Author Topic: ISS nighttime passes week of April 10-15?  (Read 1385 times)

Offline JAFO

  • Full Member
  • ****
  • Posts: 606
  • Liked: 248
  • Likes Given: 186
ISS nighttime passes week of April 10-15?
« on: 03/11/2018 09:44 PM »
Hi all,

None of the websites I've tried will give more than a 10 day forecast, but I'm trying to plan something and wanted ot see if the ISS was going to be overhead that week. Any suggestions?


TIA
Anyone can do the job when things are going right. In this business we play for keeps.
Ernest K. Gann

Offline AnalogMan

  • Member
  • Senior Member
  • *****
  • Posts: 3005
  • Cambridge, UK
  • Liked: 770
  • Likes Given: 23
Re: ISS nighttime passes week of April 10-15?
« Reply #1 on: 03/11/2018 10:19 PM »
Heavens Above will give you longer predictions:

http://www.heavens-above.com/PassSummary.aspx?satid=25544&lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT

Just use the < and > buttons next to the "search period end & start" dates section.

(You'll need to enter your preferred location from the one in the link above)

Offline JAFO

  • Full Member
  • ****
  • Posts: 606
  • Liked: 248
  • Likes Given: 186
Re: ISS nighttime passes week of April 10-15?
« Reply #2 on: 03/11/2018 10:57 PM »
Excellent, gave me exactly the info I needed. Will post what I'm doing if I get approval.
Anyone can do the job when things are going right. In this business we play for keeps.
Ernest K. Gann

Offline JAFO

  • Full Member
  • ****
  • Posts: 606
  • Liked: 248
  • Likes Given: 186
Re: ISS nighttime passes week of April 10-15?
« Reply #3 on: 03/12/2018 09:38 AM »
Followup question for ISS viewers:

Thanks to AnalogMan, we've determined the ISS will be making a pass right at the border of Civil/Nautical Twilight. In the opinion of NSF members, how easily can it be spotted in these lighting conditions?

TIA.
« Last Edit: 03/12/2018 09:38 AM by JAFO »
Anyone can do the job when things are going right. In this business we play for keeps.
Ernest K. Gann

Offline e of pi

  • Full Member
  • ****
  • Posts: 677
  • Pittsburgh, PA
  • Liked: 254
  • Likes Given: 337
Re: ISS nighttime passes week of April 10-15?
« Reply #4 on: 03/12/2018 12:43 PM »
Look at the magnitude rating Heavens Above gives it. It's like golf--lower is better/brighter, and every unit is a 2.5x increase. Thus, +1 is 2.5x as bright as +2, +0 is 6.25 times as bright as +2, -1 is 15.625 times, etc. It depends on lighting around your spotting location, though--not standing right under streetlights or looking right into the neighbor's Christmas lights helps a lot. The brightest stars in the sky range between -1 and +2 or so, so you can use how many stars you can see from where you're standing to guess what you'll be able to see in the sky that's man-made.

In my experience, anything above about a -1 is really easy to see. -1 to 0 is pretty easy but less spectacular, and +1 to 0 can be a little confusing. Sometimes I've looked right at it and spent half the pass trying to confirm I'm looking at the right thing, not a plane. +1 and below I've often had issues spotting at all in city lighting, and sometimes won't go out looking for unless there's something else brighter making a pass about the same time. Your eyes and mileage may vary.

Edited to correct magnitude factor--I was using my "it's about a factor of 2" rule of thumb which isn't technically correct.
« Last Edit: 03/13/2018 06:02 PM by e of pi »

Offline scienceguy

  • Regular
  • Full Member
  • ****
  • Posts: 760
  • Lethbridge, Alberta
  • Liked: 67
  • Likes Given: 132
Re: ISS nighttime passes week of April 10-15?
« Reply #5 on: 03/12/2018 04:44 PM »
https://spotthestation.nasa.gov/

It's NASA's spot the station page.
e^(pi*i) = -1

Offline Kansan52

  • Full Member
  • ****
  • Posts: 1119
  • Hutchinson, KS
  • Liked: 346
  • Likes Given: 398
Re: ISS nighttime passes week of April 10-15?
« Reply #6 on: 03/12/2018 04:53 PM »
My experience is that passes that go from 'corner to corner' (IE NW to SE) are easiest. They sometimes fade in or fade out. It moves quickly across the sky.

Offline John Santos

  • Member
  • Posts: 65
  • Liked: 24
  • Likes Given: 17
Re: ISS nighttime passes week of April 10-15?
« Reply #7 on: 03/12/2018 04:55 PM »
Look at the magnitude rating Heavens Above gives it. It's like golf--lower is better/brighter, and every unit is a 2x increase: +1 is twice as bright as +2, +0 is four times as bright as +2, -1 is eight times, etc. It depends on lighting around your spotting location, though--not standing right under streetlights or looking right into the neighbor's Christmas lights helps a lot. The brightest stars in the sky range between -1 and +2 or so, so you can use how many stars you can see from where you're standing to guess what you'll be able to see in the sky that's man-made.

In my experience, anything above about a -1 is really easy to see. -1 to 0 is pretty easy but less spectacular, and +1 to 0 can be a little confusing. Sometimes I've looked right at it and spent half the pass trying to confirm I'm looking at the right thing, not a plane.

1 magnitude corresponds to a brightness difference of the fifth root of 100, or a factor of about 2.5, not a factor of 2.

Offline Hog

  • Full Member
  • ****
  • Posts: 1245
  • Woodstock
  • Liked: 324
  • Likes Given: 969
Re: ISS nighttime passes week of April 10-15?
« Reply #8 on: 03/12/2018 08:25 PM »
Followup question for ISS viewers:

Thanks to AnalogMan, we've determined the ISS will be making a pass right at the border of Civil/Nautical Twilight. In the opinion of NSF members, how easily can it be spotted in these lighting conditions?

TIA.

It all depends on the brightness of the ISS when it passes in your area. 
The ISS doesn't get brighter than -3.9 for me when it passes directly over me at a range of about 408 kms.
Being able to see the ISS has more to do with its elevation above the horizon, hence distance, than it does with actual lighting conditions.  We don't know where you live so its tough to comment on what you will see.  So long as the Sun is under the horizon, you'll be able to see the ISS, esp. at closer distances.

I was able to see 2 of the last 3 Shuttle missions as separate entities with ISS, one before docking, and a direct overhead just after undocking.

On the 10th Ive got 2 passes at:
20:28hrs at -3.8mag  that passes directly over me at 408kms and is impossible to miss
22:06 at -1.0mag at it's closest is 1,386kms from me only second before it enters the shadow.

On April 11th there's only one
21:12hrs at -1.7

And no more visible passes until May 1st for my location.  I wish you clear skies.

Pics  All from Heavens Above
1) Ground Track of my -3.8mag pass April 10 1st orbit
2) The Space Track of the -3.8mag pass April 10  1st orbit
3) The Ground Track of the very next orbit which is a -1.0mag  Its a crappy pass for me, hit or miss for being visible, but may be great for most in the USA.  Next Orbit on the 10th
4) Ground track -1.7mag for me, but may be good for others.  April 11th

« Last Edit: 03/12/2018 08:30 PM by Hog »
Paul

Offline SWGlassPit

  • I break space hardware
  • Full Member
  • ****
  • Posts: 542
  • Liked: 392
  • Likes Given: 60
Re: ISS nighttime passes week of April 10-15?
« Reply #9 on: 03/13/2018 12:54 PM »
Look at the magnitude rating Heavens Above gives it. It's like golf--lower is better/brighter, and every unit is a 2x increase: +1 is twice as bright as +2, +0 is four times as bright as +2, -1 is eight times, etc. It depends on lighting around your spotting location, though--not standing right under streetlights or looking right into the neighbor's Christmas lights helps a lot. The brightest stars in the sky range between -1 and +2 or so, so you can use how many stars you can see from where you're standing to guess what you'll be able to see in the sky that's man-made.

In my experience, anything above about a -1 is really easy to see. -1 to 0 is pretty easy but less spectacular, and +1 to 0 can be a little confusing. Sometimes I've looked right at it and spent half the pass trying to confirm I'm looking at the right thing, not a plane.

1 magnitude corresponds to a brightness difference of the fifth root of 100, or a factor of about 2.5, not a factor of 2.

While the correctness is appreciated, when using it as a rule of thumb for naked-eye observation, calling it a factor of 2 is probably good enough.  We're talking about spotting the ISS, not taking astronomical measurements.

Offline e of pi

  • Full Member
  • ****
  • Posts: 677
  • Pittsburgh, PA
  • Liked: 254
  • Likes Given: 337
Re: ISS nighttime passes week of April 10-15?
« Reply #10 on: 03/13/2018 05:57 PM »
Look at the magnitude rating Heavens Above gives it. It's like golf--lower is better/brighter, and every unit is a 2x increase: +1 is twice as bright as +2, +0 is four times as bright as +2, -1 is eight times, etc. It depends on lighting around your spotting location, though--not standing right under streetlights or looking right into the neighbor's Christmas lights helps a lot. The brightest stars in the sky range between -1 and +2 or so, so you can use how many stars you can see from where you're standing to guess what you'll be able to see in the sky that's man-made.
1 magnitude corresponds to a brightness difference of the fifth root of 100, or a factor of about 2.5, not a factor of 2.
While the correctness is appreciated, when using it as a rule of thumb for naked-eye observation, calling it a factor of 2 is probably good enough.  We're talking about spotting the ISS, not taking astronomical measurements.
I'll take the correction, I was wrong, but that is indeed what I tend to use it for and why I probably remembered the factor of 2, not 2.5.

Offline JAFO

  • Full Member
  • ****
  • Posts: 606
  • Liked: 248
  • Likes Given: 186
Re: ISS nighttime passes week of April 10-15?
« Reply #11 on: 04/15/2018 04:05 AM »
Here's why I needed the info. The Sun n Fun airshow is unofficially claiming the World's Fastest, Highest, and Quietest Airshow Flyby tonight, when the ISS passed directly overhead between 2022-2027 during the AeroShell Aerobatic routine.
« Last Edit: 04/16/2018 12:32 AM by JAFO »
Anyone can do the job when things are going right. In this business we play for keeps.
Ernest K. Gann

Tags: