My first "real" light curve

Its a worthwhile use of scope time - especially as one can publish the data in a peer-reviewed journal which would be referenced by the professionals.

Its not easy but if anyone had an interest, I could my best to help out.

Also, you *may* need to consider purchasing software, though Canopus is relatively cheap. I'm currently looking at Mira Pro - there's a good deal on it at the mo (for the next couple of weeks anyhow) and I might pull the trigger...

You *can* simply use Excel but if I recall, its laborious.

Anthony - what do you use?

Dave

Dave that is excellent stuff. The data model presented looks excellent. One question, the second minimum presented is fainter than the first. Is that a real feature of the asteroid, or is it just that maybe the latter half of the data was taken with a higher air-mass?

Wonderful stuff and look forward to seeing more. A really good example of more useful work that amateurs can do.

Dave.

dmcdona wrote:

Anthony - what do you use?

Dave,

With respect to the differential photometry, all of my work is done via AIP4Win V2.2.

The graphics generation is done using the online facility at ostrava.astronomy.cz/plotter.php with some intervention at my end thereafter since the online facility is really for variable stars and where the only item of interest is the local minimum or maximum and in contrast to exoplanet transit work where we care about three points in time, namely ingress, midtransit and egress.

Anthony.

Dave,

Thats a good resolved light curve.

I've used MIRA PRO in aperture photometry.
It's a good program.

Eamonn A

www.kingslandobservatory.com

DaveGrennan wrote:

Is that a real feature of the asteroid, or is it just that maybe the latter half of the data was taken with a higher air-mass?

Yes - its a feature of the potato-ness of the asteroid

Since the comparison stars reamin in the FOV during the entire run, airmass differences drop out of the equation. That said, to minimise errors, you should always shoot at an airmass of less than 2. And of course, choose your comparisons carefully - no variable stars etc and preferably solar in colour. Nothing too blue or red.

The "bump" at the end of the period is odd and I've no epxlanation for it. Though I did see a paper suggesting that (132) Aethra is thought be particularly lumpy... The curve follows the shape of the published data very well - bar the lumpinees at the end of mine. I don't think its an artifact of my system either - two of the three runs that covered that aprt of the curve showed pretty much the same pattern. I guess more data would tease it out and characterise it better.

With amateur asteroid discoveries reaching the end of the road, photometry seems to be be a very worthwhile goal with many objects requiring study. But I'd like to have a go at any object that varies...

Anthony - I hadn't considered AIP4WIN. I'd be interested on your thoughts in terms of its perfromance for exoplanets - especially where you're well into the millimag zone.

Eamonn - how easy is Mira Pro? And do you know if it can handle zero points and first and second order extinctions? i.e. does it have the algorithms to get you on the standard (Landolt) system?

Cheers
Dave

dmcdona wrote:

Yes - its a feature of the potato-ness of the asteroid

Now don't start getting all technical on me McDonald.

So the obvious question. Have you classified the 'potato-ness' ot this asteroid? Rooster or Kerr Pink? When are you going to image a 'turnippy' asteroid? Lets see if you can sell that classification system to the minor planet centre.