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I have been posting items about satellites under the dark skies news
forum. But in many ways the problems of satellite proliferation (and other potentially harmful developments in space) are not the same. While both issues have impacts on amateur astronomy they need different approaches. For instance, satellite proliferation is an international issue and campaigns against it are best coordinated internationally.
So, I am setting up this thread in the hope of finding out what BAA members think about what is happening outside Earth’s atmosphere. Do enough of us see the need for a new BAA campaign?Yes and no, IMO.
At the moment, and conditions may change, the “pretty picture” brigade have a readily simple mechanism to cope. They either discard subs impacted by satellites or they use (for example) sigma-rejection to discard the affected areas of their subs.
The spectroscopists and (especially) photometrists are a little more constrained. If the satellite goes over (or too close to) the target all they can do is throw away that data. For photometrists,if the satellite goes over (or too close to) a comparison it is necessary to remove that one from the ensemble for that sub. A real PITA, admittedly, but hardly crippling if there are a good number of other comparisons in the ensemble. The major problem, IMO, is teaching the pipeline to reject those occurrences without human assistance.
Caught a ridiculously bright satellite glint in the all sky camera last night, straddling two 10 sec exposures. (At first I thought is was a meteor but the faint track can be followed across the sky in the stretched images)
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Here are some recent items of interest to give flavour of satellite proliferation issues. These are mostly about space junk https://www.space.com/space-junk-new-deadly-era-no-one-is-ready
https://pirg.org/edfund/resources/wastex-environmental-harms-of-satellite-internet-mega-constellations/For more on the Kessler Syndrome see:
https://www.kesslerrebellion.comHi Robin.. Way down south of you M40 Jn3.. Your quaint Image and description excited my Interest.. Luckily I think that I eventually discovered a ‘typo’ in the wordage of your Image.. relative to the Date and wordage of your Input.. Then with my Arthy fingers becoming tired.. i was delighted to see.. at my less than regularly accurate time setting.. a Beautiful Bright Fireball with a Staggered Start.. Serendipity Indeed.. I will certainly do the necessary to extract a copy.. and Post here.. I do so miss that wonderful Archive of UKMON.. which regularly had me finding Bright Meteors inthe area of Sky above my valley..which I now cover with Old Unwanted Security cameras..[Shades of Mike Maunder].. Just refound an Image of my first Winchester Meeting and a pre Fame Heather..
Hi Stan,
The flare and time stamp on the image file name should be correct within a few seconds (2024-08-12 23:27:40 UTC) What time was your fireball ?
The camera takes 10 sec exposures per frame for fainter objects in the deeper sky rather than video for meteors but I am pretty sure what I saw was a satellite, not a fireball.
In the stretched images I can see the faint track for about 50 seconds before the flare, the flare lasted about 20 seconds and the track then continued as before the flare for at least another 10 seconds.
The animation is too big to post here but I have uploaded it to my website here.
http://threehillsobservatory.co.uk/allsky_camera/sat_flare_202408012T23_27_40_stretched.gif
The animation is 20x true speed. Each frame is a 10 second exposure, the yellow arrow marks the track in each image.Did any of the myriad of NEMATODE/GMN cameras in the south of the country pick up your fireball perhaps?
Cheers
RobinI have many concerns about the unconstrained used of near space for commercial and geopolitical advantage. From an amateur astronomer view, as Paul Leyland says, a few photometric observations could be spoiled but stacked images can still be edited. Using a smartscope recently to observe in real time I noticed that a satellite track quickly dimmed and was almost invisible in the final image.
But if the predictions of a general increase in global sky glow prove correct (see first link below), will it not reduce the contrast achievable by all instruments everywhere? One implication of this is that dark sky reserves could become a bit irrelevant.
When adding up the other potential threats (such as increasing radio noise, human rights impacts on diverse cultures, the risks of a Kessler syndrome event, the potential for military /commercial instability…), I think this is a topic that everyone should be aware of and have a democratic say about.
Are there (enough) BAA members willing to come forward and start a campaign?A paper on ArXiv today discusses “Initial Observations of the First BlueBird Spacecraft and a Model of Their Brightness”, https://arxiv.org/abs/2505.05820
“Based on a large set of visual observations, the mean apparent magnitude of BlueBird satellites is 3.44, while the mean of magnitudes adjusted to a uniform distance of 1000 km is 3.84. Near zenith the spacecraft can be as bright as magnitude 0.5. While these spacecraft are bright enough to impact astronomical observations, they can for periods be fainter than the BlueWalker 3 prototype satellite. A model for their brightness shows that design changes since the BlueWalker 3 mission can explain the behavior of BlueBird.”
The prolieration of satellites is also a big problem for Radio astronomy. In particular for radio meteoroid detection where there are many positive events mixed in with false positives.
https://uk.pcmag.com/networking/157759/ast-spacemobile-makes-deal-to-curb-its-huge-satellites-astronomy-interference This news story describes plans for 2nd generation Bluebird satellites having an array area of 2400 square feet, compared with the 693 sq. ft. of the first generation version. The article says that AST will curb its reflectivity but has not disclosed how it will do this. It’s not just visual magnitude and radio interference but IR signatures.
CfDS thanks attendees and event organisers for facilitating and participating in an opinion poll on the Saturday of the Winchester Weekend. The value of the poll was to engage with members, who often had significant knowledge and ideas to share. Visual observers (of Jupiter for example) were seeing several crossings a night but imagers were finding ways around the problem. This phenomenon may be short lived because new technologies may take over. Radio observations can employ algorithms (AI) to filter satellite interference, apparently.
Results from the poll: 42 members thought CfDS should run a campaign to mitigate against the increase in light pollution and radio noise caused by satellite constellations. 5 members thought CfDS should not bother, citing various and valid reasons. Quite a few people expressed that they were fairly neutral on the issue.
My impression from the day is that it is important that we protest against the more harmful side effects of satellite constellations. A new campaign should be collaborative in nature, encouraging best practices from the space industry. However, this should not detract from light pollution campaign efforts, so new members to be sought to work on this.
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