Seeing conditions

[Barry-W-Fenner]

Hi all,

I am looking for some opinions. I managed to get an hour of observing in last night, The sky here had some intermittent cloud but between this it was generally clear. I noted that the sky was surprisingly dark considering the moon was close to full, However the stars were no where near as bright as usual, Even prominent stars such as Vega had lost its sparkle.  Objects in my higher powered 8mm BST were kind of blurry and in  meduim/lower power such as my 15mm objects were still not particularly clear either. Am I correct in saying the result of this was down to seeing conditions? If that is the case what do you tend to do in this situation? just view what you can in very low power eye pieces? Or just call it a day! I am interested to know as sometimes we can only work with the hand we have been dealt! 🙂

 

Cheers

Baz

[Stu]

I can only assume that the brightness of the cloud was making the sky seem dark in comparison, when actually it was still brighter than normal due to the moon.

Often when there is cloud blowing through and strong winds you get turbulent air, which causes poor seeing. I think on nights like that and with a bright Moon, it's best to either look at the Moon or go and surf the web for new kit 🤣🤣

Last night for instance was not great for me, patchy cloud moving through and a bright moon. All I did was take the 10x50 binoculars out and attempt a few simple naked eye and binocular challenges I had set for my local club. Things like spotting the Double Cluster, M31 and M44, all of which I managed, along with a nice view of the Moon. Enough to give me a little fix.

Often you will find that poor seeing goes along with good transparency, and poor transparency with good seeing. When seeing is good I tend to focus on higher powered targets like planets, doubles and the Moon. With good transparency and poor seeing, it is best to focus on lower power, larger objects which show better under these conditions.

If seeing and transparency are poor, then probably best to call it a night.

[Les Ewan]

HI Baz,

Yes,seeing is to blame.

Unfortunately a lot of the time the choice of targets are not up to us as far as seeing is concerned as Stu points out.

However I've noticed on crystal clear still winter nights when seeing for high power work is poor things more often than not improve markedly around 3am  (assuming it doesn't cloud over that is). 

Objects you struggle with on one night may stand out easily the next night,and you wonder what all the fuss was about,even on the same night sometimes.

I don't observe much on windy nights but I have had some fine views of close double stars in such conditions, I assume because of the lack of the dreaded thermals from the ground, but the massive downside is of course telescope shake.

 

[Stu]

48 minutes ago, Les Ewan said:

However I've noticed on crystal clear still winter nights when seeing for high power work is poor things more often than not improve markedly around 3am 

I think that is very true, obviously things vary but it does take a while for the heat to dissipate from the land, for central heating to go off and houses cool down. Once this has happened, seeing conditions do often improve. Trouble is it is not often I can put in an all nighter on a school night!

[John]

I think there is a sort of "sods law" that the seeing conditions are best 10-15 minutes after you have packed your gear away, just when you are having a last peek at the sky before turning in

The other time you often seem to get superb seeing is when you get out of bed to go to the loo and peer out the window just out of curiosity.

 

[Ouroboros]

@John You've noticed those two things too. 🙂 

[paulastro]

The only thing I'd add is about having persistence.  Like everyone else who was out this morning, for me the seeing was not good (pretty awful in fact).  But with the Moon and planets it's always worth spending a few minutes at the eyepiece.  Even in the worse seeing there can be the merest brief moments of better seeing - but if you've just had a quick glance in the eyepiece and gone straight back to bed, you'll miss them of course.  I did have the odd moments of good seeing, you just have to be ready and make the most of them.  I took a quick snap of the Moon at 3.20 am this morning, and for the 1/320 sec the shutter was open it wasn't so bad. (I admit I took many more snaps in the hope of getting lucky and grabbing a better moment).  Here's a link I posted in Lunar Imaging with the pic I'm talking about.

 

[Paz]

I agree with the idea of getting out there and observing even in sub optimal conditions and taking those half chances where you set up and sometimes find yourself immediately packing up because the cloud has just rolled in.

At the weekend I set up as Venus was doable. It was low and the seeing was poor, it was also cloudy on and off. I got maybe 15 minutes of wobbliness on Venus before the cloud rolling in became too bad. I looked around for anything else before the cloud cover was everywhere and got 5 minutes on M45 and then I was clouded out.

That is a fairly typical outing at the moment.

[Barry-W-Fenner]

My favorite one at the moment seems to be getting set up, Spend 10mins getting my eyes adjusted ready to start viewing, Clouds roll in, Wait 10 -15mins and they dont pass. Pack everything away, Look out the window 20 mins later and its crystal clear again 🙂

 

[Stu]

15 minutes ago, Barry-W-Fenner said:

My favorite one at the moment seems to be getting set up, Spend 10mins getting my eyes adjusted ready to start viewing, Clouds roll in, Wait 10 -15mins and they dont pass. Pack everything away, Look out the window 20 mins later and its crystal clear again 🙂

 

Yep, welcome to Astronomy 🤣

It's worth checking satellite images on something like www.sat24.com, then you can see which way the cloud is moving and whether there are clear spells coming over. It also shows rain radar images so you know if it's fairly safe to leave your scope out or not.

[Alan White]

15 hours ago, John said:

I think there is a sort of "sods law" that the seeing conditions are best 10-15 minutes after you have packed your gear away, just when you are having a last peek at the sky before turning in

The other time you often seem to get superb seeing is when you get out of bed to go to the loo and peer out the window just out of curiosity.

 

Fully agree with that John, but you missed out about when its been solid cloud the same applies too.

[Geoff Barnes]

There's not been an awful lot of interesting things to see lately in my limited northerly view here, which is just as well, given we've been shrouded in terrible smoke from the bushfires in eastern Victoria.

You look out the window and you'd be forgiven for thinking it is just thick mist and fog, but as soon as you step outside the smell of the smoke really hits you.

At least we're getting good rains now and the forecast is for a major rain event early next week so fingers crossed things should improve dramatically soon, and Orion is gradually moving into prime position too!  

[joe aguiar]

U could do planets if they around since they are pretty much gone then u could do double star viewing. Theres r hundreds in reach of scopes.

Joejaguar 

[Barry-W-Fenner]

Just coming back to this thread, I was wondering what advice / tips we all have for improving our viewing conditions. We all have a common enemy know as Light Pollution which affects our seeing conditions, What have you done to try and combat this as best as possible. As mentioned in a previous thread I have added a light shield to my 200p and fully flocked to improve contrast.  Any other pointers appreciated as like all of us I am trying to squeeze out the best views possible!

Regrards

 

Baz

[Stu]

Just now, Barry-W-Fenner said:

Just coming back to this thread, I was wondering what advice / tips we all have for improving our viewing conditions. We all have a common enemy know as Light Pollution which affects our seeing conditions, What have you done to try and combat this as best as possible. As mentioned in a previous thread I have added a light shield to my 200p and fully flocked to improve contrast.  Any other pointers appreciated as like all of us I am trying to squeeze out the best views possible!

Regrards

 

Baz

You can't change the seeing conditions, but can optimise your chances of getting good views. First would be to keep an eye on the jet stream forecast and choose nights when it is not running overhead when you want to use high powers.

Outside this, if you set up on grass, try to avoid looking over houses, buildings or roads which give off heat and generate convection currents as they cool at night. Heating plumes also play havoc with the seeing, aswell as aircraft contrails.

Finally, I think I've said elsewhere that observing in the early hours often offers the best conditions as everything has cooled down and the atmosphere has settled. It's the toughest time to observe, but if you don't have to get up early it can be very rewarding.

[bingevader]

13 minutes ago, Stu said:

optimise your chances of getting good views.

The chance would be a fine thing!

I've stopped worrying too much about all this.

Although "worrying" is probably too strong a word.

I can't do anyhting about my back garden and weather here has been so bad that I just take what I am given and then ponder the conditions after!

If I waited for the perfect night I'd miss out on a lot of stargazing.

I suppose the only way you can improve the viewing conditions is to move!

Or find a site that has more favourable conditions near by? 

[Stu]

3 minutes ago, bingevader said:

The chance would be a fine thing!

I've stopped worrying too much about all this.

Although "worrying" is probably too strong a word.

I can't do anyhting about my back garden and weather here has been so bad that I just take what I am given and then ponder the conditions after!

If I waited for the perfect night I'd miss out on a lot of stargazing.

I suppose the only way you can improve the viewing conditions is to move!

Or find a site that has more favourable conditions near by? 

I don't disagree with you, if it's clear and I'm free and not too tired and have a pass from the Mrs and and and, then I will go out regardless. I think you CAN affect things within your control like where observe from, and try to avoid things which interfere with the seeing too much, but if the jet stream is over head then there is little point in trying to observe tight doubles for instance.

If seeing is poor, and transparency good, try low and mid power deep sky stuff

If seeing is good and transparency poor then try brighter, higher power targets like the moon, planets or doubles.

If both are poor then it may be best to stay in and buy some new kit 🤪🤪

[bingevader]

And, if seeing is good and transparency is good! Woohoo!

[Stu]

10 minutes ago, bingevader said:

And, if seeing is good and transparency is good! Woohoo!

Absolutely! Monday night wasnt far off that for me. 👍👍

[Barry-W-Fenner]

20 minutes ago, Stu said:

Absolutely! Monday night wasnt far off that for me. 👍👍

Sunday night was a cracker for me. It must have been the best I have had in my short time at the eye piece. Couldn't make it out Monday, Then things took a turn for the worst last night, Now look at it...

At least I can dream back to the days of Monday night 🙂

 

Baz

[John]

I think the best advice that I can give is to be adaptable. Roll with the conditions that are presented and select targets accordingly

 

[Barry-W-Fenner]

9 minutes ago, John said:

I think the best advice that I can give is to be adaptable. Roll with the conditions that are presented and select targets accordingly

 

That is spot on! You have to just go with it I guess, the sky will not bend to my will so I must accept it. If only we could do something about the LP though!