Constellations III: Of the Summer Triangle

Click to see the full-sized hi-res image!

A few days after I searched for Pluto, I chose to forgo my telescopes for one clear evening and play with my digital camera.  The Summer Triangle is straight up in the evening sky right now for several hours after sunset.  As Jack Horkheimer used to say, “Keep looking up.”  This time, take his advice literally and you will see the magnificent asterism defined by the stars Altair, Deneb, and Vega.

This image was taken in a similar fashion to my prior wide-field constellation pictures, like Leo, where I took dozens of light, dark, and bias frames and then created a composite in DeepSkyStacker.  For this new image, though, I went a step further.  I have been searching for a way to accentuate the stars based on their brightness, short of manually blowing them up.  I believe I have uncovered a technique to get the desired effect.  You can easily make out the three main stars along with other stars/patterns in descending order from their apparent magnitudes.

I must admit that I was mildly shocked at how many stars are shown.  Are those really stars, or image noise?  As the images were taken straight up, to the darkest part of the sky, it seemed plausible.  Also, the Milky Way runs right through the Summer Triangle.  You cannot see the Milky Way in my picture, as I don’t think it is possible to capture in my light-polluted area without longer exposures and an equatorial mount.

In checking as many detailed online star charts as seemed reasonable, I do believe those dots are all stars!

Remember that an asterism is a pattern of stars, versus a constellation, which is a generally accepted “official” pattern.  The Summer Triangle is an asterism (a triangle, duh) but it has several constellations in and around it.  How many constellations can you see and name in this picture?

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My Hunt for Pluto, Part II: The False Star

Figure 2.1: My sketch of the area surrounding Pluto on September 14th, 2017.

“I really want to try to find Pluto again one more time this season…If I do get a chance, I will post a follow-up next month.” – Me, August 29th

With the Moon safely out of the way and a clear sky opportunity available, last week I resumed my quest to find Pluto.  Much of this post relies on information from my first attempt last month, and so I will be referring to that post frequently.

Recall that I leveraged the easily recognized “teapot” asterism in the constellation Sagittarius to star hop over to the approximate location of Pluto.  The main anchor star in the area of Pluto, both last month and now, is Albaldah.  Albaldah and a few nearby neighbors are the last stars I can see unaided.  So targeting Albaldah with my telescope was the first order of business.

The journey past Albaldah was guided with the help of both the Stellarium app on my tablet as well as my prior post.  I should note here that the “app” version of Stellarium is far less detailed than the PC version when investigating such faint objects in small spaces.  Further, based on my two observation sessions, I now believe there is an error in the PC Stellarium map, which I will explain in a moment.

Using the same 2″ Q70 eyepiece as last month, I quickly found HIP 94372, the 6.35 magnitude “mini-anchor” star near Pluto visible only with my telescope.  From HIP 94372 I located the 8th-magnitude star pattern I nicknamed k-lambda, assuring that I was in the correct vicinity.

At this point I was aggressively looking at the images from my prior blog post, the Stellarium app, and my telescope eyepiece.  I decided early on that it would be best to switch to a higher magnification than the 2″ eyepiece allowed, so I changed to my 1.25″ 14.5mm Planetary.  This eyepiece illuminated a much clearer view around HIP 94372.

Then I began sketching, referring to Stellarium only to assure that I was still in the location I wanted to be and drawing at the correct perspective size.  In my drawing above (Figure 2.1) it is difficult to see which stars are faint and which were really faint to the point that averted vision was necessary to see them.  The three stars I labeled as #1, #2, and #3 were the brightest, forming a triangle.  The three arcs were the approximate boundaries of the eyepiece.

With my sketch partially done, I had to make an assumption – that the small star close to HIP 94372, identified only by the Stellarium PC version, does not exist.  This probably threw me off last month, at least a bit, in determining if I truly had seen Pluto.  It is listed at magnitude 9.10, which should be easily visible, especially at the higher magnification I was now using with the 14.5mm eyepiece.  A 9.10 star should only be slightly dimmer than k-lambda, as well as the three stars forming the main triangle in my sketch.  And the few stars I drew around HIP 94372 are extremely faint, well past magnitude 9.  So either this star does not exist or its magnitude is incorrect in Stellarium.

Figure 2.2: Is this star really there?

Returning to the Pluto hunt, I knew it should be located within the three-star triangle I sketched.  In the figure below from Stellarium, I edited out the false star, as well as flipped the image to correspond to what I drew at the telescope that night.  Pluto is represented as a very, very tiny dot:

Figure 2.3: Pluto and surrounding stars as shown by Stellarium for September14th, 2017.

Remember, again, that most of these stars are very faint.  To help gauge where Pluto might be, I imaged a micro asterism forming a dipper or serpent, which starts at the star HIP 94338:

Figure 2.4: Identifying the serpent and “bright” stars.

I could see this dipper easily at the telescope so long as I knew where HIP 94372 was.  I also knew, then, that Pluto had to be just below (actually above, but the telescope reverses the image) this dipper and between HIP 94372 and HIP 94338.

Did I actually find Pluto?  I identified, at the telescope, three possible candidates, all hard to see without averting my eye a bit.  That night while still at the telescope, I drew an arrow pointing to the one I thought was most likely.  The other two candidates were to the right, the nearest dots above and below the one pointed to by my upward sketched “likely Pluto” arrow (see Figure 2.5).

Here is my sketch again, this time with the serpent/dipper lined, the three bright stars circled in orange, and the dot most likely to be Pluto, as determined afterward by comparing to both versions of Stellarium (iPad and PC):

Figure 2.5: My sketch with the most likely candidate for Pluto circled in yellow.

The best way I can confirm/reconfirm which dot was Pluto would be to sketch the area around HIP 94372 once Pluto has moved significantly.  Unfortunately by next month (after the next Full Moon passes), Sagittarius and Pluto may be too low in the sky for me to draw again, mostly due to the impacts of light pollution as they near the horizon.  And so, true final confirmation may have to wait a good seven to nine months, as the Earth and Pluto revolve around the Sun, beckoning the dwarf planet back into our East sky by late Spring 2018.

Alternative Moon Perception

The Moon…as you have never seen it before!

This is the exciting finale to a trilogy of posts about my August 30th Moon adventures.  The first showed the Waxing Gibbous Moon from that night.  The second explored several of the Moon’s craters.  And now here is the story of what came next.

As I finished up my astrophotography for the evening, I detached both the camera and eyepiece setup from my Dobonsian’s focuser.  I had, just moment before, been taking my last pictures, so the Moon was still in the telescope’s field of view.  With the focuser empty, I noticed the very bright light emanating through, like a flashlight.  This was, obviously, the Moon’s light still reflecting from the primary mirror, off the secondary, and through the focuser hole.

I have observed this “flashlight” before, but usually considered it for only a moment as I would be in the process of packing up my equipment for the night.  But on this pleasant evening for the 30th day of August, I decided to play with the light a little.  I put my hand in front of the focuser and could see the blurry image of the Moon upon it.  Moving my hand around allowed me to focus the Moon, directly on my hand.

I thought this was the end of the exercise.  But when I put the dusk plug back onto the focuser, Moonlight was still shining, this time through the translucent plastic.  It is a very simple cap, and if you are unfamiliar with these telescope dust plugs, they look like this.

Adjusting the focuser allowed me to bring the Moon into focus, right on the cover of the dust plug.  It was a strange sight.  It reminded me of the small view screens that attached to some home film projectors in the 1970s.

The Moon, but not the Moon.  Quickly I detached my smartphone from its mount and took several pictures of the phenomenon.  The above is one of those images with only minor post-processing.  The diagonal streaks across the Moon are the grains of the dust plug’s surface.

I got a lot of value out of that Moon observing session.  Right now, the Moon is waning and nearing the next New Moon.  Unfortunately my weather forecast is cloudy through the weekend; I want to get back out there and find Pluto one more time this year.

One More Name Change

For the last few weeks since I changed my display name, I noticed that it was too long to fit in many of the standard field sizes we are accustomed to.  I thought about shortening it by simply dropping “Backyard,” but that made the name too common.

So I came up with a slight variation that still has strong roots in the blog, and manages to be comfortably shorter.

As last time…same blog, same author, new author name!

Discovering the Moon’s Craters

Section of the Moon on August 30th, 2017.

When I photographed the Moon on August 30th, I felt now was a good time to start examining it at a closer level.  Having only attempted crude drawings of craters previously, I wanted to see how high I could push the magnification of my Dobsonian reflector.  So I replaced the 17mm Plossl eyepiece used for the full disc image with a 7.5mm and Barlow lens to see what I could get.

(I should note here that I was using my smartphone for pictures, hence the afocal method of putting the camera directly to the eyepiece.)

With that telescope, this eyepiece setup magnifies about 333 times!  Although well within the theoretical maximum for a 254mm aperture, it does present challenges with the atmosphere and, closer to home, vibrations when attempting to get a steady photograph.  Many of my attempts came out motion blurry.

The situation presented itself as the ideal opportunity to study the Moon map that came with one of my equipment orders last year.  This particular section of the Moon is near its Southern pole.  At first, I had no idea what I was looking at, as the map and my image appear a tad different due to shadows.  Plus, there are a lot of craters, too many to count!

To pinpoint these specific craters and determine their names, I performed a modified approach to star hopping, but of course for the Moon.  Checking the map, I first leveraged the easy large Mare in the North, then from there simply hopped from large crater to large crater, until I arrived at the location of my picture.

In learning these names and locations, I was humbled to realize how little I know about the Moon.  I have taken lots of pictures for over a year but have never studied the surface.  How does the saying go…I hear but I do not listen?  Surely this is the equivalent for sight.

My embarrassment started when I had no idea the famous Tycho crater is sitting right there in my picture.  It has that internal shadow with a center protrusion.  Below Tycho, the largest crater shown is Clavius, a name I know I have heard before.  It has several smaller craters within.  Maginus and Moretus are also visible.

Here is the same picture, this time with the craters labeled:

This exercise has kindled a desire for me to learn more about the Moon and truly see it in all its amazing detail.  I now know and have seen four craters.  Hundreds more are out there waiting!

Better Than a Quarter Moon

Click for the hi-res image.

August 30th, 2017, 8:59 p.m. local time

Me: “Wow, such an amazing Moon tonight!  I should get my telescope or at least digital camera to take some pictures.”

Me Too: “Well, since you did only a smartphone capture last night, let’s drag the big telescope out for this one.  Even I have to admit this is too good of a Moon to waste.”

Me: “Great!”

Me Too: “Ok.  Just make sure you produce something fantastic worth both our time.”

Two Sides of the Quarter Moon

August 29th, 2017, 7:10 p.m. local time

Me: “Wow, that’s a great looking Quarter Moon tonight!  I should get my telescope or at least digital camera to take some pictures.”

Me Too: “You’re pretty tired.  Are you sure you want to lug all that equipment outside?  Plus, it’s a work night.”

Me: “How about a compromise: I’ll go get my smartphone and snap a few images?  That will take hardly any time at all.”

Me Too: “Ok, deal, but you’re cooking dinner tonight.”

My Hunt for Pluto!

On the evening of Friday, August 25th, 2017, I decided to take my homemade 10-inch Dobsonian out to my back deck.  The Moon was still young, so the sky would be fairly dark a few hours after sunset.  Paired with surprisingly cool August temperatures, it looked to have the makings of a great stargazing night.

It had been weeks since I last used the big “light cannon.”  A combination of summer temperatures and humidity, all sorts of nighttime bugs, and the pre-eclipse fervor put my normal telescope usage on hiatus.  I planned out what I wanted to see, leveraging Sky Map.  The star clusters in Sagittarius seemed like good targets, followed by other deep sky objects like the Ring Nebula.  And oh yeah, Pluto is in the sky, so for kicks I put it on the list as well.

I started around 10:40 p.m., after the Moon was fully set for the night.  I turned my attention first to the South and Sagittarius.  Its remaining time in the 2017 nighttime skies is fading, and it may not be practically viewable by next month from my location.  Unfortunately, I had no luck in pinpointing the several star clusters in the heart of this constellation, due to them being already low in the sky and overtaken by my local light pollution glow.

So I scratched the South star clusters off my list and decided to try Pluto next, since it was in the vicinity of Sagittarius.  I held little hope of finding Pluto, but felt the need to try anyway, as I have been wanting to for a while.  Locating a 1,400-mile long object over three billion miles away is not easy, to put it mildly.  This would be unexplored territory for me, requiring all my rudimentary stargazing experience to date as well as the power of my 10-inch reflector.

I started by locating the “teapot handle” in Sagittarius.  It is barely visible from my yard, but leveraging the brightest star in the area, Nunki, makes for finding the handle quickly.  Nunki’s apparent magnitude is 2.05, a little less than Polaris’s, to it is still within easy viewing at my location.

As of mid-2017, Pluto is above the Sagittarius teapot asterism when looking from Northern locations on Earth.  The closet bright star to Pluto is Albaldah, with an apparent magnitude of 2.89, so still easy to find.  Albaldah is directly above the teapot, as shown in Figure 1:

Figure 1: The Sagittarius “teapot handle” including star Nunki, with the Pluto guide star Albaldah above it.

Albaldah is more officially known as Pi-Sagittarii, and it forms a triangle with two other “Sgr” stars in the area, Omicron-Sagittarii and Epsilon-Sagittarii.  This triangle provides a visual cue to where Pluto should be in the August 2017 sky, to the left of the triangle, as shown in Figure 2:

Figure 2: The three Sagittarii stars and the approximate location of Pluto, circled in orange. Click to enlarge.

Assuming you are looking at the full image, you should see one brighter star within the orange circle along with two dimmer stars.  This brighter star is called HIP 94372, and with an apparent magnitude of 6.35, it is not visible to the eye.  So here is the leap from naked eye observing of the three Sagittarii stars to telescope viewing of HIP 94372.  Figure 3 below gives the Stellarium details on HIP 94372 along with an even closer view, now showing Pluto’s location on the evening of August 25th:

Figure 3: HIP 94372 with nearby stars, and Pluto on 08/25/2017. These are visible only with a telescope.

At this point in the observation session, I was heavily consulting Stellarium on my iPad, as there was no way to see the following-discussed stars unaided.  I leveraged my best-quality two-inch eyepiece, the 32mm Orion Q70 Wide-Field.  I post the name and link here not as an ad for Orion, but so you get a sense of the equipment used for this difficult exercise.  The Q70 is better than average as I have found that it significantly reduces the coma effect (blurriness around the edges) common in many 2″ eyepieces.  In hindsight and for next time, I should also have had at-the-ready a high-powered 1.25″ eyepiece.

To get a sense of the field-of-view through the Q70, I was able to see both Albaldah and Omicron-Stagittarii at the same time in the same eyepiece field, with each star near the edge on opposite sides.

It is important to note here that we are discussing the limits of common star map apps.  We are getting down to 10th and 14th magnitude objects, so the overall accuracy of the maps may start to get fuzzy.  I am not saying Sky Map or Stellarium are wrong, only that this exercise approaches the limits of their usefulness.  Because as I discovered, it becomes very difficult at these magnitudes to align the computer map with what you see in your telescope.

HIP 94372, at 6.35 apparent magnitude, is easily seen through a 10-inch reflector telescope.  The second-brightest star in this area is unnamed with an apparent magnitude of 9.80 (see Figure 4).  This was still very visible via the telescope but much fainter than HIP 94372.

Figure 4: Stars near Pluto, August 2017.

And so we come to the task of actually identifying Pluto.  At an apparent magnitude of over 14, is it visible at all from my Western Chicago suburban skies?  I could see, near HIP 94372, the ever-so-tiniest dot, which I assumed to be Pluto!  “Assumed to be” is key here as I cannot say for sure.  When you look at the Moon, Venus, Jupiter, Saturn, or Mars, you can say with 100% confidence what you are looking at.  But with Pluto, I am relying on approximations of a nearby bright star (Albaldah) to make even more approximations of faint star patterns seen only with a telescope.

Figure 5: Pluto’s location and details in Stellarium, August 2017.

I wanted to confirm my finding as best as I could, so I started hunting for noticeable star patterns in the area of HIP 94372 that I could recognize with the help of Stellarium.  Below and to the East I found one small set (see Figure 6).  But the “Rosetta Stone” was the pattern a little farther to the East still.  It is easily seen as a faint pattern in the telescope.  I call it “k-lambda” as I imagine it is the fusion of the letter k and Greek letter lambda in a Star Trek transporter accident. 🙂

Figure 6: Recognizable star patterns very close to Pluto in August 2017,

All of the stars in k-lambda are in the apparent magnitude range of 8.2-8.3, which make them faint but still easily seen in my telescope.  Figure 7 shows the details of one of these stars, called HIP 94784:

Figure 7: The stars of my k-lamba asterism.

Finding these stars seems easy with the hindsight of a few days.  It involved a lot of “feeling around” past Albalduh to get my bearings at the scope.  Even moderately bright stars are easy through a telescope, but going past that 6-7 apparent magnitude threshold was like walking through a forest at night with little-to-no light.

So by leveraging these two small and faint star patterns, mapped towards the “bright” faint star HIP 94372 and anchored to the naked-eye star Albaldah, I can safely say that I found the location of Pluto that evening, even if I cannot say for 100% certain that I saw Pluto itself.  See Figure 8 below for Albaldah, Pluto, and my k-lamba all in the same Stellarium image.

Figure 8: Click to enlarge.

I really want to try to find Pluto again one more time this season with the experience I now have.  Unfortunately the Moon is growing towards Full each night, which will make the evening sky too bright for such fine work over the next week and more.  I estimate the Moon should be out of the way again around September 13th.  By then, Pluto will have nudged a bit towards the West, as shown below in Figure 9.  If I do get a chance to try for Pluto one more time this year, I will post a follow-up next month.

Figure 9: Pluto’s location from Earth on September 13th, 2017.

Thanks for reading to the end!

(And yes, I did find the Ring Nebula after my Pluto trek.)