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Is STARLINK going to impact astrophotography?

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#126 freestar8n

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Posted 24 February 2020 - 03:02 AM

I am in Melbourne, Australia and I have used Heavens-Above and TheSkyX to observe many types of satellites over the years from around the globe: NY, Dublin, and now Melbourne.

 

It is often cloudy here and I have light pollution with approx mag 18.6 skies - so I have limited opportunities to look for particular satellite events.  But the ISS is always on target.

 

But I have made a number of attempts to observe what should be fairly bright starlink flyovers based on Heavens Above.  And I have yet to see a single one.

 

Maybe I am entering something wrong or the predictions are particularly volatile.  But I image on clear nights and track satellites with video fairly often - and the objects I choose tend to be where I expect them at the time I expect them.

 

But I haven't seen a single one of the Starlink satellites yet - despite trying.  Something to look forward to, I guess.

 

I haven't gone to a dark site to try to see them since the idea in threads like these is they are bright.  If they are as bright as the big dipper - they sure oughta be easy to spot even where I am.

 

Frank



#127 InFINNity

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Posted 24 February 2020 - 03:08 AM

Hi Thierry,

 

thanks for this update. Normally I would "Like" an informative post like this, but I am not sure if hitting that button sends out the right message this time... Once again: great job you did, that is the part I truly like! It is amazing that "Darksat" once again is not dark at all, or even better: it was the brightest of the pack. It is of course just the way the solar panels are oriented that makes them stand out in the night sky.

 

What was the sun's altitude during the exposure and what is the time-span we are looking at?

 

Passing on your work to Gallozzi e.a. has helped, your name is growing: https://www.cnet.com...ging-night-sky/

And I noticed your tweet on Musk's account, so he knows your work :-): https://twitter.com/...598015247536129

 

Nicolàs


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#128 t_image

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Posted 24 February 2020 - 07:28 AM

I am in Melbourne, Australia and I have used Heavens-Above and TheSkyX to observe many types of satellites over the years from around the globe: NY, Dublin, and now Melbourne.

 

It is often cloudy here and I have light pollution with approx mag 18.6 skies - so I have limited opportunities to look for particular satellite events.  But the ISS is always on target.

 

But I have made a number of attempts to observe what should be fairly bright starlink flyovers based on Heavens Above.  And I have yet to see a single one.

 

Maybe I am entering something wrong or the predictions are particularly volatile.  But I image on clear nights and track satellites with video fairly often - and the objects I choose tend to be where I expect them at the time I expect them.

 

But I haven't seen a single one of the Starlink satellites yet - despite trying.  Something to look forward to, I guess.

 

I haven't gone to a dark site to try to see them since the idea in threads like these is they are bright.  If they are as bright as the big dipper - they sure oughta be easy to spot even where I am.

 

Frank

I haven't bothered with h-a. I use the latest TLE's accessible but for the ones that haven't reached final orbit I don't expect a static TLE to be precise about targets that are currently dynamic.

Have you paid attention to which objects you've tried to see?

I have had an altogether different experience than your results.

My thought is your expectations for results based on your methods don't match the techniques needed.

 

I haven't gone to a dark site to try to see them since the idea in threads like these is they are bright.  If they are as bright as the big dipper - they sure oughta be easy to spot even where I am...

Again the understanding that a given type of satellite will pass on night x with a given brightness is not reasonable.

Try tracking the ISS over 20 straight nights and you'll see why.

Satellites are not stars with a basic fixed magnitude. Many on CN often have wrongly projected such idea onto satellites.

Sometimes they'll be within one's limiting magnitude, sometimes they won't be.

Details like pass position and Sun angle and observer position matter.



#129 freestar8n

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Posted 24 February 2020 - 07:37 AM

Hi t_image-

 

So although H-A works well for all kinds of things - it shouldn't be trusted for StarLink?

 

I have TheSkyX Pro - should I download the latest tle's from the web and use that?  Will that work?

 

I thought these things were pretty well behaved - especially shortly after a launch when they are all in a line.

 

In H-A I look at these long lists of passages and if a long run is brighter than mag 3 or so and high up - I assume I will see some.  That is from a prediction on the same day.  Is that not trustworthy at all?

 

Could there be something special about southern hemisphere?  Are others in Australia able to use heavens-above to see these things brightly and on schedule?

 

Frank



#130 Thierry Legault

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Posted 24 February 2020 - 09:16 AM

Hi Thierry,

 

thanks for this update. Normally I would "Like" an informative post like this, but I am not sure if hitting that button sends out the right message this time... Once again: great job you did, that is the part I truly like! It is amazing that "Darksat" once again is not dark at all, or even better: it was the brightest of the pack. It is of course just the way the solar panels are oriented that makes them stand out in the night sky.

 

What was the sun's altitude during the exposure and what is the time-span we are looking at?

 

Passing on your work to Gallozzi e.a. has helped, your name is growing: https://www.cnet.com...ging-night-sky/

And I noticed your tweet on Musk's account, so he knows your work :-): https://twitter.com/...598015247536129

 

Nicolàs

Thank you Nicolas! The altitude of the Sun was between -19° and -16° (close to astronomical twilight) and time span was 19 min


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#131 Thierry Legault

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Posted 24 February 2020 - 09:22 AM

 

Maybe I am entering something wrong or the predictions are particularly volatile.  But I image on clear nights and track satellites with video fairly often - and the objects I choose tend to be where I expect them at the time I expect them.

all footages of Starlinks I made were based on Heavens-Above predictions and all looked very accurate!


Edited by Thierry Legault, 24 February 2020 - 09:22 AM.


#132 dawziecat

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Posted 24 February 2020 - 01:50 PM

I have made no attempt to deliberately view any Starlinks. But I have noticed, what seems to me, to be a marked increase in tracks through my images these past couple of weeks!

 

Now, not to blame Starlink for the death of every sparrow that falls, perhaps NONE of these are Starlinks. I don't know. Making no claim to that effect. But there are a lot of them! I haven't "done the math" as to what the solar angle below the horizon was either. Here's an egregious example!

 

BlinkScreen.jpg

 

OK . . . I checked. At the time this 5 minute sub was taken, 22:41AST, Feb 20th, the sun was a full 49 degrees below the horizon! shocked.gif  This was what made me reluctant to think they even COULD be satellites at all, as I knew the sun was "long gone!"


Edited by dawziecat, 24 February 2020 - 01:54 PM.


#133 Thierry Legault

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Posted 24 February 2020 - 02:15 PM

I have made no attempt to deliberately view any Starlinks. But I have noticed, what seems to me, to be a marked increase in tracks through my images these past couple of weeks!

 

Now, not to blame Starlink for the death of every sparrow that falls, perhaps NONE of these are Starlinks. I don't know. Making no claim to that effect. But there are a lot of them! I haven't "done the math" as to what the solar angle below the horizon was either. Here's an egregious example!

 

attachicon.gifBlinkScreen.jpg

 

OK . . . I checked. At the time this 5 minute sub was taken, 22:41AST, Feb 20th, the sun was a full 49 degrees below the horizon! shocked.gif  This was what made me reluctant to think they even COULD be satellites at all, as I knew the sun was "long gone!"

if you aimed close to the celestial equator, it's probably geostationnary satellites (visible all night except during short eclipses around equinoxes)



#134 dawziecat

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Posted 24 February 2020 - 02:20 PM

Thanks, Thierry, but absolutely not! Markarian's Chain is near dec plus 55 degrees.



#135 555aaa

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Posted 24 February 2020 - 03:28 PM

I have observed several as part of developing my satellite tracking code. They are quite bright but as posted above it's not uncommon to have three magnitudes of brightness variation depending on the phase angle ( sun to sat to observer). Also for me, in winter, many passes cross into the earths shadow. When I say bright I mean maybe mag 3, going down to maybe 6.

Edited by 555aaa, 24 February 2020 - 03:34 PM.


#136 Francois

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Posted 24 February 2020 - 04:13 PM

OK . . . I checked. At the time this 5 minute sub was taken, 22:41AST, Feb 20th, the sun was a full 49 degrees below the horizon! shocked.gif  This was what made me reluctant to think they even COULD be satellites at all, as I knew the sun was "long gone!"

OneWebs are illuminated all the way to 49.5 degrees past the terminator. I'd guess those are possibly what you're getting. Incidentally, that's why I hate them more than Starlink.


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#137 t_image

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Posted 24 February 2020 - 05:44 PM

Hi t_image-

 

So although H-A works well for all kinds of things - it shouldn't be trusted for StarLink?

 

I have TheSkyX Pro - should I download the latest tle's from the web and use that?  Will that work?

 

I thought these things were pretty well behaved - especially shortly after a launch when they are all in a line.

 

In H-A I look at these long lists of passages and if a long run is brighter than mag 3 or so and high up - I assume I will see some.  That is from a prediction on the same day.  Is that not trustworthy at all?

 

Could there be something special about southern hemisphere?  Are others in Australia able to use heavens-above to see these things brightly and on schedule?

 

Frank

Hey Frank,

Thanks for the followup and interest. I'm a fan of h-a, not saying it would be in reliable.

What is key is to define which specific starlinks we are talking about.

initially after launched they are sent out in a tight string. Until each reaches final orbital position (orientation, altitude, spacing from adjacent sl's in orbital plane, they are 'on the move' in contrast with sats in stable orbit)

My point is, like a police chase of a suspect vehicle, the radioed position is only helpful until the suspect vehicle moves again.

One sat in a plane of sats spreading out from each other by raising altitude might be 'more on schedule' than others from the same launch......

Note not all will move at the same time,either.

TLE's are helpful for objects in stable orbit.

The fresher the TLE source, similar to the fresher police chase update call.

I challenge anyone to claim all starlinks are in stable, final position.

Looking at plot of recent TLEs this is obviously not true.

They are in various states,

So it is not helpful to speak of them as all the same.

I have seen h-a,calsky, and space-track have different epoch tles for the same sat at the same time, so just saying sometimes especially in deploying sats, 'freshness' can be an issue.

Best practice is be early and wait after allowing for variance, also allowing for a shift in pass position, allowing for orbit residuals.

 

You might look at sl numberings,notice which launch associated with, etc.

Cheers!



#138 freestar8n

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Posted 24 February 2020 - 06:16 PM

Thanks t_image and Thierry. I will give h-a a try again when clear. There are many bright star links in each daily list of bright satellites so I sure should be able to see one if they are real.

Frank

#139 t_image

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Posted 24 February 2020 - 06:41 PM

Thanks, Thierry, but absolutely not! Markarian's Chain is near dec plus 55 degrees.

 

Hmm,

I plate solved,

And the trails are parallel but 20 degs off the geobelt (not geos),

Not consistent w starlink orbital planes nor one web sat plane.

Maybe artifact of plane pass. Top and bottom trails are suspiciously the same as far as 3 trail spacings.

IDK........



#140 Thierry Legault

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Posted 25 February 2020 - 01:00 AM

 

Maybe artifact of plane pass. Top and bottom trails are suspiciously the same as far as 3 trail spacings.

 

 

I think you're right it's probably airplanes following the same air corridor, closer examination shows regular flashes along the trails!



#141 dawziecat

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Posted 25 February 2020 - 09:19 AM

Think I agree that it's aircraft. Not sure why there seems an increase in activity though. Of course, I am not outside at the 'scope watching and only see these things well after the fact.



#142 InFINNity

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Posted 03 March 2020 - 05:36 AM

There is an interesting development: Russia's Academy of Sciences will complain to the United Nations about the light reflected from the Starlink satellite system.

 

In addition NASA Wants You to Photograph Starlink Satellites With Your Smartphone.

Nicolàs


Edited by InFINNity, 03 March 2020 - 05:45 AM.

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#143 reddog1972

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Posted 03 March 2020 - 03:57 PM

Use Kappa Sigma Clipping during stacking - should take care of the starlink problem.



#144 Jon Rista

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Posted 03 March 2020 - 05:55 PM

Use Kappa Sigma Clipping during stacking - should take care of the starlink problem.

Maybe. We'll see when there are 42,000 of them up there. And another 10,000 more from Amazon, and another 5000 more from OneWeb, and...... 

 

And pixel rejection is only an option for stacked images. What is going to happen to all the wide field milky way photography? Meteor shower photography? Comet photography? It's going to be a disaster...


Edited by Jon Rista, 03 March 2020 - 05:56 PM.

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#145 Lucullus

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Posted 03 March 2020 - 06:09 PM

How long until Facebook, Twitter, Apple, and Alibaba publish plans of similar constellations?!!



#146 fate187

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Posted 04 March 2020 - 12:58 AM

I think I will employ sigma clipping with my eyes during visual observation. I guess I have to blink with a certain frequency thinking1.gif .



#147 catalogman

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Posted 04 March 2020 - 01:23 AM

How long until Facebook, Twitter, Apple, and Alibaba publish plans of similar constellations?!!

 

Not long at all, unfortunately:

 

https://www.wired.co...rnet-satellite/

 

https://www.popularm...ellites-iphone/

 

--catalogman

 

<insert down vote here>



#148 Lucullus

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Posted 04 March 2020 - 03:49 AM

I had a thought. Someone somewhere in the web stated that he/she loves astronomy, but is not arrogant enough to weight astronomy higher than good internet access to poor communities. This made me think - together with the statement of someone that the net benefits of better education for those might result in a profit for astronomy...so or similar was that statement.

Here's my thought as a compromise, not so much concerning astronomical observations but concerning education vs. capitalism: what if we had those constellations, or at least only one or two, but that or those companies are forced to grant absolutely free access to all developing countries?

Not in the sense to be contra capitalism at all costs, but in the sense as to show capitalism that there are, or at least should be, limits to making profits above everybody's heads.


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#149 freestar8n

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Posted 04 March 2020 - 03:59 AM

A little update from me.  I have had a few nights to try to observe 3+ mag passes nearly overhead and still haven't seen any.  I'm not trying to be careful or look exactly in the right spot at the right time.  I just use heavens-above to find some of the brighter and higher passes for the evening and look for them around the right time.  It's intentionally crude just to gauge how intrusive they are at this stage.

 

At this point I still haven't seen any Starlinks.  So I will aim to ramp things up and do it more carefully just to make sure I see one of these - or a series of them.

 

Much darker skies would clearly help a lot - but if these are high up in the sky and 3-ish mag then they should be pretty easy to notice.

 

I took the extra step of downloading TLE's and importing them into TheSkyX Pro to make sure the passes agreed at least roughly with what heavens-above was saying - and they did appear consistent.   So I don't think I'm doing anything dumb about my coordinates or something in the HA interface.

 

Frank



#150 555aaa

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Posted 04 March 2020 - 01:48 PM

A little update from me.  I have had a few nights to try to observe 3+ mag passes nearly overhead and still haven't seen any.  I'm not trying to be careful or look exactly in the right spot at the right time.  I just use heavens-above to find some of the brighter and higher passes for the evening and look for them around the right time.  It's intentionally crude just to gauge how intrusive they are at this stage.

 

At this point I still haven't seen any Starlinks.  So I will aim to ramp things up and do it more carefully just to make sure I see one of these - or a series of them.

 

Much darker skies would clearly help a lot - but if these are high up in the sky and 3-ish mag then they should be pretty easy to notice.

 

I took the extra step of downloading TLE's and importing them into TheSkyX Pro to make sure the passes agreed at least roughly with what heavens-above was saying - and they did appear consistent.   So I don't think I'm doing anything dumb about my coordinates or something in the HA interface.

 

Frank

I was using TheSkyX the other night for finding satellites including Starlink and I noticed that it lets you download the updated TLEs and it plots the passes nicely but it's not very obvious when the satellite is in the earth's shadow. It seems to happily plot satellites that are shadowed (eclipsed) by the earth and I don't know how to suppress this. In my copy of TheSkyX (the pro version) you have to select the satellite and then scroll down on the info window on the side and there is a flag that is a "1" or a "0" to tell you if it's eclipsed by the earth or not (would much prefer "Y" and "N" to "1" and "0"). Most passes later in the evening are eclipsed and many are eclipsed for part of their pass. I seem to recall that PRISM draws a line across the sky for the pass and they change the color of the line when the satellite is shadowed but frankly I can't get this to work consistently.

 

Maybe someone here can help me / us out and is there a tool that can give you all the passes for the evening which are not eclipsed so you can actually plan stuff out. Does heavens-above do this?

 

They're up there, Frank. Trust me. I agree that they're not that intrusive presently. But there sure are a lot of them even now.

 

-Bruce




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