Jupiter & Saturn

[Damien2904]

Hello, 

I thought I’d share some photos that I took last night (03Aug) of both Jupiter & Saturn. 
All taken using my SkyMax 180 Pro & ASI224 MC in FireCapture. Processing after with PIPP, AutoStakkert & Registax for wavelets. 

I’ve included a small animation of Jupiter…however I think I need to clean my Barlow lens, not sure what the sploge is at the end…🙄 unfortunately I missed the GRS when doing closer shots. 

Please feel free to post any suggestions about how I can brush up on anything you think I’m doing wrong.
Only been doing this a few months so I’m still teaching myself lol. 🤓

[orion25]

Great shots, Damien. I see that we have similar kit (180mm Mak & ASI224 MC). Your images look a lot like mine, lol. Nice color and detail. I can't get the animation to play tho  

Cheers, Reggie 🚀

Edited August 4, 2021 by orion25

[Damien2904]

Thanks Reggie, great to hear that I'm on the right path. 

Oh...let me try again, I uploaded the original post from my iPhone so maybe something went wrong...? I'll also include the one I made of the Ganymede transit back mid July. Hope you can see them....

Hoping to maybe catch the Europa transit later tonight, but it's not getting started until quite late & I have work tomorrow. 

[orion25]

Nice animations, Damien! The second one looks as if something crashed into the cloud tops, lol. Keep up the great work

Cheers, Reggie 🚀

[Tommohawk]

Looks good to me - I wonder what gain and exposure and frame rate you are using, and how many frames you are keeping in Autostakkert? 

[Damien2904]

On 06/08/2021 at 21:18, Tommohawk said:

Looks good to me - I wonder what gain and exposure and frame rate you are using, and how many frames you are keeping in Autostakkert? 

Jupiter photos : Exp 80.2 Gain 129 & Gamma 63 - took around 2,000 frames. 

Saturn photos : Exp 652.9 Gain 111 & Gamma 60 - I believe Saturn was 1,000 frames if lucky

Do let me know if you think I should adjust any of these for better results. 

I seem to still be having a problem where the planets slowly move out of my FOV even though I'm using my AZ EQ5-GT mount ....think I have to read up more about alignment, the scope is obviously not following them correctly, I'd like to get them to stay still but I think I'm missing something, so I'm pausing the captures to adjust the planet back to the centre. 

I did manage to take this close up of Saturn on Friday night (3 Aug), bit noisy...a but for me it is definitely progress in taking closer shots of Saturn. 

[CraigT82]

Nice set of results well done, onwards and upwards! I'd ramp up the gain and bring down the exposures to help 'freeze the seeing'.  Also leave the gamma alone set it to 50 (off) you can change it in post processing if you feel the need but you're handcuffing yourself by setting it in the capture.

[Tommohawk]

Agree with Craig - try around 20ms and crank up the gain if necessary to get around 75% on the histo - be sure not to clip in either RG or B.

You can probably run for 3 minutes with Jupiter - Autostakkert does a great job of effectively derotating. I usually use PIPP and keep the best 50%, and then Autostakkert and keep the best 20% of the remainder, or something like that. I don't know exactly how the software grades the images but by running through both I reckon should get the best of both.

Saturn looks good given how low it is.

[vlaiv]

I agree that you should lower exposure length - but I disagree about the histogram - just don't look at it at all - it is useless and misleading for planetary.

Exposure length should be at about 5-6ms and not longer. Gain should be used to control read noise.

As you can see - gain 350 has the lowest read noise - so use that. Don't worry about possibility of clipping due to high gain - if you use short enough exposure to freeze the seeing - it can't happen. Capture will be dim - but don't worry about that either - that is something to be adjusted in processing.

Drop the barlow, Mak180 is F/15 instrument and you are using camera with 3.75µm pixel size - that is perfect match without barlow.

With 6ms exposure length you have chance of doing 167FPS (1000ms / 6ms = 166.666....). In order to utilize that - you'll need to use ROI:

I outlined combinations that won't limit FPS. Just remember, if you go for shorter exposure length - like 5ms - you'll be able to achieve 200fps, while with 4ms - 250fps. Choosing ROI to support that is good thing. Using USB3.0 connection and computer that is capable of recording at such high FPS is another important bit.

[Tommohawk]

I was passing on "received wisdom"... but will defer to vlaiv!

[michael.h.f.wilkinson]

3 hours ago, vlaiv said:

I agree that you should lower exposure length - but I disagree about the histogram - just don't look at it at all - it is useless and misleading for planetary.

Exposure length should be at about 5-6ms and not longer. Gain should be used to control read noise.

As you can see - gain 350 has the lowest read noise - so use that. Don't worry about possibility of clipping due to high gain - if you use short enough exposure to freeze the seeing - it can't happen. Capture will be dim - but don't worry about that either - that is something to be adjusted in processing.

Drop the barlow, Mak180 is F/15 instrument and you are using camera with 3.75µm pixel size - that is perfect match without barlow.

With 6ms exposure length you have chance of doing 167FPS (1000ms / 6ms = 166.666....). In order to utilize that - you'll need to use ROI:

I outlined combinations that won't limit FPS. Just remember, if you go for shorter exposure length - like 5ms - you'll be able to achieve 200fps, while with 4ms - 250fps. Choosing ROI to support that is good thing. Using USB3.0 connection and computer that is capable of recording at such high FPS is another important bit.

You don't want to push the gain high enough to saturate the ADC. The histogram will tell you that. I always check I am not saturating any of the bands (I am looking at you, Menelaus and Aristarchus) using the histogram.

[vlaiv]

6 minutes ago, michael.h.f.wilkinson said:

You don't want to push the gain high enough to saturate the ADC. The histogram will tell you that. I always check I am not saturating any of the bands (I am looking at you, Menelaus and Aristarchus) using the histogram.

It is really hard to saturate when you are at the critical sampling rate, even with high gain. I think that with critical sampling, you'll get something like 80000 photons per second per pixel. Multiply that with few milliseconds of exposure and QE of sensor - and you get couple of hundred of electrons under ideal conditions. Really short exposures won't saturate even the highest gain settings.

 

[michael.h.f.wilkinson]

13 minutes ago, vlaiv said:

It is really hard to saturate when you are at the critical sampling rate, even with high gain. I think that with critical sampling, you'll get something like 80000 photons per second per pixel. Multiply that with few milliseconds of exposure and QE of sensor - and you get couple of hundred of electrons under ideal conditions. Really short exposures won't saturate even the highest gain settings.

 

On Saturn and Jupiter, saturation isn't an issue, but on the moon, the sun, and Venus it has happened. Actually, many of my best images of sun, moon, and planets are taken at slightly longer exposure times than the critical rate, depending on conditions. Furthermore, to get optimal focus, especially in solar, where you cannot use a Bahtinov mask to get focus on a star, I push gain up high enough to get good enough contrast on the screen to judge focus. This does mean you have to beware of possible saturation. In the case of lunar imaging, I generally focus on the terminator, as it provides most contrast. I then start imaging panes of a mosaic from there, but that does mean I have to check for saturation as I move from terminator to the other limb. In solar imaging, areas which show flaring or bright plage can saturate the ADC at gain settings that work fine for most of the disc.

[neil phillips]

On 08/08/2021 at 14:25, vlaiv said:

I agree that you should lower exposure length - but I disagree about the histogram - just don't look at it at all - it is useless and misleading for planetary.

Exposure length should be at about 5-6ms and not longer. Gain should be used to control read noise.

As you can see - gain 350 has the lowest read noise - so use that. Don't worry about possibility of clipping due to high gain - if you use short enough exposure to freeze the seeing - it can't happen. Capture will be dim - but don't worry about that either - that is something to be adjusted in processing.

Drop the barlow, Mak180 is F/15 instrument and you are using camera with 3.75µm pixel size - that is perfect match without barlow.

With 6ms exposure length you have chance of doing 167FPS (1000ms / 6ms = 166.666....). In order to utilize that - you'll need to use ROI:

I outlined combinations that won't limit FPS. Just remember, if you go for shorter exposure length - like 5ms - you'll be able to achieve 200fps, while with 4ms - 250fps. Choosing ROI to support that is good thing. Using USB3.0 connection and computer that is capable of recording at such high FPS is another important bit.

Histogram meters are not useless in the context if someone doesnt have experiance to see when a planet is seriously clipping. It can at least let a newbie know they have a problem Vlaiv. I have 20 years experiance looking at planets. And i still find it useful to look at meters. relying on eyeballing clipping to a inexperienced imager. Is a bit risky. Serious clipping will lose detail

Edited August 9, 2021 by neil phillips

[vlaiv]

1 minute ago, neil phillips said:

Histogram meters are not useless in the context if someone doesnt have experiance to see when a planet is seriously clipping. It can at least let a newbie know they have a problem Vlaiv. I have 20 years experiance looking at planets. And i still find it useful to look a meters. relying on eyeballing clipping to a inexperienced imager. Is a bit risky. Serious clipping will lose detail

I agree, although sometimes it is hard to tell that planet is clipping even from histogram (histogram shows spread of pixel values and if only handful of pixels is clipping - it might not show on histogram).

If I'm not mistaken, SharpCap has aid to show clipped pixels? Maybe that is better option?

[neil phillips]

24 minutes ago, vlaiv said:

I agree, although sometimes it is hard to tell that planet is clipping even from histogram (histogram shows spread of pixel values and if only handful of pixels is clipping - it might not show on histogram).

If I'm not mistaken, SharpCap has aid to show clipped pixels? Maybe that is better option?

Its quite heartbreaking to get good captures only to find detail lost that cannot be pulled back. Personally i agree its good to get a eye for clipping i almost never ever clip anymore i can just instantly see it.

However if i want the strongest signal possible i think it can help to use both approaches, and avoid clipping. Just my personal take on it. Each has to find whats comfortable for them. But yes histogram can also be misleading agreed. But not when its seriously clipping. You would be surprised how many newbies might not notice serious clipping. Infact i see it on images all over the place. On here recently infact. 

 

Edited August 9, 2021 by neil phillips

[Tommohawk]

From a practical standpoint, I tend to work with a fairly dim screen when imaging, so it's easy to underestimate the actual image brightness. That's my main reason for referring to the histo. 

[Damien2904]

Thanks everyone for your comments & guidance. 

Last night after work I noted down everything advised and gave it a go, albeit there was a lot of high cloud around. I didn't have much luck with Saturn...using FireCapture I set the Exposure to 5.9ms, Gain 353 & Gamma 50(off), the planet was extremely dim on the screen however visible enough to make out where it was....so I captured a number of videos, however when heading to PIPP, it was unable to pick out the planet...and even after increasing the object detection threshold. Saturn disappeared after that (TREES!!!! ), so I had no time to make any adjustments. 

I moved to Jupiter (which was very watery in the sky)....

FireCapture : Exp=30.1, Gain=353, Gamma=50(off)

PIPP : selected 50% of frames (I took 3mins worth, about 5,000 frames)

AutoStak : Analysed & selected 25% of frames...Norm Stack 90%, Sharpened Blend RAW 50%, Drizzle off, Auto AP to 48 & stacked.

Registax : Dyadic, Gaussain, Wavelet layer 1 (100), 2 (27.5) with slight sharpen & denoise, RGB balanced & in the histogram chopped down just before RGB lines.

Result was this....

615EB694-3CE8-4147-B6D9-36E9DE554884.tiff

I'm quite happy with it even though the weather wasn't great....

Edited August 9, 2021 by Damien2904

[neil phillips]

1 hour ago, Tommohawk said:

From a practical standpoint, I tend to work with a fairly dim screen when imaging, so it's easy to underestimate the actual image brightness. That's my main reason for referring to the histo. 

A good point there 

[Damien2904]

Evening all, 

Just wanted to say thank you all for the advise you have given me, I've been putting it to good use.

Below is an animation I made today of last nights Io transit, unfortunately due to the timing & a tree in my neighbours garden I only got the lead up & beginning of the transit. Gutted I couldn't go further as it was quite good seeing conditions. By the time Jupiter reappeared from behind the tree, Io had already moved on. Hey ho...next time.  

[Pete Presland]

great looking set of images