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Poor Seeing Adjustments

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#1 Older Padawan

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Posted 02 March 2021 - 11:11 PM

I was wondering what some of you more advanced EAA folks do when seeing is really bad. I wanted to get a galaxy or two tonight but seeing was really bad and I just ended the session. Any suggestions on how to over come bad seeing or is it just one of those nights. My camera is an ASI224MC and my telescope is a Skywatcher 10". I'm using Sharpcap to control my camera

 



#2 GaryShaw

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Posted 02 March 2021 - 11:51 PM

You don’t ‘overcome’ bad seeing. You either accept its limitations or go inside and relax with a good book and a glass of your favorite....

 

cheers!


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#3 Older Padawan

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Posted 03 March 2021 - 12:00 AM

You don’t ‘overcome’ bad seeing. You either accept its limitations or go inside and relax with a good book and a glass of your favorite....

 

cheers!

That's what I thought Gary thanks for easing my mindbow.gif



#4 SanjeevJoshi

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Posted 03 March 2021 - 01:45 AM

If there are tasks like testing and calibration i can complete, i do that - not much serious observing.   Could be related to telescope tuning, camera tuning, mount tuning, etc.  An IR pass filter is useful for observations when seeing is ok (2/5) but not terrible (1/5).


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#5 Noah4x4

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Posted 03 March 2021 - 02:57 AM

I observe from my indoor observatory (converted out-building). I suffer from terrible persistent cloud and even on clear nights we can suffer a swirling North Sea mist. Not much I can do except be prepared for what commences as a decent live stack appearing to go unexpectedly noisy and unusable, especially as I fiddle with gain and exposures forgetting to poke my head outside. On many occasions I have blamed CPWI for not finding my target then looked outside to see that my clear skies have become horizon to horizon cloud inside 20 minutes
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I have a TV in my observatory. I might make some more darks and flats for my library. Spend some time watching YouTube astronomy features. Contribute to Cloudy Nights. Not much else feasible. .

Edited by Noah4x4, 03 March 2021 - 03:01 AM.

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#6 Rickster

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Posted 03 March 2021 - 09:29 AM

It depends on what the seeing problem is.  As a general rule, the first thing to try is to look for targets that are directly overhead so that you are looking through less air.

 

Some times, especially in the summer, high level haze moves in, and although there are no clouds in the sky, it takes longer exposures to get the same results.  If it gets too bad, the only option is to give up.

 

If low level fog moves in, then its time to quit.

 

If skies are turbulent, as in stars are jumping around, then reduce sub-exposure times and turn on FWHM and brightness filtering.  Also look for targets, such as large nebula, that need less resolution.  In this case, fast focal ratios, short focal lengths and mono cams have an advantage.   This is a common problem for me.  So I keep a small fast scope piggy backed to my large scope.  Right now, it is a 6in imaging Newt that is reduced to f3.  For example, last night I had very clear skies, but the stars were jumping around in my large scope (16in f5 2000mm fl).  I switched to overhead targets, dropped sub-exposures to less than 1 second and set the filters to screen out bad subs.  Even then, I wasn't getting the resolution that I wanted.  So I switched to the smaller scope and checked out a nebula.


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#7 alphatripleplus

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Posted 03 March 2021 - 09:33 AM

I usually have haze or wind problems rather than seeing, but if you are trying to squeeze every bit of resolution out of your camera it can be an issue.



#8 cpl43uk

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Posted 03 March 2021 - 11:31 AM

A funny story from a newbie to EAA. I still struggle bit with the tracking etc of my AltAz system and sometimes the stars will trail badly after a goto as the mount loses sync with AAP (a long story) but after a good session when things just worked all evening I started to see numerous "stack errors, not enough stars" on Rosette. It often says this when I play with the Live Stack exposure but I couldn't figure out why no changes made a difference and I feared I had lost lock with the mount (again). So I went outside .... and saw it was REALLY cloudy and indeed I have no idea how the ASI533 had taken a pretty decent first stack or two!! The perils of going indoors for your observing!

 

I do find one night condition issue that does affect me more between EAA and visual observing and that is windy conditions. I use a dew shield on my 8" SCT and generally when visually observing I have no issues with a gentle (and not so gentle) breeze but with EAA I realise that stacks over 50 x 5sec can suck if a breeze hits the shield and nudges the camera so that I get a blip and that is the live stack "ruined" although all the .fits are being captured and, if you wanted to, you could eliminate for post processing.

 

And while seeing a satellite track across was "fun" in visual days I get surprisingly annoyed if it tracks across during a live stack!


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#9 GaryShaw

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Posted 03 March 2021 - 11:49 AM

You can easily be alerted to changes in incoming clouds or satellites if you set up a widefield digital ‘Finder’ using a cheap 8mm F1.5 CS lens attached directly to an inexpensive ASI120 or ASI290 mini camera. I use the latter and find it great for watching clouds approach or move out of the way. 
 

Once, while observing M67, I wondered why stacking had started to fail. I stepped outside to see if there was a power problem and found it was snowing rather heavily. With the digital Finder now on the scope, I can’t stop the snow but at least I can see it starting. 
Gary


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#10 Borodog

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Posted 03 March 2021 - 01:14 PM

You have available to you a wide field EAA option, and you enjoy different objects, up to and including entire constellations. I use a $23 C-mount lens.



#11 Older Padawan

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Posted 03 March 2021 - 03:37 PM

Thanks for all the information. Last night the stars were blinking like Christmas lights on a tree. I checked the clear skies chart and it showed seeing as BAD. I didn't disagree. Went inside and watched some television with the wife. Try again tonight.waytogo.gif



#12 Noah4x4

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Posted 03 March 2021 - 04:38 PM

Thanks for all the information. Last night the stars were blinking like Christmas lights on a tree. I checked the clear skies chart and it showed seeing as BAD. I didn't disagree. Went inside and watched some television with the wife. Try again tonight.waytogo.gif


That wouldn't have stopped me. Most of the time I am stuck under thick cloud. If I can see a complete constellation even if twinkling I will give it a go. Makes for poor imaging, but observing is still better than through an eyepiece.
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