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Mercury f20 2/10/13

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#1 sfugardi

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Posted 10 February 2013 - 02:44 PM

Taken today in poor seeing using my 1.8x barlow and an IR-685 filter. Best 100 frames of 36307 stacked with AS2! The IR-685 seem to work better than the R filter, using a small 240x240 ROI, I collected 160fps data and very low gain setting of 1605, approx 50%. I collected in .SER 16bit mode, not that it mattered in poor seeing. No detail can be seen in the image, but a nice rendering of the 75% phase is present.

Finding Mercury was easier than I thought. First I slewed to the sun with my solar filter and reset the compustar computer coodinates to match the actual sun values. Then slewed to Mercury coordinates and removed the cover and easily noticed the tiny globe with my 55mm low power eyepiece. I started imaging at prime but the disk was so small I went with my lowest barlow mag. While I don't do much daytime observing, I noticed that the mirror was "cold" relative to the ambient air, completely opposite of the night time conditions. Even after 2hrs of forced air to the back of the mirror, it was still cold and I had no choice but to keep the fans on during imaging full blast to keep the warm boundary layer minimized. It appears that I should have been pulling the warm air out of the OTA vs forcing in cold air. This would be opposite of the night time configuration. Not sure if anyone else has observed this issue and reverses the fan direction in day time imaging.

Regards,
Steve

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#2 sfugardi

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Posted 10 February 2013 - 02:49 PM

Here's my post blizzard snowblown pathway to my observatory. Somewhere between 1-2feet of snow. My dogs really appreciated the paths...

Regards,
Steve

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#3 lcd1080

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Posted 10 February 2013 - 04:04 PM

Very well done Steve, Mercury is always a tough target made doubly so by poor seeing; I can empathize with what you went through to get this image having tried myself to image Jupiter last night in the wake of the Nor-easter. I ended up with a blurry mess so congrats on pulling Mercury out of the fire so to speak!

Pete

P.S. Oh and I love your observatory in the snow pic; it looks like the perfect set-up in a winter wonderland!

#4 sfugardi

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Posted 10 February 2013 - 04:11 PM

Pete, thanks! The 100 frames is less than 0.3% of the total collected, talk about slim pickens. Here's a humble re-do trying to "pull out" more detail. Mercury reaches greatest elongation 2/16 so any time in the next weeks should be good. Ideally it happens on a weekend to avoid taking a 1/2 day vacation. One small advantage of a dome, it does not accumulate much snow in a blizard due to the round shape.

Regards,
Steve

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#5 ToxMan

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Posted 10 February 2013 - 04:20 PM

Very nice, Steve.

I guess you weren't kiddin' about snowblowin' a path to the observatory. I didn't think you would actually be out imaging. But, some of the best sky is after a big storm passes.

#6 Kecktastic

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Posted 10 February 2013 - 06:51 PM

Well done Steve and thanks for posting the shot of your observatory, looks great. I have never been to the snow, certainly looks different to the red earth out where I live in OZ. When I went to Mauna Kea it was the right altitude but wrong time of year for snow. Your 2nd Mercury looks to show a hint of some albedo shading mid way along the terminator and perhaps even toward the top of the image near the limb. Certainly worth pursuing further over the next few weeks.

Regards
Trevor

#7 wenjha

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Posted 10 February 2013 - 08:41 PM

very nice!seems some detail you captured

#8 sfugardi

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Posted 10 February 2013 - 09:23 PM

Paul, very clear sky today but poor seeing unfortunately. CSC was right again.
Trevor, Thanks! I only wish the snow pack would help the seeing.
Sam, Thanks!

I am thinking about moving the dew heater strip from under the corrector plate to around the mirror to balance the temps for daytime imaging next time? Just the opposite of night time use. Have you guys ever tried this?

Regards,
Steve

#9 sfugardi

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Posted 10 February 2013 - 10:45 PM

One last try with this data, frame stack doubled to 200 and brighter,

Regards,
Steve

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#10 Chris_H

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Posted 11 February 2013 - 04:06 AM

Nice! Don't see many Mercury pics around here.

#11 Kokatha man

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Posted 11 February 2013 - 06:42 AM

Good effort Steve! :)

I reckon Mercury is about as hard as it can get to pull some "detail" out.....full marks for having a go! :waytogo:

#12 sfugardi

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Posted 11 February 2013 - 06:58 AM

Chris, Thanks! It's my 3rd attempt all time for Mercury and first in broad daylight, previously I was using my Toucam trying to image at 10-15deg altitude through the leafless trees at dawn. Needless to say, results were poor. The key is to collect a ton of frames and hope you get at least 100 good ones. Technically, you can call it my "personal best".

Mo, Thanks! I'm not one to image in poor seeing but it's been so long since I've used my scope I couldn't resist trying through the crisp blue sky. With a mirror that was 0.8-1.0degC cold with the fans on and 2.5-3.0degC cold off, I was not dealing with a stable system. Focusing was wicked between the seeing and the sun, so I had to drape my scope cover over my computer and head just to see the screen. Even the FC auto-align couldn't lock on to Mercury.

Regards,
Steve

#13 Rutilus

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Posted 11 February 2013 - 04:05 PM

Super images of Mercury.

#14 Mike Phillips

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Posted 12 February 2013 - 12:15 AM

I think you're brave than you realize Steve! :)

Well done and I really like that technique!

Mike

#15 DesertRat

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Posted 12 February 2013 - 01:27 AM

Thats great work Steve! Hope you get better seeing for another try. We don't see enough of Mercury and thanks for posting!

Glenn

#16 sfugardi

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Posted 12 February 2013 - 12:26 PM

Rutilus, Mike, Glenn, Thanks! Mercury has always intrigued me, mostly due to closeness to the sun and being hard to visually spot. My best all time view was looking out of jet window just after takeoff, above the clouds, in an early evening years back. One advantage of daytime astronomy is that you can see everything and I don't have to worry about hitting my head on the 5ft door frame or the low skateboard wheel guides holding the dome on. I did discover how terrible my 2" diagonal mirror looks. The 25+ year mirror looks more like fine sandpaper as I took a q-tip "trying" to clean the "dust" off. Replacing it will be my next purchase. If I can figure out the daytime thermal balancing, I'll post it.

Regards,
Steve






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