Mercury has gone missing.

[LukeSkywatcher]

Here's an image of Venus i took about an hour ago. Venus is very obviously there but Mercury is nowhere to be seen. It should be just to the right of Venus. I couldnt even see Mercury naked eye or with bins OR scope.

Oh well...............least i have an image of Venus to add to my collection.

[EA2007]

i was watching TSAN the other...night, and well where those guys said Mercury was was nowhere near where it was.

Maybe that tree in your pic is hiding it.

[Tycho Brahe]

A couple of days ago it was visible here to the naked eye, but last night it was invisible... took ages to find it in the binos and getb the scope on it!!! Why would its luminosity change so much?

[LukeSkywatcher]

i was watching TSAN the other...night, and well where those guys said Mercury was was nowhere near where it was.

Maybe that tree in your pic is hiding it.

I DID see Mercury a couple of nights ago right beside Venus. Tonight when i looked i could not find it ANYWHERE. I checked Stellarium and if anything it was closer to Venus tonight then it was when i saw it. I thought that it may be hidden behind the tree but Stellarium showed it soo close that i thought it could not possibly be hidden by the tree.

In saying this....................

When i observed both planets the other evening i was in my lounge looking out the window. Tonight i was in the room next to my lounge (my office) but essentially the view is the same and Venus and Mercury are at roughly the same elevation that they both should be visible together from either room.

It really is a puzzle.

[LukeSkywatcher]

Here is an enlarged image of Venus tonight. I am wondering if my camera with the 300mm lens attached kind of captured the phase of Venus?

If you look carfully you will see that the light from Venus is dimmer in the top left (9pm-1am) position while the light from the rest of the planet is brighter. I have checked Stellarium and this matches the current phase.

I know its not a great image but what do you expect from a fixed tripod image with a 300mm lens.

LOL.

I think it shows a HINT of the current phase.

[Demonperformer]

Probably a silly question, but was it the same time of evening that you were looking? When I was out on Thursday evening, Venus was visible for a good 20 mins before Mercury became visible. And the sky still looks quite bright in your photo.

[brianb]

Also Mercury is now on its way in from max elongation towards inferior conjunction - fading rapidly. Mercury is at its easiest about a week before max evening elongation pr after max morning elongation ... the increasing illimunation more than compensating for the slightly smaller size.

[LukeSkywatcher]

I really cant explain it. Mercury SHOULD be just to the right of Venus in that image. If i invert the colours on the image there is SOMETHING there but nothing conclusive.

I spotted Mercury once this week beside Venus but have not seen it since.

Its a blumming puzzle.

[Jaffa007]

I couldn't see it either last night, after checking it's position on SN. Granted, it should of moved position, but it was no where to be seen.

[brantuk]

Good pic Luke - it looks like venus is gibbous to me

[LukeSkywatcher]

Good pic Luke - it looks like venus is gibbous to me

Thanks Brant. Yes the phase was Gibbous when i took the image so i'm happy that the phase does show in that image (300mm lens on my 450D camera).

I'm just puzzled as to why i am still not picking up Mercury. I saw it about a week ago but no sign of it since.

[LukeSkywatcher]

I think i have solved the mystery of missing Mercury. Last night while imaging the moon and Venus i noticed that my camera picked up a trio of stars close to the moon that i could not detect with the naked eye or bins. The problem was/is that horrible layer of pollution that hangs around just before,during and after sunset. It is obviously shrouding Mercury from my view. The problem must have not been as bad last week when i saw Mercury and Mercury was higher then it is now?

[Starman]

Mercury's a lot fainter now and easily hidden by haze. The shot below shows it last night but be warned that the frame has been rotated to fit the trio in.

The position of Mercury since the 4th April is shown in this composite image:

http://www.digitalsky.org.uk/conjs/April2010-Mer-Ven_Sequence-8-15-001-flat.jpg

The reason the brightness of the planet changes so much is that it's a balance between distance to Earth and its phase. As it gets closer to Earth it gets larger and brighter but this is countered by the fact that as it does this its phase also gets less. When it's on the far side of its orbit as seen from Earth, its disc looks virtually full and is reflecting the most light back to Earth. However, when its in this position its also at its maximum distance from us and this dims its brightness as we see it. The combination of orbital motion and phase gives rise to this ever changing brightness.

Another factor is the planet's apparent distance from the Sun. When it's well separated and high up, it can appear in a darker part of the sky and is easier to see. Of course it can also have a maximum separation from the Sun and be low down in which case it'll be tricky to see.

Basically it's a balancing act of all these factors.

EA2007 - sorry to hear you thought the position was wrong in TSAN. I've rechecked the graphic and it was correct for all dates shown.

[LukeSkywatcher]

Aha !!!!

Thanks Pete. That image really DOES explain it. Last night i was imaging the moon and Venus also. I struggled to fit Venus into the same frame as the Moon because i dont have a 3-way head for my tripod and i was using my 300mm lens to get close-ups of the Moon. Judging by your image, not only is Mercury lost in the haze but it is lower down then i thought and would also be hidden by houses opposite my observing location.

I'll have to take a walk up to the top of the estate tonight to get a clearer western view.

Mystery solved.

Once again many thanks.

Here is my Moon and Venus from lastnight. Mercury is somewhere way off to the bottom right. I was using my 75-300mm lens for this shot. It was set to 75mm. Venus was just about to vanish behind a house.