Exoplanet transit of TrES-3 attempted tonight

PS. Is the graphic produced using Excel or do you have some other package?

The curve is not "recorded" as such...

Essentially, images were taken through an R-Band filter (R-band as in johnson-cousins, not RGB...), calibrated/reduced and then analysed in Canopus (a photometry program). This program looks at the magnitude of the target plus up to five comparisons. It then does some trendy maths stuff and produces magnitude differences for each image. It then takes each data point and slaps it into a chart.

Whilst Canopus indeed plots light-curves, it is best suited to asteroids. So I exported the data to Excel and then finished it off there.

There were 227 images in the mix (they are the orange lines). They were then distilled down to five-point averages (the blue dots). Finally, a trendline was added using Excel. It was simply a polynomial line set to five orders - whatever the heck that means. It produced a reasonable line though. My knowledge of excel is limited and so I don't know if it can do a better job of the trend line or if a different maths program would do a better job.

So Anthony - no serious maths analysis yet - I'm hoping the team (Eamonn/Mike) can do better with the software they have (Mira I believe).

As regards airmass, yes there are corrections that can be applied but like you, I don't know how that is done. Its a bit more complex than simply subtracting/adding values to your data. It involves an analysis of the target and comparisons, particularly their colour, then applying the correction. BG's book may well go into it. If you find out, let me know!

There are anumber of interesting exoplanets that are within the range of amateurs - TrES-1, WASP-1, HD149026, XO-1 etc etc For the very brave, you could try HAT-P-2 with its 5 millimag drop :shock:

Give it lash and see how you get on. It seem R-Band is popular but I've seen data with other filters too. More kit to buy...

Cheers
Dave

It was simply a polynomial line set to five orders - whatever the heck that means.

f(x) = a + b(x) + c(x**2) + d(x**3) + e(x**4) + f(x**5)

It produced a reasonable line though. My knowledge of excel is limited and so I don't know if it can do a better job of the trend line or if a different maths program would do a better job.

It would be of interest to see what degree polynomials others fit to smooth out their light curve.

As regards airmass, yes there are corrections that can be applied but like you, I don't know how that is done. Its a bit more complex than simply subtracting/adding values to your data. It involves an analysis of the target and comparisons, particularly their colour, then applying the correction. BG's book may well go into it. If you find out, let me know!

I will certainly check and follow-up here.

There are anumber of interesting exoplanets that are within the range of amateurs - TrES-1, WASP-1, HD149026, XO-1 etc etc For the very brave, you could try HAT-P-2 with its 5 millimag drop :shock:

We have good overlap. Last night I prepared future sessions for HAT-P-1, HAT-P-2, HD 189733b, HD 209458b, TrES-1b, TrES-3b and XO-1b. I have a few more to add which should/may be within reach and certainly worth a try.

Give it lash and see how you get on. It seem R-Band is popular but I've seen data with other filters too. More kit to buy...

I was looking at either R or V .... anyway, I will post once I start to have results. My first test run will be on Saturday with TrES-3b (mag 12.2, depth = 26 mmag) and with the real run being on May 2nd when the moon is not an issue (I realize that the presence of the moon is not necessarily an issue but I prefer total darkness).

PS. I checked my list to see why I did not have WASP-1 .... and I see it is out of season (Andromeda).

Good luck with the trial run on TrES-3 - it'd be great to see more data.

TrES-1 is up tonight (00:37) and with a depth of 25.5 mmag is do-able... R-Band seems the most popular filter though clear and V have been used too.

TrES-3 popular filters are R and Clear though V has also been used (once).

Here is a link to a bunch of spreadsheet templates that look very detailed and intetresting:

brucegary.net/book_EOA/xls.htm

Good luck!

Dave

Good luck with the trial run on TrES-3 - it'd be great to see more data.

Agreed and I will be ready for action Saturday evening. Since I will be using a RED filter, I am not very much worried about the moon. The good thing about TrES-3 is that the check and comparison stars I have identified are virtually the same magnitude and they also seem to be the same colour. As a result, the air mass extinction correction would not seem to be necessary.

By the way, BG's book covers the topic of air mass extinction quite well in Chapter 14. Due to the fact that we have a different atmospheric extinction for each of the three primary colours of the visual spectrum, differential photometry is adversely impacted when the host exoplanet star and comparison/check stars have different colours between them. The corrections for air mass that you see address this problem.

TrES-1 is up tonight (00:37) and with a depth of 25.5 mmag is do-able... R-Band seems the most popular filter though clear and V have been used too.

Being two hours east of you, regrettably I cannot pursue it since I will be well into daylight when the transit is over. I must wait till late June to pursue it (and I will!).

TrES-3 popular filters are R and Clear though V has also been used (once).

I am certain I will be going with RED. Thanks for the info.

Here is a link to a bunch of spreadsheet templates that look very detailed and intetresting:

brucegary.net/book_EOA/xls.htm

Good luck!

I had managed to download them on an earlier occasion but I have redownloaded them since at least one seems to have been updated.

Anyway, I see fun times ahead with this exoplanet transit work.

Thanks for the various tidbits of information!