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robin_astro

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About robin_astro

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    http://www.threehillsobservatory.co.uk

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  1. I said hello to him in passing at the AAVSO/BAA meeting in the summer but did not get a chance to catch up with him. I'm not sure whether or not he is still taking measurements. Last time I spoke to him he was working on consolidating all the results he had for others to make use of but the latest update on his website is April last year http://www.stanwaterman.co.uk/variablestars/
  2. robin_astro

    Detecting exoplanet

    Using Michael Richmond's photometry calculator http://spiff.rit.edu/richmond/signal.shtml you should be able to get a signal/noise ratio ~ 1000 (ie a measurement uncertainty of 0.1%) on a mag 12 star with a 0.5m aperture and 30s exposure so easily good enough to detect a 2.7% transit. A median count in the star image of 6000 seems rather low to me for a telescope this size though this will depend on the FWHM of the star image (focal length seeing focus pixel size etc) . What was the integrated count and what is the camera gain? Robin
  3. robin_astro

    Detecting exoplanet

    Have you tried measuring the brightness in your check images? What uncertainty does the software report? (You will need to enter the gain of the camera in e-/ADU) This will tell you how many sub exposures you would need to combine to detect the transit. Robin
  4. The potential study of of exoplanet atmospheres via transit depth and timing at different wavelengths is an interesting one though which could in principal be undertaken at visible wavelengths using the Star Analyser, looking for methane for example perhaps. (The limiting factors would lie elsewhere than in the "crudeness" as you put it of the Star Analyser) though the technique is more applicable to IR wavelengths where the typical spectroscopic signatures of atmospheres are found https://www.physics.uu.se/research/astronomy-and-space-physics/research/planets/exoplanet-atmospheres/ Robin
  5. Hi Jerry, Yes that is why I was surprised to see it referred to in Bill's article on exoplanets: " The MSRO is equipped with the following for exoplanet detection: A 200 line‐per‐millimeter spectroscopic grating with an effective resolution of about 13 angstroms/pixels" Robin
  6. robin_astro

    Home Built telescope first images

    It doesn't work if you are downconverting at the dish LNB unfortunately (which you would normally be doing at 10GHz) unless the individual local oscillators are locked in phase. If you dont, you lose coherence. It is feasible to do this at 21cm though where you can use matched low noise amplifiers at the dish to offset loss in the feeders and combine the coax feeds before the main receiver Robin
  7. robin_astro

    Home Built telescope first images

    What are you using for LNB ? Are they standard domestic TV ones? if so how do you get into them to sync the local oscillators ?
  8. robin_astro

    Home Built telescope first images

    Yes phase locking LNBs sounds tough. Much easier at 21cm where you can combine before downconverting. Ive sometimes wondered if it might be possible to get interference fringes on brighter galactic sources at 21cm with a couple of say 1.8 dishes Robin
  9. robin_astro

    Home Built telescope first images

    The main area of solar radio work done by amateurs is not what you might think as traditional radio astronomy using big dishes but monitoring Sudden Ionospheric Disturbances (SIDs) using long wave radio receivers, https://www.britastro.org/radio/vlf.html Robin
  10. robin_astro

    Home Built telescope first images

    Take a look at this recent thread as an example of what can be done with a small dish. (Milky Way Hydrogen line observations) https://stargazerslounge.com/topic/319651-anyone-doing-hydrogen-line-observing/?page=2&tab=comments#comment-3508554 Robin
  11. robin_astro

    Home Built telescope first images

    Detecting the Moon is easy with a small dish and a satellite finder at this wavelength eg my simple setup here http://www.threehillsobservatory.co.uk/astro/radio_astronomy/radio_astronomy_1.htm but the resolution is only ~2.5 deg. You would need a very big dish or dishes on a long baseline to begin to resolve any solar features. (1 arcmin resolution would need ~100m aperture at 10GHz) Robin
  12. robin_astro

    Detecting exoplanet

    It is tempting to catch ingress or egress but I would say you would be better doing the test run outside transit. Then you will know for certain if your processed results are good enough to detect the transit, ie your light curve should be a horizontal line with variability less than the transit depth
  13. robin_astro

    Detecting exoplanet

    I would say if this is to be successful, preparation is going to be everything (even down to keeping an eye on the weather forecast. I know these are good sites but you don't want to be clouded out half way through a run. ) To maximise the probability of success, I would probably do a short, say 10-15 min trial run outside transit first and analyse these before committing to a full run to understand better what the potential issues are. Robin
  14. robin_astro

    Detecting exoplanet

    Can you change exposure on the fly with these systems ie fine tune on the run into the transit or are you committed to preprogrammed sequence of exposures ? I would take a test shot or two first before committing to a full 3 hour run to check exposure keeping in mind that the star will get brighter as it gets higher. Also check the image field with the telescope and camera you choose to make sure you have some useful comparison stars in the field and these are correctly exposed. Robin
  15. robin_astro

    Detecting exoplanet

    By my reckoning a single transit using 3 hours on the T17 would cost about $600 (or $300 during full moon) https://go.itelescope.net/info.aspx Robin
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