# What celestial object am I seeing? **URL:** \ **Category:** Factual Questions\ **Created:** [February 26, 2008, 7:01am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199 "2008-02-26T07:01:44Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![fifty-six](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@fifty-six](https://boards.straightdope.com/u/fifty-six)\ **Post date:** [February 26, 2008, 7:01am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/1 "2008-02-26T07:01:44Z")
I am at lat 59 in Homer, Alaska. About an 2 hours ago about SSE about 30 degrees up form the horizon I saw a very bright colorful twinkling star. Blue and red and quite large as far as stars go. I look at the sky a fair bit and up here this time if year stargazing. Plus I smoke so I go out regularly. I noticed it right away as something a bit different. So I went out and looked for it again on my next smoke break. The funny thing is that it is moving. Not fast like a satellite and not like a planet much faster than that, nor like an airplane to slow for that. The brightness is steady so that rules out aircraft I think. I would say it moved about 20 degrees across the sky in about 1 hour or so. I am not even really an amature I have some OK software and figure it to be somewhere in the vicinity of Sirius and will pass below Orion’s feet in about an hour. Thanks ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [February 26, 2008, 8:46am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/2 "2008-02-26T08:46:27Z")
If it’s moving, it’s not a star. It’s either a plane or a balloon or a high-altitude satellite. Most likely a balloon. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [February 26, 2008, 9:32am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/3 "2008-02-26T09:32:36Z")
According to [Nasa Live Tracking](http://science.nasa.gov/realtime/jtrack/Spacecraft.html) (warning: Java app on that page), the Chandra X-Ray satellite is above Alaska at the moment, and it’s got a [long elliptical orbit](http://www.src.le.ac.uk/projects/chandra/) around the earth, so wouldn’t move like regular orbital satellites. ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [February 26, 2008, 9:49am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/4 "2008-02-26T09:49:44Z")
[QUOTE=jjimm] According to [Nasa Live Tracking](http://science.nasa.gov/realtime/jtrack/Spacecraft.html) (warning: Java app on that page), the Chandra X-Ray satellite is above Alaska at the moment, and it’s got a [long elliptical orbit](http://www.src.le.ac.uk/projects/chandra/) around the earth, so wouldn’t move like regular orbital satellites. [/QUOTE] Cool. I never knew that page existed. I wonder what its observing… _goes off to check schedules_ 😃 ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [February 26, 2008, 9:51am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/5 "2008-02-26T09:51:39Z")
[QUOTE=Angua] Cool. I never knew that page existed. I wonder what its observing… _goes off to check schedules_ 😃 [/QUOTE] Hold on a minute… _I_ posted something about _space_ that impressed an _astrophysicist_!?!? ::Makes note in diary:: ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [February 26, 2008, 9:56am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/6 "2008-02-26T09:56:48Z")
[QUOTE=jjimm] Hold on a minute… _I_ posted something about _space_ that impressed an _astrophysicist_!?!? ::Makes note in diary:: [/QUOTE] 😛 Hey, its a big wide universe out there… 😛 Oh, and Chandra’s currently observing a spiral galaxy… ---
**Author:** ![Larry\_Griffin-Kentzel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/larry_griffin-kentzel/32/14787_2.png) [@Larry\_Griffin-Kentzel](https://boards.straightdope.com/u/Larry_Griffin-Kentzel)\ **Post date:** [February 26, 2008, 2:30pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/7 "2008-02-26T14:30:44Z")
Questions with factual answers belong in **General Questions**. I’ll move this for you. **Cajun Man** for the SDMB ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 26, 2008, 3:07pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/8 "2008-02-26T15:07:53Z")
Sirius should be about in the SSE at the time you went out. Some nights it looks incredibly bright and twinkly. [QUOTE=fifty-six] I would say it moved about 20 degrees across the sky in about 1 hour or so. [/QUOTE] That’s consistent with the object being Sirius. The ‘fixed’ stars move at 15 degrees per hour. That movement is more readily apparent for stars near the celestial equator, such as Sirius. [Trails of stars near the north celestial pole](http://www.definity-systems.net/~apw/astro/images/star_trails.gif) [Trails of stars near the celestial equator](http://apod.nasa.gov/apod/ap071208.html) ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [February 26, 2008, 4:18pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/9 "2008-02-26T16:18:22Z")
[QUOTE=Squink] Sirius should be about in the SSE at the time you went out. Some nights it looks incredibly bright and twinkly.That’s consistent with the object being Sirius. The ‘fixed’ stars move at 15 degrees per hour. That movement is more readily apparent for stars near the celestial equator, such as Sirius. [Trails of stars near the north celestial pole](http://www.definity-systems.net/~apw/astro/images/star_trails.gif) [Trails of stars near the celestial equator](http://apod.nasa.gov/apod/ap071208.html) [/QUOTE] I think you’re right. Alaska is GMT -9 hours, and so assuming a local time around 2000, then according to [Heavens Above](http://www.heavens-above.com/wholeskychart.ashx?lat=59.643&lng=-151.548&size=700&SL=1&SN=1&BW=0&time=54522.20833), Sirius would have been up, close to the horizon, and to the SSE (the big dot just under where it says Monocerus) ---
**Author:** ![KlondikeGeoff](https://avatars.discourse-cdn.com/v4/letter/k/3e96dc/32.png) [@KlondikeGeoff](https://boards.straightdope.com/u/KlondikeGeoff)\ **Post date:** [February 26, 2008, 4:40pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/10 "2008-02-26T16:40:10Z")
[QUOTE=fifty-six] Plus I smoke so I go out regularly. [/QUOTE] Er, just what were you smoking at the time? ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [February 26, 2008, 4:47pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/11 "2008-02-26T16:47:00Z")
Or you could install [Stellarium](http://www.stellarium.org/) and see what the sky actually was suppose to look like last night. Very cool application. ---
**Author:** ![fifty-six](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@fifty-six](https://boards.straightdope.com/u/fifty-six)\ **Post date:** [February 26, 2008, 5:26pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/12 "2008-02-26T17:26:06Z")
Thanks for the replies. I will pay more attention to Sirius and watch it’s movement in relation to the other stars. It could be as simple as that. It’s brightness and twinkling were impressive but its movement in relation to other stars is what lead me to post it eemed unusual _to me_. I like the idea of an elliptical satellite. ---
**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\ **Post date:** [February 26, 2008, 10:05pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/13 "2008-02-26T22:05:24Z")
You can also look at customized star maps at many websites. This is the one I use, but it requires free registration: [http://www.skyandtelescope.com/observing/skychart/](http://www.skyandtelescope.com/observing/skychart/) ---
**Author:** ![Troy\_McClure\_SF](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troy_mcclure_sf/32/4150_2.png) [@Troy\_McClure\_SF](https://boards.straightdope.com/u/Troy_McClure_SF)\ **Post date:** [February 26, 2008, 10:29pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/14 "2008-02-26T22:29:07Z")
It’s a farking streetlight. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [February 26, 2008, 11:14pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/15 "2008-02-26T23:14:38Z")
[QUOTE=Squink] Sirius should be about in the SSE at the time you went out. Some nights it looks incredibly bright and twinkly.That’s consistent with the object being Sirius. The ‘fixed’ stars move at 15 degrees per hour. That movement is more readily apparent for stars near the celestial equator, such as Sirius. [Trails of stars near the north celestial pole](http://www.definity-systems.net/~apw/astro/images/star_trails.gif) [Trails of stars near the celestial equator](http://apod.nasa.gov/apod/ap071208.html) [/QUOTE] But the part that doesn’t match the answer “Sirius” is the apparent movement across the sky _relative to the other stars_. I derive this apparent movement from the comment that the object was looking like it would cross under Orion’s feet in an hour or so. Still, I suspect it is Sirius. Likely, **fifty-six** simply thought there was relative motion when, in fact, there was not. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 26, 2008, 11:30pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/16 "2008-02-26T23:30:31Z")
[QUOTE=DSYoungEsq] But the part that doesn’t match the answer “Sirius” is the apparent movement across the sky _relative to the other stars_ [/QUOTE] It matches if he’s comparing a star near the celestial equator to a star near the pole. It’s an angular displacement, so you don’t notice polar stars zipping across the sky so much as equatorial stars. ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [February 26, 2008, 11:54pm UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/17 "2008-02-26T23:54:25Z")
[QUOTE=jjimm] Hold on a minute… _I_ posted something about _space_ that impressed an _astrophysicist_!?!? ::Makes note in diary:: [/QUOTE] It’s better than that - she’s actually got an observing run on Chandra coming up in the next few weeks and she’s now all enthusiastic about using that site to follow the satellite in real time as it takes her data for her.[sup]\*[/sup] I reckon you should try to wangle an acknowledgement in her next paper. \*[sub]Presuming she’s pointed it in the right direction.[/sub] ---
**Author:** ![jasonh300](https://avatars.discourse-cdn.com/v4/letter/j/46a35a/32.png) [@jasonh300](https://boards.straightdope.com/u/jasonh300)\ **Post date:** [February 27, 2008, 12:49am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/18 "2008-02-27T00:49:34Z")
[QUOTE=fifty-six] About an 2 hours ago about SSE about 30 degrees up form the horizon I saw a very bright colorful twinkling star. [/QUOTE] Doesn’t the **twinkling** part indicate that it’s a star? I always thought that a body such as a satellite or planet didn’t twinkle as the result of it being reflected light and stars have a pulsation that causes the twinkilng. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 27, 2008, 1:04am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/19 "2008-02-27T01:04:40Z")
Twinkling is caused by turbulence in the upper atmosphere. If it’s rough enough up there even planets will twinkle. ---
**Author:** ![aerodave](https://avatars.discourse-cdn.com/v4/letter/a/f08c70/32.png) [@aerodave](https://boards.straightdope.com/u/aerodave)\ **Post date:** [February 27, 2008, 1:50am UTC](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199/20 "2008-02-27T01:50:33Z")
Stars twinkle easier than planets because stars are so far away they are just points with next to no size. Planets may not seem any bigger to the naked eye, but in actuality they appear to observers on Earth as very small circles. That’s why you can magnify a planet’s image to a bigger circle, but a star still looks like a point under the highest magnification you can get. Since planets actually subtend a (albeit very small) angle in the sky, the diffraction caused by turbulence in the air has a chance to be averaged out out over the visible disk of the planet, so the total amount of light reaching the eye doesn’t vary much. Stars make a point so small that they can be completely distorted by the turbulent pockets of air between you and them. That’s why stars twinkle readily, and planets only twinkle when the air is a total thermal mess. [Next page](https://boards.straightdope.com/t/what-celestial-object-am-i-seeing/439199.md?page=2)