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Was Sputnik Visible Naked Eye?

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#1 Cotts

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Posted 25 August 2007 - 08:57 PM

A friend of mine, not in the astronomy hobby in any way, claims he saw Sputnik as a child at summer camp in 1957. I do not remember seeing it and my suspicion is that the satellite was far too small (basketball-sized) to be visible and wasn't in orbit long enough for many people to potentially see it. I certainly remember seeing ECHO, the dozens-of-feet-in-diameter, shiny communication satellite in the early 60's. Perhaps my friend is remembering the fuss over Sputnik and the actual sighting of ECHO which was seen by millions of people. Can anyone recall what really happened? Thanks, d.c.

#2 b1gred

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Posted 25 August 2007 - 09:52 PM

Oh yeah, there were even parties to try to spot it... I remember as a little kid being scared that the satellites could see us through the roof.

#3 Carol L

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Posted 26 August 2007 - 03:05 AM

Yep, it was visible naked-eye. :D

I was almost five years old when Dad took us out to the local park (Chicago) to see it. There were a lot of people there, and naturally everyone was talking, so it was pretty noisy.

Then someone yelled "There it is!" and the park got as quiet as a church in about two seconds. It was weird to see a tiny light gliding across the sky, not making any noise or even blinking.. just silently scooting along, oblivious to the throngs of people watching it.

#4 bobalex

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Posted 26 August 2007 - 06:00 AM

I remember seeing it as it passed from SW-NE over my house when I was a kid. It fluctuated in brightness as it passed over, easily visible to the naked eye.

Bob

#5 KennyJ

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Posted 26 August 2007 - 08:12 AM

As a young boy , I remember the excitement associated with the launching of Sputnik One .

I don't think it was visible naked eye .

What WAS probably visible as a pulsating silver flash was it's 28 metre long third stage booster , which accompanied it for part of it's orbit .

Regards , Kenny

#6 oldsalt

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Posted 26 August 2007 - 10:19 AM

Definitely was visible naked eye.

#7 KennyJ

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Posted 26 August 2007 - 11:08 AM

Sputnik One was only the size of a basketball , and orbited the earth more than 150 miles above it .

It was almost certainly not Sputnik itself that could be seen -- it was the booster !

Regards , Kenny

#8 Cotts

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Posted 26 August 2007 - 11:20 AM

Sputnik One was only the size of a basketball , and orbited the earth more than 150 miles above it .

It was almost certainly not Sputnik itself that could be seen -- it was the booster !

Regards , Kenny


My thoughts exactly. Is there appropriate math available to determine the magnitude of an object the size of a basketball with an albedo of 95% (very shiny) flying 150 km above my head?
On Wikipedia it notes that Sputnik 1 was launched in October and stayed up a couple of weeks or so. Not visible form a 'summer camp' as my friend remembers.
But there were a number of Sputniks after #1 which were much larger, as much as 5000 kg, launched well into the 1960's.
Perhaps people saw these or their booster rockets as some have said.

#9 brentwood

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Posted 26 August 2007 - 11:50 AM

"I can remember watching Sputnik with my Dad, when I was a little boy"
Well there's another childhood myth shattered! I found this.
The Sputnik 1 rocket booster also reached Earth orbit and was visible from the ground at night as a first magnitude object, while the small but highly polished sphere barely visible at sixth magnitude more difficult to follow optically. Several replicas of the Sputnik 1 satellite can be seen at museums in Russia and another is on display in the Smithsonian National Air and Space Museum in Washington, D.C.

#10 KennyJ

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Posted 26 August 2007 - 12:10 PM

David ,

It was 150 MILES ( 240 kilometres ) above earth !

Regards , Kenny

#11 DblVision

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Posted 26 August 2007 - 12:38 PM

FWIW - I've tracked another, similar, sat from that period, when sats were each a "ball with antennae sticking out from it"... 20" diameter Vanguard II, ONLY with optical aid (Yes, it is still up there). If I remember right, that size was chosen so that the Baker-Nunn cameras would have a chance at it. It's been months since I've seen it, and seem to recall that the best pass was still in the Mag 8 - 9 range. Given that Sputnik I was similar in size...

#12 b1gred

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Posted 26 August 2007 - 01:17 PM

Ok, let's not argue about it, please folks.

It was a long time ago, and does it really make a difference?

#13 KennyJ

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Posted 26 August 2007 - 02:52 PM

< Ok, let's not argue about it, please folks.

It was a long time ago, and does it really make a difference? >

Randy ,

I for one am certainly not TRYING to deliberately come across as being " argumentative " as you put it .

You're right in a way of course -- it doesn't REALLY matter -- but then again , in the great scheme of things , neither do 95% of matters discussed on CN forums !

I just think it's an interesting thing to consider and discuss .

Resolving a sphere measuring just 23 inches in diameter from a distance of over 150 miles , by naked eye , is quite some accomplishment !

It's roughly the equivalent of resolving a golf ball from a distance of 15 miles , through naked eyes , or resolving a small peanut from a distance of 1.5 miles !

Would you not agree that is INTERESTING ?

Regards , Kenny

#14 b1gred

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Posted 26 August 2007 - 04:14 PM

It's not so much resolving the sphere, most of what we see of orbiting satellites is not "resolved", it's detecting the reflection of sunlight off a shiny object. Just like you may not 'see' the house 20 miles away from which you get a glint of sunlight reflected off the window, you still see the flash of sunlight.

With GEO satellites, you'll never 'resolve' the shape of the bird from 22600miles away, but the reflection of the sun off the solar panels or 'foil' that covers the surfaces is still visible.

Only the largest of satellites can actually be resolved (ISS, hubble and the Shuttle come to mind, but they're huge - even the shuttle is roughly the size of a DC-9, Hubble is the size of a railroad tank car) all the rest of what we see are generally just reflections of sunlight off a shiny surface.

Sputnik, as I said was a highly polished aluminum sphere, intended to be tracked visually as well as via radio from it's continuous 'beep, beep, beep', which indicated temperature and pressure within the satellite.

#15 David Castillo

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Posted 26 August 2007 - 05:47 PM

Say what you will. I was out in the street with a group of neighbors who all had the same visual experience: an object, very small and inconspicuous passing through a field of stars in the night.
------
Dave

#16 KennyJ

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Posted 26 August 2007 - 06:03 PM

< Say what you will. I was out in the street with a group of neighbors who all had the same visual experience: an object, very small and inconspicuous passing through a field of stars in the night. >

So was I -- except that , as I recall , it was very early in the morning , before dawn , and it seemed a VERY eerie experience to me as a five and a half year old , almost as if we had seen Father Christmas flying past with his reindeers !

Our village was a MUCH quieter place then , with no lights on the country lane we lived along , no outdoor lighting whatsoever , no motorways , no local brewery lit up like Blackpool illuminations and hardly any motor vehicles passing ( no - one within viewing distance of our house even owned a car , and the milk was delivered every morning from the local farm by horse and cart ! )

Regards , Kenny

#17 Bruce MacDonald

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Posted 26 August 2007 - 07:35 PM

I'm not doubting the reminiscences of some contributors here but the chances are that most observers saw the rocket body and not the payload in the case of Sputnik 1. As Kenny has pointed out, the R-7 rocket body was 28 metres long and 3 metres in diameter, compared with the payload which was a 58cm sphere (albeit a highly reflective one).


Given that the payload was on a 227km by 945km orbit, an observer would likely see the payload at a range of around 500km. The standard brightness of a satellite is defined as the brightness of a body 50% illuminated at a distance of 1000km. A 1m spherical satellite would have a magnitude of about +8.

At a rough estimate, with half that distance and half the size, and making allowance for the highly polished surface, it would not be unreasonable to say that Sputnik 1 had a brightness of mag +6 or thereabouts on a favourable pass, though mag +8 would be more typical. The rocket on the other hand would be mag 0.

Now, if I've got my figures right, that means that the rocket body was 630 times as bright as the payload (mag 0 compared to mag +8).

I hope this illuminates the discussion (pun intended :p)

#18 b1gred

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Posted 26 August 2007 - 08:09 PM

We're not going to resolve this argument.

Let's drop it, please.

RandyR - Moderator.

#19 Jimbo100

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Posted 27 August 2007 - 12:38 PM

We're not going to resolve this argument.

But perhaps we could see the sun's reflection off of it, ...hey Randy!!! :grin:

#20 Bruce MacDonald

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Posted 27 August 2007 - 01:26 PM

It doesn't matter if people saw the payload or the rocket body, they still saw a historic event - the first manmade objects placed into an Earth orbit. I would have loved to have seen that.

Remember that the rocket was satellite 1957-01A/00001.

#21 David Knisely

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Posted 27 August 2007 - 01:40 PM

I remember seeing it as it passed from SW-NE over my house when I was a kid. It fluctuated in brightness as it passed over, easily visible to the naked eye.

Bob


The actual Sputnik-1 satellite was just visible to the unaided eye, but it was actually fairly faint (6th to 7th magnitude), as the little ball was only about a two feet across (23 inches to be exact). The brighter object seen varying in brightness was the spent rocket body that launched the satellite. Clear skies to you.

#22 Rick Woods

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Posted 27 August 2007 - 03:38 PM

I remember as a little kid being scared that the satellites could see us through the roof.

Prophetic little tyke, weren't you?
- Rick

#23 JIMZ7

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Posted 27 August 2007 - 05:32 PM

I remember seeing Echo when I was young,but not Sputnik. Many of the people on my street saw a long fast bright meteor go by and they thought it was Echo. Well if it was then it took only 2 seconds to clear the sky. Of course it wasn't. I remember the newspapers gave times when it would cross our skies and I would get out my 60mm f/11.7 Tasco refractor and track it. Many neighbor's wanted to view it for themselves and found out even at low power it moves very fast! Nowadays I don't even try to look for satellites and they appear much too often either visually or through a telescope.

#24 PGW Steve

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Posted 27 August 2007 - 05:32 PM

This is interesting!!! I'm glad the question was asked, and there are people here that DID experience it. If it was a mag 6 object, and the skies back then were truely dark, not to mention it is easier to see a moving object as opposed to a stationary one, I believe it, all factors have to come into play.

#25 JIMZ7

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Posted 27 August 2007 - 05:51 PM

The sky was much darker back then and the "eyes" were much better.


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