Cloud detail on Venus?

[Size9Hex]

Belated happy Christmas (or early new year) everyone!

I had the 10 inch pointed at Venus and Mars during twilight yesterday (Dec 28th). Lovely sight with Mars just starting to peep through the deep blue skies to the naked eye. 

Wanted to ask about Venus though... is it possible/realistic to see cloud detail? I saw a persistent long dark feature, aligned north-south, roughly parallel to the terminator. It was only dark by Venus' usual standards - still bright of course. It was fairly sizeable, extending over both hemispheres most of the way to the poles and was also somewhat broad east-west (i.e. rather than a thin scratch). Overall impression was of a bright rim round the planet, a bright terminator and a rather darker shape in the centre.

250x magnification with no filters. Seeing was ok but not brilliant and required a bit of patience at 250x. The planet showed what I believe (could be wrong) to be atmospheric refraction colours above and below. Big refraction spikes from the scope too. So, not ideal conditions but there was definitely something there, whether it was on Venus itself, or just a phenomenon in the atmosphere, kit, or physiological trick in the eye/brain.

Any ideas?

[John]

Yes it is possible to see subtle variations in contrast on Venus's cloud tops but they are difficult to see and it is challenging to separate what is actually there from tricks of the eye / light / atmosphere.

mikeDnight has captured some details recently with his 4" Takahashi refractor. He is an excellent observer though and a tough act to follow I've found

 

[Size9Hex]

Thanks John, that's really helpful. First time I've seen a detailed report of Venus in fact. I guess there's not so much to see compared with Mars through Saturn but it's good to know that it's possible to see something! Last night and the report above have certainly inspired me to try again on Venus in the coming weeks. 

 

[John]

I enjoy following the phase changes and the apparent size gradually increasing even if seeing detail on the disk is challenging

 

[Peter Drew]

I would think that any obvious details would be artefacts caused by the stark difference between the, dark by comparison, sky surrounding the brilliant Venus. Cloud features, such as they are, tend to be elusive.

[Woolnut]

I took a look at Venus a few nights ago and was only able to see an extremely bright looking planet with no real detail, it almost looked like it was on fire! Was the first planet i have looked at with my 'scope  

[Size9Hex]

47 minutes ago, John said:

I enjoy following the phase changes and the apparent size gradually increasing even if seeing detail on the disk is challenging

 

Spot on :-)  It has been fantastic seeing it play out over the last weeks. There's something so exotic about seeing a partially lit planet and watching the mechanics unfold. It's an scene straight from science fiction!

[Size9Hex]

7 minutes ago, Woolnut said:

I took a look at Venus a few nights ago and was only able to see an extremely bright looking planet with no real detail, it almost looked like it was on fire! Was the first planet i have looked at with my 'scope  

Excellent! Youll have many great views to come. You can lose hours on Jupiter. Saturn is stunning. Mars is great but seems to need a bit more persistence. Mercury is elusive and requires a bit of cunning! And the lovely colours of the ice giants. So much to see :-)

[Mr Spock]

I always find Venus is best observed in bright twilight. For me, the rest of the time, it's just a bright blob.

[Woolnut]

8 minutes ago, Size9Hex said:

Excellent! Youll have many great views to come. You can lose hours on Jupiter. Saturn is stunning. Mars is great but seems to need a bit more persistence. Mercury is elusive and requires a bit of cunning! And the lovely colours of the ice giants. So much to see :-)

, yeah i am really looking forward to taking a good look at Jupiter and Saturn, would i be able to see Uranus and Neptune with my 'scope? 

[John]

19 minutes ago, Woolnut said:

, yeah i am really looking forward to taking a good look at Jupiter and Saturn, would i be able to see Uranus and Neptune with my 'scope? 

Uranus and Neptune are well placed right now and certainly will be visible with your scope. They can actually be seen in a 50mm finder but you need some magnfication to show their planetary disks. Uranus is currently approximately 3.6 arc seconds in apparent diameter and Neptune even smaller at 2.3 arc seconds - tiny disks !

Neptune is not far from Mars in the sky at the moment and so needs to be observed relatively early in the evening before it gets too low.

[Mr Spock]

I saw Neptune while it was well placed a month or so ago and managed to get a small disc in my C9.25 - small being the operative word!

[chiltonstar]

I don't think observing shadows on Venus is totally impossible.........in my 40 years observing history, I've managed it a few times, usually with my 4" long focus refractor and a pale blue (80A) filter. On one occasion, I had several experienced observers with me who all described the same thing, which stayed unchanged with different EPs (ie probably not an artefact) and was intensified with the blue filter. It is more difficult with my 127 Mak (not tried with the 180 Mak yet), probably because of the lowered contrast caused by the obstructed optical system.

Chris

[Size9Hex]

Thanks for all the replies everyone. I had another look at Venus last night with the scope cooled for longer, somewhat better seeing conditions and a more patient approach... but nothing to see!  A lovely view regardless. I noticed the diffraction spikes really did wash over the surface of the planet. The view with the 3" aperture mask was clean but it lost the resolution. Probably need to stop thinking about this in case I decide a planetary frac is needed (not your fault Chris although your comments above have got me wondering!).