Details on Mars

Matt and I set up my 16" modified Lightbridge to look at Mars on Saturday night near San Antonio.

I was using my 10mm Radian eyepiece at 180X.

With no filter, Mars appeared as a rather large disk with no features that I could see. It was a big red version of Uranus which I had seen many times over the summer. However we ran my set of filters to see what might emerge.

With a yellow filter, I was able to see a bright lenticular shape on the north end of the planet. This was the first time I had ever seen planetary detail on Mars. Just like with double star observing, North was determined by seeing which way the planet fell out of the eyepiece field upon waiting a minute. The direction that the planet moved was West. North was therefore 90 degrees counter clockwise from that direction.

An orange filter did not add much more detail than the yellow provided.

A deep red filter was useless for me. All detail seemed to have disappeared including the ice cap.

With a green filter, not only was the ice cap visible, there were some smoky smudges on the disk. I especially thought I saw more of this toward the west and a little north of the Martian equator.

A Lumicon Deep Sky filter showed little detail, though the ice cap could be seen.

A Lumicon UHC filter showed both the icecap and almost as much smoky detail as the green filter.

The scope sat outside all evening before we observed at about 930 PM. However, there was still considerable thermal activity on the mirror observed in a star test. I was able to see the polar ice cap about half the time I was looking at the disc. The smoky areas, with the green filter, seemed to be present about 1/3 of the time.

It was interesting trying to filter out my own eye floaters from the image my brain was trying to interpret. The disc is just small enough that a floater which passes over the disc calls attention to itself as though it might be a planetary detail.

Rick

Ruminations on Astro Sketching

I think one of my central problems with drawing is that I want to draw
more detail than what I see.

When I sketch a tree, or a landscape, I have learned by experience that
the secret to making it represent what I really saw is to include less
detail than a photograph would.

I think I need to start thinking about astro sketching the same way.
Maybe I should - like John E - go back to sketching a constellation.
Accurately putting each star that I can see in its place, but not
worrying about getting every star into the drawing.

Instead, my impatience too often leads to unfortunate results when I get
tired of drawing what I see and suddenly create a mass of close dots to
represent an area of cloudiness. In the end, it is a sense of rush that
leads me to ruin what I have put time into drawing.

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.