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I was taking a photo with the nikon D5600, of 2 people sitting on a bench. As you can see, there is the Moon in the background and a few stars. But what is the small line near the top ? I hope I am not seeing UFOs.

The photo details are

  • Exposure = 2.5 sec at F/5.0
  • Focal length = 18 mm
  • ISO 8000
  • Location GPS - 20°14'58.3"N 85°46'29.7"E
  • Date - 15.05.2021
  • Local time - 19:16:10

enter image description here

To get some idea, of the exact direction of that white light in the sky. I am including screenshot of a compass app placed at the exact same location where the 2 persons are sitting in the photo.

Also, by now i realise that this seems to not be a camera issue , but rather some satellite, and so may not be within the scope of photography stack exchange. So, it is okay , if the moderators want to delete this

enter image description here

enter image description here

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  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – AJ Henderson
    Jun 25, 2021 at 17:04

2 Answers 2

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Your camera's clock was likely off by about 2 minutes. But that is almost certainly the International Space Station.

Space Station Orbit Track

I used an iOS app named Orbitrack to find these. There are a LOT of satellites that show up in astrophotography images. The ISS is the brightest satellite because of the size of the solar panel arrays ... which reflect a lot of sunlight.

International Space Station compared to Soccer Field

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  • \$\begingroup\$ At its brightest, the ISS is certainly one of the brightest satellites. But if it is in the earth's shadow it's as dim as pretty much all of them. The angle of the solar arrays relative to both the sun and the observing position is another variable that can affect the magnitude a great deal. Distance above the horizon also affects apparent magnitude. \$\endgroup\$
    – Michael C
    Jun 22, 2021 at 20:20
  • \$\begingroup\$ @MichaelC it will fade and disappear as it enters the Earth's shadow. Brightness tends to vary based on the altitude above the horizon for that particular pass. A low pass (e.g. 10° above horizon) might be mag -1. A high pass (near zenith) might be mag -3.7. For comparison, the brightest star in the sky (apart from the Sun) is Sirius in the constellation Canis Major. It's approximately magnitude -1.5. Any pass where the station rises above 30° above horizon will almost certainly have a magnitude brighter than -2. It's easy to spot it as long as it isn't in Earth's shadow. \$\endgroup\$ Jun 22, 2021 at 21:57
  • \$\begingroup\$ Which is my entire point. It's not always the brightest satellite in the sky. Sometimes it's dimmer than another flying high overhead. \$\endgroup\$
    – Michael C
    Jun 23, 2021 at 16:51
  • \$\begingroup\$ @MichaelC when the ISS is 'dim' it's still around mag -1. Other satellites are typically between mag +5 to +6 (+6 is generally regarded as the limit of human vision -- people with really good eyes can see things a little dimmer, but that's not common). The magnitude scale is designed such that a difference of 5 points on the scale is exactly a difference of 100x brightness. (each 1 point is the 5th root of 100 or about 2.51x) This means when you compare a typical satellite at +5 to even a very dim ISS at -1 the ISS is still 100x brighter. \$\endgroup\$ Jun 24, 2021 at 17:53
  • \$\begingroup\$ When the ISS is in the Earth's shadow it's a lot darker than -1.5. More like 15 or 20. \$\endgroup\$
    – Michael C
    Jun 25, 2021 at 6:59
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Possibly a satellite flare. Some satellites have large light-reflective antennas and you can happen to be exactly where the sun is reflected to you for a short time (usually a few seconds). This is bright enough to be visible during the day if you look in the right direction. At night, it looks like the satellite (which is until then only faintly visible) switches on, then off a big search light. The Iridium satellites were infamous for this, astro sites such as heavens-above could predict when a flare would happen in your area. These specific satellites are being phased out but some still remain.

Another possibility: the ISS can also be bright enough to be visible during the day.

Using an astro site such as heavens-above, and entering time and location of observation can tell you which satellite that was.

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  • \$\begingroup\$ I tried that website. I could not find anywhere where you can enter a location and a time in the past. \$\endgroup\$ Jun 21, 2021 at 9:33
  • \$\begingroup\$ @silverrahul enter your location, then go to "Daily predictions for brighter satellites", change the date/time at the top of the page to when you took the photo, and then hit "Update". I'd also recommend selecting magnitude 3.0 or 3.5 so that only the very brightest passes are listed. \$\endgroup\$
    – Michael C
    Jun 21, 2021 at 10:14
  • \$\begingroup\$ @MichaelC Very interesting, I tried that . The only satellite that matches the time at that location is ISS, but it shows a brightness (mag) of -2.5 . Even though i had selected a minimum brightness of 3.0 . What does negative brightness represent ? \$\endgroup\$ Jun 21, 2021 at 10:25
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    \$\begingroup\$ Negative brightness is VERY bright. The brightest star in the sky, Sirius, is magnitude -1.4. The higher a magnitude number, the dimmer an object is. It's kind of like aperture. High number = dim. Low number = brighter. The full moon is about magnitude -12.5 when high in the sky. The Sun is -26.74 when high in the sky. \$\endgroup\$
    – Michael C
    Jun 21, 2021 at 10:41
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    \$\begingroup\$ If the ISS was at -2.5 in that part of the sky from your location at the time your image was taken, you've identified the object. \$\endgroup\$
    – Michael C
    Jun 21, 2021 at 10:45

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