Guest speaker at RAG tonight 31/5/2019 – ‘Hunting Out Young Stars Project – Citizen Science’ (Dr Dirk Froebrich, Univ. of Kent)

May 31st 2019 – Guest speaker @ RAG ( DF) – ‘Hunting Out Young Stars Project – Citizen Science’ (Dr Dirk Froebrich, Univ. of Kent).

Brilliant lecture tonight from Dr Dirk Froebrich – who drove all the way up from the University of Kent. His Talk was on the Citizen Science Project ‘Hunting Out Young Stars’ – HOYS-CAPS. The concept is fascinating, and has tempted some of us to assist Dr Froebrich and his Team, by contributing to their research – uploading our photos of the night sky.
Contact details for the team can be seen in the photos below from the lecture tonight.

Andy

         

Eta Carinae: Mucking about with someone else’s data

With the long evenings precluding any weekday astro activity at the moment I decided to get a fix from Pete Williamson’s data that Andy provided for RAG members on this blog.

I didn’t want to get data for something that I could image myself so I went for Eta Carinae Nebula, which is a Southern Hemisphere object. You can read more about it here, but in summary it’s a very large and bright nebula (4 times the size of Orion, although further away) and after spending a bit of time playing with it on a computer I’d love to point a telescope at it.

The data is, as you would expect from top end gear working in a complete absence of light pollution, terrific. It comes pre-calibrated (although the SHO image below had a few hot pixels appearing in it), and both the images below had 3x 5 minute subs for each channel (so the HaRGB is an hours data, whilst the SHO is 45 minutes). I’ve never managed to get my head around pre-processing on Pixinsight so I used DSS to stack each channel then registered and merged them in Pixinsight using Pixelmath. I was able to drop background extraction (which tackles light pollution and other issues) and noise reduction from my usual workflow, and used only a tiny bit of sharpening.

I’m more taken with this approach than I expected: it doesn’t bring the same feeling of achievement that creating your own image does, but it was great to be able to explore such a large and beautiful object that you can’t see from this side of the planet and I love the finished product. It also gave me a chance to work with mono data for the first time and learn how to create an image in the SHO palette as per Hubble. In summary, I’d rather work with my own data, but this was a fun thing to do and I’ll certainly look forward to finding another Southern Skies object to explore in this way.

Observing Jupiter 28/5/19

Swadlincote. C6r refractor.

Some entertaining views waiting for Jupiter to rise . Amazing view of unfiltered M27. The Summer Triangle was high giving views of Cygnus. Serpens and Ophiuchus gave great views of open clusters , the “summer beehive ” IC 4665 and “Graff’s” , IC 4756, stood out as very fine. M5 is a gem to resolve.

After midnight a very bright Jupiter arrived. Opposition will be on the 10th of June. Although as quoted as being low in the south , it was nicely positioned to observe. Even low power showed Ganymede off the limb and the shadow of Io in transit. The size of the disc at x320 was amazing  at 47″. Best views were about x160. The south polar area being dark. The bands had dark edges with a lot of activity to the equator. Thin cloud acted as a good filter giving lots of contrast. Seeing soon deteriorated. Best just to keep focus and let the views come. A very interesting session , keep observing throughout the summer , under clear skies ! Nick.

 

Spectroscopy of Jupiter Andrew 29/5/2019

After Angella and Alan and Chris left tonight, I was packing away my equipment when Jupiter became visible – having previous been obscured by cloud – so I took some quick spectra before it disappeared again.

Andy

I thought I could use the above to calculate the speed of rotation of Jupiter at the surface but I was wrong.

Surface speed from my data = 1/4 (Doppler shift in practice needs to be counted 4 times) x 300000km/s (speed of light) x change in wavelength (1200A above)/wavelength (5780A)

= 15570 km/s.

Real speed of rotation: Since Jupiter is a gas planet, it does not rotate as a solid sphere. Jupiter’s equator rotates a bit faster than its polar regions at a speed of 28,273 miles/hour (about 43,000 kilometers/hour). Jupiter’s day varies from 9 hours and 56 minutes around the poles to 9 hours and 50 minutes close to the equator. (From coolcosmos.ipac.caltech.edu/ask/200-Which-planet-spins-the-fastest-)

My own calculations =

Jupiter’s circumference = 439,264 km

Rotation period (length of day in Earth days)
Jupiter’s day = 9.8 Earth hours

So surface speed = 439,264/9.8 =  44,822 km/hour = 12.45 km/s

So I am way out!!

Looking up methodology for calculating surface speed my method is wrong (hence incorrect result) – the real way to do it requires high resolution spectrograph and measure the spectrum at the equator. This spectrum will show a tilt due to doppler shift and from that SINGLE spectrum the speed of rotation at the surface can be calculated from the amount of tilt. See https://www.shelyak.com/planets-rotation/?lang=en for more details.

Identifying spectral lines on Jupiter:

I have attempted to do this using diagram as my source from https://www.researchgate.net/figure/Jupiter-Spectrum-The-white-boxes-represent-the-Fraunhofer-lines-and-colored-boxes_fig2_283695178

Not sure whether I have identified the correct lines!

Spectroscopy of Vega, Polaris and Deneb with Angella, Alan and Chris Ford 28-29/5/2019

Angela, Alan and Chris Ford came to my house tonight and did a brilliant job calibrating CCDSPEC spectrometer on Equinox Pro 80mm, and hand guiding it to obtain three spectra. Amazing for first ever try!

Andy

The team (Chris Ford, Angella, Alan, Andrew):

Angella controls the imaging software while Alan hand guides the scope:

Calibrating the CCDSPEC (Angella, Alan and Chris):

The image below taken with Samsung S7 phone hand held at eyepiece of CCDSPEC spectrometer shows compact fluorescent bulb with spectrometer slit and cross-hairs of illuminated eyepiece:

Compact fluorescent bulb spectrum:

Compact fluorescent bulb spectrum profile in RSPEC after calibration (after calibration shows angstroms of wavelength rather than pixels on x-axis):

Angella used the following graph to calibrate the spectrum of the compact fluorescent bulb – it shows known wavelengths of specific lines in the length (prepared using data in Wikipedia):

Vega (Angella and Alan) – the profile showing the Vega spectrum compared to that of reference library A0V spectrum shows close match with hydrogen Balmer lines:

Polaris (Angella and Alan) – much fainter and more difficult to obtain high quality spectrum tonight – nevertheless some significant lines can be seen to match on the rather noisy spectrum obtained tonight:

Deneb (Angella and Alan):

 

Spectra from Science Surplus “DIY Spectrometer” comparing sky, tree trunk and CFL bulb, through Sky Watcher Evostar 72ED telescope 28/5/2019

Spectra from DIY Spectrometer comparing sky, tree trunk and CFL bulb, through Sky Watcher Evostar 72ED telescope 28/5/2019. Note that although the x-axis is the same scale for all three graphs, the y-axis scale differs.

Coma beam splitter 1.25″.

Ocean Optics collimating lens at telescope end of fibre optic where enters beam splitter.

I can’t see any meaningful difference between sky and tree trunk spectra but the CFL bulb clearly different.

Andy

Window-sill Jupiter 27/05/2019

GRS transiting again at a reasonable time last night, but had to get up early this morning, so no chance to get the “proper” scope out, Anyway, lots of cloud about so getting the big scope out would have been fatal.

So took advantage of the window-sill’s “instant availability” to dodge the cloud and get this image. Looks like this is about the best that can be done with this set-up. (Not entirely a surprise!)

 

Creositing the home observatory

I felt it was worth painting a protective layer of creosote on edges of the log cabin home observatory roof before I tacked down the shingles over the edges.

This I did today – weather looked fine.

Just as I finished the rain came down!

The gloves I am wearing are vetinerary gloves designed to allow vets to put their arms in cows’ bottoms up to their elbows! I used them to stop getting creosote on my arms when I was painting the stuff on to the cabin under the eves – worked although creosote dissolved the gloves and I had to keep changing them so good thing that they came in packs of 50!

Andy