Well this week we have been looking for Mercury, mostly through the clouds, but can report how we eventually had some partial success, then some failure, and finally a real successful photo of Mercury.
Why did the idea of Mercury come up and eventually turn into an observing plan? Well, first of all, we know that Mercury usually is very close to the sun so it is difficult to see without getting blinded, so it is the only planet that I have not put a camera on. Ok, ok, it is true that even though I have tried to see Pluto with my camera or scope and have failed, so far, but as we all know, sadly for some, that Pluto is not a planet anymore, so Mercury is the remaining planet to be seen for me!
So, when the November 30, 2019 issue of New Scientist arrived in the mail box and it had an article on how on November 28 was the planet Mercury was at its furthest western elongation from the sun, this was an idea time to try to put the camera on it. The only drawback at this time of the year is that you have to get up early in the morning.
|Abigail Beall brought attention to why now is good time for seeing Mercury (Source: New Scientist, 30 Nov 2019)
So, we find that this is an ideal time to try to get Mercury in the camera field of view. Mercury is the furthest from the Sun right now, which means that as it rises above the horizon, the skies will still be quite dark because the sun will be about 10 degrees below the horizon. Since Mercury has an orbital period of about 88 days, if we don't capture Mercury now, in about another month the planet will be on the other side of the sun, which means our chance of seeing it then will only be in the late afternoon, after sunset. Thanks for alerting us to this opportunity, Abigail!
So, how will we know if our observing location has clear enough view for seeing Mercury if it is just above the horizon and we can't delay too long because the sun will shortly be up above the horizon too? From several of our iPhone apps we know that Mercury will just be rising above the horizon and the sun will not be far behind, may 10-15 degrees or so. We will need good low elevation observing sites to get this to happen. How to ensure we are in the right observing location?
This might be the right time to bring up how the "lazy astronomer wannabe" does it. This lazy astronomer wannabe is not going to drive to the ideal site, like the OCA Anza dark sky site, like many OC Astronomers would. Since having been at Anza site once, after experiencing the 2 hour drive through, with, at that time, the last portion a bone jarring ride, after which you have to tighten up all the nuts and bolts on your vehicle, little alone your telescope, this was not going to be an option for me. Besides, for me a night of remote observing should also include hotel maid service and a martini bar, so, nope, going to Anza was not an option. Many OC Astronomers enjoy the dark skies at Anza, while others like Bob, Dave and Bruce end up with new observatories in Arizona or remote observatories in New Mexico. Hmm, I like the idea of a remote observatory where I can just stay in my easy chair and wait for the images to download. That would be the life of the lazy astronomer wannabe, but after hearing about how much work is involved in putting together a remote observatory, I think it is not for me!
So, for me, just a three and a half minute walk down the street offered a pretty good possible observing location. Here is a photo of the sun just rising above the roof tops at 7:18 am. This is going to be my Mercury observing location. But is the view low enough to be able to see Mercury before the sun comes up?
|Using the sun at 7:18 am to estimate lowest observable elevation above the horizon (Source: Palmia Observatory)
With a little help from iPhone GoSkyWatch app, we can see in the following screenshot, that the elevation of the sun at 7:18 am, we see that the sun is at 5.9 degrees elevation. So, if in the next couple of days and if the clouds cooperate and if Mercury is above 5.9 degrees, we should be able to capturing it in the camera.
Finally, the cloud forecast looked quite a bit better so Friday morning I'm up and out at my "easy" observing site. Hmm, the clouds are still pretty heavy and I can't see any stars in the direction of Mercury and there is a bright streetlamp right there too. I was not too worried about the streetlamp and found that I could set up right by a stop sign, which conveniently blocked my direct view of the streetlamp.
|Using a portable stop sign, or the one that is usually there, to block out the streetlamp (Source: Palmia Observatory)
I was up early enough that Mercury was supposed to be about 3-4 degrees above the horizon so I just had to wait and keep scanning the horizon. The cloud layer was still above the horizon and I just waited while sipping my warm coffee.
Anyway, I elected to try getting one long exposure image to see if just by chance something might show through the clouds. I set the exposure time to 5 seconds and tried to see if a long exposure might still show up Mercury. Nope, Mercury was not visible, but Spica, magnitude 1, did show up, to the right of the palm tree, in the 5 second exposure. I couldn't find Mars, magnitude 1.7, anywhere though. Photographing Mercury was just not going to happen this morning.
|Darn!; Mercury, rises behind clouds at 5:54 am, but Spica, right of palm tree, is visible (Source: Palmia Observatory)
So, here we are, three very cloudy days later, on Monday morning, which was the next opportunity with a forecast of just partially cloudy. Hooray, the clouds are mostly gone and I set up just 20-30 feet to the right of last time so that Mercury could not hide behind the palm tree trunk. Hooray, I could see Mercury rising above the horizon, above the trees. I watched it for several minutes, just to make sure it was some far off airplane lights. The GoSkyWatch prediction showed that Mercury was just 7.5 degrees above the horizon and the sun was just 7 degrees below the horizon. The sky was getting brighter by the minute and this image is the last one taken that morning and my first of the planet Mercury!
|Mercury in this early (6:03 am), DSLR, 300 mm, ISO 100, 4 second shot (Source: Palmia Observatory)
Until next time,