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Visual Galaxy Observations in Coma Berenices (COM)

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Visual galaxy observations in Coma Berenices (COM) I have selected Coma Berenices for my visual observation of galaxies for SGL XI. It is well placed at the moment and rich in galaxies. I have observed 94 galaxies including seven messier objects in this constellation to date. COM has no stars brighter than mag 4 so it is somewhat less explored than those around it. In front of the galaxies we have – The Melotte cluster Before we get to the galaxies don't neglect the foreground objects. The fine naked eye Melotte cluster makes an upside down v shape and is just 260 light years away. It’s the third closest cluster to us and is not moving toward or away from us. The Sun would be mag 9 at the distance of this cluster. Then we come to two double stars Nick – Cotteless55 recommends the following double stars in Coma. 35 Comae Berenices (Σ1687) – This is right near M64 which is later in this paper. 35 Comae Berenices is 280+ light years away so a little further than the Melotte cluster. Nick described this as a good triple view, orange / yellow and blue. The AB split is 1.2", a good test of seeing, observer and optics, its magic when a close companion pops out as you increase the magnification. AB take 359 years to orbit and they are now just past their closest point! For those with Dobs (per Nick!), an easier target is 24 Comae Berenices. It is 610 light years away do further out than 35. Wide split of 20.1", giving orange and royal blue. Superb colours which Nick says are a must with doubles! And then on our way to the galaxies we find two globular clusters As you look towards COM you are looking straight "up" out of the milky way. Despite this you do have two globular clusters at a distance of 50,000 light years above our milky way. M53 is a binocular object and is very special in a big scope. Compare it to NGC 5053 nearby which is about the same distance away. We reach galaxies Now onwards to galaxies. As noted earlier, we are looking towards the galactic pole in COM. So we do not have our milky way blocking the view. Our milky way and local group are in a big layer of galaxies which loops across our skies in a similar way to the milky way. At this time of year the loop runs up from Virgo and then through Coma and on up through the Plough and then down through Pegasus. Here is an image of the first galaxies we come to as we journey in to space towards COM. One of the first bright galaxies we come to is M64 (NGC 4826) which is at 24 million light years. It is part of the CVn I cloud of ten galaxies which includes M94. M64 - Binocular object This is the brightest galaxy in COM and is visible with a pair of 50mm binoculars. It was a bright object in my 80mm binoculars at SGL in 2012. It has a famous black dust patch that has given it the name black eye galaxy. The ease of seeing the black area is debated online, it is certainly is easier with a larger scope. NGC 4565 - Large binocular object As we travel further out we come to a load of galaxies at around 50 million light years distance. These are generally outlying members of the famous Virgo cluster. Just before we get to this group we come across NGC 4565 & NGC 4725 at 44 million light years away. I have seen NGC 4565 in my 100mm binoculars with averted vision. It is one I have looked at in lots of scopes. If you get a chance to use one of the large dobs here this weekend get them to point it at 4565..It is just stunning! M99 At the bottom right of Coma we run in to the Virgo group. I have picked out M99 as the next target as it is one of the forty or so galaxies that show structure. M99 is one of the few (about 10) galaxies that you can see the spiral arms visually in a modest scope. See if you can make out the prominent arm in your scope. The box - 8-16 inch scope We now travel further out past the Virgo group. As we get towards 200 million light years away we come to the box. This is a lovely group of galaxies. The wispy NGC 4173 to the top right is the hardest to see at m14 with a low surface brightness even though its actually in the foreground at a mere 35 million light years away. I struggled with it even with averted vision in my 16 inch scope. The other three NGC 4169 / 4174 / 4175 are much brighter and were relatively easy to see in my 10 inch scope. Coma group Abell 1656 - 10 inch or larger scope Pushing further back to 320 million light years away we come to the Coma cluster This cluster of over 3000 galaxies and is 20 million light years in diameter. It is centred on NGC 4874 and NGC 4889. This cluster has very few spirals. The cluster is part of the Coma "supercluster" which is a wall of galaxies that reach down to Leo. There are very few spirals in the Coma cluster but do try and spot the brightest one NGC 4921. It has a bright bar but seems to have a low star formation rate perhaps due to gas being stripped out due to interaction within the Coma Cluster. Hubble took an amazing picture of this galaxy. So how many Coma cluster galaxies can you see? Use the chart below and report back. Come on Dob mob, that’s why you’re here. Get that dark towel out over your head. X-COM – Mega Dob Want a challenge? Try this variable galaxy. It can reach mag 12.5 but is normally around magnitude 17! It is tiny so looks like a fuzzy star. It is 1.1 million light years away. .
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