Working on the Herschel List

It was very cold last night for southern Texas, well below freezing. I took the opportunity of a clear moonless sky to drive to the Hill Country State Natural Area and find a few more of the Herschel 400. This expedition took me halfway through the January objects as listed in Steve O'Meara's "Herschel 400 Observing Guide".

I really like the approach that O'Meara takes in this book. His organization of the objects keeps my scope pointed in about the same area of the sky when that is possible. His organization so far (and I have completed the September through December chapters) organizes the objects for when they are closest to the thin overhead portion of the sky.

For something different, I thought I would post the notes I made on these objects. They are organized by the time that I observed them last night (local time). I made the notes with a voice recorder and then transcribed them on computer afterward.

Here are my observations:

1647 OCl Tau
Date: 9 January 2010 Local Time:2003 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: At 90X, this is a medium bright OC with dozens of bright stars and probably hundreds of dimmer stars in the background. This is an easy cluster to find and observe. It is almost naked eye at this site.

1817 OCl Tau
Date: 9 January 2010 Local Time:2006 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: Many dozens of stars in this cluster. Not as bright as 1647, but this cluster has a more uniform appearance than the previous. There is central gathering of these stars as though I am looking at a large fourth of July starburst. Though this cluster is in Tau, it is more easily found in relationship with the stars of ORI.

1664 OCl Aur
Date: 9 January 2010 Local Time:2015 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: At low power, this OC is relatively dim and poor. There is a “home plate” shaped asterism in the center of this cluster. There are 20-30 reasonably bright stars in this cluster. Though there is some central tendency of this cluster, the asterism is relatively empty of stars at its center.

2126 OCl Aur
Date: 9 January 2010 Local Time:2024 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: Easily found by starhop. Quite dim OC with one bright star near it and then the rest of the cluster is a background blush of stardust to the west of the bright star. Poor cluster with some central consolidation. Best observed with averted vision.

1857 OCl Aur
Date: 9 January 2010 Local Time:2033 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: A very small and very dim OC, dominated by a central star which appears reddish. This is a very poor cluster with few individually discernable stars. There is not quite enough of it to determine if there is central consolidation.

1907 OCl Aur
Date: 9 January 2010 Local Time:2036 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: Small but reasonably bright OC next to M38. It is easily seen with my finder scope. At low power it appears mostly as a blur with a few individual stars. At 180X there are 30-40 stars seen with central consolidation.

1931 C/N Aur
Date: 9 January 2010 Local Time:2040 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: Small nebula which is quite bright and easily seen. At low magnification it appears almost circular and like a planetary nebula. At 180X it is not round. It has a lobule of brighter material to the west side and a flat side on the eastern side of the nebula.

2281 OCl Aur
Date: 9 January 2010 Local Time:2045 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: This is a cute OC, east of AUR. Clearly visible with finder scope. With low power appears to have an asterism that looks for all the world like a capital “S”. The cluster is moderate in richness and has central consolidation.

2169 OCl Ori
Date: 9 January 2010 Local Time:2048 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: Small but bright OC. At low power appears as an offset trapezoid with about 15 members. There is a bright trio of stars in the shape of an equilateral triangle near the center of the OC. They are remarkably the same brightness and remind me (minus one) of the central quadrilateral in the Orion Nebula.

2194 OCl Ori
Date: 9 January 2010 Local Time:2058 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: A small, dim OC found easily with its relationship with 2169. It is poor, with 10-12 members and has central gathering of its stars.

2186 OCl Ori
Date: 9 January 2010 Local Time:2105 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X
Note: Very small and very dim OC. No central consolidation. Appears as a haze on top of other unrelated stars in the foreground and background. This is one of those objects that takes great imagination to call an object at all.

2022 PlN Ori
Date: 9 January 2010 Local Time:2115 Seeing: 5.0 magnitude Aperture: 16” Power: 56X 90X 180X
Note: Finding this planetary required a medium length starhop. Appears at high power (180X) to be a dirty snowball. It is not starlike. It is reasonably easy to pick out at low power as well.

Astronomy Resolutions for 2010

Here are my personal astronomy goals for the coming year:

- Complete the Herschel 400 list (I have about 300 objects to go)

- Complete the Master level of the Outreach club of the Astronomical League (about 70 more hours of star party fun)

- Learn how to do more sketching at the eyepiece (Maybe this means the open cluster club, Asteroid club, or the Lunar II club?)

- Attend the Texas Star Party for the second time.

- Find at least 3 more dark sky sites I can easily access within 2 hours of San Antonio including one with low horizons.

Dark Skies to all

Risk

Sunspots are back

Several times this December, I have taken a look at the sun with my 10 inch scope and a Baader filter. The filter works fairly well in seeing sunspots and other white light features of the sun.

Yesterday, I tried taking a few photos with my phone camera through the eyepiece. Most of the images were not very good. A few were worth looking at. The image attached to this post was taken through a 10mm Radian eyepiece at a magnification of about 120X. The cropped area is about 1/20 of the original photo. It clearly shows the two pairs of spots which I saw visually.

I have read that sunspots always appear in pairs, that the spots are the two points where a local magnetic field line crosses the visible surface of the sun. In this photo, there are two nearly equal pairs. There is an inner pair of small spots and an outer pair of larger spots. Also, spots appear in pairs that are parallel to the sun's rotation, which is approximately parallel with our rotation around the sun. These pairs did move leftward in my reflector, so the west is to the left and the east is to the right. South is up and north is down in these views.

Dark Skies, Good People

We had nice weather in San Antonio over the weekend too. Saturday evening was a club outing to a dark sky site. The weather and the company were great. I was able to finish off the December portion of the Herschel list, as O'Meara has it programmed. I am now up to date, having finished up September to December. There were some long star hops in the December list.

I spent the rest of the time in my binocular chair, doing a mini Messier Marathon of the available objects.

By morning, what had been a moderate dew, had frozen solid on my dew covers.

All in all, a nice observing night.

Cleaning a Primary Mirror

After a summer/fall of frequent observation and two major rebuilds of the furniture for my 16 inch Lightbridge optics, there was a fair amount of earthy dust and even more saw dust coating my primary mirror.

I had a good long conversation with the owner of a 24 inch StarMaster scope at the Texas Star Party about cleaning mirrors. Before forgetting all his advice, I decided to do a full baptism of my mirror last weekend.

I removed the mirror cell from the base box like I have a number of times in my building project. Taking it out is never a problem. (Putting it back in is not quite so simple. It takes a steady hand, carefully placing the mirror cell on three springs without knocking the springs over. )

Next, I removed the three mirror clamps from the periphery of the cell. That does not release the mirror, because there are four places on the periphery where black RTV calk was used to further hold the mirror in the cell. I took a sharp knife and cut through each bead of calk next to the mirror. (Marking the mirror to know what rotation angle it was in the cell is a really good idea.)

I then was able to slide the mirror out of the main cell casting. It came out with the rear-of-the-cell spider pieces attached. There are three independent supports that make up this “spider”. Each support consists of two three cornered plates on a balance beam. Each three corner plate had one sticky pad attached to the mirror with double sided paper tape. After fiddling with these tape pieces unsuccessfully for a few minutes, I just pulled the triangles off the mirror, leaving a paper spot on the mirror in 6 places.

I then took the mirror to the back porch, placed it mostly vertical against the house, and hosed the mirror off. That took most of the contamination off the mirror, I am quite sure. But I wanted to go a little further.

I filled up a roll under the bed Tupperware container about half way. This was a new container I bought for this purpose and hosed out. These containers have a bottom which is just a little more than 16 inches by about 27 inches. I put a couple drops of dish washing detergent in the water and used the hose to spread that out.

I put the mirror in the water bath with about an inch of water over the top of the mirror.

I had previously obtained some cotton balls that were 100 percent cotton. There was no way to verify that they did not have any softener in them, like surgical cotton. But they were called 100 percent cotton and did not list any other ingredients.

I used a cotton ball and gently ran it from the center of the mirror to the edge. I threw that cotton ball away and did the same with another ball just a half inch or so from the first one. I continued in this manner around the mirror – one pass of each new cotton ball from the center to the edge. My intent was to have the smallest risk of collecting a scratching grain and scratching the mirror over and over with it.

After this cleansing, I took the mirror out of the bath. I put it vertically next to the house again, and rinsed it with a quart or so of distilled water.

Almost all the water drained off the mirror leaving it without drops. There were a few drops and I collected them with the corner of a piece of toilet paper.

After the mirror had finished drying, I saw that I had missed a few places on the mirror where I had evidently not used a cotton ball. There were some small streaks of dusty appearance between my radial strokes - but there were not many. Evidently, using the cotton balls had removed a layer of dust that had remained adherent during the spray cleaning and the immersion.

After the mirror dried, I was able to put the rear support beams with triangular plates in place, and then to slide the mirror back into the cell so that the cut surfaces of the RTV calk exactly matched. I put the three mirror clamps back on. (Remember not to do this tightly.) Then The mirror cell was bolted back in the bottom box of the scope.

It was all pretty simple and the mirror was obviously much cleaner after the operation. Even just a spraying with a hose would clean the mirror a lot the next time round.

I don’t think I would do this more than every year or so, but it is nice to have a clean mirror again.

Failed Astronomy

Some nights, things just don’t work out. I had one of those nights on Sunday.

After a long week of cloudy skies, Sunday daylight broke with hints of sunshine on the top of a fog bank. As Diane and I sat in Starbucks having coffee and coffee cake, my spirits began to rise with the glucose and caffeine levels in my blood stream.

Confidently, I said that the clouds would burn off by noon and we had the potential of a clear sky for the evening. That was a nice thought because we were very close to new moon and the Geminid meteor shower was scheduled to peak before midnight.

I set about to cautiously think about an observing evening. Maybe the night would turn out well.

As I worked around the house during the afternoon, I was overjoyed to see that the sky was bright blue. The recent rain had pushed out haze and left the sky cloudless.

I looked up Hill Country State Natural Area on the internet and saw that a public hunt was scheduled to start on Monday. The park would be closed at 10 PM. That was good enough for a nice night of Herschel observing, but it was a little disappointing that the park would not be open for the peak of the meteor shower.

I called the park office, intending to let them know that I would be at our observing site that evening, and that I would be out by the 10 PM closing time. The nice ranger on the phone told me that the park would actually be closed beginning at sunset, not 10PM. Not wanting to argue, I thanked the ranger and started to think of other options.

“Oh well”, I said to myself. “I have observed from a pull off on the park road before”, and I decided that I could do it again. Yes, I knew that I could expect to have 15-20 cars with bright headlights come by, but the rest of the time I would have 5.5 magnitude stars visible. It could be a nice night of Herschel observing (maybe I could finish the December list in O’Meara’s book) and then I could settle down to watch meteors toward 10 or 11 PM. The drive home would be 10 minutes shorter as well!

I arrived at my observing spot about 6:30 PM. Diane begged out because she had some work to do as Santa’s Elf. No one else answered my email on the San Antonio Astronomy Yahoo group when I posted that I would be out near the park. I planned on being by myself. I was.

When the sky turned dark enough to see the “faint fuzzys” on the Herschel list, I pulled out the O’Meara book and reached for my trusty digital recorder. But that recorder was back in my house in Helotes, 40 minutes away. Oh Well! I looked at a couple of the objects, but lost interest fairly quickly, knowing that I was not set up to record my observations. I looked at a number of Messier objects with my 16 inch scope. But I was a bit bummed out.

About that time, I realized that the rising Orion constellation was dimming noticeably. I looked straight up. The Milky Way had disappeared too. I looked further west, and Jupiter was shining brightly and those constellations were all present.

So it was just a local cloud.

Except that about 15 minutes after the sky cleared, there was a general dimming of all the stars and then they all winked out. They stayed that way. It was 8:45 PM. I never saw another star.

On this little trip, I had experienced loss of an observing field to a “hunt” on the State Natural Area park lands. I had to set up where bright car lights spoiled my night vision every 10 minutes or so. I forgot to bring a little recorder which spoiled my ability to run the list I had intended on. And finally I was shut out by a thick bank of clouds that suddenly formed from a perfectly clear sky. The sky has stubbornly remained cloudy all week long, ever since.

I just thought I would post this, to remind me how special it is when everything works out splendidly! Surprisingly often, the weather, the moon, the place, and the gathering of friends are all perfect. As I sit here today, I am planning on that all working out for this Saturday evening.

Wishing you Dark Skies and a Merry Christmas,
Eternally the optimist,

Risk

Simple dew shields from "Fun Foam"

I went to Hobby Lobby last week to buy a few sheets of 2mm thick black foam rubber. I found them in the children's education part of the store. I bought the foam to make a backdrop for my secondary on the ring structure of my new Looking Glass.

While I was there, I bought a couple more sheets to play with. Nearly simultaneously, Matt R. was there and working with the foam. He kindly made me a pair of dew shields for the Eyes of Texas, my 80mm binocular. He also cut a sheet for my Telrad.

From my scraps of Fun Foam, I built a simple wrap-around dew shield for my 50mm finder. I built it so that I could put a hand warmer packet inside the ring if I desired.

Last night, in my observing session at Hill Country State Natural Area, the dew was pretty heavy and early. (On the way home, there were blankets of radiation fog in every valley.) I had put the finder scope dew cover on and it kept that objective clear of dew all evening. I ended up needing to wrap a hand warmer around the eyepiece of the finder with a rubber band. that worked, but I was late in choosing to do this and had to deal with occasional dew on the eyepiece.

The Telrad cover was attached by wrapping rubber band around the long axis of the Telrad base. The cover was held nicely in place by the rubber band. This kept the Telrad remarkably free of dew without sacrificing the utility of the finder.

I was finally done in for the night at about 830 PM, two hours after I began to observe, by dew forming on my secondary. I forgot to bring my hair dryer for that. With a hair dryer, I would have been able to continue for a while longer, until fog formed in the observing area.

For just a couple bucks, these "throw-away" dew covers are extremely easy to make and work very well. Their outer surfaces were *covered* with dew by the time I packed up, but the optics were nice and clear.