SVC Tip #6 - Preferential treatment!

March 7th, 2020

As you may have figured out by now, I have been using Sky View Cafe for quite a while. Occasionally, I find something new (or quirky) so I thought I would bring a few things to your attention.

First, I like to set the calendar tab as my default view since I want check the moon phase and to choose the day first anyhow. This can easily be done using the blue button up on the right hand corner marked “More …“. When you click it, you get … more (of course), including a set of “preferences”, Just select the little gear icon and click. The second field allows you to set the Default view. Easy.

Next, I found a couple of quirks, one being that even though there seems to be some printer settings I have had no luck with any printing feature at all. So, you may have to look for other tools for this. Finally, even though the built-in Help is really good, you may need help finding it. The help link up in the right hand pane seems broken. So, instead, use the Help ? link up in the very top center or the one in the More … button. Viola! More easy!

I hope you are enjoying SVC as much as I am. If so, check out the other tips here SVC Tip #1 & SVC Tip #2 & SVC Tip #3, SVC Tip #4 and Tip #5.

Viewing the Lunar Straight Wall

February 29th, 2020

One of the interesting aspects of observing our Moon is that many features are only visible during certain times within the full cyclic phasing of the moon. Details come and go depending on the angle of sunlight reflecting off the lunar surface and coming back to Earth. As Galileo noticed over 400 years ago, the shadow line (known as the Terminator) moves across the lunar landscape and illuminates the surface differently as it progresses across. He even used this phenomena as a tool for measuring the height of lunar features.

One such detail that is only revealed at two specific times in the cycle is the so-called “Lunar Straight Wall“. This feature is one of the best examples of a linear fault, also called a rille. When you’re looking anywhere near Mare Nubium, it’s quite prominent as an almost straight line. However, it turns out that it is easy to see ONLY on the first day past 1st Quarter or 3rd Quarter. The reason why it’s only visible around this time is because of the shadow that it casts when struck with the sunlight at just the correct angle. For the rest of the month, it’s virtually hidden because it doesn’t create a good shadow.

I have found several references online, like the one from Wikipedia in my previous post. The Lunar Straight Wall is also known by it’s Latin name Rupes Recta. I’ve included another link below from Sky and Telescope magazine with more great images of the feature. Here, lunar observing authority Charles Wood has a great article about Rupes Recta with some very fine images of this feature.

You can find it easy enough with a small telescope of perhaps 50 mm or more. That also puts this object within reach of binoculars though you’ll need to steady your hold by bracing against something or using a tripod. Use the resources above so you know where to find it and look for it on the day after first quarter or third quarter. That’s only two nights per month, making it a little more precious of a view. So, for the next two months, those dates are - March 3 and 17, April 2 and 15 and May 15, and a bonus view on May 30.

Good luck with the weather! Clear Skies! (hopefully)

Gauging the sky with the Great Dippers

February 7th, 2020

This time of year is a great time to reconnect with The Big Dipper in Ursa Major and it’s cousin the Little Dipper, in Ursa Minor. Even though Daylight Savings Time is going push dusk well into the evening, you will still be able to follow these great asterisms into early night as they climb over the trees.

As twilight progresses after sunset, the individual stars of the celestial bears gradually come into view. The brighter stars appear first of course, but the main stars in the Big Dipper are within a fairly small range of magnitude - about 1.8 down to about 2.4. In order of magnitude, you have Dubhe, Alioth, Alkaid, Mizor, Merak, Phecda. Megrez, where the handle connects to the bowl is 3.3 magnitude, but still bright enough to catch in suburban skies.

If you can see all of the Big Dipper, then you should be able to easily see Polaris at the end of the Little Dipper. It’s the brightest star in the constellation. You will also be able to see the end of the bowl of the dipper and the next brightest stars Kochab and Pherkad. The remaining stars are dimmer than 4.3 magnitude so they are much dimmer than most suburban nights will allow. But you never know your luck!

If you create a chart with these two constellations and write in the magnitudes, you will have a very useful reference to use to gauge the sky. Wikipedia has good information on all the constellations and the Celestial Bears are no exception. Follow the links below to get a lists of these stars with their magnitudes and charts that you can print to make a field reference - Big Dipper & Little Dipper. As with all the Wikipedia constellations pages, there’s also a lot of detail on the mythology and star lore of the heavens.

The Winter Hexagon

January 30th, 2020

The shortened days of the winter months grant an extra chance to get out under the stars. Even with cold weather forcing star gazers to “rug up”, there are at least several objects that appear early enough in the evening such that you don’t have to brave the chill for too long into the night. A great circle of stars known as the Winter Hexagon appears overhead in the early evening forming a ring connecting a grand collection of constellations.

Starting with Sirius, the brightest star in the heavens, we can work around counter clockwise to Rigel, Aldebaran, Capella, Pollux, and Procyon. These are all prominent stars whose brightness shines through even a light veil of clouds. The circuit takes in the major constellations of Canis Major, Orion, Taurus, Auriga, Gemini and Canis Minor.

These stars range in magnitude from -1.5 with Sirius down to Pollux at mag 1.1. So, they are peeping out early and high overhead this time of year. As the night deepens, one can easily make out the figure of Orion, easily spotted by it’s belt of three stars. The ring of Auriga is usually next to become clear, forming it’s own circle of stars. The triangle of the face of Taurus slowly takes shape as the great expanse of the Big Dog about Sirius moves up into the southern sky like a big meat cleaver.

All these objects shine through even moderate light pollution. So, whether you’re in the suburbs or the country, you can practice your geometry using these fine beacons of the winter night, as in six, half dozen or the other! Enjoy!

Astronomy in the Suburbs - Spring 2020 Class

January 21st, 2020

I am pleased to announce that I will be teaching the astronomy class again at Emory Continuing Education this coming March. This is a four week, two hour each Wednesday evening session under the title “Astronomy in the Suburbs - An Introduction to Stargazing”.

If you are interested in attending or know someone that may want to take such a class, you can go to the information page on the class. There is a charge for this class from Emory and I cannot provide any discounts. But I think it still good value as these classes go and you’ll be well prepared by the end!

If you wish to write me directly with questions about the class, send me an email.

Moon tools Pt 1 (The Intro)

December 16th, 2019

I’m a tool kinda guy. You know .. Swiss Army knife, a good flashlight, some vice grips, and, of course, a good astronomy app. Web based tools and apps for astronomy and stargazing are really the good stuff. This series is going to delve into various tools I’ve found on the web that help understand our moon better. This is part one, which, implies additional parts, theoretically. So, we’ll see how my research goes and how many tools we find.

Bar none, my favorite web site is still Sky View Cafe (SVC). You can see some of my other posts with details on the features, but my main tip here is to set your SVC startup view to be the calendar instead of the default Sky view. This is easy to do using the “More…” button up in the right corner.  Click on more and then on Preferences. Change the second setting value to Calendar and then click OK. This will set the applet to go to the calendar whenever it starts. From here, the moon phases are in full display with a graphic for each day.

In one of my previous postings, I featured an animation to show the Moon orbiting the Earth. This is a great applet from The University of Nebraska that has three different views of the effect of lunar phases from Earth’s perspective. At the same website, I also found a really useful animation that shows how the effect of the moon’s gravity and our proximity to the sun sets up the tides.

See how far you get with these suggestions. You can even howl if you like!!

Planning on Venus - pt2

November 28th, 2019

In part one of this post, I described the basic use of Sky View Cafe for planning your viewing of Venus this summer. I hope you’ve had a chance to see our sister planet off in the west after sunset. Now, I wanted to show how this internet tool can be used to generate an ephemeris. By definition, this is a chart or table of times at a regular interval with the positions of objects in the sky.

You can use this table to plan your siting of Venus (or any other object) by time, RA/Dec, azimuth and altitude. I find the time azimuth and altitude numbers most useful since they allow you to determine where to look by the compass bearing, then the angle up from the horizon.

In order to generate a simple 1 week ephemeris with SVC, first connect to the web site and set your coordinates or use the city list. Then set the time of day for the approximate time of sunset. That time will be good for the upcoming week, more or less. Then select the “Tables” tab from the main display. Within the tab there are three drop down lists. These run across horizontally across the top of the tab space. At the far right is a button labeled “Generate Table”.

In the first list, choose “Ephemeris”. In the second one, choose “Venus” (of course!). In the third list, I suggest starting by choosing “1 week/1 day”, but you can experiment later once you’ve got the hang of it. Finally, click on the “Generate Table” button and you get a nice text list. The columns in the list give you the date, RA/Dec, Azimuth, Altitude, Visual Magnitude and Illumination Fraction. Now you have a planning tool for your observations for the next week. If you want to make additional lists, choose from the top three drop down lists and you can keep adding text to the work area.

Finally, I suggest making yourself a planning sheet. First, use the button at the lower right labeled “Copyable Text”. This places the text you just generated into a clipboard space you can copy from into a new document for printing. The text workspace can be copied using your mouse pointer to select it, then paste it into your favorite editor or word processor. You can clean up the text and even add more text as you generate new tables. When you have a nice neat list of items in your table, print it out as a field reference.

Happy planet hunting!!

Planning on Venus - pt1

October 31st, 2019

Our sister planet Venus has returned in the western sky for 2019 and into 2020. She will be with us for a number of months. This post will be the first one to discuss observing Venus this summer but the topic has been a favorite of mine for a while now. I first discussed the phases of Venus earlier this year and you might want to revisit the links on that previous post. Today, we’ll start by just finding Venus using our naked eye vision.

When planning your viewing of Venus, it’s helpful to use some kind of tool ahead of time to give you an idea where to look. You can start with a graphic view using one of my favorite tools - Sky View Cafe. For the task of spotting Venus, I first open the Sky tab, then select “Horizon - 45 Span” from the options. This reduces the size of the view of the sky, magnifying your field of view. Move the view to the west by dragging it with a mouse or by selecting a specific direction. Venus will be in the northwest for the coming weeks and arcing back up and south as the summer progresses.

Give the graphic view of the sky a try online first. You can roll the date and time back and forth and thereby determine when you will get the best line of sight from your vantage point. Also study how the twilight darkens the sky day by day. Once you get an idea where Venus will be in your field of view, then you can adjust the time and direction of this graphic view. Experiment with the best settings and then print it out as a field reference.

Good luck in your search. I’ll be back in a couple of posts with some more suggestions. We’ll make an ephemeris so you can see the progression of Venus day by day. I’ll be working through that set of steps in part two. Using that data, we can begin to further explore the phases of Venus through a small telescope, just like Galileo did!

Saturn is back for 2019

July 9th, 2019

Saturn is back and easy to find in the southeastern sky, a little east from the handle of The Teapot in the constellation Sagittarius. In the telescope, the planet’s pail yellow color is a easy to detect and fun to compare to the brighter hues of Jupiter to the west.

The ringed world has been getting higher in the sky daily, making for better views each week. This apparition, the rings are around 24 degree tilt, a little less than last year but still looking very impressive. The Cassini division is still easy to make out with much of the rings face still exposed.

We have been getting better and better views of the ringed planet through Fernbank’s 36 inch Cassegrain. Even early during twilight, we can begin to pick out Titan and the other moons quite easily.

There will be plenty of opportunities to catch the Lord of the Rings between now and early November.

Jupiter’s 2019 return!

June 10th, 2019

Another year here on Earth and another orbit around the sun. And another chance to “catch up” with Jupiter in its orbit. The King of our Solar System is hovering just east of Antares in Scorpius for the coming months.

We will get a good line of site on Jupiter at Fernbank Science Center (FSC) in June, although its still quite low in the evening sky for the coming weeks. But not to worry, there’s plenty of time since our largest planet will be visible through late October, at least. Every week, Jupiter climbs about 6 degrees higher in the eastern sky so each night we get a better chance for views through a ever thinner atmosphere. By mid August, the reverse will happen and the planet will be working its way down to the west each night.

The weather has been more and more challenging this last couple of years. It’s not just cloud but also more windy weather so the seeing has not been compatible with good views of the Great Red Spot (GRS). When the atmosphere is stirred up even on these breezy days, the fine highlights get smeared and hard to focus. But you never know your luck with Jupiter. If one is vigilant, sometimes the King reveals wonderful details of it’s clouds and their structure.

Keep your lucky charms handy and keep your eyes upward towards Jupiter, King of our Solar System!