Seeing terrible in Sydney tonight

[Startrek]

Set up to do some imaging tonight but seeing is terrible
Took some test images for focusing and Stars were not super sharp
Started guiding and it was all over the place , wouldn’t stabilise
Dew was really heavy too , everything wet
Anyone else having issues tonight ?

[bigjoe]

Sure is buddy ..just gove up trying to crack Lambda Ophiuchi in a Big refractor it's that bad .
Jetstream again too on the interactive chart

https://www.netweather.tv/charts-and-data/global-jetstream#2019/08/05/0600Z/jetstream/surface/level/overlay=jetstream/orthographic=133.79,17.98,480
Bigjoe.

[mental4astro]

Curiously, over my way in Maroubra, seeing was the best its been for a very long time! I was able to push my 7" Intes Mak to 300X, and be able to see little white spots and soft dusty festoons on Jupiter and spy out a swarm of firefly satellites around Saturn. By far the best conditions I've had in ages.

Wavy came by too, paying me a surprise visit with his new 6" Intes Mak, and had to two beasties loose on Jupiter. Candy on a tripod...

Alex.

[Wavytone]

Yup a rare night with very, very, steady seeing at Maroubra, the moons of Saturn simply hanging there showing little diffraction disks. We could pump magnification to the max.

Visibly steady here at a Killara too, where I am among semi forest and low density housing with gardens so no significant heat sources nearby.

I know you guys think it’s the jet stream affecting you but I’m certain the real cause is much much closer and local to your vicinity - almost certainly thermals from houses with dark tile roofs that warmed up in the afternoon sun and giving off heat well into the night, and poorly insulated buildings - especially offices and apartment blocks - with central heating and ventilation systems.

[bigjoe]

Hi Alex..
Actually here in CONCORD poor ,same during week at Castelreagh.
I used to live at Blake street Dover Heights a few years back and go up to Rodney reserve and get top seeing there even in winter a lot..and dark as East over the ocean high up away from too much salt..
Bigjoe.

[Wavytone]

... and at Rodney reserve you would have had laminar airflow over it, as it presents a good rise in east or west airflow.

Most of the poor seeing is due to low altitude turbulence.

[bigjoe]

Too True Wavy a lot of THERMALS from all the building works here near Burwood.near me also back at Castelreagh it's usually good and I can see what I want.. many Belts and barges on Jupiter etc. Summer is magic at Castelreagh!
Bigjoe

[bigjoe]

Yep Wavy had there as one of my scopes a 4 inch UNITRON I stupidly sold ..it was magic
Bigjoe.

[Startrek]

Even though looking up last night it didn’t seem all that bad , but I’m located very low in a gully ( 10m above river level ) and you could actually see the moist air around the neighbourhood
According to CFN Jetstream was running at 60kt and humidity was around 60%
Not a good mix
My 12” f5 Goto visual scope and eye pieces are down the coast at my dark site ( holiday house ) so if I can’t image it’s shut down , bring the laptop inside , put the covers on , have a cuppa and watch the idiot box or read a book

[mental4astro]

Much of what is being mentioned in this thread does come to also work into site selection for astro. Sure, if you are doing this from home, there's not much choice and one needs to deal with the conditions that are.

However, this does also present the opportunity to examine what factors that do present difficult conditions, and then to identify those geographic and environmental situations that provide for a BETTER and more optimal astro location. We spend and invest a lot of time and money into astro, and we only do half cocked job if we don't investigate site selection any further than "here is an open grassy field, this will do".

Dew does not need to be the unavoidable bedfellow of astronomy.

It is possible to find locations that more routinely offers better seeing conditions.

If dew is eliminated from the equation, the associated mist that comes with it is also diminished, and then transparency is also enhanced.

Yes, what I have mentioned above does little for one when doing astro from home. But the broader context of this thread's "bad seeing in Sydney" does lend itself to the discussion and identification of what factors do provide the best conditions for astro.

As an example, the dark site my observing buddies and I used this last Saturday, we had no dew what so ever, our exposed optics stayed bone dry as was all our gear. Yet in the surrounding areas, everything was sodden with dew. Not one battery needed to power a single dew heater.

Alex.

[Startrek]

Resuming imaging tonight and everything is humming along nicely
Currently captured 25 x 2 minute dithered guided subs on M20
Just done a meridian flip and on to my next 30 or 40 subs , darks etc...
Guiding is running at 1.20 to 1.30 arc sec error which is ok for the HEQ5 with 10 kg on board
What a difference from last night , packed up after half an hour , tonight putting in +4 hours and no dew around either
Mother Nature sure can be temperamental

[Ross G]

Hello Martin,


It has turned into quite a good night for suburban Sydney.



I am imaging NGC6357 from my backyard with a HEQ5 mount and Nikon 300mm lens.


At the start of the night, about 7pm, the guiding was running about 1.2 to 1.3.
It has now dropped to about 0.5 and still no dew.


Shame I have to get up for work or I would stay up all night.


Good luck.
Ross.

[Startrek]

Yes great night for imaging last night
Finished up at 1.30am
Processing today
Thanks Ross