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Observing Pluto

Started by bikeboy, 08/25/2018 02:05AM
Posted 08/25/2018 02:05AM Opening Post
Hello Everyone!

It has been awhile since I posted.  Good to be back on astromart:-)

I’m am going to try for a Pluto observation.  Anyone out there in Astromart land have any suggestions for successfully observing Pluto?

Keep Looking Up,

Posted 09/09/2018 11:07PM #1
I suggest a good star charting program. Pluto is easy to confuse with the faint background stars. When I observed it with my C14 I had to identify it by its position among the other faint stars in the eyepiece field. I was going to re-identify it a few weeks later by its motion among the stars but I was so unimpressed by viewing it that I never did. Viewing it did allow me to check it off of my unobserved object list though.

Keith (Scopejunkie)


40 year old restored C14 with recirculating cooling

w/Skywatcher DOB GOTO Conversion (CPC14)
Posted 09/10/2018 05:11AM #2

Thank you for your reply.  I have tried twice now.  First try I had a bad outdated app that gave me the wrong position.  Saturday night I tried again with two better sources and I got to the spot then the clouds rolled in... I’m going to give it another shot this week before the moon comes up.

Keep Looking Up,

Posted 09/10/2018 05:57AM #3

Good hunting! Let us know how it goes. BTW, what scope will you be using for your Pluto quest?

Keith (Scopejunkie)


40 year old restored C14 with recirculating cooling

w/Skywatcher DOB GOTO Conversion (CPC14)
Posted 09/10/2018 03:24PM #4

I am pushing the limits with a 12" dob.  I need that magical perfect night to get the 14.2 mag Pluto.  Crossing my fingers:-)

I have been cross referencing Pluto's position with Stallarium and

Keep Looking Up,
Posted 09/10/2018 11:29PM #5
I mostly observe from sites near Fresno in Central California, both on the floor of the San Joaquin Valley and in the nearby Sierra Nevada mountains.  In the summer (Pluto's current season), it is usually clear here for weeks, even months, on end.  It rarely rains in Fresno from about mid-April through mid-October.  It rains more often in the Sierra Nevada during this time due to "mountain weather" phenomena and  out-of-place tendrils from Arizona's monsoon season.

Our transparency here is mostly affected by smog/haze in the valley, smoke from forest fires (depends on the year…this year was bad due to the large Ferguson Fire near Yosemite National Park), and localized weather in the mountains.  Seeing is mostly affected by breezes/winds flowing turbulently over rugged terrain.

I have seen Pluto in my 8" SCT (Celestron CPC-800) from the valley floor and failed to see it in my 11" SCT (Celestron CPC-1100 Edge HD) in the mountains.  It all depends on conditions.  Regardless, a good finder chart is an absolute must.

The first time I saw Pluto was in 2008 with the 8" SCT during the best three nights of seeing/transparency I have ever experienced.  Our club has a primitive camping site/observing site near Courtright Reservoir (8200 feet) east of Fresno.  In 2008, Pluto was at magnitude 13.9 and I was able to visually ID stars using direct vision down to magnitude 15.4, which is nearly the theoretical limit for an 8" telescope at 200x.  Needless to say, Pluto was an easy pick since it was actually the brightest object in the field of view of my 10 mm Vixen Lanthanum eyepiece.  For that weekend, I made my finder charts using Cartes du Ciel, which is free.  I now use SkyTools 3 for most of my finder charts.

A couple years later, I saw Pluto with the 8" SCT from Eastman Lake north of Fresno (elevation 600'), but only after a rare summer rain to clear the air and only then using averted vision.  In my wife's 10" Orion dob, Pluto was at the limit of detection using direct vision.  Over the years, the 8" SCT has shown me Pluto only three more times:  once at Glacier Point in Yosemite National Park (elevation 7200 feet) and twice more at Courtright (including both times I found asteroid 163 Hilda, which was at about magnitude 13.8).  All three times, Pluto was just at the limit of detection using direct vision.  Several other attempts over the years failed due to my visual limiting magnitude being in the 12.5 to 13.5 range due to conditions.

I have had the 11" SCT for about a year and I have been relatively more successful in spotting Pluto with it due to the larger aperture.  I haven't tried for Pluto yet from Eastman Lake, but I have seen it several times from Glacier Point and Big Stump in King Canyon National Park (elevation 6500 feet).  I didn't get to Courtright this year due to smoke from the Ferguson Fire over the Perseid weekend.

The moral of the story is that, if you can get good seeing and transparency, Pluto should be easy in a 12" scope.
Posted 09/11/2018 03:53AM #6
Sounds like you have had some great observing sessions.  The skies around Yosemite are amazing!  

I grew up in Arizona.  I remember some great skies there.  Now I live in Colorado.  We have some good skies here also but not as consistent as AZ.  The summer monsoons are tricky here.  This summer has also been tough for viewing with the smoke from all the fires out west.  I generally like to travel east out on the plains verses the mountains.  The plains tend to be more stable and still around 5,000 to 6,000 ft.  The various mountains ranges cause little micro climates.  So the times I been in the mountains here for observing it has not been that steady. 

My 1st Pluto attempt this summer was with an 8" dob in August.  It was our first non hazy night for about a month.  I recently picked up a 12" dob.   and went 2 hours east of Denver.  The skies started great then the humid and skies went bad.  So I just gonna keep going for it.

I have seen Pluto before.  I worked at Lowell Observatory during my undergrad 20 years ago in Flagstaff.  I used the 24" Clark refractor to spot it.  I made a sketch of the sky one night and came back 3 days later to track the movement and there it was!  That was a great moment.  And the perfect historical scope to do it on:-)

Now I am trying for it with my own equipment.  Unfortunately tonight the seeing and transparency is not the greatest.

Clear Skies:-)

Posted 09/12/2018 06:11AM #7
Success!!!  Tonight at around 9:30 PM MDT I found Pluto:-) It was faint but I was able to pick it out.  It actually aligned nicely with 4 other 13/14th mag stars to make a sideways “M” asterism.

I went about an hour east of Denver.  The clear sky clock predicted about 2 hours of good seeing and transparency. 

I brought my 12 year old son with me.  He was also able to pick it out also. 

I hit up these other objects before I had to force myself to go home:-)

Veil nebula
Perseus double cluster. 

Keep Looking Up,

Posted 09/12/2018 06:35PM #8
Excellent sky hunting with your yard cannon!  coolgrin

Keith (Scopejunkie)


40 year old restored C14 with recirculating cooling

w/Skywatcher DOB GOTO Conversion (CPC14)
Posted 09/14/2018 03:51AM #9

Congratulations.  I like observing challenges.

Next, I suggest you try G1, the brightest globular cluster in the Andromeda Galaxy.  It's magnitude 13.7, but it has some size (about 10" photographically), so its low surface brightness makes it a challenge.  I tried at least a dozen times over several years with the 8" SCT without success.  I even tried two nights in late August 2016 with a 7" AstroPhysics refractor at the Shooting Star Inn near Flagstaff (an astronomy B&B that is now "offline" due to the owners' retirement).  I always found most of the stars in the FOV I was targeting, but could never get quite deep enough for G1.  Then, on October 1, 2016, on a great night at Big Stump, I finally spotted it, first with averted vision then finally with direct vision.  My two tries with the 11" SCT failed due to poor conditions, but it's on the list for this fall.