Tuesday, May 23, 2017

Chasing Comets

A quick look to Comet C/2015 V2 Johnson

At the end of last year I realized 2017 was going to be a good year to watch comets in Binoculars and indeed it has been. Unfortunately, I missed some of those comets because of health problems with my back and when I wanted to go back to look for comets, there were stoppers: moon and clouds. I even tried comet 2P/Encke  at the end of February and I though I saw it, I could not confirm or sketch it because of the clouds.

Anyway, here I am in action again and I got to see my first comet with my small 10x50 binoculars. I honestly thought it  would not be possible, but a quick trip to rural skies (Bortle 3/4, blue zone), good transparency (NELM 5.9) and a moonless night gave me access to comet Johnson. I went about 10 kilometers (6.2 miles) from my home to the east, between a little chinese village and the mountains. The sky was totally dark in the north and east; west showed some light pollution, with a huge dome of light in the south.

Johnson was traveling close to Printsteps, the delta star in Bootes.  I tried to use the tripod to hold the binoculars, but Bootes was at the zenith so using the tripod wasn’t an option. Then I laid down on my back and holding the binos found it.  It was in middle of two stars of 8th magnitude at only 2 arc degrees from Printsteps. I struggled trying to sketch it because I had to put the binos down each time I added more stars to the paper and then look for it again, but finally got a decent result that allowed me to perform a digital sketch.

Please turn off the light and try to find Johnson in the sketch. If you succed it means that before it fades, it is time to get those binoculars out and try to find it in the dark skies.



Edited by Jennifer Steinberg (editor in chief).

Sunday, May 21, 2017

A foursome of Planetary Nebulae

After I had seen the 4 planetary nebulae (PNs) in the Messier list, I became fascinated with them so I started to look for more. I found senses of color on some while others were showing a particular structure in it.  But to me, the real challenge was to see the tiny star in the middle of the PN not only visually speaking, but because the amazing atomic story behind it.  In the course of this time in China, I have seen a little more than 20 PNs and sketched some of them so now that the heavy rainy season is about to start in southern China, it is a good time to show some of them.

Let’s start with Cleopatra’s eye, located on the shore of Eridanus river. For some urban stargazers, none of the stars in Eridanus may be visible with the naked eye so they would have to star hop from Rigel in Orion. For those who stargaze from darker skies, the best option is start the journey in the star Zaurak (34 Eri)  and hop back about 3 arc degrees towards Rigel. With only 37.5x it is an obvious dot, but magnification is the name of this game. I achieved the best view with 166x. With direct vision it seemed like a tight and bright core surrounded by a dimmer halo and with averted vision it was possible to see the central star of magnitude 12.2. I referenced the dimmest star in the sketch, of magnitude 13.7.

The second PN in order of my observation was Saturn Nebula, in the constellation of Aquarius. If one has seen M72 or M73 before, Saturn Nebula is just 1 or 2 degrees to the east of them. The night I saw it, seeing was just average (3/5) and it did not let me push the magnification beyond 166x. I could not see much of it, except a pretty bright “egg”.  It kind of resembled the view that I have of the planet Saturn with my 15x70 binoculars except the color. It honestly left me a little dissapointed, specially after seeing sketches in color showing internal structure. But after all I am just using 6” of aperture and those sketches were made with more than 18” of aperture and magnifications of over 500x.

The next one is Eskimo Nebula in Gemini. It escorts the twin brothers from a position just 2 degrees east of the star  Wasat, in the waist of Pollux. Visually, it seemed to make a perfect match with the star HIP36370 (Mag 8.20) with the only difference in color: The PN seemed to shine on greyish blue while the companion star in white. With averted vision, one can also see an small halo around the star, which shows similar color. I feel pleased with the view of this PN in my telescope, but once again magnification and large aperture will give a more details on this PN.

Finally we have NGC 2346,  Butterfly Nebula. It is bipolar PN located in Monoceros. I was expecting to see some glance around the star or something else but frankly I saw nothing other than the centar star.  I can’t blame my small telescope only, because the light polluted sky helped to washed out the nebular details. At the time of the observation, Monoceros was exactly in the most light polluted area from my suburban sky and since I came to China in 2014, I have noticed that the glance from the city had grown. On multiple times I tried to convince myself to see something else more than a stellar object in this PN, but  I just simply could not see more.  I guess a darker sky and a nebula filter such a OIII filter would reveal more details even with the same aperture.

Now, I am glad to introduce you all to the foursome of PNs:

I made this collage with enough size to be enjoyed with a higher resolution. You can also click on every raw image to see it in detail and check the notes if they are of some help.

Once again, thanks for reading my blog and see you next time.


Edited by Jennifer Steinberg (editor in chief).

Saturday, May 13, 2017

M71, A Globular Cluster in Sagitta

Many of us have heard of the constellation Sagittarius in the austral skies, but Sagitta is an unknown constellation for many amateur astronomers. Even I can’t remember where it is located in the sky and it is difficult to trace in polluted skies because  it has no star brighter than 3rd magnitude.

Discovered in 1745, M71 is a dim and loose globular cluster located in Sagitta, right between Aquila and Cygnus, two birds that govern the summer skies.  The best way to find M71 is to star hop from the  1st magnitude star Altair , the eye of the Eagle (Aquila). From there, trace a line to the star Sadr in Cygnus and in the first third of that line you will be close to the area where the globular should be.  To the west of the glob, there is an a unique asterism that looks like a tiny arrow made by four stars: 9 Sge (Mag 6.20), HIP97818 (Mag 7.65), HIP97840 (Mag 8.30) and a fourth one of magnitude 9.10.  If you see it, you can‘t miss M71.

It is visible with binoculars under moderate light polluted skies (Surburban skies).  It looked like a ghosty patch next to the asterism decribed below. In fact, one has to use some averted vision to see it. It does not show a definite core, but the whole surface has the same low brightness. I have seen it with my telescope at 100x.  Even at such magnification on 6” of aperture, it  looked like a nebular smudge with about 10 dim stars in it.

Sumer is coming soon so it would be a good time to plan on catching M71!

Clear skies,