Planetary Imaging Camp - Nambucca, end June 2008

[iceman (Mike)]

Time for an update I guess..

Yesterday was a nothing day, sat around processing some images, Anthony doing a bit of work, etc. Another lovely, clear, sunny and warm day.

The night was again beautiful, clear and dark. Unfortunately the seeing was terrible again. Maybe slightly better than the previous night - Anthony recorded 1 or 2 runs but that's it. I had the ED80 on and did some deep space imaging of M17. I kept checking Anthony's scope for signs of good seeing, at which time I'd chuck my 12" on, but it never came.

I was up again at 4ish to image Comet Boattini again this morning, and finally didn't stuff up with the settings and get distracted by the moon etc. It was another lovely sunrise, the very thin crescent moon was absolutely lovely down in the orange glow over the ocean.

It's been another nice day today, went for a jog along the beach, met with some friends for lunch, and now going through emails and forums and more image processing.

Who knows what the night will bring, seeing wise. We just can't predict it anymore and just have to wait and see. I'll do the usual and start off with some deep space imaging of some kind and then go to planetary if the seeing turns out good.

I haven't seen a single cloud since I got here on Saturday. It's just such a beautiful place. We watched whales through the telescope today, and while I was waiting at a cafe on the edge of the river in town today, a pod of dolphins swam by. It's gonna be tough going back to the other life

We've had a constant stream of people coming to check out what we're doing every night.. people in the nearby cabins, others walking by, all stop for a look at Jupiter or Saturn or to talk about space and 'the stars'.

2 more nights to go for me.. hope we can get some good seeing.

[AlexN]

i can't wait to see all the resulting images! I'm still stuck on the comment you made a few days ago about seeing fine detail during capture.

[Matty P (Matt)]

Good luck for tonight guys, I'm looking forward to some ripper images. Hopefully the seeing conditions will improve for you.

I'm truly jealous, we have been having some pretty bad weather in the past few days. No clear skies just cloud.

[Satchmo]

Originally Posted by iceman

It's also been very interesting to compare our side by side views on the laptop - Anthony's raw images show much more consistent clarity, and we agree that it's due to:

a) my lack of active cooling and the tube currents
b) his more sensitive and less noisy camera

And maybe just maybe , some small amount of credit due to a hand figured custom made set of optics as against a low cost mass-produced one ?

[bird (Anthony Wesley)]

mark, could easily be... however a lot of the difference was visible as image wobbling and fast moving distortions, the sort of thing that can be attributed to tube or mirror currents. This was happening on Mikes scope while mine, just a few metres away, was showing a very stable image.

We've got Mikes cooler up and going now, so if we get another good night before he goes back then we should be able to get a good idea of how the optics compare.

cheers, Bird

[Satchmo]

I'm with you. I wonder whether , given all the processing and contrast enhancement that is used whether optical quality is nearly as significant with CCD inaging as for purely visual observing. I know from experience that there is a huge differenece visually in the ease of visibilty of low contrast planetary detail in the presence of any optical aberrations.

Addendum: A case in point would be the work of Damien Peach. With a mass production 14" SCT and 40% obstruction at the baffle obstruction the real Strehl ratio would be down in the low 70's or high 60's. No serious visual observer would choose such an instrument for planatary observing. The visual appearance of low contrast detail would be poor indeed, and yet with a combination of superb seeing sites and great processing he takes pictures that are among the best in the world. This suggests that the optical requirements for visual observers and CCD imagers are different.

[bird (Anthony Wesley)]

Mark, I don't think there's any doubt that if you tested 2 scopes of the same aperture and focal length side by side in the same conditions, then the one with the better optics will always deliver better results.

cheers, Bird

[Satchmo]

Anthony, My suspicion is that while better quality optics will always win out , a lower strehl ratio scope can still get spectacular results for CCD planatary imaging, and that differences may be only quite subtle, compared to the optical demands of a purely visual observer.

As the eye doesn't have the opportunity for stacking and contrast boosting, the kind of wealth of subtle detail will only be visible on a very high Strehl ratio scope, yet smeared out and indistinct in a low ratio scope. The difference seems to be far less apparent in digital imaging, the work of planetary imagers with heavily obstructed instruments like C14 bears this out .I have done quite a bit of visual with a C14 years ago, and the effective 0.7 Strehl ratio due to obstruction makes it pretty lack lustre visual instrument.

Look forward to your JUpiter images guys I'll shut up now :-)

Cheers, Mark