# interesting astronomy question **URL:** \ **Category:** Factual Questions\ **Created:** [January 28, 2005, 3:51am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049 "2005-01-28T03:51:45Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![teppink](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@teppink](https://boards.straightdope.com/u/teppink)\ **Post date:** [January 28, 2005, 3:51am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/1 "2005-01-28T03:51:45Z")
on dec 29,2004 i was on the continental divide just west of denver colorado at elevation ~11000ft at noon. i just happened to look up and i saw the sun and the moon almost next to each other in the sky. how was this possible? i cant figure it out. please enlighten me i would love to know. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [January 28, 2005, 3:56am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/2 "2005-01-28T03:56:45Z")
Unless I’ve erred, always a big chance, [this site](http://aa.usno.navy.mil/cgi-bin/aa_pap.pl) would suggest that the sun and moon were not in the sky at the same time on Dec. 29. > [@](#): > > Sun and Moon Data for One Day > The following information is provided for Denver, Denver County, Colorado (longitude W105.0, latitude N39.7): > > ``` > Wednesday > 29 December 2004 Mountain Standard Time > > SUN > Begin civil twilight 6:50 a.m. > Sunrise 7:21 a.m. > Sun transit 12:02 p.m. > Sunset 4:44 p.m. > End civil twilight 5:14 p.m. > > MOON > Moonrise 6:33 p.m. on preceding day > Moon transit 2:14 a.m. > Moonset 9:46 a.m. > Moonrise 7:35 p.m. > Moonset 10:15 a.m. on following day > > ``` ---
**Author:** ![Twoflower](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/twoflower/32/22_2.png) [@Twoflower](https://boards.straightdope.com/u/Twoflower)\ **Post date:** [January 28, 2005, 4:00am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/3 "2005-01-28T04:00:23Z")
Hmm … not sure what kind of mushrooms might be up that time of year in Colorado, but you must have found a good one! :rolleyes: ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [January 28, 2005, 4:00am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/4 "2005-01-28T04:00:46Z")
Sorry to have to say this, but the only possible explanation is that you were dreaming or hallucinating. As [this site shows,](http://www.luckymojo.com/moonphases.html) on that day, the moon was three days past full, and so was almost exactly opposite the sun, and wouldn’t have been visible at noon anywhere on earth. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 28, 2005, 4:10am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/5 "2005-01-28T04:10:05Z")
Not possible. The full moon was on Dec 26, 2004. On the 29th it was about 86% illuminated. The full moon is 180° away from the sun, and thus rises when the sun sets. The moon is only seen near the sun when it is very old (waning phase) or new (waxing phase) The moon moves about 14 degrees a day relative the sun, with it’s closest approach on the day of the new moon. Perhaps you saw a reflection in the window? ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [January 28, 2005, 4:21am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/6 "2005-01-28T04:21:56Z")
What you saw might possibly have been a [sun dog](http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/opt/ice/sd.rxml). ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [January 28, 2005, 6:15am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/7 "2005-01-28T06:15:09Z")
When the moon appears to be “next to” the sun, you can’t see it, because it’s virtually a new moon. The opposite side of the moon is illuminated, not the side facing you. This is why you don’t see the disk of the moon during a partial solar eclipse. You’re just seeing the absence of the sun in that area. ---
**Author:** ![EvanS](https://avatars.discourse-cdn.com/v4/letter/e/59ef9b/32.png) [@EvanS](https://boards.straightdope.com/u/EvanS)\ **Post date:** [January 28, 2005, 7:20am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/8 "2005-01-28T07:20:16Z")
> [@commasense](#): > > Sorry to have to say this, but the only possible explanation is that you were dreaming or hallucinating. As [this site shows,](http://www.luckymojo.com/moonphases.html) on that day, the moon was three days past full, and so was almost exactly opposite the sun, and wouldn’t have been visible at noon anywhere on earth. Sad that some people are so quick to pass derogatory judgement. Teppink, there’s lots of explanations for what you saw, not just the put-downs listed by **commasense** , who seems to think he/she has some preferential access to infinate knowledge. Unfortunately there are posters here who get a charge out of belittling others. They are thankfully a minority; get into the habit of ignoring them. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [January 28, 2005, 8:27am UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/9 "2005-01-28T08:27:54Z")
> [@EvanS](#): > > Sad that some people are so quick to pass derogatory judgement. What derogatory judgement? The OP could not have seen the moon next to the sun on that date; that much is fact. It’s also true that the moon would be almost invisible when it’s close to the sun, especially mid-day. It would be an extremely thin crescent, usually lost in the sun’s glare. I agree it may have been a sundog. I can’t think of a better explanation right now. It would help if the OP could explain how close the two were, and how the “moon” appeared (crescent or full, well-defined shape or fuzzy, any patterns on it, etc). Did this phenomenon last a long time? What was the weather condition like? ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [January 28, 2005, 12:36pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/10 "2005-01-28T12:36:12Z")
> [@EvanS](#): > > Sad that some people are so quick to pass derogatory judgement. > Teppink, there’s lots of explanations for what you saw, not just the put-downs listed by **commasense** , who seems to think he/she has some preferential access to infinate knowledge. Unfortunately there are posters here who get a charge out of belittling others. They are thankfully a minority; get into the habit of ignoring them. **EvanS**. You seem to know your way around the Board pretty well. If you wish to Pit a poster or Pit their position, take it to BBQ. This is inappropriate for GQ. **samclem** GQ moderator ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [January 28, 2005, 2:57pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/11 "2005-01-28T14:57:29Z")
Call my sense of humor dry, if you like, but I meant no “derogatory judgment,” and if any offense was taken, I apologize. ---
**Author:** ![Twoflower](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/twoflower/32/22_2.png) [@Twoflower](https://boards.straightdope.com/u/Twoflower)\ **Post date:** [January 28, 2005, 4:58pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/12 "2005-01-28T16:58:36Z")
I think we actually were rather kind. What \*\*teppink \*\* claims to have seen just plain wasn’t there. (Even if it was a sundog, they’re pretty hard to confuse with the moon.) Suggesting that he was hallucinating at least is giving him credit for having actually \*seen \*it, reagrdless of all rational explanations to the contrary. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 28, 2005, 5:09pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/13 "2005-01-28T17:09:01Z")
Well, I think at high altitude where there is little dust and other detrius in the air to scatter sunlight would permit the seeing of a thin crescent moon somewhere in the vicinity of the sun, as a WAG maybe 20[bup]o[/sup] away. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 28, 2005, 5:11pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/14 "2005-01-28T17:11:27Z")
What dumb SDMB software! It seems to me that it should certainly recognize [bup] as meaning [sup]. Let’s get with it Board managers! ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [January 28, 2005, 7:10pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/15 "2005-01-28T19:10:40Z")
> [@David Simmons](#): > > Well, I think at high altitude where there is little dust and other detrius in the air to scatter sunlight would permit the seeing of a thin crescent moon somewhere in the vicinity of the sun, as a WAG maybe 20[bup]o[/sup] away. But according to my link above, the moon had set at 09:46. The OP mentioned that he saw this apparition at noon. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [January 28, 2005, 7:55pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/16 "2005-01-28T19:55:33Z")
> [@David Simmons](#): > > Well, I think at high altitude where there is little dust and other detrius in the air to scatter sunlight would permit the seeing of a thin crescent moon somewhere in the vicinity of the sun, as a WAG maybe 20[bup]o[/sup] away. I live at sea level, and the thin crescent of the moon near the sun is often visible here. One just has to look for it (without staring at the sun). ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [January 28, 2005, 8:19pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/17 "2005-01-28T20:19:30Z")
Am I on _everyone’s_ ignore list? ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 28, 2005, 8:25pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/18 "2005-01-28T20:25:24Z")
> [@KarlGauss](#): > > Am I on _everyone’s_ ignore list? Mybe his watch was still on Eastern Std. Time. ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [January 28, 2005, 8:33pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/19 "2005-01-28T20:33:34Z")
According to the US Naval Observatory, > [@](#): > > Although the date and time of each New Moon can be computed exactly (see, for example, Phases of the Moon in Data Services), the visibility of the lunar crescent as a function of the Moon’s “age” - the time counted from New Moon - depends upon many factors and cannot be predicted with certainty. In the first two days after New Moon, the young crescent Moon appears very low in the western sky after sunset, and must be viewed through bright twilight. It sets shortly after sunset. The sighting of the lunar crescent within one day of New Moon is usually difficult. The crescent at this time is quite thin, has a low surface brightness, and can easily be lost in the twilight. Generally, the lunar crescent will become visible to suitably-located, experienced observers with good sky conditions about one day after New Moon. However, the time that the crescent actually becomes visible varies quite a bit from one month to another. The record for an early sighting of a lunar crescent, with a telescope, is 12.1 hours after New Moon; for naked-eye sightings, the record is 15.5 hours from New Moon. These are exceptional observations and crescent sightings this early in the lunar month should not be expected as the norm. The issue of how early in the moon’s orbit a new moon can be seen is of immediate and abiding concern to Muslims, because they use a purely lunar calendar, and the start of any given month and the dates of holidays, etc., are based on when the first crescent can actually be seen in a given location. It’s not sufficient to say that astronomically the moon has passed the exact point of being new; a crescent must be seen by someone. According to a couple of Muslim sites I have just found, the earliest at which a new crescent can reliably be seen seems to be slightly under 18 hours past the moment of conjunction. If you’re interested in learning more about this, just Google “earliest new moon visible” ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 28, 2005, 9:07pm UTC](https://boards.straightdope.com/t/interesting-astronomy-question/287049/20 "2005-01-28T21:07:33Z")
> [@KarlGauss](#): > > Am I on _everyone’s_ ignore list? Yup, you’re a message board of ONE! 🙂 [Next page](https://boards.straightdope.com/t/interesting-astronomy-question/287049.md?page=2)