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Sunday 24th May, from 7:30pm BST, 200p F/5, EQ3-2, diy Onstep Goto.
I've enjoyed watching Venus wane to a thinner & thinner crescent recently, but have never observed Mercury. Having the 2 planets & the Moon only a few degrees apart this week was an opportunity not to be missed. But the gap between the trees & the hill to my West is only about 1 "fist" wide - maybe 40 minutes of observing time. And the late sunset time means Venus would have moved behind the hill before becoming naked-eye visible.
I don't have a permanent setup & can't see Polaris from my patio so I observe from a very rough "polar alignment" & have marked the tripod leg positions on the patio so I don't need to Polar, or Star align every session.
So, having made sure to "Park" the scope at the end of the previous night's session I could just plonk the setup on the marks, "Unpark", "Goto Venus" & lo and behold a tiny crescent Venus appeared about 1 degree from the centre of the the 9x50 Finder in a sky that was clear of cloud but still pure white from the solar glow ! Isn't Goto wonderful ?
Venus was such a beautiful thin 4% crescent with "horns" stretching to the meridian. At first it was shimmering but that must have been a heat plume because a tiny tweak of the focus steadied the image. The seeing was surprisingly good for the low altitude. I enjoyed the view at up to X250 (4mm TMB), before a Goto to Mercury.
Mercury was not visible in the Finder but was a tiny dot in the 32mm Plossl. At higher powers I saw it as a 45% crescent. I know it was about 62% illuminated so the sky must have been too bright for me to see its full extent. I don't claim to have seen any detail - the brightness just reduced steadily from the limb towards the terminator.
I still couldn't see the Moon naked eye so did another Goto & looked in the Finder. Nothing ! But the bright sky must have been fooling my eye because when I forced myself to focus at infinity it popped in sight. The visible crescent was about half the thickness of a crosshair ! In a 20mm Plossl I could see about 6 medium sized faint, ghostly craters along the limb of a 4% crescent.
So in about half an hour I had my first sight of Mercury, & seen my thinnest crescents of Venus & Luna. Isn't this hobby fantastic ? 😀
We are hoping to observe the transit in school (Don’t panic - we have done several transits and partial eclipses in the past so we are fine on the safety aspects - thanks). However does anyone know how I can get hold of some links to use in advance of the day that we can use to put some professional feeds up on the large screen tellies we have linked up to the computer systems these days – I am told that links on YouTube are the easiest to handle on the slightly clunky system we have to control them.
My question comes from reminiscing with colleges that my daughter and I had stayed up to watch first contact of the last transit of Venus live from Hawaii before swapping to Mt Wilson. (We were also up before dawn on top of the local hill fort as the sun rose having lugged an old 4” reflector up there.) Of course at the time we were just browsing through the internet not taking good note of sites we were on.
We are running a session at my local society on transits and occultations. One station will focus on exoplanet transits, and we'd like to build a very simple model to demonstrate this. We have a star (light source) and an orbiting "planet" but I need to work out how to detect the changes in light intensity and display this on a laptop, like a classical transit photometry trace below (taken from https://heasarc.gsfc.nasa.gov/docs/tess/primary-science.html).
Is there a way to take a feed from a DSLR through the USB output to do this, else I could get an adapter for my ZWO and put an EOS lens on the front of that. I really do want a light intensity vs time trace in real time on the laptop. This model will be run in a darkened room.
Thanks for any comments.
Hey guys. Thought about starting this thread. I feel like we all should inform eachother and newer members alike about the magngifications that can be achieved on planets,that provide the best sharpness/size ratio,depending on the scope and seeing. After this thread has grown a bit, i feel like this should be pinned,as to provide a little guide to newer members that are not experienced with planetary observing,as many will be fooled with the typical 50x per inch of aperture and get disappointed when they find that that image will be dim and blurry.
For my 8” F/6 Sky-Watcher Dob
For Saturn i like to use 150x in medium seeing and if i want something a bit bigger , switch to 240x ,which will give me a bigger,but blurrier image.iBut In good seeing, i found that 240x was very usable.When we have perfect conditions, i m certainly trying 300x.
Mars, isnt very big in the sky right now,so even at high magnifications like 300x it still appears as a small orange dot. For observing mars,I suggest waiting for it to reach opposition.It benifits hugely from it! However,this happens once every 2 years....But 5ere are other planets to keep you occupied until then, such as jupiter,saturn and Venus.
For Venus, i use 50-100-120 depending on its phase.
For Jupiter, i like to use 150x, as it provides a very sharp image,with key features of the planet such as bands being very detailed.Waiting on my 6mm UWA Skywatcher to bring it to 200 and see how that plays out. Be careful! Don’t magnify jupiter too much, as it will loose much of its features and sharpness.
Neptune and Uranus: These two will not impress, but are certainly have a nice colour to them. Even ar high magnifications, such as 300x and 400x, they will look like small discs with color in them.Uranus will look be colored green and Neptune a fainter blue.
Mercury About mercury...Havent gotten the chance to observe it ,so the guys will have to inform you about that?
Feel free to give your own opinions as to give members a wider source of information to help them observe better !
Cheers and clear skies.