<story><title>How bad are satellite megaconstellations for astronomy?</title><url>https://www.leonarddavid.com/blinded-by-the-light-megaconstellation-clash-with-astronomical-peer-groups/</url></story><parent_chain><item><author>StellarScience</author><text>There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They&amp;#x27;re wide field of view, long-duration exposures. That &lt;i&gt;used&lt;/i&gt; to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one particular spot in space) and use image stacking, a technique where many individual images are processed to form the final image (very simplistic overview: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.skyatnightmagazine.com&amp;#x2F;astrophotography&amp;#x2F;astrophoto-tips&amp;#x2F;a-guide-to-astrophotography-stacking&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.skyatnightmagazine.com&amp;#x2F;astrophotography&amp;#x2F;astropho...&lt;/a&gt; .) Using image stacking and armed with accurate catalogs that predict precisely where every satellite will be at any time, enables the removal of satellites during the image stacking process. Or they can just use that information for better scheduling: wait a minute or two to image a particular spot, so there won&amp;#x27;t be satellites in the field of view.&lt;p&gt;The article definitely gets this part right:&lt;p&gt;&amp;gt; “Some astronomers see this as a true ‘hair on fire’ emergency, heralding irretrievable losses to space science; others present a more sanguine face, depicting this as yet another challenge to be surmounted in surveying a decreasingly pristine sky,” Koplow remarks.&lt;p&gt;Being involved in both space and astronomy plants me squarely in the latter camp. It takes a bit more work and software, but having so many satellites in space is a surmountable challenge for terrestrial astronomers. (Not to mention, these days some of the best astronomy is performed by telescopes in space, so astronomy overall benefits by having easier access to space.)</text></item></parent_chain><comment><author>thayne</author><text>If you are looking for short period events, losing a single frame can mean losing critical data.&lt;p&gt;&amp;gt; Or they can just use that information for better scheduling: wait a minute or two to image a particular spot, so there won&amp;#x27;t be satellites in the field of view.&lt;p&gt;Which means more time and effort, and ultimately money needs to be spent on scheduling observations to avoid the thousands of these satellites.&lt;p&gt;And sometimes it isn&amp;#x27;t an option. What if a GRB happens in the same field of view as one of these satellites and you want to observe it as soon as possible?&lt;p&gt;Now there are some types of observations that won&amp;#x27;t be impacted that much. If you can tolerate scheduling around it, or throwing away some of your frames it is just a minor annoyance. But a lot of observations are also more sensitive to such disruptions.</text></comment>
<story><title>How bad are satellite megaconstellations for astronomy?</title><url>https://www.leonarddavid.com/blinded-by-the-light-megaconstellation-clash-with-astronomical-peer-groups/</url></story><parent_chain><item><author>StellarScience</author><text>There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They&amp;#x27;re wide field of view, long-duration exposures. That &lt;i&gt;used&lt;/i&gt; to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one particular spot in space) and use image stacking, a technique where many individual images are processed to form the final image (very simplistic overview: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.skyatnightmagazine.com&amp;#x2F;astrophotography&amp;#x2F;astrophoto-tips&amp;#x2F;a-guide-to-astrophotography-stacking&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.skyatnightmagazine.com&amp;#x2F;astrophotography&amp;#x2F;astropho...&lt;/a&gt; .) Using image stacking and armed with accurate catalogs that predict precisely where every satellite will be at any time, enables the removal of satellites during the image stacking process. Or they can just use that information for better scheduling: wait a minute or two to image a particular spot, so there won&amp;#x27;t be satellites in the field of view.&lt;p&gt;The article definitely gets this part right:&lt;p&gt;&amp;gt; “Some astronomers see this as a true ‘hair on fire’ emergency, heralding irretrievable losses to space science; others present a more sanguine face, depicting this as yet another challenge to be surmounted in surveying a decreasingly pristine sky,” Koplow remarks.&lt;p&gt;Being involved in both space and astronomy plants me squarely in the latter camp. It takes a bit more work and software, but having so many satellites in space is a surmountable challenge for terrestrial astronomers. (Not to mention, these days some of the best astronomy is performed by telescopes in space, so astronomy overall benefits by having easier access to space.)</text></item></parent_chain><comment><author>gammarator</author><text>&amp;gt; They&amp;#x27;re wide field of view, long-duration exposures. That used to be the way astronomers imaged space,&lt;p&gt;Sorry, but one of the two example images (&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;noirlab.edu&amp;#x2F;public&amp;#x2F;images&amp;#x2F;iotw1946a&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;noirlab.edu&amp;#x2F;public&amp;#x2F;images&amp;#x2F;iotw1946a&amp;#x2F;&lt;/a&gt;) is a single 333-second exposure with a modern survey camera, the Dark Energy Camera.  This is not particularly long nor does it represent some outmoded observational strategy.  Large, wide-field imaging sky surveys (such as the upcoming Rubin Observatory) are among the highest-profile ground-based astronomy projects today.&lt;p&gt;Masking and stacking can mitigate the problem but it does not of course compensate for the lost area and sensitivity.  And the brightest satellites (like BlueWalker) saturate the readout electronics and spoil the whole exposure.&lt;p&gt;Narrow field instruments (such as spectrographs) have less geometric chance of seeing a satellite but tend to take longer exposures (tens of minutes), so there is a greater loss of telescope time when a streak does happen.&lt;p&gt;Even space telescopes are affected by streaks (&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.space.com&amp;#x2F;hubble-images-spoiled-starlink-satellite-steaks&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.space.com&amp;#x2F;hubble-images-spoiled-starlink-satelli...&lt;/a&gt;).&lt;p&gt;&amp;gt; It takes a bit more work and software&lt;p&gt;Equivalently, it takes more money and time.  That just means less science, given flat to declining funding from Congress.</text></comment>