Poor Seeing - Help I need somebody help!

[BlackNebula (Mark)]

Good Morning,
Let me start by introducing myself, have been in Aus for about 18 months now, originally from South Africa. Am in sunny Perth where the weather has been really super cool this winter so far (Oops, jinxed it!). I joined iceinspace not long after arriving but sadly star gazing has taken a back seat with settling in and well it just gets away from you, a month turns into two then six and before you know it, well you get the picture.

So, my interest has finally come back and I'm loving it! But, was up this morning at about 3:30am to take in Orion, Jupiter, Venus and hoping for a glimpse of Andromeda and maybe a few other things thrown in but alas, although I enjoyed the early views of the sky my seeing through the eyepiece was a total let down. This is where I need some help from you brainy, clever, super cool and friendly folks (Enough complements?&#128516

Some details on my rig, 8" Celestron Nexstar, hmmmmmm is that it? Yup I guess, oh yeah have a few eyepieces as well... Used a combination of the 24mm pan and 13mm nagler this morning

On to my "issues", the 4 stars in the trapezium in Orion were very fuzzy, no amount of fiddling with the focuser could get them nice and clear, next Jupiter, again very hazy, could not make out the bands at all!!!😭 The viewing continued in this vain, so not a great morning out but still enjoyed just being "out there".

Last viewing session about 2 weeks ago was more successful, but still some clarity issues if you know what I mean.

So, could this be:-

1.) My optics, i.e. dirty diagonal or corrector plate, there are some water marks on the corrector plate and the diagonal seems to have some brushy type marks, almost like its been wiped and not cleaned properly. I have certainly not done this and had bought the scope new, and have always kept the covers on, so dont think this is a problem but... And I know the absolute last resort should be to try and clean any surfaces so don't really want to go down this road, but just checking.
2.) just plain bad seeing conditions, if its this that would be great!
3.) Colmination issues, I have never Colminated the scope, had it for about 3 years, could this be my issue?? Probably a good idea to colminate not that I know how.

Any help or suggestions would certainly be most appreciated.

And what a great forum, love it guys!!
Mark

[Lester]

Hi Mark, I don't know how stable the air is where you are, but a view of the star twinkle would tell you. If the stars are twinkling above 30 degrees from the horizon, I'd say that is part of the problem. Next when your scope is pointed at a bright star, defocus it and see if the dark central spot is central with the bright ring. The star needs to be kept central in your field of view while doing this, as when the star moves towards the edge of the FOV the central dark spot will misalign. Also could dew be building up on the corrector? If the humidity is above 70% this could be a cause of dimished seeing.

I doubt that dirty optics are going to be a main cause, unless a toddler has been let loose on your scope.

All the best.

[alocky (Andrew lockwood)]

Hi Mark,
In general terms Perth's seeing is usually pretty rubbish in summer, but it's winter that we do get the good occasional night. My suspicion, given the amazingly cold mornings we've been having is that you took your scope from a warm house to 3 degrees outside, and didn't give it the hour it needed to come to equilibirum (by which time it probably would have started to dew up).
One way of telling if the jetstream is about (our main source of poor seeing) is to de-focus and have a look at the turbulence in the out of focus image.
I wasn't up at 3, but earlier in the evening the seeing was fair.
cheers,
Andrew.

[Rigel003 (Graeme)]

You have a good scope and eyepieces so this was almost certainly a seeing issue. You will find there are some nights when the atmosphere doesn't reveal Jupiter as anything but a quivering blob, no matter how good your scope. You must make sure it's cooled to ambient temperature though. It will take at least an hour. If I were doing early morning observing, I'd leave the covered scope out all night. Definitely worth reading up on collimation. It's not hard with an SCT but I doubt that's the major issue here.

[BlackNebula (Mark)]

Hey Guys,
Thanks for the advice.
Makes sense, as you say the morning was rather chilly. I'll happily right it down to poor seeing.
I did have the dew shield on but only waited about 30-40 mins for cooling before diving into alignment. Difficult as there wasn't much time before sunrise, good idea on leaving the scope outside, could leave it in the garage to assist with reaching equilibrium. Thanks for this.

There wasnt too much much dew about, I've seen it much worse. But a good idea to de-focus to check the turbulence and the Colmination, will try this next time out!

Now just need to recover from last night, after some good rugby and great swiss fondue with good friends!

Cheers