a screenshot and applying u/sharp mask or LR deconvolution does sharpen the image a tad, but as you say, the dust bunnies literally hit you in the mouth then..!  

How many frames are you stacking (btw, toss Registax for aligning & stacking & use AS!2.....but Reggie is still needed for wavelets though.)

When you say that you were amazed how clear the Jovian bands were, are you saying clear and defined with contrast variations within them and other details along their edges or are you just saying clear as in boldly defined as strips of coloured contrast wrt the rest of the disk and no real detail within these strips of colour..?

If the latter (and your single frame suggests so to me) then it is poor seeing and/or poor focus quite likely coupled with an OTT focal length employed - and I would never advise anyone to use a Bahtinov Mask to focus for Jupiter as it would never be as good as focusing on the planet itself to extract the utmost details...

Sadly you really must attack that filthy sensor ASAP though...regardless of what's amiss with your captures here - here's a sure-fire way that I posted in CN sometime ago...

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/Imaging/Number/6108604/page/8/view/collapsed/sb/5/o/o/fpart/all

[jambouk]

Thanks all. I had never seen Jupiter looking as big on the sensor as it did last night (new combo for me to try the flip mirror in the set up), so I think the long focal length is definitely a contributor. A friend just emailed me the same idea about focusing on the moons, so I will try that next time. I might try and do some flats now, I know roughly what position the camera was in, but no idea how (or if) they'll help on this occasion - I might just write it off as a learning experience (story of my life lol).

I tried the manual align points but it didn't help.

Thank again all.

James

[leelee970]

I myself don't use Sharpcap - I use WXastrocapture (but should be almost the same).

Here are my settings for an SPC900 and x3 barlow + x2 tube +IR filter

Video format I420

FPS 10

shutter 1/33

gain 50% - this is the min, 60% is the max

gamma 0%

number of frames 2000

brightness 50%

contrast 30%

saturation 70%

white balance set to "freeze"

WBR 53%

WBB 16%

Hist - red - 170/255, green 170/255, blue 190/255

the image is pre registax processing, but I have to say I never get dust bunnies so it could be focus

[jambouk]

Thanks again all. And thanks for your settings leelee.

I've just blown the sensor with a rocket shaped air blower and looked at the light through sharp cap and it's much improved! This certainly couldn't have been helping matters, along with my other errors

Interestingly I've just noticed there are two ways to select the same camera in Sharpcap, one as a direct detected camera, and the other as ASI camera; the latter give more options of imaging (Raw8, raw16, RGB, mono8) whereas the direct detection method only RGB24 and mono8; which is the best form to capture the data in? The ASI camera option also seems to result in more options down the right hand side of sharpcap, like output format (avi, ser, fits), flip image, two white balances (R and and turbo USB!

Right, I'm looking forward to having another go next time it's clear and I'm setting up. Thanks again for all the helpful advice and comments and not for making me feel too stoopid

James

[oldfruit]

Hi James, i have to agree with what has been said above but also, looking at your wavelet settings on Registax it looks like you have it set to auto? Plus the wavelet settings look to be unmoved except for the top one. Have you tried adjusting the wavelets manually?

[jambouk]

I'd played with the wavelets, but it made no difference to Jupiter, just the dust bunnies which was annoying! The screen shot doesn't show that though.

I'm excited about having a go next time

James

[leelee970]

The main thing is not to give up, you'll be so pleased when you get things just as you want them.

Good luck and clear skies.

[SnakeyJ]

James - not sure if it will make any difference to this image, but Michael may well be right about the Registax latching on to the dust bunnies.    It might be worth having a go at the same data with AS!2.    Although I still use R5 & R6 for lunar and wavelets, personally I find Autostakkert better for Jupiter and Saturn.

Aside from the dust bunnies I think the image in the sharpcap window shows pretty good colour and detail for a single frame.

[jambouk]

Ok, i'll stuff it in AS2 and see what happens; i dis do manual align in RS but it still stacked dust bunnies. I did have one stack which eas dust bunny free but Jupiter looked like a smeared triffle and again wavelets did nothing; i just feel as though the wavelets are only altering a layer above the image of Jupiter, not Jupiter itself.

I'll report back later.

And thanks again.

James

[jambouk]

Used auto align points in AS2, and stacked the best 50% of 3400 frames (so 1700 frames stacked). Loading it into RS6 again has the same effect where the wavelets appear to only be acting on a semi-transparent layer above the main image:

James

zzjupiter 28_11_2013 00_55_08.tif

[jambouk]

A very short extract to show you what I ended up with in terms of raw data:

https://dl.dropboxusercontent.com/u/1673286/jupiter%2028_11_2013%2000_48_17.avi

Thanks

James

[Space Cowboy]

Without the dust and OTT image scale you will have some pretty darn good data James. Your focus looks ok to me just the massive scale that makes it look so soft. The dust is clearly fooling the stacking and aligning process.

[jambouk]

I'm just a bit confused why the dust now is causing a problem. I last used the camera in the spring for some planetary and had some good results. The IR cur filter has been on the camera over the summer, and when looking at the moon a week or so ago with the camera i noticed the dust bunnies and thought it was the filter, so took that filter off last night. I was also surpriaed that focus was so bad, given using a bhatinov on an adjacent star is a technique imd heard about and used before.

I wonder if the dust bunnies are bits of paint / metal as the nose piece screws onto the body with a metal on metal junction, and both screwed surfaces are painted.

It's much cleaner now, so just hope it's better next time.

I'm really grateful for the help and pointers from SGL.

James

[leelee970]

It could well be paint.

I myself us AS!2 for most of the processing/stacking, then useRS6 for wavelets and Gimp.

It can be frustrating when you do an identical image run and problems are thrown up.

the other night I did a 10 panel mosaic of the Moon. I didn't take the red laptop film off and so didn't notice I'd recored everything BLUE. - oh well, I've now learnt that I have to check EVERYTHING.

[jambouk]

Blue moon? You should write a song about that.....

[leelee970]

I think there would be copy right issues, lol

[leelee970]

but that was not the end of my problems.

I decided to still process it all - just used greyscale.

but look - I MISSED a bit - Doh

[jambouk]

I think it looks very sinister; you could sell it to Hollywood to use as a backdrop to their next sci fi film

[SnakeyJ]

Easily done that!

We're not alone

[jambouk]

I saw that thread, yes. But it's still impressive!

I did a four panel mosaic at the last full moon using my dslr to record video:

http://www.eastmidlandsstargazers.org.uk/topic/6345-my-first-mosaic/

I'd like to try again next time and put the power mate in front of the dslr and do a more detailed mosaic, or maybe fit the dslr to one of my baader eyepieces. Another project to add to the growing list!

James

[leelee970]

I was going to use some clip art and have a worm or maggot coming out of the missing part.lol