Jupiter this morning, 24th March 2007

[bird]

I tried to beat an approaching low pressure system this morning and get one more image. The best seeing was around 3am with this image, not long before the change arrived.

The session was cut short when the change arrived around 5am, the seeing never got much above 5/10.

regards, Bird

[matt]

Good stuff, Bird.

5/10 eh?

That's about what I thought. A lot of star twinkle this morning;)

[bird]

Matt, the seeing was excellent around 3am - there was no star twinkle where I was, but my cooling system on the scope means I have to wait about half an hour after I turn it off before I can image.

This morning I broke that rule and imaged just after turning it off at 3am, even though the mirror was about 3 degrees below ambient. I was worried about the approaching change, and wanted to make sure I got something while the seeing was good.

I had to make a call yesterday evening as to when I was going to try and image - I could have chosen to be ready at 3am, and so I'd have turned the cooling off at 2.30. But I decided to take a risk and let the cooling run longer, and be ready to image at 4.30am when the seeing could potentially be at its best.

So most of the "poor seeing" in this image was self induced.

Bird

[matt]

Oh, OK.

I wouldn't worry too much over your mirror temps hampering your efforts this morning.

The jetstream maps confirmed the ordinary conditions.

And they've gotten worse in the last 12 hours. Not that you can see the sky now.

Not that jetsream maps are the be all and end all:)

From what I saw, I would have to agree with you and put the conditions at no better than 5/10.

Not many great images coming out of the east coast overnight. Actually, none that I've seen yet. Apologies if I've overlooked anyone's cracking image;)

Cheers

[bird]

It was an unusually warm night last night as well - the minimum was about 19C. I had the cooling set for 15C when I went to bed, so it was out by a few degrees when I got up at 3am.

This normally isn't too much of a problem, by 4.30am the mirror would be back to ambient and ready to go , but sadly the seeing fell away before then.

That's the thing with larger mirrors - you lose the flexibility to image at the drop of a hat, and end up arranging everything for a specific time and just hope to find good conditions :-)

cheers, Bird

[davidpretorius]

still a good image and hope for me yet!!!

this is as good as my best so far.....i am still being tricked into thinking the seeing is better due to the brain liking the faster frames rate.....silly brain.

i have modified the cooling system so i can reverse voltage to the peltiers and heat the system if way under and also to touch the primary mirror dew along a bit!