Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_30_second_exp_2_winners.thumb.jpg.b5430b40547c40d344fd4493776ab99f.jpg

Petar b

Detecting exoplanet

Recommended Posts

Checking one of the 30sec exposures, I get an integrated count of ~70k so assuming the camera gain is set so the well depth of 100k matches 64k counts, this would be ~100k counts which would give ~0.3% 1 sigma uncertainty. (I am assuming you will use an ensemble of comparison stars and that will not significantly contribute to the stochastic uncertainty). Enough signal in principle to see the transit even in the single exposures. 

(The FWHM was ~3 arcsec so perhaps not as good as I might have expected for a good site. The star is K2v so a V filter would be ok.  Plugging these into Richmond's calculator gives a predicted uncertainty of 0.18% )

Edited by robin_astro

Share this post


Link to post
Share on other sites

It looks like the conditions were a bit variable so it was either a bit of high cloud or variable seeing.  Nevertheless either the 30s or 60s exposures should be fine (I would recommend the 30s as you can always bin the data).  

Clear can be dependent on your interpretation.  In professional circles you have what is called photometric conditions which is when there are no clouds at all (even high cloud).  Clear is usually referred to as conditions when there is likely to be a bit of high cloud that will impact on photometric calibration of objects.  For the depth of transit you are looking at 'clear' should be fine (by using comparison stars you will remove most of the effect of clouds).

As to whether something needs to be in focus it depends on what you are observing.  In your case you want to be at best focus you can (up to a point and not spending hours doing it).  For very bright stars sometimes people deliberately defocus to stop stars saturating even in very short exposures.  It's no different to having poor seeing and you can just broaden the aperture when you are doing the photometry - the object is that bright you don't need to worry about it.

Share this post


Link to post
Share on other sites

I've never used it myself so have no experience personally.  However, the results seem consistent with the other site so it is probably OK.

Share this post


Link to post
Share on other sites

Hi,

Exoplanets sounds exiting. When analyzing the light curve you can use AstroImageJ. I used it when analyzing Kepler data, but not for exoplanets, I looked for variable stars.

You find AstroImageJ here:

https://www.astro.louisville.edu/software/astroimagej/

 

And here what I found:

http://www.astrofriend.eu/astronomy/science-data/science-data-kepler.html

 

Not bad to use a space telescope !

 

/Lars

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.