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Interesting. I don’t think the comparison between the mass deorbited and the amount of material in the Van Allen belt is particularly helpful as the two are not comparable (We already receive ~ 40T/day of metals from meteorites) but at the future projected rate of 23 satellite deorbits a day (in the paper) the amount of additional material would appear to be comparable.
I have just been listening to one of the scientists involved in that study on BBC world service Science in Action
https://www.bbc.co.uk/sounds/play/w3ct4sdl
starting at 22:40Robin
There could be some financial advantage to extending the time over which power can be generated rather than increasing capacity on the ground. For a region heavily dependent on solar power, the price of night time electricity must presumably attract a high premium due to the high cost of storage or alternative generating capacity.
I don’t see any convincing arguments for using LED lights with a high blue spectral content for outdoor lighting and many reasons why it should not be used. Why any council lighting engineers should still be pushing back on this these days when alternatives with a lower blue content are available is beyond me
Here is his Mario Motta’s review from a US perspective.
https://www.mariomottamd.com/street-lighting/See a presentation on this at the 2018 joint BAA/AAVSO meeeting
https://britastro.org/event/baa-aavso-joint-meeting-on-variable-stars
Mario Motta – American Medical Association statement on street lighting
There could be a video of it somewhere on the website
I tried pointing out to the local lighting officer and my County Councillor that lower colour temperature LEDs were better, as they reduced scattered light in hazy/foggy conditions
You would probably have more success going on social media saying blue LED lighting causes cancer. (Unlike with 5G there is apparently some evidence to support this and has caused some towns in the US to rip out their recently installed blue LEDs in favour of lower temperature versions. See a presentation on this at the 2018 joint BAA/AAVSO meeeting). Failing this, pointing out the effect on wildlife might gain more traction among the general public, particularly if yo have any green councillors
Richard Berry is trying the Origin out for variable star photometry. There is the opportunity to use the green channel as with DSLRs, or all the light, depending on the goal of the observation.
The HOYS Citizen Science Project are accepting observations from ZWO Seestar 50mm telescopes, these use a colour CMOS chip. This is a research project run by Dirk Froebrich at the University of Kent, to monitor young stars.
Both of these approaches use the raw files saved by these smart-telescopes, rather than the processed images displayed on smartphones and tablets.
AndyThese ideas might attract people into scientific applications of their kit but these solutions are pretty suboptimal. It reminds me of the days of converting webcams for deep sky imaging. The results were impressive given the limitations of the kit but far from what came after based on the huge interest in imaging it generated. Hopefully the smart scope manufacturers might see there is a market for mono sensors which can take filters. ZWO should be perfectly placed to do this for example as their SeeStar uses the same CMOS sensor in colour version as another of their cameras which uses the mono version (There are apparently already people using Star Analyser on the front of this scope and even hacking into it to mount it internally, though the colour sensor is a big drawback)
There are other examples of areas where there is a tension between what is good for (marketing to) imagers and not for science. For example fancy mulit-coatings which make the difference between 95 and 98% are a disaster for short wavelength measurements.
Perhaps with these smart telescopes a swap out for a mono sensor might be feasible ? I used to do this kind microsurgery on webcams back in the day but my eyes and hands are not up to that now and I expect the pins are much closely spaced. If it uses a separate off the shelf camera module it might be possible though if there is a mono version. (Plus a firmware hack to get at the raw image before debayering)
With the Unistellar, being an open tube you can get in to put filters (or even a diffraction grating) in front of the camera
BTW looking at the example solar spectrum in the video, the resolution is nowhere near 2nm (more like 5-10x that). Compare with my simple “SEPSA” (Slit-EyePiece-Star Analyser) setup for example
http://www.threehillsobservatory.co.uk/astro/spectroscopy_18.htm
or the slitless collimated Junk Box design
http://www.threehillsobservatory.co.uk/astro/spectroscopy_19.htmThese are just a bit of fun though. A slit/fibre fed spectrograph really needs a guider module so you can find, focus and place the star on the slit/fibre and keep it there
Cheers
RobinFigure 1 is interesting
That pretty much matches what Christophe saw with the Star Analyser. If you normalise the spectra in the red/green then Neptune shows a slight blue excess and both planets have similar depth Methane absorption bands
The kit I would really like to have is at least fifty times the price
The difference is the one 50x the price would actually work (for astronomy) 😉
Beyond the introductory Star Analyser at ~ the same price as this, for around £1k you can get a pretty capable and versatile 3D printed astronomical spectrograph kit, the StarEx
http://www.astrosurf.com/solex/sol-ex-stars-en.html
The optical components are supplied by Shelyak and you can get the 3D components as a kit if you don’t want to print them yourselfCheers
RobinWe have Uranus spectra in the BAA database but Neptune only in the IR
I remember a comparison of the spectra by Christophe Pellier using a Star Analyser
https://www.cloudynights.com/topic/645833-neptune-full-spectrum-comparison-with-uranus/
(Very similar but Uranus has slight red/green bias compared with Neptune )Cheers
RobinDefinitely a Curate’s Egg here. Apr-Jun were excellent but the past 6 months have been truly terrible
Attachments:
Concerning the ageing demographics (of which I am a member,though not an honorary one!) and taking a hard nosed approach I suggest the money saved by scrapping the honorary membership going forward (which lets face it few are likely to resign over the matter) and instead using the money to offer free trial (electronic) subscriptions to young members might be a good way to increase numbers and start redressing the age imbalance ?
Coming to your local sky soon maybe?
Also seen here
https://www.bbc.co.uk/news/uk-england-humber-67095602There it seems to imply the decision to draw the blinds is temperature dependent not to reduce light pollution and is likely to occur again under certain circumstances
Unfortunately hackers trashed the forum some months ago. They have been working to restore it from backups but has been slow going. (I think the messages are intact but I believe it is restoring the links to the embedded images which is giving problems.) I hope it does come back eventually. It is a huge source of information and tracks the history of the developments over a number of years. Suggestions for targets and calls for observations are posted on the connected spectro-l forum though
https://groups.io/g/spectro-l/topicsCheers
RobinShouldn’t it possible to extract useful information from the sky background in the photometrically calibrated images and spectra we take ? If so there could already be a huge (untapped ?) historical source of data covering a range of passbands, locations, air mass and atmospheric conditions
Cheers
RobinWhat causes the curved dark streak? Is this a region devoid of dust or perhaps a shadow cast from an out of plane dense dust jet ? (There does seem to be a corresponding bright streak to the left which could be the source of the shadow. Would this be consistent with the current geometry relative to the sun ?)
Robin
