11 replies to this topic

[aatdalton]

Last night around 2:30 while checking out various DSOs while my imaging rig was running, I happened to notice that both Uranus and Neptune were in pretty decent placement to view as I was swiping around Stellarium on my phone. I did a pretty long star hop starting in Pegasus and ending up at Neptune, just outside Aquarius. 

 

Wow! While still very small in my 8" dob with ES82 11mm, the color of Neptune was incredible. Brilliant deep blue. Much richer color than any blue stars I've seen. I could faintly make out the disc of the planet, and could confidently say it was not just a point source of light. My skies had a little bit of high level haze, so I didn't try for a high magnification. 

 

Next I turned east to track down Uranus. After another star hop, I had it clearly in my eyepiece. Wow again! This one had a much more distinct disc to it, clearly not a star. The other dead giveaway was the pale green hue. Reminded me of some planetary nebulae. Absolutely beautiful staring deeply at Uranus. I'm fairly certain I could pick up Ariel as well. I'm sure I could have seen other moons if I had realized where they were and tried identifying. 

 

I think it's so amazing that with fairly amateur gear, I can directly observe these incredibly distant planets from my backyard. And of course my wife and I had some fun laughs about me looking at Uranus last night. 

 

Clear skies all!

[Migwan]

Love that blue.  Never thought of moons with either of those.  Sounds like you had a good night. jd

[Cali]

Have you been able to check out Titan?

 

- Cal

[Redbetter]

I have typically found Triton to be fairly easy to see with the 8" SCT looking at Neptune in rural sky.  However, I haven't tried for it in recent years in the much brighter suburban backyard with its incredibly poor seeing.  I did try for it once a year or two ago with the 110 refractor at a low elevation rural site, but the seeing was poor  (even for ~4" scope), effectively obliterating dim objects next to "bright" ones.  I have been wanting to try that again with the refractor at a site with better seeing, but I don't typically haul it to the dark site when the 20" goes...just too much extra time in setting up/taking down a refractor this size when I already have the big scope in action.

 

I doubt you saw Ariel with the 8", especially at only ~110x and with haze.   Not sure of the time zone, but there was an 11th mag star NNW of the planet, somewhat outbound from Ariel last night.  If you saw only one moon candidate and it was not that star, then Titania is the most likely.  For perspective, in dark, transparent, and steady skies I could typically catch Titania with the 8" SCT (barely, but with certainty each time) and rarely Oberon. This was in the 225 to 300x range.  Never succeeded on Ariel or Umbriel with that scope that I can recall.  With the 20" in dark sky I can catch the dimmer two with sufficient power if the seeing is not too poor, but that is typically 500x or more to get some separation.  I have seen the set of four easily with a 17" in good seeing and dark sky.  For these inner moons seeing is a major player.

[aatdalton]

Yeah, it appeared up and to the left in my eyepiece so southwest in the sky I guess. Probably that other star but it was definitely tucked in tight. Would definitely like to come back and look harder for moons.

[ww321q]

I watched Neptune early Saturday morning. My 6" reflector showed a pretty clear disk but the color wasn't is good as you had. I've been able to find it pretty easy using  my widest true fov eyepiece.I use this site to help me know where planets are. I'm hopefully going to get up early tomorrow and try for Uranus. https://www.timeandd...ght/usa/atwater

[Zorbathegeek]

I'm looking forward to finding Neptune when the moon is less bright. It will be 40% alt' by 11pm next week from my latitude. I star hopped to find (16) Psyche, (15) Eunomia and (39) Laetitia last week - until my brain melted down! So Neptune should be fairly easy. I only have a 6" Dob' but find the field of view great for tracking asteroids. (135) Hertha and (21) Lutetia next month! Gonna have to wait a while for Uranus. I always have good intentions that I can get up at 4.30am but generally flag it when the hour arrives. 

[Richard Whalen]

I observed Neptune last night in my 5" f15 refractor. Best view was at 500x, small blue round disk. Very sharp view. Neptune is well placed and easy to find right now.

[Pcbessa]

I spotted Uranus and Neptune with my new 10" for the first time these last days. Whilst I clearly spotted the beautiful sharp disks of both - especially between 250x and 500x - I failed to detect any moons. Uranus has a very strong glare (as it is very bright), that makes it difficult to spot the Titania. In Neptune, Triton is very near the planet, and it is also faint, and I couldn't spot it. But it seems it would have been easier than seeing Titania. I patiently looked out for the moons in both planets for 20min. I will wait for the opposition.

Edited by Pcbessa, 01 September 2019 - 04:58 PM.

[tchandler]

Congratulations on your discoveries! I take it that these were your first observations of the outer planets?

 

Uranus is a beautiful pale teal in my 152/1200 refractor. Definitely a disk, even at 100X. Have yet to see any of the moons. 

 

Neptune is conveniently located near the 4th magnitude star phi Aquarii. Last week I observed Neptune with a friend’s 24” f/3.7 Newtonian. Pale blue - almost grey - with barely a hint of green. Seeing not great but a disk was observed at 200x and up. At 300x and up Triton popped into view. Several others took a look as well and I was surprised that a few were unable to see the moon about 12 seconds from the planet.

[Redbetter]

Seeing has a great deal to do with recognition of dim moons near planets that are many magnitudes brighter.  Crappy seeing operates as a glare magnifier, perhaps a second order effect.  First order is the increased glare, and second order because of the increasingly diffuse nature of the dim component do to seeing spreading its light over a far larger area as well. Both of these are contrast losses.   [The caveat is that contrast impact on visibility is often more of a half mag response per magnitude background change due to sky brightening/contrast...so the net might be closer to adding two 0.5 order effects to get first order.]    Add to that poor seeing often involves rapid and large focus shift,  and makes it harder for the eye to track such changes--younger eyes might handle this much better.

 

And some folks have more difficulty seeing a faint object next to a bright one.  For whatever reason their visual acuity for dim targets next to bright ones seems to have a smaller dynamic range.  That is applied to side-by-side comparison.  You really can't compare vastly different seeing and sky darkness for different observers.

[tchandler]

Thanks Redbetter,

 

I appreciate your concise explanation. Additionally, observer experience contributes as well, including how/where to orient the eye at the eyepiece, further confounded by the relatively rapid apparent motion of objects in the FOV at high magnifications. It’s like shooting a fruit fly while jumping from a moving train! Anyone who successfully observes these challenging objects should know that they deserve a small round of applause!

Edited by tchandler, 02 September 2019 - 08:01 AM.