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A comparison of Saturn with good vs poor seeing

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#1 Rouzbeh

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Posted 23 September 2019 - 12:46 AM

Here is a demonstration of  very bad seeing vs good seeing.

 

With the image of the left, at f/16,  I was able to get 2 x 90 seconds per filter in 45 mins and was only able to use 15% of each.

 

The image on the right was under stable seeing conditions but poor transparency (that can be compensated for). It was drizzled at 150% as well and 30 to 45 mins of data was used and derotated with multiple stacks per filter.

 

The image on the right had no IR data either and was shot at f/19.

 

 

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  • 2019-09-20-1535_2-RG50 -RG610GB-LRGB COMPARE.jpg

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#2 TareqPhoto

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Posted 23 September 2019 - 09:32 AM

Good effort, thank you very much!


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#3 Rouzbeh

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Posted 23 September 2019 - 01:31 PM

Good effort, thank you very much!

Thanks Tareq.

Ill be trying different F ratios and settings.



#4 TareqPhoto

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Posted 23 September 2019 - 01:55 PM

Thanks Tareq.

Ill be trying different F ratios and settings.

Try and show, it will help, and we appreciate it waytogo.gif



#5 RedLionNJ

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Posted 23 September 2019 - 04:57 PM

Once again, you have a most peculiar perception of "very bad seeing".

 

With very bad seeing on Saturn, you can't even use the Cassini Division as a focus reference.


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#6 TareqPhoto

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Posted 24 September 2019 - 02:14 AM

Once again, you have a most peculiar perception of "very bad seeing".

 

With very bad seeing on Saturn, you can't even use the Cassini Division as a focus reference.

WOW, you have 5 ZWO planetary cameras? maybe more?



#7 aeroman4907

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Posted 24 September 2019 - 08:21 AM

Once again, you have a most peculiar perception of "very bad seeing".

 

With very bad seeing on Saturn, you can't even use the Cassini Division as a focus reference.

I have to agree with Grant here.  Of course each has their own idea of what the seeing is, and it does become relative to aperture of the scope being used.  Regardless, "very bad seeing" would generally be seeing so poor that you pack up the scope and don't even bother to image.  Based upon looking at the R, G, B captures of the 'very bad seeing', I would personally quantify that as mediocre or marginal seeing for a 14" scope.  I'd guess with my 8" scope at the same location I probably would have classified it as "good".

 

The images listed as "good seeing" do in fact appear to be "good", but not "great" or "excellent".  I base that upon the G channel being close but still short on quality of the R channel, and B looking respectable.  Arbitrarily I would call seeing 'solidly good' when the G channel matches the R channel for resolution.

 

In some of the images I have seen from others, namely Darryl, he has some B channels that look very, very good, which indicate more 'great' or 'excellent' seeing, particularly since he also uses a 14" scope.


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#8 Rouzbeh

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Posted 24 September 2019 - 12:32 PM

Once again, you have a most peculiar perception of "very bad seeing".

 

With very bad seeing on Saturn, you can't even use the Cassini Division as a focus reference.

Perhaps the result looks misleading. I have used any technique I could think of to extract the image above. 

 

I could use 2 files per channel, here is blue capture playback:

 

https://www.youtube....h?v=RZGQRRPVt3E

 

I'd like your honest opinion, you usually seem to doubt my description of "poor".



#9 Rouzbeh

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Posted 24 September 2019 - 12:41 PM

I have to agree with Grant here.  Of course each has their own idea of what the seeing is, and it does become relative to aperture of the scope being used.  Regardless, "very bad seeing" would generally be seeing so poor that you pack up the scope and don't even bother to image.  Based upon looking at the R, G, B captures of the 'very bad seeing', I would personally quantify that as mediocre or marginal seeing for a 14" scope.  I'd guess with my 8" scope at the same location I probably would have classified it as "good".

 

The images listed as "good seeing" do in fact appear to be "good", but not "great" or "excellent".  I base that upon the G channel being close but still short on quality of the R channel, and B looking respectable.  Arbitrarily I would call seeing 'solidly good' when the G channel matches the R channel for resolution.

 

In some of the images I have seen from others, namely Darryl, he has some B channels that look very, very good, which indicate more 'great' or 'excellent' seeing, particularly since he also uses a 14" scope.

 

The aim of that night was not imaging, with this kind of seeing I would pack up.

 

The aim was to test the new camera and imaging train against what I normally use. The seeing was too bad to get any results but it seems the new setup is promising.

 

Here is the Green channel playback:

 

https://youtu.be/txtNSpRK1bs



#10 Rouzbeh

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Posted 24 September 2019 - 01:00 PM

I have had a few rare nights when seeing was very stable. This is  what I would call very good seeing, this was 1 night in the entire year to date:

 

https://youtu.be/PpOgIKu1OVM

 

 

It's a bit unfortunate that people seldom pay much thought to the fact that a lot of meticulous care has been taken to achieve results. Paying attention to every little detail and exhausting every avenue possible to get a little more out.

 

A common response is "wow you are lucky to live in a location with such good seeing" without knowing how much effort was actually put into the work.

 

Its funny the members of the local astronomy group know what the seeing is like here (and always complain about) so they're common response is "wow you are lucky you have a C14".

 

Results come from working towards them and experimenting with every possible scenario/setup. Thats been my thinking at least.

 

I can't through all the steps taken with scopes, mounts, hardware and processing here but I can tell you its more than "being lucky" ;) .


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#11 aeroman4907

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Posted 24 September 2019 - 03:00 PM

I have had a few rare nights when seeing was very stable. This is  what I would call very good seeing, this was 1 night in the entire year to date:

 

https://youtu.be/PpOgIKu1OVM

 

 

It's a bit unfortunate that people seldom pay much thought to the fact that a lot of meticulous care has been taken to achieve results. Paying attention to every little detail and exhausting every avenue possible to get a little more out.

 

A common response is "wow you are lucky to live in a location with such good seeing" without knowing how much effort was actually put into the work.

 

Its funny the members of the local astronomy group know what the seeing is like here (and always complain about) so they're common response is "wow you are lucky you have a C14".

 

Results come from working towards them and experimenting with every possible scenario/setup. Thats been my thinking at least.

 

I can't through all the steps taken with scopes, mounts, hardware and processing here but I can tell you its more than "being lucky" wink.gif .

Rouz, aside from the minor issue of your barlow usage, I don't think anyone is really critiquing your imaging skills.  It appears evident to me you put great care into your images and the efforts show in the quality of your images.

 

When discussing seeing though, particularly if you think your location is bad, you will get some response from us northerners.  The planets are low for us, so even 'decent' seeing near the zenith will often mean that the planets are in zones in elevation where the seeing degrades to 'mediocre' at best, or often 'poor'.  I know other northern countries have had their seeing issues, but living in North America myself, I can tell you that the Jetstream has been pretty brutal most of the year.  I also unwittingly got interested in high resolution lunar imaging on the leeward side of the Rocky mountains where temperature differentials are commonly 30+ degrees F every day.  I even live south of Denver near an area called the Palmer Divide that is known for unsettled weather patterns, which makes my specific area even worse.  Its kind of like being a snow skiing enthusiast where you live - not the ideal place to pick up the sport!

 

With regard to how things looked with your green channel Saturn image taken under 'poor' conditions, I would have to say I would not personally consider that poor.  When I imaged Saturn with my 8" scope this year, the seeing overhead appeared to be 'good', but with the lower elevation of Saturn, the image was 'poor'.  And by 'poor' I mean that Saturn looked like a waving flag, image appeared to jump in and out of focus dramatically (determining critical focus was pretty much impossible), and very few frames had the Cassini division visible.  Even in these conditions, we haven't had many nights as 'good' as this.  Sorry I don't have a video to show as reference because I have to delete my videos once processed.  And yes, the scope was cooled outside for hours and I had fans running internally during capture as well.

 

I mostly image the Moon, but only on nights I feel I can get at least 75% of the resolution potential of my 8" scope.  That means a Pickering of 4 or 5, which isn't that great at all.  With this criteria, I've been able to image the moon only on Jan 14th, March 16th, May 12th, and August 21st.  This month has been an entire bust with the Jetstream.  When Sirius is blinking like mad, you know conditions are bad!

 

I hope this clarifies we are not trying to demean your imaging skills, which I think are quite good.  It is just that North American imagers are having a particularly tough time, and I know our friends in Europe and other northern regions are experiencing the same thing.

 

All this being said, I am glad someone is getting good images of the planets, so thanks for sharing and I hope the even larger scope works out for you.  I will continue to live vicariously thought others for some time to come.

 

Best regards!


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#12 Rouzbeh

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Posted 25 September 2019 - 08:40 AM

Rouz, aside from the minor issue of your barlow usage, I don't think anyone is really critiquing your imaging skills.  It appears evident to me you put great care into your images and the efforts show in the quality of your images.

 

When discussing seeing though, particularly if you think your location is bad, you will get some response from us northerners.  The planets are low for us, so even 'decent' seeing near the zenith will often mean that the planets are in zones in elevation where the seeing degrades to 'mediocre' at best, or often 'poor'.  I know other northern countries have had their seeing issues, but living in North America myself, I can tell you that the Jetstream has been pretty brutal most of the year.  I also unwittingly got interested in high resolution lunar imaging on the leeward side of the Rocky mountains where temperature differentials are commonly 30+ degrees F every day.  I even live south of Denver near an area called the Palmer Divide that is known for unsettled weather patterns, which makes my specific area even worse.  Its kind of like being a snow skiing enthusiast where you live - not the ideal place to pick up the sport!

 

With regard to how things looked with your green channel Saturn image taken under 'poor' conditions, I would have to say I would not personally consider that poor.  When I imaged Saturn with my 8" scope this year, the seeing overhead appeared to be 'good', but with the lower elevation of Saturn, the image was 'poor'.  And by 'poor' I mean that Saturn looked like a waving flag, image appeared to jump in and out of focus dramatically (determining critical focus was pretty much impossible), and very few frames had the Cassini division visible.  Even in these conditions, we haven't had many nights as 'good' as this.  Sorry I don't have a video to show as reference because I have to delete my videos once processed.  And yes, the scope was cooled outside for hours and I had fans running internally during capture as well.

 

I mostly image the Moon, but only on nights I feel I can get at least 75% of the resolution potential of my 8" scope.  That means a Pickering of 4 or 5, which isn't that great at all.  With this criteria, I've been able to image the moon only on Jan 14th, March 16th, May 12th, and August 21st.  This month has been an entire bust with the Jetstream.  When Sirius is blinking like mad, you know conditions are bad!

 

I hope this clarifies we are not trying to demean your imaging skills, which I think are quite good.  It is just that North American imagers are having a particularly tough time, and I know our friends in Europe and other northern regions are experiencing the same thing.

 

All this being said, I am glad someone is getting good images of the planets, so thanks for sharing and I hope the even larger scope works out for you.  I will continue to live vicariously thought others for some time to come.

 

Best regards!

 

Thank you for your kind words. I think it takes a planetary imager to appreciate planetary images and understand the requirements for a good image.

 

I'm sure the more North you go, with the planets getting lower, the atmosphere plays a bigger role. Jupiter and Saturn are imaged from 3o to 40 degrees here now. The jetstream got to 160 MPH a few months ago during winter/spring. The baking sun does really heat the ground here and it's radiated back at night, so now the jetstream is very slow but seeing is still unstable. I'm assuming its the heat.

 

My worry is that I may move my gear to Canada in the future and don't know what to do then at those high latitudes. I've even contemplated converting that classical cassegrain into a fast f/3 deep sky imaging scope!

 

I see you are using a color camera? I'm assuming you are using an ADC as well. I personally feel (Chris Go insists) the mono has an edge over the OSC in terms of flexibility and use of filters to help with seeing. I must have about a dozen filters and different wavelengths and are still experimenting with them. 

 

As for the barlows, I'll hopefully be able to omit them and stick to the native f/15 ratio and pick either the 2.4 or 2.9 micron camera.


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#13 aeroman4907

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Posted 25 September 2019 - 08:50 AM

I see you are using a color camera? I'm assuming you are using an ADC as well. I personally feel (Chris Go insists) the mono has an edge over the OSC in terms of flexibility and use of filters to help with seeing. I must have about a dozen filters and different wavelengths and are still experimenting with them. 

I am the odd man out wanting to take full lunar mosaics in color, even though the moon has minimal color.  I just wanted to do something a little different than everyone else.  The importance of using a color sensor for me is that I don't have the time to image R, G, B for whole lunar mosaics.  I generally have barely enough time to get a full mosaic done with a full color sensor as it is.  With regard to the ADC, I haven't yet used in on the moon and I try to image the moon at elevations above 45 degrees to minimize the effects of imaging without and ADC.

 

I have used the ADC for imaging the planets this year, but with an 8" aperture, I don't feel that is enough to get the angular dimension on the planets I would like.  Unfortunately, the seeing here is poor enough it would never justify a scope the size of a 14" EdgeHD for example, so I don't foresee ever doing much in the way of imaging the planets.


Edited by aeroman4907, 25 September 2019 - 08:53 AM.


#14 kevinbreen

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Posted 25 September 2019 - 10:23 AM

I have to agree with Grant here. Of course each has their own idea of what the seeing is, and it does become relative to aperture of the scope being used. Regardless, "very bad seeing" would generally be seeing so poor that you pack up the scope and don't even bother to image. Based upon looking at the R, G, B captures of the 'very bad seeing', I would personally quantify that as mediocre or marginal seeing for a 14" scope. I'd guess with my 8" scope at the same location I probably would have classified it as "good".

The images listed as "good seeing" do in fact appear to be "good", but not "great" or "excellent". I base that upon the G channel being close but still short on quality of the R channel, and B looking respectable. Arbitrarily I would call seeing 'solidly good' when the G channel matches the R channel for resolution.

In some of the images I have seen from others, namely Darryl, he has some B channels that look very, very good, which indicate more 'great' or 'excellent' seeing, particularly since he also uses a 14" scope.


I’ll chip in and say that for me with my ASI224MC, very good seeing for me is the ability to see a razor sharp Cassini Davision and a steady planet.
I agree with Grant that bad or worse seeing means that focus isn’t possible due to no apparent CD.

#15 TareqPhoto

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Posted 25 September 2019 - 02:38 PM

I am in the same country where Rouz is [UAE], and i know how the seeing is here, so i focus even if the seeing is poor and i have half of that 14" scope anyway, and all my results i am not happy with while many liked them i keep telling it is a poor or bad seeing simply, i keep experimenting as well, but i am not lucky enough to have so many gear to experiment everything or compete with top quality results, and i doubt that every single night in my country is a poor seeing, but i don't know if some will keep doing it or keep complaining about it.

 

Focusing with mono is really easier than with a color due to sensitivity, but as aeroman said, i do shoot the moon the most, so for me the color camera is always a time saving, and while i do the moon i keep practice on planets as well, sometimes i swap, but many times i don't need to mainly i am using this 7"/8" scope, so i don't bother to use mono and filters much really, later when i will get the large scope then i will use all stuff i have mono and color and see that results i will get.




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