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We are running a session at my local society on transits and occultations. One station will focus on exoplanet transits, and we'd like to build a very simple model to demonstrate this. We have a star (light source) and an orbiting "planet" but I need to work out how to detect the changes in light intensity and display this on a laptop, like a classical transit photometry trace below (taken from https://heasarc.gsfc.nasa.gov/docs/tess/primary-science.html).
Is there a way to take a feed from a DSLR through the USB output to do this, else I could get an adapter for my ZWO and put an EOS lens on the front of that. I really do want a light intensity vs time trace in real time on the laptop. This model will be run in a darkened room.
Thanks for any comments.
Back in March I was granted an observatory code ( Q69 ) by the Minor Planet Center ( MPC ) and since then I have been spending all my available telescope time ( which due the weather has admittedly not been very much ) to capturing images of asteroids, that the MPC is interested in recieving data for, and sending in the positions that I have determined.
Mostly I have been focused on asteroids that have not been observed/reported on during their current return to visibility.
2014 LA21 was my first after getting my code ...
Here I was the first to report astrometry for 2014 LA21 since 2016 - not like discovering a new comet I imagine but still, a small achievement and a nice feeling
You may have noticed that I don't as yet supply any brightness data; this is because I have not figured out how I can do this reliably ( most of the asteroids I am chasing are very dim and so my 4 minute exposures tend to spread them a little making them hard to compare to nearby stars ).
I have been getting reasonably good position data though, with a "variation to average path" across the samples of sub 1 arcsec ( typically less than 0.5 and sometimes down as low 0.15 )
Anyway, I was just thought I would let people know what I have been up to and why you have not seem me latley over on deep sky imaging forum and also, I was wondering if there is anyone else here on Stargazerslounge doing the same thing ...
I've been trying to do some photometry with my DSLR with a view to using it on variable stars as a quick "grab and go" solution when there is a gap in clouds etc.
Rather than looking at variables I decided to start off with comparing some fixed stars to identify how well I can estimate magnitudes with my DSLR, and the table above shows the results.
Using only two stacked frames (5s, ISO 800, F3.5 on my 5DMk2) with no darks, light polluted london sky, and just one comparison star I seem to be able to get to around 1% variance for the majority of the readings, with the worse being 2.54% out. Trying Chi Cas, against Upsilon1, Upsilon2 and omegaAnd comes up with M4.67 which is mag0.03 different (0.55%).
I'll be honest I am surprised at the results as it is not all that far off the 0.01-0.02 mag range often quoted for looking at exoplanet transits for example. Has anyone else tried this exercise as i'm interested to know how these results stack up - good or bad. The only thing I know for sure is I couldn't get it that close visually using my eyes!
By Guy Wells
On March 31, 2018 issue of the Minor Planet Circular, the asteroid previously known as 2001 HQ16 was named.
(72834) Guywells is a Main belt asteroid with a diameter of 3-6 km. It last came to opposition in February 2018 when it reached 18th magnitude. Now it is moving through the constellation Cancer, observable at mag +19.5.
(72834) Guywells was discovered by L Ball, in 2001.