First Official Report

[Buzzard75]

I was recently asked by my astronomy club to become an admin for their Facebook page. I'm extremely new to the club, but they appreciated that I took the time to answer peoples questions on the page before an admin had, how courteous I was to the community on the page and the public that we deal with face to face. Apparently some people had responded well to some comments that I had also made which included some brief observations from a previous outing. As such, they asked me to write up an observational report on the Facebook page from last night and I thought I'd share here as well. It's fairly detailed and probably has a lot more information in it than would be necessary for an astronomy forum, but when you're dealing with the general public, I find some people really appreciate those details being explained to them. So here it is. My first official report.

 

For those who don’t want to read the full observational report, here is a short list of the objects that were viewed by myself at the star party that was hosted by the Crystal Coast Stargazers. The event took place at the dark site located at the North River Wetlands Preserve between Otway and Smyrna on 9/22/2017. If you want more details of the observations, see the full report below this list:

Crescent Moon
Jupiter and moons
Saturn and moons
Ring Nebula, M57, w/ and w/o OIII filter
Lagoon Nebula, M8, w/ OIII filter
Trifid Nebula, M, w/ OIII filter
Blue Snowball, C22, w/ OIII filter
Globular Cluster, M15
Andromeda Galaxy, M31, w/ and w/o UHC filter
Satellite Galaxy of Andromeda, M32, w/ and w/o UHC filter
Uranus
Neptune
Search for comet C/2017 O1

Another Crystal Coast Stargazers event, another fantastic night of viewing. The dark site is an incredible place. It’s amazing what you can see out there that you can’t normally see even with the smallest amount of light pollution. Within city limits, there’s a considerable amount of light pollution from all the street lamps, security lights, business signs, etc. It’s pretty easy to pick out the constellations, but it takes a while for the stars to even show after sunset and you don’t even realize how much light pollution there really is. Even at the Fort Macon bath house site where we were last week, there’s some light pollution from the city, the Coast Guard base, and some of the surrounding housing. However, if you look close enough, the Milky Way actually starts to become visible and there are many more stars that come out. At the dark site though, the Milky Way is extremely obvious and there are thousands and thousands more stars. In fact, there are so many stars that are visible from the dark site, it becomes extremely difficult to pick out the constellations.

This last trip to the dark site was no different. The weather couldn’t have been any better. There wasn’t a single cloud in the sky and the moon was just a sliver, which really helps with the viewing of stars and other deep space objects, or DSO’s as they’re commonly referred to. The larger the moon and the higher it is in the sky, the more difficult it can be to see the dimmer objects.

Last night the seeing conditions were fairly good. The atmosphere was fairly still and the only component we really had to deal with was the humidity. When you’re looking at an object in the sky through a telescope you’re magnifying it, but you’re also magnifying everything between you and it. Depending on the conditions of the atmosphere, it can make things appear hazy or they might have a slight shimmer to them. The effect is similar to seeing heat waves coming off of a surface as you look across it. Seeing conditions are defined by the ability to magnify an object without introducing those disturbances in the image.

So, what can you actually see at the dark site? Just about anything you can possibly think of. Planets, stars, nebula, and other galaxies are put on display. Planets and stars are easy to do from just about any viewing location. Nebula and other galaxies are where it starts to get more difficult and the benefits of the dark site really start to show themselves.

After everyone was setup, the event started with the crescent moon. You don’t even need to wait for it to get really dark to see that. When magnified, you can still see details on the dark section of the moon, but the interesting thing to me is actually the shadows within the craters caused by the rim of the craters themselves. They appear very dark compared to the shadow on the rest of the moon, which is actually caused by the moon itself.

Once it got a little darker, the first stars began to come out. One of the first is Vega, almost directly overhead in the constellation Lyra. It’s the fifth brightest star in the night sky, but only second brightest in the northern hemisphere behind Arcturus. At the start, Arcturus wasn’t quite visible because it’s in the western sky, which still had some light from the sun. After a few minutes, those of us with computerized mounts were able to set our alignments using those two stars so our telescopes knew where they were and would know where everything else was in the sky.

One of the next objects we looked at was Jupiter. It was very low on the horizon just above the tree line and difficult to see, but it was there and the four Galilean moons (Io, Europa, Ganymede, and Calisto) were out and visible.

From there we moved on to one of the other large planets in our solar system, Saturn and its rings. At 150x magnification, the rings are prominent and you can see their separation from the planet. At 300x, the seeing conditions start to have an effect, but the Cassini Division or Gap (the gap between the A and B rings) becomes extremely evident and the darker cloud bands on the planets surface may be visible. While it’s possible to see Saturn’s moons, it’s extremely difficult because they are so small and so far away. Titan is the easiest and most common to see as it’s the largest, but is easily mistaken for a distant star. I could easily pick out Titan. Rhea, Dione, Tethys, and Enceladus are possible, but so much more difficult to see because of their size, especially with the seeing conditions. Depending on the magnification, it may also be possible to see Iapetus, but it would be just as difficult as Rhea as they are roughly the same size and magnitude. Mimas has potential as well, but it’s even smaller than Enceladus. And that’s to say nothing of the other 46 moons surrounding Saturn that we know about. The Cassini probe that was deorbited around Saturn last week found six new moons, so there’s no telling just how many more there are and how many more may yet even form within the rings.

Solar system objects are fun targets with a good amount of detail. But some of the more interesting targets to me are nebulae. After viewing Saturn, I switched my target to one of my favorite nebulae, the Ring Nebula, or M57 in the Messier Catalogue. It’s one of the brightest nebulae and one of the easiest to see. It can be seen even with a moderate amount of light pollution within city limits. It’s located in the constellation Lyra. It’s a planetary nebula and is an expanding cloud of ionized gas that was expelled by a red giant star during its last stage of evolution to a white dwarf. A planetary nebula is called such because of their rounded shape which is similar to that of a planet. Under the right conditions and high enough magnification, the central star can actually be resolved. Unfiltered, it’s appears as a haze with a slightly brighter haze around the outer ring, hence the name. With an Oxygen III (OIII) filter, the core fades a bit and the outer ring becomes more prominent. The OIII filter lets through the two OIII emission lines of the visible light spectrum and filters out everything else. It provides a higher contrast on certain types of nebulae, which in turn provides more detail.

The next nebula was the Lagoon Nebula, or M8 in the Messier Catalogue. It’s classified as an emission nebula. It’s very faint and appears as a gray cloud under normal observation. It does not really benefit from the OIII filter. This particular nebula is in the Hydrogen II (HII) region, meaning it is comprised mostly of ionized atomic hydrogen. Viewing would benefit more from a Hydrogen Alpha filter, which works on the same principle as the OIII filter, and passes through the emission line of hydrogen in the visible light spectrum.

Very close in the interstellar neighborhood to the Lagoon Nebula is the Trifid Nebula, or M20. This nebula is unusual and extremely interesting. When you first look at this region of space, you’ll notice the very obvious open cluster of stars. To the unfiltered view, it will look similar to the Lagoon Nebula as just a cloud. However, there are a few different types of nebula combine in this one nebula. There is the emission nebula, a reflection nebula, and a dark nebula. Using an OIII filter will help show the dark nebula, which is the dark sections or dust lanes that actually separate the different sections of the nebula. This nebula is also in the HII region and would benefit more from an H-alpha filter than an OIII filter.

The Blue Snowball, NGC 7662 or C22 in the Caldwell Catalogue. It looks like a blue snowball. This nebula is also classified as a planetary nebula and is located in the constellation Andromeda. It’s very similar in structure to the Ring Nebula. With an OIII filter the structure of the gas cloud becomes that much more prominent.

Right next to the constellation Andromeda is the constellation Pegasus. Within Pegasus is a globular cluster of stars known as M15. It’s an extremely densely packed cluster with over 100000 stars. There are various different types of stars in this cluster such as variable star, pulsars, and one double neutron star system. It also contains Pease 1, which is the first planetary nebula discovered within a globular cluster. It’s also believed that at the center of the cluster lies a black hole. Most of these details aren’t visible to those of us in the astronomy club with our telescopes, however, the view provided by the cluster of all those stars is no less amazing.

Moving back to the constellation Andromeda, we focused on the Andromeda Galaxy, M31, and it’s smaller satellite galaxy, M32. The Andromeda Galaxy is also known as our sister galaxy and at 2.5 million light years is also the closest galaxy to us. Just like our own Milky Way, it is a spiral galaxy with arms that spiral out from the center. Within view of Andromeda is M32. It is a dwarf elliptical galaxy. Andromeda and the Milky Way are actually orbiting each other. Our orbital paths are so elliptical though that a collision is imminent in approximately 4.5 billion years, at which point the two galaxies will combine to form an elliptical galaxy of their own.

After hopping around interstellar space for a while, it was time to turn our sights back to our own home solar system as two more targets came up above the horizon. The first being Uranus. This was my first time actually viewing Uranus. I focused on it and quizzed one of our more knowledgeable members to tell me what I was looking at and, unsurprisingly, they were able to figure it out just from the visual information they had. As with all the planets in our solar system, Uranus reflects the sunlight and appears as a dull disc rather than a point of light like a star. It is classified as one of two “ice giants” in our solar system given that it has a core of ice and rock. Its atmosphere is comprised mostly of helium and hydrogen and contains ices of water, ammonia, and methane. This chemical composition is what gives it its blueish white hue. One of the more interesting facts about Uranus is that relative to the plane of the ecliptic, it is rotating on its side as if it’s just rolling along its orbit around the sun.

The furthest planet (Pluto is a dwarf planet, but it’s still a planet in my book) that’s visible by the telescopes used by members of the astronomy club is the second and largest of the two “ice giants,” Neptune. It’s much more difficult to spot as it’s considerably farther away. At lower magnifications it’s so faint that it could easily be mistaken for a distant, faint star. Once you locate it and increase the magnification, it resolves itself as another dull disc just like Uranus, however, it’s much more blue than white. It has a very similar chemical composition to Uranus, however are much higher in methane which attribute to its bluer appearance.

At this point, it was getting extremely late, the public had gone home and all that was left were a handful of club members. I chose to end my night by searching for the recently discovered comet, C/2017 O1 or ASASSN1. It’s currently located near the Pleiades cluster and the constellations Taurus and Auriga. It is said to be visible using just binoculars and appears as a small fuzzy patch of light and may have a greenish tint caused by gases like diatomic carbon. I scanned the sky for over 45 minutes and unfortunately, I was unsuccessful in locating it. However, over the course of the next couple of weeks it will approach closer and closer to Earth and the sun. I certainly keep trying at some of our future events.

Speaking of future events, there are several each month at different locations and I encourage everyone who’s interested in astronomy to come out at least once. The events are open to the public, all ages are welcome, and it’s a family friendly environment. It’s always an enjoyable experience and is often times even educational for everyone.
Clear skies!

~Brandon

[Knighty2112]

 Nice report Brandon. Out of curiosity (unless I missed it in your report) what scope where you using for this event to view with please?

[Buzzard75]

9 minutes ago, Knighty2112 said:

 Nice report Brandon. Out of curiosity (unless I missed it in your report) what scope where you using for this event to view with please?

My 12" Orion XX12g dob. Has a 1500mm focal length. Most of the viewing was done with my Tele Vue 10mm Delos in combination with a 2x Barlow for some targets. I borrowed an Orion OIII filter from one of the other members so naturally now I want one, but I think I'm going to go with either a Baader or an Astronomik for a higher light transmission.

[andrew63]

Great event Brandon -  and a nice mix of objects for people to view.  I was interested to read under dark skies you had trouble spotting comet C/2017 O1.  I have tried also and failed, it looks like it might not brighten as much as expected.  Hope you have continued success with future events.

 

andrew

[Buzzard75]

6 minutes ago, andrew63 said:

Great event Brandon -  and a nice mix of objects for people to view.  I was interested to read under dark skies you had trouble spotting comet C/2017 O1.  I have tried also and failed, it looks like it might not brighten as much as expected.  Hope you have continued success with future events.

 

andrew

I didn't have any binoculars out there last night and my method of searching was just scanning the area with my telescope. I didn't have a very long focal length eyepiece and it has a pretty narrow field of view so it's pretty difficult. I want something a little bit longer and about 30deg wider for wide field views. Next time I go out I'll take my binoculars with me. I have a GoTo on my dob and I was dead on the Dec and the RA where it should have been, but didn't see it. Maybe next time.

[rockystar]

Nice report,  good bit of education in there as well.

Is Sirius not visible from your location?  Brighter than both Vega and Arcturus. Another interesting Vega fact: in about 12000 years it will be the start nearest  the North Celestial Pole.

Sounds like you've got some great skies

 

[Buzzard75]

3 hours ago, rockystar said:

Nice report,  good bit of education in there as well.

Is Sirius not visible from your location?  Brighter than both Vega and Arcturus. Another interesting Vega fact: in about 12000 years it will be the start nearest  the North Celestial Pole.

Sounds like you've got some great skies

 

You're absolutely right about Sirius. I made a mistake. What I should have said was northern celestial hemisphere rather than just northern hemisphere. Thank you for bringing it to my attention. That being said, Sirius doesn't actually come up here until 2:30am this time of year. We were long gone by then.

[Stu]

19 hours ago, Buzzard75 said:

The next nebula was the Lagoon Nebula, or M8 in the Messier Catalogue. It’s classified as an emission nebula. It’s very faint and appears as a gray cloud under normal observation. It does not really benefit from the OIII filter. This particular nebula is in the Hydrogen II (HII) region, meaning it is comprised mostly of ionized atomic hydrogen. Viewing would benefit more from a Hydrogen Alpha filter, which works on the same principle as the OIII filter, and passes through the emission line of hydrogen in the visible light spectrum.

Very nice and useful report Brandon, sounds like it was an excellent evening.

One comment I would make is about the above quote. Our eyes are actually not very sensitive to light in the deep red where an H Alpha filter is targeted. An OIII or UHC filter is the best option for viewing this, I found that either of these was useful and showed different facets of the Nebula nicely.

This is a link which is often posted but is a very useful guide to which nebulae respond to which filter.

http://www.prairieastronomyclub.org/filter-performance-comparisons-for-some-common-nebulae/

I hope you find it of use.

Look forward to you next event report