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Possible First Exoplanet

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#1 Nick Rose

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Posted 30 December 2012 - 04:14 PM

Last night I wanted to see if my equipment could get data of a exoplanet transit. The target I picked was WASP-50b. Because of guide camera problems I just started 4min. before transit was to occur. My LX modded webcam quit on me so there was no guiding for 80sec subs and some subs have not round stars. Also the moon was near full last night.

I did use C-Munipack, but I really have no idea how to use it. Is there a way for anyone here to use my photos to see if I really did get the transit? Its around 235MB.

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#2 Hubert

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Posted 31 December 2012 - 04:41 AM

You can see the dip in your observations so you got the transit.

#3 gavinm

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Posted 04 January 2013 - 02:41 PM

You've just discovered that pre- and post- transit are pretty much vital. If you miss pre- (which happens a lot because of a range of telescope issues like guiding etc) you need to keep imaging for over an hour after the transit has finished.

Looks good though.

#4 old_frankland

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Posted 04 January 2013 - 05:37 PM

Certainly looks like your system is capable of producing quantitative data. Nicely done. Was this shot with the starshoot or DSLR. Good stuff.

#5 Nick Rose

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Posted 05 January 2013 - 12:08 AM

This was with the Orion StarShoot Deep Space Monochrome Imaging Camera III. I have the exo-planet fever, can't wait to go out again.

What's everybody's opinion on how much to defocus the stars? I see some with focused stars some with slightly defocused and some with donut stars.

#6 Hubert

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Posted 05 January 2013 - 03:16 AM

The precision gets better if the stars are a bit defocused.

#7 gavinm

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Posted 05 January 2013 - 02:34 PM

The usual reason researchers defocus is to avoid saturation when using larger apertures 1m+, it can also improve precision. However, we generally want the highest signal possible for the shortest exposure so that generally means tightly focused stars.

But try it and find out. Tell us how you get on :)

#8 brianb11213

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Posted 08 January 2013 - 03:35 AM

we generally want the highest signal possible for the shortest exposure so that generally means tightly focused stars.

Actually it makes very little difference - the signal being distributed over a large number of pixels doesn't matter when you sum them over the integrating aperture. Defocusing means that you get less chance of the brighter stars saturating invididual pixels, increasing the dynamic range by allowing brighter stars to be measured (or used as comparisons) ... and reducing the measurement errors (due to quantum noise) when there is a moderate to large light signal.

Nothing (except increasing aperture and/or exposure) can reduce the quantum noise inherent in very weak signals - however tight the focus is, the quantum noise is constant.

The real downside of defocusing (increased integrating aperture radius) is that light sources start to overlap.

#9 gavinm

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Posted 10 January 2013 - 03:30 PM

Never thought about it like that. Makes sense.

#10 Nick Rose

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Posted 13 January 2013 - 09:25 PM

What's everyone's view on binning or no binning? Does binning give better data or does it depend on the equipment if binning works better?

#11 groz

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Posted 20 January 2013 - 12:21 PM

Binning is just another tool in the toolbox. If you want higher sensativity and/or higher signal to noise, binning will help with that. It also allows for shorter exposures. On the down side, it decreases resolution, so, in a crowded field, has potential to cause more interaction with neighbors.

In the end, it really boils down to what your resolution is with each configuration, binned and unbinned. In some cases, it can be a very useful tool, in other cases, it can introduce an insurmountable problem. Depends on camera characteristics, focal length, and density of the target field.






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