Eclipsing Binary Star AD Andromeda

[Dave Smith]

Eclipsing binary star AD Andromeda. Multiple 45s exposures collected with SGPro and processed with AstroImageJ. The noisy bit at the end is due to the star approaching the horizon. Total of 643 readings!

Dave

[michael.h.f.wilkinson]

Very nice. Might have a go at something like that myself

[fwm891]

Quote

 

Great result Dave - proper astronomy

[Dave Smith]

20 minutes ago, michael.h.f.wilkinson said:

Very nice. Might have a go at something like that myself

Thanks Michael. You can do this without any special equipment. The software needed is free although I find SGPro invaluable to get the star right in the middle of the FOV. Almost any scope can be used.

Dave

[Dave Smith]

14 minutes ago, fwm891 said:

Great result Dave - proper astronomy

Thanks Francis. I did get a bit bored with imaging in particular because it was not really of much use scientifically. Doing variable stars does appeal to my physics background and is actually useful to the professionals. I now regularly get emails from the aavso to say that a professional or a student has made use of my data.

Dave

[Helen]

13 minutes ago, Dave Smith said:

Thanks Francis. I did get a bit bored with imaging in particular because it was not really of much use scientifically. Doing variable stars does appeal to my physics background and is actually useful to the professionals. I now regularly get emails from the aavso to say that a professional or a student has made use of my data.

Dave

^^ This ?

 

We're looking to encourage and enable more of this Dave.  I think many of us have got to the 'what next' stage of imaging.  In my case it would be longer and deeper exposures to get better images, but I live in Wales and the weather/opportunity....  So doing something different, and useful, really appeals to me too.  I'm starting with analysing comets (as it's my PhD subject), but having done variable stars and exoplanets transits at Uni I'd love to give that a go too.  And spectroscopy!  So much universe, so little time!

I was at a Pro-Am meeting in the summer and the Pros really are keen to get amateurs to submit the data and images they gather.  The more data points available in any analysis the better.

So, do you think you could do a short tutorial of how you do this? 

And then perhaps we can pick a few targets and anyone interested can have a go and we can share results?

Thanks

Helen

 

[Dave Smith]

Thanks Helen. I see no reason why I can't write a short tutorial on this. I am giving a talk on variable stars to my club early next year and so preparing for that and a tutorial should go hand in hand. It may take some time (weeks) so I will keep you informed when I have made some progress.

Dave

[Helen]

1 hour ago, Dave Smith said:

Thanks Helen. I see no reason why I can't write a short tutorial on this. I am giving a talk on variable stars to my club early next year and so preparing for that and a tutorial should go hand in hand. It may take some time (weeks) so I will keep you informed when I have made some progress.

Dave

That would be great Dave   It is a long term project, so no pressure.

I'm doing something similar with comets - started with the outline presentaion at the star party, now working on tutorials linking with some work I'm doing with the Faulkes Telescope schools project.  The core material will be the same, the level of detail will vary by audience.  My timing is a little more pressing though - we want to start observing 46P once the moon is out of the way in a week or so ?

Helen 

[giorgio_ne]

This is some very inspiring work Dave! I'm also getting increasingly interested into variable star photometry and exoplanet transits. It is a much more empirical discipline if compared to astrophotography. So, whilst waiting for your tutorial I would be gratedul if you could answer a few questions:

- You mentioned this work can be done with almost any scope. I am  interested in using a small refractor  or telephoto lenses so that I can setup everything more quickly and easily. I have an SX-825 (ICX825) that I could use on my FS-60CB (with flattener) but I feel the image scale might not be adequate (3.55 ArcSec/Pixel).

- You took 643 45s exposures, was there any interval between each exposure?

- Did you also take bias, flats and dark frames? If yes how many of each?

- Do you use any particular technique to calculate exposure times to avoid saturating the variable or comparison stars?

- Once you set your exposure time do you change it during the course of the session to adjust it against other factors, like for instance the elevation of the variable star on the horizon hence a thicker atmoshpere?

I'm looking forward to seeing more light curves!

Giorgio

[Dave Smith]

Thank you Giorgio.

With all the Christmas, New Year and Family activities it had slipped my mind that I was writing a tutorial so thanks for the reminder. 

I will attempt to answer your questions.

Your setup is certainly ok for variable stars. Many reports I have seen are from a telephoto lens. The size of the scope may restrict how dim the stars can be, which is why I did upgrade my scope. I was able to detect an exoplanet with my 90mm refractor so it is worth a try with 60mm.

When I did 643 45s exposures there was no intentional interval between each exposure only the inevitable delay while the image downloads from the camera. Whether you have an interval orr not depends on the time scale of the variation. With some stars the period of variation can vary from an hour to years.

It is essential to use bias, flats and darks as in astro imaging. I usually have around 50 of each.

AstroImageJ has a feature that enables a sample image to be examined to ensure that stars are not saturated. 

With comparative photometry, as long as the target star(s) and comparison stars are in the same field of view then no correction is needed for altitude or even light pollution (e.g. moonlight).

 

Hope that helps

Dave