Viewing Neptune & Uranus

Hi all,

I'm moderately adept at finding most things I wish to observe, but would not
consider myself "proficient" at starhopping. I usually use my charts & such
to get in the general neighborhood, then do my best to figure out where things
are. I *have* been getting better, but I still tend to stumble across things
rather than actually being able to go right to them - still, I enjoy the hunt
almost as much as the observing. Plus, I'm often content to look at easily
found things like alberio, the ring nebula, the andromeda galaxy & the beehive
cluster for hours on end.

Anyhow, I've never tried to find any planets beyond the ones that are readily
identifiable (Venus, Mars, Jupiter, Saturn). I'm tempted to look for Neptune
and Uranus, but have a couple of quick questions...

Using my 6" newt in skies that are definitely NOT dark (close to Milwaukee,
WI - maybe mag 4):

(1) can I expect them to look planetary or will they appear more stellar? I
guess what I'm really asking is will I just see a point of light or will it be
a circular object?

(2) can I expect to see any color?

(3) could I expect to see them in my ST80?

I'm pretty sure that Pluto is likely to be beyond my equipment's (and probably
my) ability and Mercury just doesn't interest me, so I'll let those go until I
win the lottery and can afford bigger scopes and/or develop the interest in
them!

Thanks.
scott s.

Scott S. wrote:
Using my 6" newt in skies that are definitely NOT dark (close to Milwaukee,
WI - maybe mag 4):

(1) can I expect them to look planetary or will they appear more
stellar? I guess what I'm really asking is will I just see a point
of light or will it be a circular object?

Depends on the magnification. Uranus is 3.6 arcseconds across, while
Neptune is 2.3 arcseconds across. That means they're about 1/10 the
apparent diameter of Jupiter and Saturn, respectively. (That's very
approximate, but should give you an idea. Right about now, Jupiter and
Saturn are essentially behind the Sun, and appear smaller than usual,
even if you can see them.)

What this means is that your telescope can probably resolve the disc
of the two planets, but in order for your eyes to see the disc, you'll
probably have to use a relatively high magnification, which will depend
in part on your eyes. Probably, if you can cleanly resolve the Double
Double (epsilon Lyrae) at a given power, you'll also be able to see the
two planets as discs at that same power.

(2) can I expect to see any color?

In Uranus and Neptune, I would expect so. Uranus looks bluish-green to
me, and Neptune looks greenish-blue.

(3) could I expect to see them in my ST80?

Sure thing. Neptune, the dimmer of the two, is still only magnitude
7.9, meaning that even under fairly bright skies, the ST80 provides more
than enough aperture to see it. Identifying it is the trick.

I'm pretty sure that Pluto is likely to be beyond my equipment's (and
probably my) ability...

Probably, forget about the ST80 on Pluto. The 6-inch is a possibility,
provided you go to some very dark skies. It's certainly not going to
happen under magnitude-4 skies!

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Hi Scott !

"scott s." wrote in message
...
Hi all,


[snip!]

Using my 6" newt in skies that are definitely NOT dark (close to
Milwaukee,
WI - maybe mag 4):

(1) can I expect them to look planetary or will they appear more stellar?
I
guess what I'm really asking is will I just see a point of light or will
it be
a circular object?

They will NOT appear as stars. Uranus especially should appear non-stellar.
Not
large; about a tenth the size of Jupiter, but not like a star.

You can spot Uranus for sure, and I believe Neptune from relatively dark
skies, through
a 50mm scope like an 8*50, by two things; if the stars are twinkling, these
two won't be,
and they have a color unlike any star I've seen, pale shades of green and
greenish-blue.
Uranus, if memory serves, really leapt out due to these factors and the fact
that at 5th
mag there still aren't many stars that it has to compete with. Neptune is
different; at
8th mag there are a lot more stars competing with it, but again, the steady
light and the
color should help.


(2) can I expect to see any color?

Yes, pale, almost pastel shades of green for Uranus and greenish-blue for
Neptune. But
I've not heard reliable reports of seeing any surface features except
through the largest
of amateur scopes, and then only with extremely high powers with excellent
seeing
conditions.


(3) could I expect to see them in my ST80?

I've seen them as disks in a 60mm f/15 refractor many years ago, so you
should see something.



I'm pretty sure that Pluto is likely to be beyond my equipment's (and
probably
my) ability and Mercury just doesn't interest me, so I'll let those go
until I
win the lottery and can afford bigger scopes and/or develop the interest
in
them!

Pluto has been glimpsed in scopes as small as 4 inches, as friends of mine
have done,
but I believe they also succeeded because they knew where to look after
seeing it in
much larger scopes. It's 15th mag or so, and the difficulty, aside from
seeing a 15th
mag starlike object, is to identify it from all the myriad 15th nag stars up
there.

"Brian Tung" wrote in message
...
(2) can I expect to see any color?

In Uranus and Neptune, I would expect so. Uranus looks bluish-green to
me, and Neptune looks greenish-blue.
Brian Tung

Say Brian, what's the difference between bluish-green and greenish-blue ;-)?

Thanks,
Ron B[ee]

Hi there. You posted:

(1) can I expect them to look planetary or will they appear more stellar? I
guess what I'm really asking is will I just see a point of light or will it be
a circular object?

A six inch at higher power should be able to show their disks.
Currently, Uranus is about magnitude 5.7 and 3.6 arc seconds in width,
while Neptune is magnitude 7.8 and is 2.3 arc seconds across. For
comparison, the disks of the larger moons of Jupiter are less than 2 arc
seconds in diameter, so both planets will appear larger than this.
Indeed, last month under dark skies (limiting magnitude 6.7 at the
zenith), I could see Uranus with my unaided-eye fairly easily, and
Neptune is visible in a decent finderscope or binoculars. At very high
power, you can see the limb darkening of Uranus at the edges of the
disk, but little else.

(2) can I expect to see any color?

The color on both planets is fairly subtle and even in my ten inch, they
are fairly pastel. Uranus appears faintly bluish (a sort of pale
"robins-egg blue"), while Neptune is a bit deeper blue with perhaps just
a hint of a greenish cast.

(3) could I expect to see them in my ST80?

You should be able to see them in an ST80, but to try and show their
disks, I would recommend a larger aperture telescope.

I'm pretty sure that Pluto is likely to be beyond my equipment's (and probably
my) ability

Well, there are reports of Pluto being seen in a 4 inch and many people
succeed in finding it with a six inch at moderate to high power and
under dark skies, so don't give up hope. A good computerized star atlas
such as MEGASTAR or THE SKY should be able to help you locate the field
fairly easily. Pluto is pretty faint right now (about magnitude 13.8),
so it takes a good dark night and some carful observation to pick it
up. However, the difficulty of the observation is what makes it a
challenge worth attempting. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

Anyhow, I've never tried to find any planets beyond the ones that are readily
identifiable (Venus, Mars, Jupiter, Saturn). I'm tempted to look for Neptune
and Uranus, but have a couple of quick questions...

Uranus is easy to identify because it's very bright (in the scope) and
has a distinctive pale greenish color that no star has. In your
scope, the disc should be readily visible at 100-150x. I'm not sure
how vivid the color will be with 80mm aperture (it certainly doesn't
stand out in my 50mm finder), but in larger scopes the color is the
giveaway for me.

Neptune is much easier to confuse with field stars, mainly because its
color isn't as bizarre as that of Uranus. Try 200x for the disc.

Ritesh

"bwhiting" wrote in message
...
That's easy Ron....I suspect Brian meant that Uranus
is basically green-colored with a tinge of blue, and
Neptune is the reverse....basically bluish, with a tinge
of green....and I completely agree with his color assessment
of those two planets....in fact, well spoken, on his part, I think.
IMHO, FWIW,
Tom W.

PS...of course, one night I saw Uranus where it was really, really
deep green colored....turns out John Baker, one of our newer club
members, had forgotten to remove the O-III filter before swinging
his scope from 7009 (Saturn Neb) over to Uranus!!!
(we thought for a second that he had a NEW planet in sight)! ;-)
Moral...don't forget to remove the O-III filter!

Hi Tom !

On the other hand, has anyone tried to view either planet, or for that
matter Jupiter
or Saturn or Mars, through any of the other filters we normally use for deep
sky objects,
just to see if there are details that come out, or not, employing them? I
think it would
be a good experiment.

--- Dave

In article ,
scott s. wrote:

Anyhow, I've never tried to find any planets beyond the ones that are
readily identifiable (Venus, Mars, Jupiter, Saturn).

Try Mercury! It's fun to catch, and it's often visible by the naked
eye; it's mostly a matter of choosing the right date and time to try
and see it.

I'm tempted to look for Neptune and Uranus, but have a couple of
quick questions...

Using my 6" newt in skies that are definitely NOT dark (close to Milwaukee,
WI - maybe mag 4):

(1) can I expect them to look planetary or will they appear more stellar?
I guess what I'm really asking is will I just see a point of light or will
it be a circular object?

Uranus will definitely appear non-stellar. Neptune might appear non-stellar.
Try!!!!

(2) can I expect to see any color?

Possibly -- I guess that depends on your eyes' ability to see color at low
light levels.

(3) could I expect to see them in my ST80?

DEFINITELY !!!!!!!!!!!!!!!!!!!

Uranus is visible to the naked eye under dark skies. Which means
Uranus will be easily visible in even the tiniest of binoculars.

Back in 1963, I knew approximately (to within a few degrees) where
Uranus was in the sky. But since I then had no star map going
fainter than mag 5, I couldn't just look it up. So I used a pair
of 7x50 binoculars and drew the star field around Uranus (which
then was near Rho Leonis). I repeated the process every other week
or so -- and after about 2 months I had identified the "star"
which moved: Uranus.

Neptune is marginally visible in 7x50 binoculars, and easily visible
in an 80 mm aperture. In July 1989, right after having viewed the
very rare occultation of 28 Sgr by Titan, I liiked up Uranus, Neptune
and Vesta, which all were in the Sagittarius/Ophiuchus region, using a
pair of 20x80 binoculars. The Sun was mereoy 7 degrees below the
horizon (it never gets darker than that in Stockholm, Sweden during
a night in early July), which means I had a "magnitude 1 sky" ....
But despite that, I was able to see both Uranus and Neptune.

I'm pretty sure that Pluto is likely to be beyond my equipment's
(and probably my) ability

Yep. If you were a very experienced observer under very dark skies,
Pluto might have been marginally visible with your 6". But Pluto isn't
very interesting to watch anyway ... it's just a faint dot of light
in any scope an amateur can afford. Neptune's moon Triton is probably
easier to see than Pluto.

and Mercury just doesn't interest me, so I'll let those go until I
win the lottery and can afford bigger scopes and/or develop the
interest in them!

Mercury won't need a bigger scope -- it is visible with your naked eye
under favourable circumstances.

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://www.stjarnhimlen.se/
http://home.tiscali.se/pausch/

In article YfmRa.1087$ff.656@fed1read01, Ron B[ee] wrote:

"Brian Tung" wrote in message
...
(2) can I expect to see any color?

In Uranus and Neptune, I would expect so. Uranus looks bluish-green to
me, and Neptune looks greenish-blue.
Brian Tung

Say Brian, what's the difference between bluish-green and greenish-blue ;-)?

Bluish-green is greener than greenish-blue..... and blue-green is between
these two.

You can consider the suffix "ish" as a kind of diminutive. Thus,
"bluish" is less blue than "blue".

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://www.stjarnhimlen.se/
http://home.tiscali.se/pausch/