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First Jupiter from the C9.25

JamesF

By JamesF
in Imaging - Planetary

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JamesF

JamesF

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Last night wasn't perfect, but was at least a first chance to use my C9.25 for planetary imaging having got the dew heaters working (ish) and my SCT cooler mostly finished.

I think I need to get an external focuser for the SCT now, and a separate monitor for my laptop for processing (or install Windows on some other machine I can use for processing) as the screen on my laptop just isn't up to the job.  The noisy blue channel in this looks nowhere near as bad as it does on my desktop :(

Anyhow, here it is: 4500 frames captured using my C9.25 and ASI120MC and 30% stacked in AS!2.

jupiter-2014-01-19-01-reg.png

As discussed in Stuart's image processing thread, I think perhaps the only way to control the noise in the blue channel is probably to split the channels, deal with the noise and recombine.  For a first image though, I think I can be happy.

Now I just have to work my way through the other 79 capture runs :D  I also want to give it a try with drizzle to see if it gives me anything more.  Anyone have recommendations there?  3x and rescale down?  1.5x?  Anything else?

James

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JamesF

JamesF

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Thank you :)

I've been fighting with the SCT for a couple of months or more, to be honest.  First to get the external dewing under control, but then also to get internal condensation sorted.  The OTA is kept indoors and whilst our house doesn't often make it above a balmy 19C in winter, I was getting condensation forming inside the OTA on the corrector, primary and secondary within the amount of time it took to get the scope mounted, the camera and kit all rigged up and slewed onto Jupiter.

I eventually came to the conclusion that it must be warmer air from the house stuck inside the OTA and losing moisture as it cooled by 10 to 15 degrees after moving it outside.  Making the cooler and forcibly shifting that air out of the tube seems to have made a big difference.  The dew heater also seems to be working well though I did have a bit of fiddling last night to find the right level.

James

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SnakeyJ

SnakeyJ

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Excellent image James and hopefully there will be a few more within last nights capture.    Not an easy night with patchy high cloud, fair to moderate seeing and high humidity to test the dew heaters in anger - looks like this is working very nicely indeed.   Higher humidity tonight according to the met, but perhaps another chance to get out and image if commitments allow.

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JamesF

JamesF

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That looks like native focal length, did you use a barlow?

I did.  The focal length is about 5m for this, but there's no rescaling or drizzle during processing.

In fact, I can work it out :)  The image is about 300 pixels wide, the camera pixels are 3.75um across and Jupiter is about 46 arcseconds wide at the moment, so that means the focal length is 206265 x 300 x 0.00375 / 46 = 5045mm :D

James

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JamesF

JamesF

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Excellent image James and hopefully there will be a few more within last nights capture.    Not an easy night with patchy high cloud, fair to moderate seeing and high humidity to test the dew heaters in anger - looks like this is working very nicely indeed.   Higher humidity tonight according to the met, but perhaps another chance to get out and image if commitments allow.

We're forecast some clear skies early this evening, but with 90%+ humidity and a "yellow fog" alert.  Not sure how that's going to work out, but I'm busy shifting the 150GB of data from last night off my laptop hard drive to make room for more just in case :)

James

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JamesF

JamesF

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Thats more like it! Looking good James now you are using a proper scope. :cool:

I've never had success with 3x drizzle especially in average seeing. I'm finding 1.5x drizzle aint so hot on this kind of seeing either when up at f24ish.

Yes, I'm in the same sort of region.

I now have a new (to me) Tele Vue 2x barlow that I gave a quick test run last night.  I'll be using that when I fit an external focuser otherwise the focal length will probably be getting too extreme with the extra 100mm or so on the back.

James

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JamesF

JamesF

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Cloudy here in Norfolk, not sure of the costs the feathertouch replacement focuser came in at £200 from FLO super smooth and the 10-1 makes it pin sharp if the conditions are right......

The Feathertouch looks nice, but ideally I want something that's relatively straightforward to motorise and most importantly I want to stop the mirror-shift.  On a 1/4" or 1/3" sensor at f/25 or so even a tiny amount of shift moves the image a long way across the sensor.  Adding a secondary focuser seems like the only way to deal with that.

James

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ChrisLX200

ChrisLX200

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The Feathertouch looks nice, but ideally I want something that's relatively straightforward to motorise and most importantly I want to stop the mirror-shift.  On a 1/4" or 1/3" sensor at f/25 or so even a tiny amount of shift moves the image a long way across the sensor.  Adding a secondary focuser seems like the only way to deal with that.

James

Exactly my opinion also. I made arrangements to lock the mirror and am awaiting delivery of secondary focuser (tomorrow). I hope that works better. An off-axis guider helps too.

ChrisH

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SnakeyJ

SnakeyJ

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We're forecast some clear skies early this evening, but with 90%+ humidity and a "yellow fog" alert.  Not sure how that's going to work out, but I'm busy shifting the 150GB of data from last night off my laptop hard drive to make room for more just in case :)

James

Painful isn't it - My laptop only has 10/100Mb network, so I get around 11MBs/second for transfer when I take it into work - for some reason though it always comes up on it's wireless NIC first, which I have to disable or I'm running at around 5MBs!    It took around 2hrs to transfer my capture from last night over to my desktop.      However, I just managed to get hold of a broken HP Probook i3 - it needs a new screen, but has gigabit network and USB3.    Well worth £ 40 for a replacement screen, and might even treat myself to an HD screen for £ 60ish.     A USB3 external disk or small NAS will be nice and fast in comparison.

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JamesF

JamesF

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Sounds like a good deal :)

What's really irritating is that I've barely started processing last night's capture yet, so I'll have to copy them and delete the originals to make space for anything I get this evening, then move it all back to process later.

Still, it gives me something to do when the weather's rubbish :)

James

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Tinker1947

Tinker1947

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Don't know if you have seen or use one of these, i leave one in the focuser tube all the time the scope is in a Obby so its never cooled or warmed but the gels do go green, couple of days on a rad turns them clear again....it might help in the fight against Dew.....

http://www.firstlightoptics.com/adaptors/flo-125-2-inch-desiccant-cap.html

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Barv

Barv

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The Feathertouch looks nice, but ideally I want something that's relatively straightforward to motorise and most importantly I want to stop the mirror-shift.  On a 1/4" or 1/3" sensor at f/25 or so even a tiny amount of shift moves the image a long way across the sensor.  Adding a secondary focuser seems like the only way to deal with that.

James

James, put a Moonlite on it, that's what I've got on my C11, - perfect, - it eliminates that horrible image shift completely! Easy to motorise too and very smooth!

Cheers Harvey

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