Sunday, January 10, 2010

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.