Jupiter or Uranus

[jabberwocky]

I need help identifying which one I was looking at this morning. Between 3.30 and 3.50 this morning I was looking at a planet over the houses in the east. It was the last bright object in the east as the sun was coming up. Def a planet but just a White disc no detail at all. So was it Jupiter or Uranus?

My guess is Jupiter but need confirmation.

[blackparticle]

Jupiter probably at Mag -2.02.

Uranus is currently at Mag 5.87 according to Stellarium so it's unlikely to be that.

The trees are still hiding Jupiter from view for me. I did a check to when it's going to be at its brightest and got 26th October for this year when it peaks at mag -2.78.

I've not seen it yet through a scope and really looking forwards to it.

[mag10]

Nice problem!

In order to answer you, I set my Starry Night virtual planetarium for your location, and set the time at 04:30, so right in the middle of the bracket you mention.

Well! Your choice was not limited to Jupiter or Uranus! Your sky was full of planets this morning!

At 60 degs NE, and 5 degs high: Venus;

At 70 degs NE, and 10 degs high: Mars;

At 90 degs E, and 15 degs high: Jupiter;

At 120 degs SE and 25 degs high: Uranus;

and

At 160 degs SE and also 25 degs high: Neptune!

But with the clues you gave, it's relatively easy to solve:

White disk, featureless, last object seen before sunrise:

It was Venus. (I also checked the phase Venus was in, and it was almost full, not a crescent, so that confirms it for me).

I see you have a SW 130, and I cut my teeth on a SW 130 Dob, so I know what you can see.

It was'nt Mars, it would have been orangy-tan kind of red;

It was'nt Jupiter, you would have seen features and (most telling) three of the four moons for sure, and possibly also Io;

It might have have been Uranus, but had you seen it, you should have seen the blue-green tint, although at that level of pre-dawn light, I doubt it was visible to you at all;

Neptune? No way: A blue, mag. 8 planet in a lightening sky? And it was way too far to the South.

So it was Venus, I'm pretty sure.

This Starry Night Sky Explorer virtual planetarium software is probably the best $15 (about 10 pounds) I ever spent. I use it not only to plan my observing sessions, but also, like right now, to confirm what I (or anyone, anywhere!) observed after the fact. Unfortunately, they don'y make this inexpensive model any more. (I don't know if they're available in the UK, but if you see one at 10 pounds, get it!). Otherwise they now start at $90 and can go all the way up to $300 (between 60 and 200 pounds!).

I hope this helped.

Clear skies!

[mag10]

Good point Blackparticle brought up: I forgot to tell you Venus' magnitude (because it's always bright) and this morning was no exception: -3.88!

[mag10]

Sorry Jabberwocky!

I went back and read your post again, and I realize I misread you. I thought you said between 3:30 and 5:30 (instead of 3:50!).

So Blackparticle is right. It had to be Jupiter. But I'm surprised. I can understand how the predawn light might have blurred the bands of clouds to make it "featureless" or "no detail" as you said, but did you not see the three moons to the left (as seen through your eyepiece?).

Jupiter's moons are definetely an easy way to ID that planet.

But perhaps you made the same mistake I did, the first time I saw Jupiter through binoculars, and thought they were background stars.

I was going to suggest you go back tomorrow (this morning, actually right about now for you in the UK!) but after checking Starry night I see the 4 moons still wont be in their characteristic line (three of them will be all huddled too close to Jupiter). But tomorrow! (June 15th) check it out and you'll see Io, Europa, Ganymede in a line to the right, and Calisto all the way out to the left, on the same axis!

I never get tired of how Jupiter's four galilean moons dance from night to night!

Enjoy, and sorry about Venus! I read your post too quickly the first time!

Sorry!

[jabberwocky]

Thanks guys, no moons at all were visible, I guess the rising sun was washing them out completely and was also responsible for the totally featureless disc. One of the drawbacks of using iPhone aps to identify what I'm looking at is inaccuracies in pointing it at objects. When plenty of stars are visible you can star hop on the screen and allow for inaccuracies but it becomes difficult when you are looking at single objects in the sky.