A Great Star Party

[samgray1]

Date/time: Saturday, August 20, 2011 (1930 - midnight)

Conditions: At the San Diego Astronomy Association’s dark site near Tierra Del Sol, California (Tierral Del Sol Dark-sky Observing Site). The skies there are Bortle Dark-Sky Scale class 3 (blue). Transparency was 4/5, seeing was 3/5, temperature was a nice comfortable 70 dropping to 55 degrees Fahrenheit, and the wind was calm. The sky was partly cloudy (from 10 to 20 percent covered) and some dew started forming around 2200. My dew heaters took care of most of the problem, but near the end of the evening my UHC filter got some dew on it while sitting out on the table, putting it out of commission for the rest of the night. By the Internet, the moon rose at 2308, but it wasn’t in direct view until about 2330 because of the local hills and desert brush.

Observations: It was public star party night at TDS, and there were quite a few visitors that had come out to look through our telescopes. I ended up giving small sky tours to some of our visitors, which reduced my time at the eyepiece, but that was no problem because they were a great bunch to interact and share the views with.

After collimating my telescope, as the sky was darkening I started out with Saturn, which is a real good target to check and adjust your finders on. After I had my Telrad and 8x50 right angle finder both tweaked to perfection, I noted that because it was low in the sky and the seeing wasn’t very good, I could only see two of its moons and the Cassini Division was not really distinguishable. This time of year, by the time it is dark Saturn is too low to see well. Regardless, I had several folks look at it and they were quite happy.

M3 was next. It was nice, but the sky wasn’t at its darkest yet and the glow of San Diego behind it didn’t help either.

M5 was pretty, but not as nice as when I saw it Thursday night. The seeing just wouldn’t support a really good view.

I tried several times during the night for a view of M81 and M82, but it seemed like there was s strip of cloud that just kept hanging in front of them. Oh well! C'est la vie!

Some folks wanted to see the Ring Nebula (M57) so lined it up and let them have a look. I decided not to go above 107X magnification as I had on Thursday, since I don’t have auto-tracking and keeping the telescope centered on the target for guests would have been a pain at 300X. Wanting to see more nebulae, we went on to check out the nebulae in Sagittarius (M8, M20, M17, and M16) continuing to use my ES 14mm 100 degree EP (107X) and the UHC filter. They were all really nice, but not quite as good as they were when I saw them two days ago. I did, however, note that I was able to see more detail than on previous trips to this site. I think experience has helped me learn to “see” objects better. I love the way that M17 (Swan Nebula) looks so 3-D sitting up there in the sky. My guests were joking around, saying it looked like the “duck” was swimming away from you.

Next was the Veil Nebula. I used my 30mm and UHC filter and it was really beautiful, almost like the pictures you see of it. I have seen more detail in it before, but the view was definitely nice. I was able to see all three parts of it (East, West, and Central).

I was checking out the easily visible North America Nebula and Pelican Nebula with the same set-up when a nice lady came by for a look. I shared the views with her and explained where we were looking using my S&T Pocket Sky Atlas. My charts reminded me that there was a large nebula surrounding Sadr (Gamma Cygni – the center of the cross), so we checked it too and we were able to clearly see all of it. I learned while typing this report that part of it is called the Butterfly Nebula, and could see from the pictures why it is called that. (This is another advantage of typing up reports after observing)

About that time, I noticed the angle of Cassiopeia in the sky and realized that M31 would be nice and high, so I showed my new friend how to find it and we verified that we could both see 2.5 million light years away without any optical aid other than our eyeglasses. Then, with the telescope fitted with my 30mm 82 degree EP, we were rewarded with a spectacular view of M31, M32, and M110 in one FOV. My guest could see M31 and M110, but didn’t recognize M32 as a galaxy until I put it in the center of the FOV and told her it looked like a bug fuzzy star. For me the view of M31, M32, and M110 was absolutely amazing as I noted that although the light became more and more difficult to see nearer the edges, the large oval shape of M31 was extending beyond both sides of the 1.6 degree TFOV in my EP.

After that I found the blinking planetary (NGC 6826) in Cygnus for the first time. At 300X with my UHC filter I was able to clearly see it with direct vision. I spent some time trying to see the blinking effect by switching between direct and averted vision, and all the time I was thinking that the central star was too bright to blink in and out. Then, while writing this up, I looked it up in Wikipedia and found that I was mistaken, because it is the planetary nebula (not the central star) that disappears when using smaller telescopes. They explain that when you look directly at the central star using a small telescope, the nebula disappears.

Most of our visitors left about that time, so I was able to get down to some more serious observing. I spent time in Sagittarius finding two star clusters that I had previously skipped, M21 and M25. I found M21 just a short distance northeast of M20, (within the same FOV on my 14mm EP) and noted that it had a very interesting asterism of an almost perfect circle in it. I had some trouble locating M25 because there are so many stars in this area of the sky, but I finally found it by noting that it is an equal distance from Mu Sagittarii, but almost directly opposite M8. If you imagine a line drawn between the top of the teapot (Gamma Sagittarii) and Mu Sagittarii (the bright star directly above Gamma Sagittarii) as the straight line part of an arrow, M8 and M25 would be the two opposite sides of the tip of the arrow with Mu Sagittarii being the tip of the arrow (albeit a super-wide tip).

About that time, another SDAA member came by on his visiting rounds and showed me a cute little pair of globulars, just off the tip of the teapot spout (NGC 6528 and 6522). As he was looking through my telescope at them, he expressed that he really liked the wide and sharp to the edges view through my 14mm ES 100 degree AFOV EP. (my favorite and most often used EP)

One of my favorite globular clusters, M22, was next. I took my time and savored the view, with both direct and averted vision, noting how much brighter it was and how much more I could see with my vision averted about 30 degrees. I noted that it had a core that looked like soft cotton. From M22, I went to M13 and did a comparison. M13 is definitely one of the most beautiful globular clusters with its spatter of bright stars in front of its bright central core. Averted vision made M13 look like a bunch of diamonds against black velvet, especially when pushing the magnification up to 300X.

The Wild Duck Cluster (M1) was one that I had seen before, but not for quite some time. Every time I have tried to see it this year, I have been too rushed and couldn’t easily find it. This time I was successful at finding it by noting on my free downloadable monthly chart from SkyMaps dot com (Skymaps.com - Publication Quality Sky Maps & Star Charts) that it is basically even with a line drawn across the first stars down from the northern tip of Ophiuchus at the point where the line would almost meet the two stars at the southern end of Aquila. M11 is such a tight open cluster that it can be easily confused with a globular cluster. I noted that most of its stars are very evenly spaced and with the exception of a few brighter stars, almost all of them are the exact same magnitude.

By that time, the moon was in plain view and most of the folks were packing it up for the night, and I did too. All-in-all it was a very enjoyable night.

[Zeiss]

Great report! Do you use the 30mm for finding and then swap in the 14 for magnification on DSOs? Are they both 2 inch? Sounds like a fun night.

[samgray1]

Thanks, and sorry it was such a long post. I tend to go on and on and on and on.

I usually stay with whatever EP I start with, unless I am going to use high magnifications like 300X; I can even find some objects at 300X, because the FOV is so wide (1/3 of a degree TFOV on my telescope). When am at 300X, I get there by using my 20mm 100 degree AFOV ES EP with my 4X Powermate.

Basically, the EP I mention in the report is the one I used for that object. There are a lot of objects that are so large that you really want to stay with the 30mm to try to get it all in (50X mag at 1.64 degrees TFOV with my 12 inch Dob). My favorite EP is my 14mm; it is my workhorse that has the best overall views.

All my eyepieces (that I use) are 2 inch eyepieces. I bought all long focal length, wide view eyepieces and use them with my 4X Powermate for the higher magnifications so I have nice long eye relief and my 2 inch UHC and moon filters fit everything I use.

[GRB1984]

Excellent report! Thanks for posting. I cant speak for others but I like longer reports with more detail.

[Dublin sky watch]

I missed this when you first posted it..
Great report Sam and very well written up.
Totally enjoyed the read.
I still have not had first light with my own new ES eps...