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Charlie in Dayton
2004-Apr-06, 12:59 AM
What am I doing wrong here?

Got the astro software fired up, and the consensus is that at the time I begin my search for Mercury, it ought to be about 15 degrees off the horizon (at least 10 degrees at worst case...)...that makes it a fist width plus up, out of the murk and clouds on the horizon into the blue...

Venus is an easy hit, and eventually Mars pops out about the same time the Pleiades do (funny, I don't remember things being that big...guess I gotta stop depending on this computer screen). I know my directions, so I'm looking the right way. Yes, I'm inside the 8th floor lounge here at The Major Midwestern Metropolitan College Of Higher Knowledge computer building, so I have an unobstructed view to the west for a good five miles to the high point on the western horizon...with minor twitching, I can tell the difference between something in the sky and internal reflections in the window glass...

I'm using my trusty dusty 10x50 binoculars. Like I said, the Pleiades and Mars are visible, Venus is a spotlight at sea, but Mercury is eluding me. I go up and start looking at about 830 eastern time. Too late?

I'm open to any and all suggestions. PlanetsVisible says I've only got the rest of this week to try and spot it before it sets too close to the Sun for me, and I'll have to wait until this summer...

It was easy to spot last time all five were in the sky...what's wrong now?

milli360
2004-Apr-06, 01:19 AM
I'm using my trusty dusty 10x50 binoculars. Like I said, the Pleiades and Mars are visible, Venus is a spotlight at sea, but Mercury is eluding me. I go up and start looking at about 830 eastern time. Too late?
Your post time says 7:59pm EDT--or has the server changed to DST yet? (Ed: yep! it hasn't)

Mercury, from Dayton, should still be high in the sky. You were probably looking for something a bit brighter than 1.5. Right now, it should be about a third of the way up to Venus, a little north.

JohnOwens
2004-Apr-06, 01:34 AM
Your post time says 7:59pm EDT--or has the server changed to DST yet? (Ed: yep! it hasn't)
Just a little technical note about BABB: The server always runs on GMT (or UTC, but close enough either way). The only reason it shows other times is because you have a time zone setting in your "Profile" information at the link up top.
On that note, it might be a good idea to remind everybody, in addition to setting your clocks ahead, you should also go to that "Profile" and change the "Timezone" setting by +1 (e.g., for PST -8 -> -7, MST -7 -> -6, CST -6 -> -5, EST -5 -> -4) if you want to be able to think of the BABB posting times the same as your regular, local daylight saving time.

Charlie in Dayton
2004-Apr-06, 01:40 AM
How interesting...JohnOwens' post wasn't there when I went to post this, but it showed on the 'topic review' scroller...

Anyway, by the time Mars and the Pleiades are visible in a pair of 10x50's, shouldn't Mercury be at least as bright/visible?

This is what's bugging me...I may have to start earlier and get a generous average for horizon elevation.

Hopefully I'll get lucky and the rest of the week will let me try again...

milli360
2004-Apr-06, 03:48 AM
On that note, it might be a good idea to remind everybody
d'oh, thanks for the reminder John

Anyway, by the time Mars and the Pleiades are visible in a pair of 10x50's, shouldn't Mercury be at least as bright/visible?
Mars and Mercury were about the same brightness, according to this software--but Mercury was closer to the sun and horizon so was probably more difficult to see. In general, my problem has always been I was looking in the wrong place. As soon as I looked in the right place, I was able to find it. Barring clouds. :)

Tobin Dax
2004-Apr-06, 04:12 AM
FWIW, Charlie, I was looking at Mercury last night and it was visible to me between 8 and 8:30 CDT. Mercury was pretty much no longer visible at 8:30, even with my binoculars. I recommend that you start looking at about 8pm.

Dax

Charlie in Dayton
2004-Apr-06, 04:29 AM
Okay...I'll cross my toenails that the skies will stay clear and I can break loose for a few minutes tomorrow nite at 8-ish...

milli360
2004-Apr-06, 08:12 AM
FWIW, Charlie, I was looking at Mercury last night and it was visible to me between 8 and 8:30 CDT. Mercury was pretty much no longer visible at 8:30, even with my binoculars. I recommend that you start looking at about 8pm.
That's the result of you living on the eastern edge of the central time zone and him close to the western edge of the eastern time zone. Charlie is in Dayton, which is around 87 longitude, and you are in Chicago right? about 84 longitude, so his view is only about three degrees different than yours--only about a fourth of a time zone. But he's on EDT, so his times for a particular view are almost a whole hour later. At 8pm CDT, for you, Mercury would be about 7 and a half degrees above the horizon last night. For him, Mercury would have had the same altitude at around 8:45 pm EDT.

Charlie in Dayton
2004-Apr-06, 09:16 AM
Observing location is within spittin' distance of:
39 deg 44' 17" N
84 deg 10' 3" W

I think ya mighta got us reversed there, 360 -- but you're onto something.

Dax, what's your longitude? For the moment, we'll take 360's observation as correct...you're around 87 deg W, 3 degs west of me. It takes four minutes to the degree for Earth's rotation, so there's only a twelve minute difference in astronomical rising/settings between us. Basing it all on UTC, Mercury sets twelve minutes later for you than for me, which pretty much matches 360's calculation of differences in observed altitude for the two of us.

Okay, there's some confirmation that my times of observation were a tad off.
The sun supposedly drops below the horizon at 8:07 tomorrow nite...Mercury should be 13 degs off the horizon at that time (call it a fist and a half). By 8:45, the elevation is down to just under 6 degrees (according to StarryNight)...okay, here's hoping the sky is clear and there's a student worker in here who can take over for a few minutes around 8 pm.

milli360
2004-Apr-06, 09:49 AM
I think ya mighta got us reversed there, 360 -- but you're onto something.
I did. Sorry, switch 87 for 84 and 84 for 87.


Dax, what's your longitude? For the moment, we'll take 360's observation as correct...you're around 87 deg W, 3 degs west of me. It takes four minutes to the degree for Earth's rotation, so there's only a twelve minute difference in astronomical rising/settings between us. Basing it all on UTC, Mercury sets twelve minutes later for you than for me, which pretty much matches 360's calculation of differences in observed altitude for the two of us.
I was using SkyMap for Dayton and Chicago, but Chicago is probably more like three and a half degrees farther west, which would bump it up to 14 or 15 minutes. And remember he's in a different time zone! :)


Okay, there's some confirmation that my times of observation were a tad off.
The sun supposedly drops below the horizon at 8:07 tomorrow nite...Mercury should be 13 degs off the horizon at that time (call it a fist and a half). By 8:45, the elevation is down to just under 6 degrees (according to StarryNight)...okay, here's hoping the sky is clear and there's a student worker in here who can take over for a few minutes around 8 pm.
Mercury was less than 16 degrees from the Sun, and only 1.5 mag. last night. A week ago, it was about 19, and brighter than mag. 0.0--much easier to see.

PS: My wife and I went out and caught Mercury about 8:15pm. The Sun had set at 7:42. The sky was still daylit near the horizon, and clouds were everywhere, but Mercury would peak in and out. Once I found it with the binoculars, I could see it naked eye. The stars of the Pleides were much easiier to make out, their background was much darker.

Charlie in Dayton
2004-Apr-07, 03:31 AM
Very cloudy tonite, absolutely hopeless...I have a feeling I'll have to wait until midsummer to see Mercury...I'm running out of time here...

Brady Yoon
2004-Apr-07, 04:01 AM
Mercury was less than 16 degrees from the Sun, and only 1.5 mag. last night. A week ago, it was about 19, and brighter than mag. 0.0--much easier to see.

Well, I guess one sighting is good enough. 8) When is it going to be easy to see again?

Tobin Dax
2004-Apr-07, 08:15 AM
Sorry for the lat reply, busy day. Googling tells me that Champign/Urbana is at about 88.2W longitude. So add a degree into 360's initial calculations. That's what, 15 or so minutes later (minus and hour)? And being as Mercury was visible here at about 8:15 (+/-10 minutes), that puts it at about 7:30 for you, Charlie.

Sorry for the confusion. I guess I've been here too long. After moving out here from Oregon two years ago, it was obvious that the sun set earlier. #-o

Charlie in Dayton
2004-Apr-07, 08:59 AM
Hmmm...didn't realize I'd have to go for it so early...thought things hadda be a bit later for the sky to dim enough to see it.

Well, I'm ready, come h3ll or high water...I can watch the sun go down with the new solar filters I finished tonite for my 10x50's (I gotta get a webcam and take a pitcher of these things...they look like the wrath of the deity of your choice, but the view is fantabulous), and look for Mercury using extreme caution not to set my brain on fire...

According to Planet's Visibility:

http://www.unavowed.net/charlie/VariousesForTheWeb/MercuryAll.JPG
Dates and times are Eastern Daylight/Standard for Dayton OH -- interpolate as necessary.

This is from a very neat little FREEWARE program called Planet's Visibility. It's one of several nice little astro programs available from Alcyone Astronomical Software ( http://www.alcyone.de/ ).
Planet's Visibility ( http://www.alcyone.de/PVis/english/ProgramPVis.htm ) will run on Windows 98, ME, 2000 and XP (I've run it myself on 2000 and XP machines -- no problemo). It's the tiniest bit light on documentation, but if you play with it for awhile and check out ALL the menu functions, eventually everything makes sense. It will display the data for the Galilean satellites of Jupiter, planets' rotation and illumination data...you can set it for your own lat/long and time zone...this program is definitely worth checking out...and like I said, it's FREEWARE!!!

I don't often drool over software, but Alcyone's got several definite winners here. The site's worth a detailed checkout...

milli360
2004-Apr-07, 02:13 PM
Well, I guess one sighting is good enough. 8) When is it going to be easy to see again?
Mercury returns to a similar configuration with the Earth about every four months. It takes 88 days to orbit the Sun, but the Earth moves on a little bit past that so it has to catch up. A couple months from now, it will be a morning star.

The Spring evening showings are some of the best, since the angle of the ecliptic is closer to perpendicular to the horizon at sundown. Similarly, the Fall morning showings are good--so look for it around Sep. 16 in the early morning when it will be mag. minus one, and up early before the Sun. You won't be able to miss it.

Sorry for the lat reply, busy day. Googling tells me that Champign/Urbana is at about 88.2W longitude. So add a degree into 360's initial calculations. That's what, 15 or so minutes later (minus and hour)? And being as Mercury was visible here at about 8:15 (+/-10 minutes), that puts it at about 7:30 for you, Charlie.
Other way! His clocks are later than yours, but he's almost in the same place. So, 9:00, but that seems late.

Hmmm...didn't realize I'd have to go for it so early...thought things hadda be a bit later for the sky to dim enough to see it.

Well, I'm ready, come h3ll or high water...
At least you weren't too late! :)

Wolverine
2004-Apr-07, 04:08 PM
This is from a very neat little FREEWARE program called Planet's Visibility.

It will display the data for the Galilean satellites of Jupiter, planets' rotation and illumination data...you can set it for your own lat/long and time zone...this program is definitely worth checking out...and like I said, it's FREEWARE!!!

Thanks for the heads-up, Charlie! Slick lil freebie indeed.