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Is this the best I can expect... Jupiter / Saturn 90mm f/11

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#1 Dirk84

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Posted 24 July 2021 - 03:38 AM

Hi all,

 

I recently tried to capture Jupiter and Saturn trough my MEADE 395 (90mm f/11) (Camera is a ZWO ASI178mm)

 

Would this be the best result I can expect or should I be able to capture them better?

 

For the first try I'm happy how Saturn turned out but I'm a little disappointing with Jupiter. (Too much noise and blurry lines.)
 

I took and .AVI of 3000 frames and stacked the best 30% 

 

But t be honestly, I don't know if I need more frames or better processing or better conditions...

 

JUPSAT.jpg


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#2 james7ca

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Posted 24 July 2021 - 04:00 AM

Better seeing conditions will always help, even with a 90mm scope. Plus, both Jupiter and Saturn are pretty low in the sky from the northern hemisphere right now so that makes the situation even worse. Because of the latter you might want to get an Atmospheric Dispersion Corrector (ADC) if you are going to do much more planetary work.

 

I captured an image of Jupiter with a shadow transit of Io last week using a Celestron C90 with a QHY5III-178C camera and below was the result. You can find more images taken with scopes six inches and smaller in the following threads here on CN:

 

  // Jupiter

  https://www.cloudyni...s/#entry5105885

 

  // Saturn

  https://www.cloudyni...s/#entry6571358

Attached Thumbnails

  • Jupiter with Io Transit Using a C90 (small).jpg

Edited by james7ca, 24 July 2021 - 04:08 AM.

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#3 Redbetter

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Posted 24 July 2021 - 05:36 AM

Prefacing to say I am not an imager:

 

Have you tried stacking smaller percentages of the frames to see if that sharpens things?  30% sounds awfully high to me unless the seeing was quite good.  I suspect too many fuzzy frames are being retained and blurring the result, based on what I see.  Better to keep a small percentage of the sharpest frames.  Maybe try 10% then 5%, just to see which way things go.  From watching others do captures and stacking while comparing with my own visual impression of the seeing at the time, I observed that they had better results when they culled more in good seeing...and suppose that this optimization needs to be done each session to match conditions.    

 

For reference, my 60mm ED is showing much more visually tonight, so I doubt your 90 is anywhere near tapped out.


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#4 Tulloch

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Posted 24 July 2021 - 05:54 AM

Hi all,

 

I recently tried to capture Jupiter and Saturn trough my MEADE 395 (90mm f/11) (Camera is a ZWO ASI178mm)

 

Would this be the best result I can expect or should I be able to capture them better?

 

For the first try I'm happy how Saturn turned out but I'm a little disappointing with Jupiter. (Too much noise and blurry lines.)
 

I took and .AVI of 3000 frames and stacked the best 30% 

 

But t be honestly, I don't know if I need more frames or better processing or better conditions...

All of these :)

 

Have a look at these tutorial videos, try to capture Jupiter for 3 minutes, Saturn for 5 minutes in 8 bit mode with a small ROI. 

http://planetaryimagingtutorials.com/

 

Keep trying, you've made a good start, you just need to get lucky with the seeing and hone your technique a bit more.

 

Andrew


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#5 mayhem13

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Posted 24 July 2021 - 06:41 AM

Nice first effort Dirk! I’m a newb to planetary imaging as well and have made HUGE improvements over the past month thanks to terrific people here! Here’s my take on what I’ve learned…….

 

You need more frames for sure………I’d say double what you’ve captured for these images…..but the 178 is a slow camera so your capture settings and computer need to be optimized for the max frame rate of 60fps….that’s 7200 frames in two minutes. After that, surface details begin to blur as Jupiter is rotating so fast. I used to push it to 3 minutes to accommodate my slow laptop but learned my lesson. 

IR/UV cut filter…..HUGE improvement in contrast which revealed more detail immediately. You don’t mention what other gear your working with so if you don’t have a filter…..get one.

 

Focus……struggled here for a while and then realized the need for the EXACT best focus possible…..and for me at a focal length of 4500 at F15, even BREATHING on the focuser sent the planets into spastic fits….enough sometimes to lose them from view altogether….this WON’T work for lucky imaging and so I purchased a motorized focus adapter…….another HUGE improvement well worth the investment given the improvement factor. 
 

You can work the advantaged of the 178 smaller pixels to your advantage by pushing the magnification factor to F/25 without oversampling……so a 2.5x Barlow will provide more detail but only if the above two are sorted out AND the seeing is excellent……with only 90mm of aperture , seeing becomes absolutely critical in your case which leads to my next experience and what help I’ve received here from the pros…..

 

To get those high frame rates, you NEED to keep exposure time low….and that’s EXTREMELY difficult with small apertures….they just don’t gather enough light to support it. You CAN combat that with increased gain BUT my experience recently with guidance from another member here is that’s a problem…which I learned during processing…..the low signal to noise ratio becomes easily apparent during sharpening and the details are littered with color noise……you simply can’t get the level of detail…….but get that gain down to 200-250 and woah!…..HUGE improvements available.  At 90mm, seeing is going to be your MOST critical obstacle with the 178’s low frame rate….so much so that the 224 or 462 might be the most readily available improvement you can make. Financially, it’s a break even for you. Yes, the 178 is capable of BETTER individual frames…..but capturing enough QUALITY frames is a huge challenge for your location and aperture.

 

So there you have it….my top tips learned from the greats here this past month and shared with you. Last nights seeing wasn’t great, BUT my captures were plentiful and properly focused with an exposure time of under 8 and gain of 200……and from my prelim look at the raw videos, I’ll be posting my best Jupiter yet later today after I get a chance to process it. I’ve had MUCH better seeing conditions when I first started, but without the above, my final images were quite blurry….some might call them ‘pleasing’ with some proper adaptive processing…..but no where near the level of detail I’m at now. I do have one huge advantage over your capacity though at 300mm, so for you, everything else has to be super high tuned. I do have to pay a price with collimating at each session to perfection though…..something you don’t have to deal with. I would imagine your letting your scope acclimate for an hour so before capturing.

 

Best of luck and I look fwd to more images from Belgium!


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#6 james7ca

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Posted 24 July 2021 - 07:43 AM

Just a note about critical sampling and f-ratio. I wouldn't go to f/25 with an ASI178MM as critical sampling can be achieve at something like f/12 given the 2.4um pixels on that camera. Thus you probably don't want to use a barlow on the OP's Meade 90mm given that it's a native f/11. If you went to f/25 that would require 25^2 / 11^2 ≈ 5X the exposure time. With the OP's setup If you want a little more scale try a drizzle integration, not a barlow.


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#7 DirtyRod

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Posted 24 July 2021 - 09:13 AM

Here is my untracked 90mm Meade ETX with a 2x Barlow and the same ASI178MC camera. Each is less than 1k frames stacked with OK seeing. Northern hemisphere at probably 35 degrees.

Attached Thumbnails

  • B3E1785C-C034-4DB2-9AE1-557F934EC524.jpeg
  • 96FC135B-FFBF-453A-B492-7AC2CC85F430.jpeg
  • EF69CF0C-541D-43E7-9023-0E66B8ED764E.jpeg

Edited by DirtyRod, 24 July 2021 - 09:20 AM.

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#8 yock1960

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Posted 24 July 2021 - 01:33 PM

Here is an image I got way back in 2008 with an ETX-80...achromatic refractor and a webcam says it all. I don't even know how I got Jupiter on the chip at f/25 with that scope! Jupiter was lower then, then now too!

 

Steve

Attached Thumbnails

  • gallery_47815_4220_1407441963_16728.jpg

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#9 Dirk84

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Posted 27 July 2021 - 01:59 PM

Sorry for the late reply but I was busy over the past few days.
I had a lot of feedback that I will try to use next time the weather will clear and I can take another shot at Jupiter.

 

 

Better seeing conditions will always help, even with a 90mm scope. 

Yeah I think i need to keep taking pictures of it in order to see how good seeing and bad seeing effects the outcome..
Do you take the weather into account, I mean Low pressure area vs a High or is there no science to predict seeing conditions?

 

 

 

All of these smile.gif

 

Have a look at these tutorial videos, try to capture Jupiter for 3 minutes, Saturn for 5 minutes in 8 bit mode with a small ROI. 

http://planetaryimagingtutorials.com/

 

Keep trying, you've made a good start, you just need to get lucky with the seeing and hone your technique a bit more.

 

Andrew

How is it possible that I never saw this link.... thanks a lot, this is definitely helpful for me! 

 

 

Nice first effort Dirk! I’m a newb to planetary imaging as well and have made HUGE improvements over the past month thanks to terrific people here! Here’s my take on what I’ve learned…….

.....

Thanks Mayhem13, This really helps, you provided me with a lot of information that I will consider. I was looking into an RGB filter setup to get some colour on my 178m but that 244 camera comes in the same budget as a RGB setup so I think the 244 will be my next step. Question on the IR filter,  what is the difference between an IR pass or IR cut confused1.gif ? 

 

 

Here is an image I got way back in 2008 with an ETX-80...achromatic refractor and a webcam says it all. I don't even know how I got Jupiter on the chip at f/25 with that scope! Jupiter was lower then, then now too!

 

Steve

Excellent!  This motivates me to keep trying!

Thanks all!



#10 mayhem13

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Posted 27 July 2021 - 05:24 PM

So an IR cut filter will cutoff IR wavelengths statrting with the wavelength determined by the coating . An IR pass does the opposite and allows only IR light to pass and cuts most of the visible light.



#11 Dirk84

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Posted 28 July 2021 - 01:58 AM

So an IR cut filter will cutoff IR wavelengths statrting with the wavelength determined by the coating . An IR pass does the opposite and allows only IR light to pass and cuts most of the visible light.

Ok makes sence now. thanks for this.
On the marketing sites they were both saying 'good for planets' so I got confused. And I was afraid that I would get red pictures with the cut filter because the glass looks so tinted on the advertising pictures.



#12 mayhem13

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Posted 28 July 2021 - 05:55 AM

Ok makes sence now. thanks for this.
On the marketing sites they were both saying 'good for planets' so I got confused. And I was afraid that I would get red pictures with the cut filter because the glass looks so tinted on the advertising pictures.

Yeah....I thought the same thing when I opened the package! LOL. But the IR/UV cut REALLY improved the contrast of my images.....it was an immediate and appreciable improvement. I bought the middle of the road Baader filter after reviewing as many online reviews as i could. The guys who bought he cheap generics complain of flaring on bright objects and the folks who bought the super expensive ones complain they spent too much.




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