In this week’s discussion topic, I attempt to answer the question “Why are Uranus and Neptune distinctly bluer than Jupiter and Saturn?”
On Uranus and Neptune, the methane absorbs red, orange and yellow light, reflecting back the blue. In contrast, Jupiter and Saturn have only minor trace amounts of methane and quite a bit more hydrogen and ammonia.
Star gazing and planet seeking were not on my Friday night list of must do things. All I really wanted to do was relax after a long stressful work week. And for the most part I accomplished that goal. But I couldn’t resist the siren’s call of the seventh planet. I peeked out the back patio door after nine o’clock and noted the bright nearly quarter moon shining in the southwest. The skies were somewhat clear, not perfect, but better than last weekend by a long shot.
I went back inside and grabbed a folding table, my star charts, the binoculars and a portable battery that includes a bright red light I could set on the table to illuminate my maps. Oh, and my reading glasses so I could actually see said maps.
I took out my observing checklist that I prepared over a week ago for the dark of the moon weekend (the one where the skies remained hidden behind clouds). I had several stars I needed to locate. Using my Pocket Star Atlas and my binoculars, I got in the neighborhood, but the objects were too faint and my night sky not dark enough to find them. I decided to switch from stars to seeking the planet Uranus.
I looked east over the roof of my house. I could see the Great Square of Pegasus, but not a single star visible in the constellation Pisces. I needed to find those stars, or I would not be able to find Uranus. I also needed the stars to move westward a bit more to clear the roof and to get into the thinner atmosphere directly overhead.
I returned to the interior of the house, where Terry and I squeezed seven lemons and added some freshly made raspberry syrup to the blender to make some iced raspberry lemonade. Our initial taste testings resulted in a quite tart concoction, which we shelved it in the refrigerator to tackle again on Saturday.
I went back outside after ten o’clock and closely reviewed the special chart provided by Sky & Telescope via an article on one of their observing blogs entitled ‘Uranus and Neptune in 2012.’ I made sure to print that PDF (something I rarely do these days) and kept it close by both my binoculars and the telescope. Despite the fact that I could not see a single star in the constellation Pisces with my naked eyes, I forged ahead with my binoculars, star hopping my way to 44 Pisces and Uranus. For a good online article on how to use a star map at the telescope, check out this Sky & Telescope link.
Here’s a breakdown of the star hop that worked for me:
I followed these landmarks repeatedly with my binoculars. I got very good at this particular highway in the sky. Translating these landmarks, first to the finder scope and ultimately to the telescope’s eyepiece proved much harder. First, the field of view in the finder scope (9×50; 5 degree f.o.v.) appeared wider than my binoculars, which are 7×35.
According to the XT8’s Instruction Manual, both the finder scope and the view through the eyepiece of the telescope produce an image that is upside down. I guess I should be grateful that the eyepiece field of view is not also reversed, like it is in my ETX-90. My brain doesn’t have any trouble flipping what my retina receives around. I learned that trick years ago as a legal secretary, when I had to stand before my attorney’s desk and keep up with what he was discussing from the sheet of paper he was reading from in front of him. I can also flip things in a mirror with little difficulty. But doing both takes a bit more brain processing power.
When I looked through the finder scope at Alpha Pegasi, I had to keep reminding myself to go in the opposite direction I had with the binoculars. Even though the field of view in the finder scope seemed larger, my brain thought it was smaller (probably because I was only using half my eyesight). I finally got to my destination, 44 Piscium and, drum roll please, Uranus.
After visiting the seventh planet for a few minutes, I moved on to fishing for the eighth and final planet. With Pluto’s demotion to a dwarf planet, and being a native Kansan, I plan to follow in the footsteps of Clyde Tombaugh and eventually discover Pluto for myself. But for the moment, I needed to fish for Neptune in the constellation Aquarius.
I found the stars near Neptune easily with my binoculars. And the short hops with the finder scope proved easier than finding 44 Pisces and Uranus. But try as I might, I could not discern which faint star might have a twinkleless blue tinge. I couldn’t confirm I found the eighth planet, so I won’t check it off my list. I did feel satisfied that I could at least get to the neighborhood repeatedly, without referring to the star charts as often.
Midnight crept up on me and I marveled at how the time slips away from me when I’m stargazing. I hoped all my practicing would come in handy Saturday night, when I planned to pack everything in the van and make the trip south to Powell Observatory for some serious observing.
I am excited about the coming weekend. I love the switch from Summer to Autumn. But I’m delighted to make it a special occasion by finding and observing Uranus, thanks to it’s rare and unusual close proximity to a star of nearly equal brightness in the constellation Pisces. If I had very dark skies, I might be able to see the seventh planet without aid, but binoculars will help separate the planet from the star and a telescope at 100x magnification will show even more differences between them.
Despite a withering 103 degree temperature during the seven o’clock hour yesterday evening, I drug out my telescope and camera gear to the backyard in anticipation of an early evening planetary and lunar line-up. Terry grilled some chicken while I setup the scope, attached it to the portable battery and got the Autostar configured with the current date and time (almost straight up 8:00 pm). With forty minutes to go until sunset, I could clearly see the waxing crescent moon (see photo above), but the telephoto on my camera just couldn’t get me close enough to my lunar observing goal for the evening.
As I continue pursuing the Astro Quest observing award, created in 1995 by the ASKC Education Committee, I wanted to focus on the lunar section this month. The first item visible after a new moon happened to be the crater Hercules. Over the weekend, I researched all the lunar objects listed on the Astro Quest observing challenge, seeking images of the items first. I then determined I needed to find a lunar atlas. I have one for stars and deep sky objects (my handy Sky & Telescope Pocket Sky Atlas), but not a lunar one. Thanks to Google, I found the open source software called Virtual Moon Atlas, downloaded and installed it. I like it. The software makes it very easy to find features on the face of the moon and shows the current moon phase for my date/time and location.
I knew where to find the Hercules crater. Using my red dot finder scope, I honed the telescope in on the upper quadrant of the lit portion of the waxing crescent moon. Remembering to flip the image of the moon left to right in my head, I found the Hercules, and Atlas, craters easily. I spent several minutes using various eyepieces and barlows to zoom in for a closer look. I forgot to take a small portable table out with me to the backyard, so I didn’t have anything handy to take notes of my observations. I must get in the habit of doing this, if I plan to pursue other more stringent observing awards sanctioned by the Astronomical League.
I opted to mount my DSLR on the back of my telescope. I took a half dozen photos, none of which, upon downloading, were focused very well (grrrr). I selected the best of the bunch, cropped, labelled and uploaded it:
By this time, Terry had finished grilling supper, so I retired to the cool, air conditioned dining room to consume honey garlic grilled chicken and grilled Italian garlic bread with rice and Asian-style vegetables. He thoughtfully brewed some sun tea earlier in the day so I enjoyed two or three glasses of iced tea as well, knowing that I planned to return outside to the heat for more observing.
After dinner, I returned to the backyard, where I could now see Saturn, Spica and Mars, as predicted by various astronomy alerts I’d received earlier in the day. I captured the southwestern horizon at 9:30 pm in Lansing, Kansas from Astronomy magazine‘s StarDome Plus Java applet to share here. I could see another star, besides Spica, above Mars, but I’m not exactly sure which one in the constellation Virgo it might have been.
Before shutting down the telescope and returning the camera to it’s tripod, and a normal lens with a wider field of view, I turned the ETX90 towards Saturn for a quick look. I did take one photo of the ringed gas giant, which turned out better than I thought it would:
I also tried again to see the polar ice cap on Mars, but the ETX90 just couldn’t provide enough light or magnification (through the eyepieces and barlows I own) to get much bigger than the head of a pin. I could clearly tell I was not looking at a star and that the color reflected back to my eye was a ruddy orangy pink, but I could not discern any other features of the Red Planet.
The moon shone just a tad too bright to easily capture the fainter Saturn and Mars in a single photograph. Of the dozen or so shots I took with various aperture settings, shutter and film speeds, I only found one that appeared adequate:
By ten o’clock, I had all the equipment back in the air conditioned house. I had voluntarily sweated outside during triple digit heat for nearly three hours to make a few astronomical observations. I spent a few blessedly cool moments sitting in front of the fan before downloading, reviewing, editing and uploading the photos I’d taken. Soon after, I fell into bed (near eleven o’clock and two hours past my bedtime), but tossed and turned all night long. When the alarm sounded at five o’clock, I slapped snooze three times until it forced me awake at half past the hour.
Another day, a Tuesday this time, and another triple digit heat index predicted for the Heart of America. Autumn can not arrive too soon.