12 replies to this topic

[vmsguy]

Hi all,

Been a long time since I've posted here for various reasons, but now trying to get back into the hobby and I wanted to try my luck at capturing the transit of a known exoplanet using my t3i and an old Nikkor 300mm /f4.5 lens.

I'm assuming that since I used a DSLR this is the proper forum, I've posted lots of images here in the past, but this time it is just graphs.

My target was HD189733b, which seems to be one of the easier transits to capture. It is also right next to M27, making it easy to find. I used the ETD (exoplanet transit database) site to determine transit times for my location. For my location, WV, there was a transit starting at 3:45am local time, ending at 5:35am local time on May 13th.

I used an unmodified Canon t3i and a Nikkor 300mm f/4.5 telephoto lens stepped with a 72-52 step down ring to about f/5.7. I took 15 second exposures every 30 seconds at iso200.

I then loaded 272 canon raw files into iris to register and align the images, and then used the automatic photometry tool in iris to generate the raw data. I used 4 reference stars on plus the HD189733 target star. I then ran 5 reference stars for a baseline. Here are the resulting light curve plots.


Target Star:



Reference Star:



Here is a link to a page with the plot data and more graphs.

DATA and PLOTS

This is my first time at detecting a known exoplanet, I hope the weather clears here so I can try some other targets.

Brent

[Footbag]

Wow! Congrats! It's amazing what amateurs can accomplish these days and with a DSLR and lens.

[whwang]

This is very cool!
Great effort.

[srosenfraz]

Very impressive, Brent - I wouldn't have thought it to be possible to do a project like this with such modest equipment. Thanks for opening my eyes!

[vmsguy]

Thanks for the nice comments.

I thought I would add a cropped image from one of the RAW images to show which stars were used for processing.

The green circle is HD189733, the yellow circles were the various stars I used a reference stars.



Here is a single 15 second stretched image to show HD189733's location relative to M27. (I should go ahead and stack the 272 light frames to see what kind of image it produces)



Brent

[JAT Observatory]

Nice work.

[copperneck]

Very Cool.

[fishonkevin]

Brent,
This is terrific using our DSLRs for actual science. At our recent club meeting, we had a Skype speaker from JPL talking about Exo-planets and he mentioned being able to do this with our cameras. It was late in the talk so I didn't get a chance to ask any questions.

For those interested in doing more like what Brent did check out the Kepler Home Page, there is a dropdown menu under Education. Also DSLR's can be used for Variable Star observing. The American Assosciation of Variable Star Observers is always looking for volunteers to help with their research.

[jgraham]

Now that's cool. I've been using my DSLR for photometry of variable stars for the past couple of years and I was recently wondering whether it could detect an exoplanet transit. Nicely done!

[Toxic Coolaid]

that is pretty amazing.

[Samir Kharusi]

Well done indeed. I take my hat off to you

[sn8matt]

I wouldn't have guessed that most of our equipment (there are a few here with some very impressive setups.) Would capture such a tiny change in stars.

Kepler is looking at a pretty small patch of the sky. Perhaps its time to step up and find your very own planet and put your name in the papers. I think if I'd have gotten as far as you have I'd give it a go.

[vmsguy]

Thanks Samir

I'm going to try again tonight. The Clear Sky Clock looks good for here.

The best option appears to be HAT-P-3B. But it's pretty dim at mag 11.86.
I'm also going to try the Nikkor 180mm ED lens to see how that works.

Here is some info from the ETD site for HAT-P-3B.

HAT-P-3B link

Brent