Exoplanet Transit Event Observed from Ireland (maybe)!

Hi Guys, just some very brief details on an observation of an Exoplanet transit event from Ireland, we will update you when we can over the next week or so. As you can gather this is a very difficult undertaking and working as a team we really best guessed from both planning to actual observation which happened all within a few days.

Last Tuesday night 26th February we, that is, I, Eamonn and Mr. Tim Long from Wales undertook to record Exoplanet transit HD17156b in which the predicted mid transit time was ~22:29 UT, predicted flux reduction ~0.6%.
We started imaging from ~21:10 UT from the Kingsland Observatory based in Boyle Co. Roscommon using the following equipment: Meade 16” SCT operating at F5, Apogee AP7 CCD, Paramount GT1100s EQ robotic mount and utilizing photometric filter in the “R” band, FOV of ~25 x 25 arcmin and with an image scale of ~2.47 arcsec.
Tim, who is expert on “ACP” remotely accessed the telescope system from Wales from the comfort of his home while enjoying a nice cup of tea may I add, while myself and Eamonn were freezing our n*ts off in the dome and all for the sake of astronomy.
We finished up around 00:45 UT with a lot of FITS images (including darks, bias and flats of course), exposures were 10s each. We had some problems throughout the night with high passing cloud but we think it shouldn’t be too detrimental to the photometry processing which we will undertake over the next week using Mira pro software. Only complaint of the night was Eamonn’s iffy radio which looked and sounded like a reject from the early 70s (reminder to oneself: bring a decent radio while observing next time).
We would like to offer an opportunity for other amateur astronomers with knowledge of photometry and advanced observing techniques to bring their knowledge and skills forward and being part of a team. We would also like to encourage any other amateurs with telescopes of moderate aperture ~200mm (and upwards of course) utilizing relatively sensitive CCDs to undertake this work with certain suitable candidate stars. I can place a list here shortly (or someone else here on the forum can of suitable target stars for observation over the next few weeks). Through this excellent forum of dedicated amateur astronomers we can share information on Exoplanet recording and analyses as the necessary skills and knowledge is both obtained and learned as time progresses.

Regards and many clear skies
Mike

Kingsland Observatory:
MPC J62
www.kingslandobservatory.com


HD 17156b:
P: 21.21725 day
Depth: 6.2 ± 0.4 mmag (R-band)
Length: 3.10 ± 0.08 hr
Eccentricity of Orbit: e= ~0.67

HD 17156:
Object name: SAO 4737
Other ID: HIP 13192
Magnitude: 8.17
Equatorial: RA: 02h 50m 30.298s Dec: +71°47'35.012"(current)
Equatorial 2000: RA: 02h 49m 44.488s Dec: +71°45'11.636"
Horizon: Azim: 329°07'24.817" Alt: +53°34'44.481"
Transit time: 16:54 Always above horizon.
Name 6: HD 17156
Name 7: B+71 171
Object type: Star
Spectral: G5
Source catalog: Hipparcos Catalog
Sun distance (au): 16139680
Hour angle: 05h 08m 48.255s
Air mass: 1.24
Magnitude B: 8.93
Magnitude V: 8.23
Proper Motion: 91.00, -32.45
Position error: 0.6000, 0.6800
Light years: 255.21
Parsecs: 78.2473
Catalog number: 4737

flickr.com/photos/oklo/2173677499/
www.transitsearch.org/hd17156b.pdf

Guys,

This will be a tremendous achievement if your data can show a positive transit event capture! Well done, and I look forward to seeing the results here when you write up the session.

Phil.

We would like to offer an opportunity for other amateur astronomers with knowledge of photometry and advanced observing techniques to bring their knowledge and skills forward and being part of a team.

Mike - any more details on the "opportunity"? J65 would be available and would have the kind of kit that would probably fit the bill...

Cheers
Dave

Hi Dave
This is a basic candidate assignment algorithm (see link at bottom of page). When you input your longitude, latitude, date and time search period, it will display list of candidate Exoplanet transits giving the necessary details.
We just happen to pick HD17156b Bright Transiting ExoPlanet (BTE), for a number of reasons and we are going to concentrate on perhaps one or two more BTEs until we can refine the observing procedure and post analyses [help here most welcome].
I would recommend that you check the following page to ascertain the prediction of transit, depth value, Ephemeris etc (see link at bottom of page).
Transit of HD17156b is estimated to produce a 6.2 + / - 0.4 mmag (“R” band) depth over a mid transit period of ~3 Hours. OOT (Out Of Transit) recording will prove useful as a correlation with OOT light curve data to those of predicted transit, perhaps another planet around the target star may also be recorded if completing OOT work, next mid transit event for HD17156b will be on the 19th March at ~03h 18m UT which follows our observation on 26th Feb based on an orbital period of 21.2 days. I’m also interested in targeting TrES-3, also for a number of good reasons in which there will be a few opportunities in the month of March.
Dave, you certainly have the necessary equipment to undertake this research, there are other people elsewhere using high QE front illuminated CCDs obtaining light curves of BTEs using telescopes of less aperture with the necessary photometric filters. All this work is perhaps new to many Irish amateur astronomers (I certainly lack the knowledge in this area for sure) but that shouldn’t stop anyone doing this work even if using moderate to good off the shelf equipment and while learning new skills, science and acquiring knowledge to refine both technique and post processing, no time like the present to undertake this work i guess.

Clear skies
Mike

207.111.201.70/transitsearch/transitassignment.html
brucegary.net/AXA/x.htm

Hi Guys,

Regarding the recording of the transit of HD 17156b on 26th February, we are having problems with the processing of the images.

Before carrying out photometry, image calibration is the key foundation to detecting any millimag difference.

Mike and myself, spent this weekend processing the images, we originally acquired 200 images. The calibration procedure involved correction of the instrumental signatures and effects like bias, darks, and flat field corrections. However, we have discovered that even eliminating nearly 50% of the cloudy images, we still couldn't obtain a calibration. There appears to be a general problem of more moisture than normal in the air in the last few months. This has not happened in previous images taken the same time one year ago.

Secondly, we had drift with the tracking over the 4 hour period. The drift on average appears to be over the limits that the processing can't handle.
We plan to address this issue this month before any potential exoplanet monitoring.

We are also planning less ambitious additional exoplanet transits, in particular of TrES-3 for the month of March. This has a large mmag drop: ~28 as compared to our previous and more difficult attempt at HD17156b which was only ~6mmag. The orbital period of the exoplanet is short at only ~31 hours and with a transit period of only ~ 114 minutes, so it's a good target star that’s well placed late in the evenings and through the night with a large light flux drop.

Eamonn A

MPC J62
www.kingslandobservatory.com