Posts Made By: Dave Mitsky

I was at the Naylor Observatory again on Wednesday night to help out with the observing portion of the ASH spring astronomy class. The B fragment seemed even more difficult to see through the 17" f/15 classical Cassegrain than it did the previous night.

Dave Mitsky

My Celestron Ultima 2x Barlow lens works fine but I rarely use much more than a 6mm focal length (67x) with my PST. I can almost always employ a focal length of 8mm (50x). Most of the time my 8-24mm Vixen zoom eyepiece is all I use.

Dave Mitsky

I would run into Paul from time to time at various star parties. IIRC, he had developed carpal tunnel syndrome or some other malady and had to give up making eyepieces.

Dave Mitsky

A number of Cherry Springs State Park regulars and I sighted the young crescent Moon without optical aid on a crystal clear Friday evening at 8:20 p.m. EDT (00:20 UT). It was quite slender but unmistakable. I took a number of prime focus Canon EOS Digital Rebel DSLR photographs through my 101mm Tele Vue refractor and with 18-55mm and 80-200mm Canon EF-S zoom lenses. I'm posting this brief report from the Galeton, Pennsylvania, library so I won't be posting images until I return home.

http://www.upstateastro.org/stars/cssp.html

Dave Mitsky

Here's the young crescent Moon with an 80-200mm zoom lens.

Dave Mitsky

Overall, I'd recommend _Nightwatch_ for its complete treatment of amateur astronomy but Phil Harrington's _Star Watch_ is a very good choice as well.

http://www.fireflybooks.com/books/3026A.html

http://www.philharrington.net/swtch.htm

Dave Mitsky

Those are two impressive images, Paul.

Dave Mitsky

The two brightest fragments (B and C) of Comet 73P/Schwassmann-Wachmann 3 have been putting on a very interesting show for the past few weeks. See http://www.skyhound.com/sh/skyhound.html and http://www.universetoday.com/am/publish/comet_73p_roundup_051106.html and http://www.spaceweather.com/swpod2006/09may06/Vandebergh.jpg

Dave Mitsky

Two of my most memorable telescopic sights have been of Omega Centauri. The first was through the 36" f/5 Tectron Yard Scope and a 27mm Panoptic at the 1995 Winter Star Party. The second was through a 22" Starmaster at over 500x from an altitude of 12,500 feet in the Bolivian Altiplano.

Dave Mitsky

There's a definition of integrated magnitude at
http://www.daviddarling.info/encyclopedia/I/integrated_magnitude.html

The concept of surface brightness is an important factor in determining the visibility of galaxies. Surface brightness is measured in magnitudes per square arcminute. Under dark skies, a DSO with a surface brightness of 12.5 or brighter should be detectable with almost any telescope. However, if the surface brightness is 14.5 or fainter, the object will be a real challenge to observe.

Face-on spiral galaxies are often hard to detect (M74 is considered to be the most difficult object in the Messier Catalogue) and the expansive M101 has the highest surface brightness figure of all the Messier galaxies, which in this case is not a good thing at all.

Here's a list of the Messier galaxies, their integrated visual magnitudes, and their surface brightnesses:

M31 3.4 13.6
M32 8.1 12.7
M33 5.7 14.2
M51 8.4 12.6
M58 9.7 13.0
M59 9.6 12.5
M60 8.8 12.8
M61 9.7 13.4
M63 8.6 13.6
M64 8.5 12.4
M65 9.3 12.4
M66 8.9 12.5
M74 9.4 14.4
M77 8.9 13.2
M81 6.9 13.0
M82 8.4 12.8
M83 7.6 13.2
M84 9.1 12.3
M85 9.1 13.0
M86 8.9 13.9
M87 8.6 12.7
M88 9.6 12.6
M89 9.8 12.3
M90 9.5 13.6
M91 10.2 13.3
M94 8.2 13.5
M95 9.7 13.5
M96 9.2 12.9
M98 10.1 13.2
M99 9.9 13.0
M100 9.3 13.0
M101 7.9 14.8
M104 8.0 11.6
M105 9.3 12.1
M106 8.4 13.8
M108 10.0 13.0
M109 9.8 13.5
M110 8.1 13.9

For more on surface brightness see http://mysite.verizon.net/vze55p46/id18.html

Dave Mitsky