is it me ,my scope ,my camera or just the time for jupiter and saturn

[iwols]

hi been used to doing dso,but changed to planetary during this month,really struggling,using my c8 and a asi178c ccd,dont seem to get a good image ,added a few images and a link to an avi,thought with the c8 things might be slightly better,anyway any comments /suggestions appreciated as always

link to avi...of jupiter       https://www.dropbox.com/s/9lfchdick07juow/23_03_01.avi?dl=0

 

and an image of saturn

 

 

 

Edited July 29, 2019 by iwols

[PeterCPC]

Looks out of focus to me - have you checked the collimation. Also do you get focus using a Bahtinov mask and a star?

Peter

[iwols]

collimation was checked a while ago and i could not focus any better no matter how finely i adjusted it peter

[dweller25]

Jupiter and Saturn are very low so they are going to be affected by the depth of atmosphere you are looking through, plus at this time of year heat issues.

Cooling is essential for best results as is collimation - which needs to be spot on with an SCT.

To check collimation make sure the scope is well cooled then centralise a high star in your eyepiece at around x200. Find best focus and then assess collimation and adjust if required.

Thats all you can do yourself, the results may still be poor so it will be awaiting game until the planets get higher....

[Stu]

It does look out of focus to me too. How high was it at the time? If the seeing is poor then with their low altitudes currently the planets are tricky.

I assume that was a single frame of Saturn, not a stack? I managed the attached shot of Saturn through my 8" f8 newt the other night with a smartphone, so I'm sure you can achieve better detail.

[vlaiv]

Not necessarily out of focus, but it might be.

What sort of exposure was this? If it is anywhere over 10ms it is going to appear as out of focus, but it will actually be motion blur due to seeing. If you want to do for example 20ms or 30ms exposure, you need really steady seeing, and even then you will get handfull of good frames out of bunch that look blurry.

If you want to stop the seeing, you need to go with low exposures - don't worry if image looks noisy it is supposed to look noisy and that is what the stacking is for.

Don't worry about histogram being here or there - these rules don't apply for lucky imaging.

[iwols]

not sure what the expiosure was will check next time,it was on the hot night last thursday or friday and it was about a metre or two above a bungalow opposite,

[dweller25]

12 minutes ago, iwols said:

not sure what the expiosure was will check next time,it was on the hot night last thursday or friday and it was about a metre or two above a bungalow opposite,

That’s probably the problem

[Stub Mandrel]

To me it looks like it hasn't been debayered.

[iwols]

debayered?? thanks

[Cosmic Geoff]

A C8 should perform a lot better than that.  It could be the awful seeing.  Is that a single frame, or the result of processing?

Not blowing my own trumpet or anything, but if you search back in this section you should find one of my images of Jupiter with a single frame and the (much better) stacked result.  I typically stack 20% of a 5000 frame video, processed in Registax6.  I generally focus on a star, not on the planet. 

  On a decent night, the live view should look a bit better than the original post image above, and the major division of the rings should show in the processed result.

If you save the file as a .ser you don't have to debayer it.

I hope this helps.

[vlaiv]

Had a look at Jupiter recording, and here are a few suggestions:

1. use x2 - x2.5 barlow / telecentric for optimum sampling

2. keep exposure around 5ms range

3. shoot raw video in .ser format (skip avi if at all possible)

4. use gain setting at around 270

5. use ROI to maximize frame rate captured (like in Jupiter video - 640x480 is quite enough to capture a planet)

6. Use 8bit capture if image is not over-exposed, another trick to maximize fps (at 5ms and 8bit you should be able to hit around 200fps)

7. Use up to 4 minutes of imaging run per planet. If everything is good you should end up with couple of gigabytes of .ser per capture (yes, quite a lot of data)

8. Shoot darks - at least 256 to 512 frames at same settings with scope covered (this should not take long - few seconds at 200fps)

9. If you can - do flats and flat darks also

10. when shooting make sure planet is centered in sensor FOV and selected FOV is in center of the sensor (as close to optical axis as possible)

11. Use PIPP to calibrate your movie and save as 16bit ser (even if you took 8bit movie). Don't debayer in PIPP so keep option "protect bayer matrix" turned on. Out of all options, you want only three in principle - don't debayer/protect bayer matrix, calibration, image stabilization (this is not necessary) and save in 16 bit ser format.

12. Use AS!3 to stack you result

[iwols]

2 hours ago, vlaiv said:

Had a look at Jupiter recording, and here are a few suggestions:

1. use x2 - x2.5 barlow / telecentric for optimum sampling

2. keep exposure around 5ms range

3. shoot raw video in .ser format (skip avi if at all possible)

4. use gain setting at around 270

5. use ROI to maximize frame rate captured (like in Jupiter video - 640x480 is quite enough to capture a planet)

6. Use 8bit capture if image is not over-exposed, another trick to maximize fps (at 5ms and 8bit you should be able to hit around 200fps)

7. Use up to 4 minutes of imaging run per planet. If everything is good you should end up with couple of gigabytes of .ser per capture (yes, quite a lot of data)

8. Shoot darks - at least 256 to 512 frames at same settings with scope covered (this should not take long - few seconds at 200fps)

9. If you can - do flats and flat darks also

10. when shooting make sure planet is centered in sensor FOV and selected FOV is in center of the sensor (as close to optical axis as possible)

11. Use PIPP to calibrate your movie and save as 16bit ser (even if you took 8bit movie). Don't debayer in PIPP so keep option "protect bayer matrix" turned on. Out of all options, you want only three in principle - don't debayer/protect bayer matrix, calibration, image stabilization (this is not necessary) and save in 16 bit ser format.

12. Use AS!3 to stack you result

hi vlaiv the settings for the avi are

[ZWO ASI178MC]
Debayer Preview=On
Pan=0
Tilt=1180
Output Format=AVI files (*.avi)
Binning=1
Capture Area=640x480
Colour Space=RAW8
Temperature=36
Hardware Binning=Off
High Speed Mode=Off
Turbo USB=60
Flip=None
Frame Rate Limit=Maximum
Gain=33
Exposure=0.315962
Timestamp Frames=Off
White Bal (B)=99(Auto)
White Bal (R)=37(Auto)
Brightness=404
Auto Exp Max Gain=255
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=None
#Black Point

and the image settings are

[ZWO ASI178MC]
Debayer Preview=On
Pan=622
Tilt=850
Output Format=PNG files (*.png)
Binning=1
Capture Area=640x480
Colour Space=RAW8
Temperature=35.8
Hardware Binning=Off
High Speed Mode=Off
Turbo USB=60
Flip=None
Frame Rate Limit=Maximum
Gain=0
Exposure=4.132799
Timestamp Frames=Off
White Bal (B)=68(Auto)
White Bal (R)=30(Auto)
Brightness=404
Auto Exp Max Gain=255
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=None
#Black Point

if that helps thanks

 

[iwols]

4 hours ago, Cosmic Geoff said:

A C8 should perform a lot better than that.  It could be the awful seeing.  Is that a single frame, or the result of processing?

Not blowing my own trumpet or anything, but if you search back in this section you should find one of my images of Jupiter with a single frame and the (much better) stacked result.  I typically stack 20% of a 5000 frame video, processed in Registax6.  I generally focus on a star, not on the planet. 

  On a decent night, the live view should look a bit better than the original post image above, and the major division of the rings should show in the processed result.

If you save the file as a .ser you don't have to debayer it.

I hope this helps.

yep your right

[Stub Mandrel]

11 hours ago, vlaiv said:

Don't debayer in PIPP so keep option "protect bayer matrix" turned on.

This is something I learned the hard way, especially if you want to drizzle in AS!3. I now always debayer in AS!3

 

[vlaiv]

9 hours ago, iwols said:

hi vlaiv the settings for the avi are

Ok, there are a few settings that are "wrong" from what I can tell.

- don't use avi - use ser (although avi is in principle fine, it supports compression and one wants to avoid compression as it leads to compression artifacts, so it's better to use plain format as ser as it is also written faster and there is no option for compression so you can't go wrong with it)

- exposure is way high in both (assuming units of seconds which should be reasonable) - no wonder it looks out of focus / blurry. Like I pointed above aim for about 5ms. Actual exposure time depends on something called atmosphere coherence time and it is not easy to judge, but it is time in which distortion of the image due atmospheric seeing does not change - it depends on something called coherence length and speed at which atmosphere is moving (this is why jet stream is bad - it moves air along at great speeds). It is in range of few ms up to 10ms or so. When atmosphere is really steady you can go 20ms or even 30ms. Expressed in units of seconds these numbers are 0.005 - 0.01, and occasionally 0.02-0.03 when you have excellent seeing. In contrast your exposure times are 0.3s and 4.13s.

- apply high gain - with higher gain you have lower read noise, and you need as low read noise as possible because it helps when you have short exposures (difference in SNR between one long and few short exposures of same total time is in read noise - smaller it is less difference in SNR and you want as high SNR as possible). For 178 sensor, gain of about 270 is going to give you lowest read noise (according to ZWO graph).

- I would not use auto white balance and set both red and blue to default values - you can white balance in processing

- if you have auto exposure and such turned on - just turn them off and set exposure manually to something like 5, 6, or 7ms (even 10ms if you have steady skies)

- Pan/Tilt tells me that you were not in the center of the sensor. This is important as image is the sharpest on optical axis. As soon as you start moving off axis there will be off axis aberrations. With SCT there will be coma (same with parabolic newtonians). This of course holds for well collimated scope. For this reason you want to be on optical axis when doing capture.

- turn high speed mode - you want to capture as much frames as you can. With this camera if you have SSD and good USB3.0 controller, you should be able to do about 200fps. Do that for up to four minutes and you should gather somewhere around 40000-45000 subs. If you stack top 5-10% of those you should improve your SNR by factor of about x50-x60. That is good enough to do serious wavelet sharpening without bringing too much noise into view.

HTH

[iwols]

some great info there vlaiv cant wait to try again appreciated,when i get the ser files do i try using them in AS3 then

[vlaiv]

23 minutes ago, iwols said:

some great info there vlaiv cant wait to try again appreciated,when i get the ser files do i try using them in AS3 then

It would be good to do at least dark subtraction (that includes bias).

In order to do that, you need to keep everything the same (don't change any settings) and just cover your scope. Shoot a short movie of about 256 to 512 frames (sorry about my binary OCD ). If you are using sharpcap for capture you can limit recording to either total duration or number of frames - use total duration for shooting planet movie and number of frames for this dark movie.

Once you have those two (but flat / flat dark would also be really good to throw in the mix - but that is taken differently - like in regular imaging, you don't need the same settings and exposure will depend on how strong is your flat panel) - you need to open them in PIPP - it is Planetary image pre processor (or something like that) - open source / free software for pre processing planetary movies. There you want to do calibration / image stabilization, also preserve bayer matrix and export as 16bit ser.

Once you have done that - then open that ser in AS!3 and do stacking. Tell AS!3 to debayer your ser (you can use bayer drizzle or some other debayer method).

You can skip PIPP and dark calibration, but you'll get better results if you do it as it removes bias signal (and very very tiny dark signal) and it should give you cleaner image in the end.