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Bob
Bob Moler's Ephemeris Blog 
bob the open space night of the 27th was spectacular only problem i couldnt stay to see jupiter i felt like i was a 10 year old kid again im (59) ive been published in sky and telescope and astronemy for wide field pics and have had a few scopes in my day. i looked threw a 10 dob a little while ago and the view was awsome even my wife was impressed. i cant wait to look threw the 25 inch will you guys be back at the open space in september if so please let me no
Do you have a 2015 calendar and/or book ( like a farmers almanac) for purchase??
Bob-
I’m trying to help a friend find a star that was recently registered in honor of a loved one who suddenly passed away. The star is located within the realm of ursa major, outside of the bowl and towards the head of the constellation. If you have time, can you please direct me to a comprehensive and basic sky chart that I could use to find it this time of year? I understand conditions are not supposed to be ideal and the chances of me finding it are without a telescope are extremely slim, but I sure would like to try. Any help would be much appreciated; again at your convenience and thank you!
Hi Alisha,
I’m sorry, I cannot help you. None of the commercial star registries are official. The only official governing body for celestial nomenclature is the International Astronomical Union (IAU), and they don’t sell star names. You can go to http://www.iau.org/public/themes/buying_star_names/ where they cover the topic. Here is a quote from the page:
The easiest star charts to get would be to download Stellarium from http://www.stellarium.org and zoom in to Ursa Major. The star names for the brighter stars do display. Most are Arabic from 1,000 years ago and pre IAU. Click on a star and you will get a Hipparchos .catalog number (HIP xxxxxxx).
By the way the Big Dipper and Ursa Major is high in the northeastern sky these March evenings.
However – Keep looking up!
Bob
On the equinox is the sun up 12 hours all over the Earth? You said here day length would be 12h 6m on the first day of spring. How would it be at the poles? Is the “equinox”–“equal night” a misnomer?
The poles, are of course, an exception because they are on the axis of the Earth, so the Sun doesn’t rise of set as a consequence of the Earth’s rotation. On an equinox the Sun would rise or set due only to the fact that the Sun is moving north or south of the celestial equator. The other odd place is on the equator, in which every day is an “equinox” with 12 hours day and night.
At the poles would the sun travel around the horizon at the vernal equinox on March 20? In the North, it would continue to get higher in the sky as we progress towards the solstice, rising to be 23 degrees above the horizon at that time? In the South, it would disappear below the horizon tip September 20?
Your statements are pretty much correct. The last sentence, you don’t mean the south pole do you? If you do, then that’s wrong. At the south pole daylight starts on the September equinox. If you mean south as a direction, then remember from the north pole, all directions are south. One additional note though, the September equinox is generally on September 23rd. Due to the eccentricity of the Earth’s orbit, and the fact that perihelion, Earth’s closest approach to the Sun, is in early January; and aphelion is in early July, the Earth’s orbital velocity varies a bit, making summer longer by 4 days than winter in the northern hemisphere.
Thanks for the correction. I should have said that on or about Sept. 20, the sun would appear for the first time at the South pole and would get higher and higher in the sky until the December solstice.
Question: when is Venus at its brightest from earth? I know, at night. The outer planets would be brightest when nearest the earth and with the sun shining from over your back shoulder when viewing the planet, but Venus is farthest away when full, and is eclipsed when nearest? When in the arc does it reflect the most to us? (Does light shining through Venus’ atmosphere produce any rainbows for earth?
Hi Richard,
The point in Venus’ orbit is called greatest brilliancy. I googled: Venus greatest brilliancy to make sure. Venus does vary its distance quite a bit, from superior conjunction with the Sun, when its the farthest from us and full, to it closest at inferior conjunction, between the Earth and the Sun, when it shows a disk larger than Jupiter. However that disk is mostly unilluminated. Greatest brilliancy, according to what I read is the point that the illuminated part of Venus covers the greatest area of the sky. As a rule of thumb it occurs about 34 days before and again 34 days after inferior conjunction. It’s when Venus appears as a big crescent.
BTW: When Venus passes in front of the Sun, the event is called a transit, not an eclipse because Venus doesn’t appear large enough to cover the Sun. We recently had two, in 2004 and again in 2012. You won’t live long enough to see the next ones, which will occur in the 22nd century. Sometimes Venus can be photographed when it appears very near the Sun at inferior conjunction. Venus’ atmosphere is so thick that the thin crescent extends completely around the planet.
Keep looking up!
Bob
Question: On the equinox the sun rises due east and sets due west. After the vernal equinox the sun rises north of due east and sets north of due west. By the June solstice, how many degrees does it rise and set north of the east-west line? Would it be 45 degrees because we are on the 45th parallel?
Not quite. At the location I write the blog for, 44.75 degrees north latitude, the Sun rises and sets 35 degrees north of the east-west compass points on the summer solstice.
Even at the equator the sunrise/sunset point is 23.5 degrees north of the east-west compass points on that day. Just below the arctic circle near 66.5 degrees north on the summer solstice the sun will set then rise in the north, 90 degrees from the west and east line. It’s not a linear thing.
So at the arctic circle on the summer solstice if the sun rises and sets 90 degrees from the east-west line, that would mean that it touches the horizon due north when it “sets” and rises immediately from that point. Is that right?
I’m looking for the 2017 monthly Calendar of daily moon and sunrises and sets.
Rising and setting event times of the Sun and Moon are dependent on the location for which they are created. I have created such calendars, as tabular lists for several locations in the Interlochen Public Radio area. I only display moonrise or moonset, whichever occurs between sunset and sunrise, since these events are only visible at night. Go to http://ephemeris.bjmoler.org and click on Calendars. The 2017 calendars will be out near January 1st.
Bob, would you be willing to write a brief summary of the Jan 31, 2018 Blue Moon, Super Moon, Blood Red Moon, lunar eclipse, in just a few sentences, and be credited?
If so, we could post this in our Elk Rapids Almanac, next week, on website and in local Elk Rapids News, which has been running our postings for a year.
You can see what we do for almanac postings at http://www.greenelkrapids.org
This is just a personal request, so please send me a note with your thoughts.
We try to get people, especially students, interested in nature.
Many thanks. Royce Ragland, chair, Green Elk Rapids.
P.S. Is it possible we could get your group here for an outreach program and invite the whole village?
(And I used to be a dues paying member of the society.)
Hi Royce,
Sure, I’ll email you something tomorrow or Friday. About the possibility for the GTAS to come out for an outreach program, We’d be happy to discuss dates with you.
Actually that note was not meant to be a post, just a way to contact you with our request.
I was at the exact location of L&L in southern Illinois during totality of the eclipse. I drove there and set up cameras. I was also in the center of someone’s cornfield parked next to a set of suspicious (nasa) black vans… I got some really nice images of the stars, and am having trouble identifying one of the objects. I’m not an astrophysicist, Nor do I study quantum mechanics, But I have put in months and months of research into this and have tried my best to teach myself the calculations necessary to identify this object and am still not able to. I have all the calculations and even have images down to the second time stamp, if you could help me with this, I’d be happy to share my information with you as I think you’d be very interested in what I have found. I am stuck. But I wouldn’t have spent so much time on this little personal research project if I didn’t think it was relevant. I am a mother of 3, married, work a full time job in nursing, do photography on the side, and do alot of biblical research. Just ur average Joe blow. But this project has me restless and unable to sleep at night. I have purchased 100’s of dollars worth of sky maps and learning material trying to solve this…
Please email me.
Mrs.katieburris@gmail.com
Thanks.
Check my logic please: 1)There must be a boundary (albeit maybe in the 4th dimension) to the expansion of space. Because, otherwise, infinity would be expanding; which isn’t mathematically possible. 2) If you never can reach zero, in the same way you never can reach infinity, how can anything move if there is never an empty space to move into?
I’m not sure that I can check your logic. I’m not a cosmologist like Dr. Katie Mack @AstroKatie. I’m a mostly informally trained amateur astronomer. As I understand it, infinity isn’t a number. It means “without bound”. Whatever number you can imagine, you can always add 1 to it for a greater number. Or square it, or whatever. Space in our universe is not cubic meters of nothing. It has energy of its own, what is called dark energy, that actually accelerating the expansion of the universe. I’m probably wrong, since I don’t have the math to really understand it.
If there is an outside the universe, I assume it is truly made of nothing, really nothing, without bound. I’m not a fan of the multiverse. Please, one headache at a time. I don’t think that helped, but thanks for the query.