Pluto and Palomar 8 (July 10, 2013)

 

 (Click on pictures for larger images.)

Here is Pluto!  See it?  It is just to the east (left) and a little south of the obscure globular cluster Palomar 8.  (You will have to click on the image, at least.)  Palomar 8 is about 42,000 light years away, which is not that far for a globular, but we see it through the mid-section of our own Milky Way galaxy.  That is why there are so many stars in this image.  Lots of gas and dust also block the view, especially obscuring blue light.  That is why the cluster is just a dusty bit of reddish fluff near the middle of the image.

The real treat here is the planet's juxtaposition with the globular.  But Pluto is hard to see!  The dimmest stars in this image are about magnitude 16.  Pluto is around magnitude 14, but quite a few magnitude 14 stars shine here.  How to find Pluto?  Well, I used two resources: the chart on pages 52-53 of the June 2013 Sky & Telescope, and sky-map.org, which plots planet locations against the DSS2 All Sky Survey.  Pluto is the only magnitude 14 object at the location, and I can see stars in the image two magnitudes deeper.  I am confident I have the planet here.  Care to find it in the above image?  If not, here is the same image with pointers:

Want a closer look?  Here is the pixelated, enlarged view.  Some star magnitudes are labeled so that you can more easily spot the planet.  You might compare this view with the survey view on sky-map.org.  Search for "palomar 8."  For a few weeks right now, the sign for Pluto will be very nearby.

There is a time warp in this image.  The light from Pluto has been traveling from the Sun (roundtrip to Pluto and back to us) for about 8 hours 37 minutes.  Light from Pluto itself (sunlight bouncing back) traveled about 4 hours 22 minutes.  Light from Palomar 8 has traveled from the other side of the galaxy for 42,000 years.  We are literally looking back in time.  Light from the Sun reaches the earth in a bit more than 8 minutes.  Pluto's relative distance from the Sun, as compared to ours, is understandable in light minutes: 8 minutes v. 262 minutes.  It's easy to see why the diminutive ball of rock is so cold.

I call Pluto a planet in this post.  Some would prefer it be designated something else.  I have no interest in that debate.

I used the AT65EDQ for this image.  I wanted to see how deep the scope and color camera combination would go.  Partly I wanted to "observe" Pluto with a 65mm scope.  I think it's amazing that such a small scope will allow me to see such a dim object.

Telescope: Astro-Tech AT65EDQ and TeleVue NPR-1073 (eff. at f/5.2)
Camera and Exposure: SXVF-H9C (39x240"), Alnitak Flat-man flats
Filter: IDAS LPS-P2
Guiding: Meade DSI Pro and Hutech 50mm
Mount: Takahashi EM-10
Software: Nebulosity, Maxim DL, Photoshop CS3
Location: The Woodlands, TX

Pluto in Barnard 92

The large patch of mostly starless night sky in this image is Barnard 92, a cloud of gas and dust that is nearer to us than almost all the stars in that direction and blocks the starlight otherwise visible. Of course, a few stars are nearer, which is why the patch is not completely devoid of stars. Also, the patch lies beyond our solar system. This image is proof of that fact, because it shows Pluto passing in front of the cloud!
The planet (or whatever Pluto is now considered) is marked. How do I know that is Pluto? Well, compare the image with this one I took two years ago of the same patch of sky. See that otherwise starlike object where it now is? I thought not. Nope, that's Pluto alright, just where Sky & Telescope predicted it would be.
The APOD for July 8, 2010, has a similar image of Pluto cruising in front of Barnard 92. It can be seen here. The APOD image was taken at about the same time as mine.

Pluto!

The arrowed 14th magnitude dot in the first image is Pluto. Pluto looks like a rather dim star, but that speck really is the planet. Compare the Digital Sky Survey II image obtained from Wikisky.org. I also have carefully compared my image with the June Sky & Telescope chart that records stars down to 14th magnitude. Pluto is exactly where both that chart and Wikisky.org place it. This observation completes all nine (former) planets!