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Dickenmeyer
2003-Jun-06, 04:24 AM
Took an hour or so last evening to do a little moonwatching, it was too hazy to do much of anything else. I spent most of my time scanning the terminator, there are always interesting things to see there, but just inside the scope's field of view there was a dim little star ( I don't know which one, the moon was in eastern Cancer or western Leo last night ). After watching for a while I realized that I could see the moon creeping towards this star and if I stayed at the eyepiece long enough the moon would occult it.
Just a few minutes later it was as though the star was perched right on the dark limb of the moon and then it was gone. It was somewhere around 10:30 EST (03:30 UT) but I don't know exactly, I wasn't wearing my watch.
A very interesting sight, I've never seen the moon occult a star before.

David Hall
2003-Jun-08, 12:20 PM
That's really cool. What do you estimate the star's magnitude to have been? Have you tried to use some kind of planetarium software to discover which star it was? I'm sure you could run the simulation through the hours you watched and see what occultation occurs.

dgruss23
2003-Jun-08, 12:28 PM
Occultations by the Moon are just plain cool!

Dickenmeyer
2003-Jun-11, 05:06 AM
That's really cool. What do you estimate the star's magnitude to have been? Have you tried to use some kind of planetarium software to discover which star it was? I'm sure you could run the simulation through the hours you watched and see what occultation occurs.
I don't have any planetarium software, but that's a really good idea. I've thought about getting Starry Night Pro at my local super giant AudioVideoComputerAppliance Mega Outlet Store but probably won't get around to it for awhile. I wonder if ALPO or anybody tracks that sort of thing? It was a pretty dim star even through my 8-inch scope, not naked eye visible under the sky conditions that night if ever, I can only see down to about mag 4 reliably from my home.

ToSeek
2003-Jun-11, 03:43 PM
I wonder if ALPO or anybody tracks that sort of thing?

I went to this site (http://www.lunar-occultations.com/iota/iotandx.htm), but nothing jumped out that sounded like what you saw.

David Hall
2003-Jun-11, 11:28 PM
I don't have any planetarium software, but that's a really good idea. I've thought about getting Starry Night Pro at my local super giant AudioVideoComputerAppliance Mega Outlet Store but probably won't get around to it for awhile. I wonder if ALPO or anybody tracks that sort of thing?

There are several good freeware programs available. Here's (http://www.seds.org/billa/astrosoftware.html) a good list. I recommend staying away from Starry Night Backyard, at least. They don't include any deep sky objects except the Messiers. That's pretty cheap (in the "poor value" sense) in my opinion.

David Hall
2003-Jun-12, 12:20 AM
(Ok, let's try this again).

I looked up your coordinates and put in the time you specified, and I came up with two possible candidate stars. Here's a screenshot of it:

http://www.occn.zaq.ne.jp/cuaea503/images/starcalcshot.gif

The most likely candidate is SAO98783, a magnitude 8 star that apparently was occulted at about 10:15pm. The other star, SAO98761 (mag 7.9) was just coming out of occultation at that time.

That is, unless I screwed something up again. I tried posting a few minutes ago, then realized I had put the wrong time into the program. (Edit, I may still be wrong. I'm not exactly sure I got the time shift from GMT right.) So I had to hurredly delete the post and start over. I hope it's right this time. :-)

Dickenmeyer
2003-Jun-12, 03:05 AM
I wonder if ALPO or anybody tracks that sort of thing?

I went to this site (http://www.lunar-occultations.com/iota/iotandx.htm), but nothing jumped out that sounded like what you saw.Yikes! A whole lotta info there. It looks like they are most interested in bright star occultations, I imagine the moon occults inconspicuous little motes with obscure catalog numbers too often for specialists to be interested in every one.

Dickenmeyer
2003-Jun-12, 03:13 AM
WOW David. :o That's some good detective work. The time and position of SAO98783 make it almost certainly the star I observed. Thanks for that list. I would agree if SN Backyard only has the Messiers then it's not giving good value to would be astronomers.

David Hall
2003-Jun-12, 08:36 AM
Minor Update. After getting a bit of sleep, I discovered that I did indeed fail to take DST into account (I was thinking that the program factored it in--it doesn't). So everything needs to be shifted back by one hour. That makes the one you saw SAO98761 instead.

http://www.occn.zaq.ne.jp/cuaea503/images/starcalcshot2.gif

So just think, if you had waited around for one more hour you could have witnessed two occultations!

Dickenmeyer
2003-Jun-13, 04:23 AM
Minor Update. After getting a bit of sleep, I discovered that I did indeed fail to take DST into account (I was thinking that the program factored it in--it doesn't). So everything needs to be shifted back by one hour. That makes the one you saw SAO98761 instead.
So just think, if you had waited around for one more hour you could have witnessed two occultations!
Not neccessarily, Indiana doesn't observe DST except for a few counties near Chicago and Cincinnati. The time here is always UT minus 5 hours. So, did you convert for DST on the first image or the second? Whichever one you didn't would be the correct one.

David Hall
2003-Jun-14, 11:27 PM
Ok, in that case the first one is the correct one, UT-5. Sheesh, I didn't know that about Indiana. I thought the only place in the US that didn't follow it was Arizona. :roll:

(Although, now that I think of it, it may have been mentioned before in one of the DST threads we had a while back. I can't remember for sure.)

Dickenmeyer
2003-Jun-16, 04:21 AM
No, the state legislature doesn't want to inconvenience the livestock so they have been very resistant to DST. Maybe they just can't bring themselves to commit to one time zone. Eons ago when I worked at Indianapolis Int'l Airport the company I worked for had to change the work schedule twice a year not because the airlines changed anything but because Indiana did not.

kilopi
2003-Jun-16, 10:53 AM
Eons ago when I worked at Indianapolis Int'l Airport the company I worked for had to change the work schedule twice a year not because the airlines changed anything but because Indiana did not.
The airlines must have changed to daylight savings time and back, right?

Dickenmeyer
2003-Jun-18, 04:29 AM
Everywhere in the civilized universe changed to DST and back so the net result for the airlines was ... zip. Their departure and arrival times for every city (except those in Indiana and Arizona) did not change so we quaint folk in our backwards little state had to do the compensating. It doesn't really matter for anyone not engaged in interstate transportation, except people who get upset when their cable TV programs jump back an hour earlier in the spring and then go on later in the fall. (The network affiliates started tape delaying everything an hour during DST about ten or twelve years ago so nobody would have to change their schedule to watch Matlock.)

kilopi
2003-Jun-18, 11:54 AM
Everywhere in the civilized universe changed to DST and back so the net result for the airlines was ... zip. Their departure and arrival times for every city (except those in Indiana and Arizona) did not change so we quaint folk in our backwards little state had to do the compensating.
That's an interesting way of looking at it. They did change--the flight that usually arrived at 8am CST would arrive at 8am CDT, or 7am CST. Either way, I'd say that was a change--especially since it's an hour earlier, by the Sun.

Dickenmeyer
2003-Jun-19, 03:27 AM
Well OK, if you look at it like that, it changed for us in Indiana, but practically everywhere throughout the system there was no need to change work schedules, arrival/departure tables or any of that stuff. It was transparent to the consumer and mostly to the industry all across North America. Except here.

kilopi
2003-Jun-19, 08:23 AM
Yep. Daylight Saving Time is a coordinated change--I was just surprised to see you characterize it as "not because the airlines changed anything but because Indiana did not". Of course the airlines changed--that's what "Spring ahead, Fall behind" is all about. They had to change their clocks. That is easier than changing their schedules--that's the whole point of DST. But they do change.

Dickenmeyer
2003-Jun-20, 04:17 AM
True enough, but frankly I'd rather change my clock twice a year and get on with life. It would seem a little wierd if we did start switching to EDT and there was still daylight at 9:00 PM though.

SeanF
2003-Jun-20, 02:29 PM
Yep. Daylight Saving Time is a coordinated change--I was just surprised to see you characterize it as "not because the airlines changed anything but because Indiana did not". Of course the airlines changed--that's what "Spring ahead, Fall behind" is all about. They had to change their clocks. That is easier than changing their schedules--that's the whole point of DST. But they do change.

Kilopi, Dickenmeyer never suggested the airlines didn't change. I think you're misinterpreting his quote. You're reading it as "the airlines didn't change" when all he said was "the airlines' change was not the problem."

kilopi
2003-Jun-20, 02:49 PM
Kilopi, Dickenmeyer never suggested the airlines didn't change. I think you're misinterpreting his quote. You're reading it as "the airlines didn't change" when all he said was "the airlines' change was not the problem."
Well, he did say that the change for the airlines was "zip". That's not true--changing clocks causes problems for one day each end (that's why they do it on Sunday), even in places outside Indiana and Arizona. Still, the problem is a combination of the two things. Saying the problem is with Indiana is a matter of personal preference--someone who disagreed with DST would say the problem lies with DST not Indiana.

My brothers used to live in Michigan and work in Indiana--which is even worse than just living in Indiana and having to endure the changes.

SeanF
2003-Jun-20, 03:13 PM
Kilopi, Dickenmeyer never suggested the airlines didn't change. I think you're misinterpreting his quote. You're reading it as "the airlines didn't change" when all he said was "the airlines' change was not the problem."
Well, he did say that the change for the airlines was "zip". That's not true--changing clocks causes problems for one day each end (that's why they do it on Sunday), even in places outside Indiana and Arizona.
He said the "net result" for the airlines was zip. If a flight during Standard Time leaves City A at 8:00 and arrives in City B at 10:00, then during Daylight Time it will still leave City A at 8:00 and arrive in City B at 10:00 -- unless one of the cities is in Indiana . . .

Still, the problem is a combination of the two things. Saying the problem is with Indiana is a matter of personal preference--someone who disagreed with DST would say the problem lies with DST not Indiana.
Hmm. The problem was that the rest of the country's clocks agreed with the airlines', but Indiana's didn't. I think that's why he considers the problem to lie with Indiana. If somebody from England comes over here and starts driving on the left side of the road, is it a matter of opinion to say the problem is with everybody else on the right side? :) {Yeah, I know, we're not talking about laws here . . .}


My brothers used to live in Michigan and work in Indiana--which is even worse than just living in Indiana and having to endure the changes.
And I didn't think there was anything worse than just living in Indiana. ;)

kilopi
2003-Jun-20, 03:29 PM
The problem was that the rest of the country's clocks agreed with the airlines', but Indiana's didn't. I think that's why he considers the problem to lie with Indiana.
I think you're right. But then, that's what I said before. A tiny group in Indiana (probably a few in the state legislature unless I miss my guess) disagree that it is Indiana's problem. :)

Dickenmeyer
2003-Jun-22, 12:21 AM
Sean basically got the point I was making, though I was simplifying the actual situation as kilopi noticed. It isn't that bad living here in Indiana, Sean, but I bet your skies are darker.

SeanF
2003-Jun-22, 01:51 AM
Sean basically got the point I was making, though I was simplifying the actual situation as kilopi noticed. It isn't that bad living here in Indiana, Sean, but I bet your skies are darker.

I hope you didn't take my comment about Indiana personally. I've never even been to Indiana - I just can't let a straight line like that go by. :)

The skies actually aren't that dark here in Sioux Falls - we've got a population of about 125,000, so there's a lot of lights. Further out to the west, though, it gets pretty dark.

Dickenmeyer
2003-Jun-23, 04:12 AM
No offense taken, Indiana isn't unpleasant but it is a bit quirky.