Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Observing >> Variable Star Observing and Radio Astronomy

Pages: 1
Nick Rose
super member


Reged: 11/01/10

Loc: San Mateo, CA
Possible First Exoplanet
      #5596464 - 12/30/12 04:14 PM Attachment (90 downloads)

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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Hubert
sage


Reged: 09/26/06

Loc: Belgium
Re: Possible First Exoplanet new [Re: Nick Rose]
      #5597385 - 12/31/12 04:41 AM

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

Post Extras: Print Post   Remind Me!   Notify Moderator  
gavinm
Carpal Tunnel


Reged: 08/26/05

Loc: Auckland New Zealand
Re: Possible First Exoplanet new [Re: Hubert]
      #5604940 - 01/04/13 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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
old_frankland
Carpal Tunnel


Reged: 03/28/05

Loc: San Francisco Bay Area
Re: Possible First Exoplanet new [Re: gavinm]
      #5605266 - 01/04/13 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.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Nick Rose
super member


Reged: 11/01/10

Loc: San Mateo, CA
Re: Possible First Exoplanet new [Re: old_frankland]
      #5605814 - 01/05/13 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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Hubert
sage


Reged: 09/26/06

Loc: Belgium
Re: Possible First Exoplanet new [Re: Nick Rose]
      #5605978 - 01/05/13 03:16 AM

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

Post Extras: Print Post   Remind Me!   Notify Moderator  
gavinm
Carpal Tunnel


Reged: 08/26/05

Loc: Auckland New Zealand
Re: Possible First Exoplanet new [Re: Hubert]
      #5606737 - 01/05/13 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


Post Extras: Print Post   Remind Me!   Notify Moderator  
brianb11213
Postmaster
*****

Reged: 02/25/09

Loc: 55.215N 6.554W
Re: Possible First Exoplanet new [Re: gavinm]
      #5611350 - 01/08/13 03:35 AM

Quote:

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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
gavinm
Carpal Tunnel


Reged: 08/26/05

Loc: Auckland New Zealand
Re: Possible First Exoplanet new [Re: brianb11213]
      #5615736 - 01/10/13 03:30 PM

Never thought about it like that. Makes sense.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Nick Rose
super member


Reged: 11/01/10

Loc: San Mateo, CA
Re: Possible First Exoplanet new [Re: gavinm]
      #5621722 - 01/13/13 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?

Post Extras: Print Post   Remind Me!   Notify Moderator  
groz
Carpal Tunnel
*****

Reged: 03/14/07

Loc: Campbell River, BC
Re: Possible First Exoplanet new [Re: Nick Rose]
      #5633097 - 01/20/13 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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1


Extra information
0 registered and 2 anonymous users are browsing this forum.

Moderator:  Rich (RLTYS) 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1914

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics