NGC206 star cluster from M31Posted By James McSheehy |
Nice guiding and colors -- looks like your big TEC is enjoying the turn of the season.
Posts Made By: James McSheehy
October 1, 2010 07:54 PM
Forum:
CCD Imaging and Processing/Deep Sky
October 2, 2010 06:32 PM
Forum:
Beginning Astronomy?
Powermates and BarlowsPosted By James McSheehy |
The Powermates, like a Barlow, increase the effective focal length of a scope. How much is "too much" will depend on the aperture, seeing conditions, and the kind of mount you're using. I always assumed the 4X and 5X Powermates were more for astrophotography than for visual use.
November 8, 2010 01:23 AM
Forum:
Telescope Making
Figuring Dall/Kirkham primary.Posted By James McSheehy |
You could do the zones/knife-edge test modified for the ellipse, but I came across a diagram in one of Ingall's classic ATM books that showed an interesting test set up for a compound scope. The scope was pointed vertically down and tested in autocollimation for a null using a large pan of oil as an optical flat. This means you'd have to make the spherical secondary before figuring the primary, and build the tube assembly (or a test fixture).
December 20, 2010 03:33 PM
Forum:
Off Topic Discussions
Putting things in perspective! ;^)Posted By James McSheehy |
Sagan wrote "On the scale of worlds, humans are inconsequential: a thin film of life on an obscure and solitary lump of rock and metal." He continues with a litany of base human behavior as if there were nothing more to our existence than toil, pain, and death.
Carl Sagan possessed a gifted mind, but like many other scientists he ignores the greatest gift of all, the gift of consciousness. The mind's eye can see the whole of Creation, and it reveals a visage of truth, beauty, and by perseverance, knowledge.
Carl Sagan possessed a gifted mind, but like many other scientists he ignores the greatest gift of all, the gift of consciousness. The mind's eye can see the whole of Creation, and it reveals a visage of truth, beauty, and by perseverance, knowledge.
December 27, 2010 06:00 PM
Forum:
CCD Imaging and Processing/Deep Sky
Picture of the TEC Flattener and AP ReducerPosted By James McSheehy |
It looks like you are comparing Yuri's FF with the smaller offering from AP. The TEC FF is designed to be usable with medium format cameras (85 mm spacing). The 2.7" AP reducer doesn't try that hard, but they also have 4" corrector/reducers that will cover larger areas.
January 25, 2011 04:26 PM
Forum:
Off Topic Discussions
Epsilon Aurigae Makes LA Times Front Page Above...Posted By James McSheehy |
Thanks for the link. It's actually a well-written article, so unusual these days. 8)
January 30, 2011 04:21 PM
Forum:
Equipment Talk
KAF8300 and PhotometryPosted By James McSheehy |
The KAF8300 well depth is low at 25ke, and it has anti-blooming that affects linearity at the high end. These probably make it less than ideal for photometry. Binning 2x2 will make the well depth comparable (100ke) to chips with higher dynamic range, but I don't know what you can do about the anti-blooming other than stay away from the saturation region where it kicks in.
February 23, 2011 11:49 PM
Forum:
Star Parties
Winter Star Party dewing?Posted By James McSheehy |
If the air temperature is less than 10F above the dew point, you will eventually have dew (or frost) on any surface exposed to a clear sky. Dew caps will delay the onset for a while. Bring a dew strap heater to be 90% dew free. I say 90% because in humid climates like Florida the air temperature usually drops overnight until it reaches the dew point, and at extremely high relative humidity even dew straps sometimes fail to keep lenses dry.
February 24, 2011 07:18 PM
Forum:
Maksutovs
MK91 and DM4Posted By James McSheehy |
Nice scope, but hanging off to the side of that DM4 and tripod, it looks like an accident waiting to happen.
February 25, 2011 11:14 PM
Forum:
No Holds Barred
Intresting video about the federal reservePosted By James McSheehy |
Back in 2008, Bernanke and (then) Treasury Secretary Hank Paulson discovered they could say and do anything they wanted, and no one challenged them. In 2009, Bernanke testified to congress and claimed the Fed had expansive, untested powers to deal with the economy, and absent any specific regulations, they could do almost anything. He essentially dared Congress to stop him!
We elected a new Congress last year, and many thought it would rein in some of these crazy abuses. From what I can see, someone is holding the reins, but it isn't Congress or the President.
Meet the new boss
Same as the old boss...
We elected a new Congress last year, and many thought it would rein in some of these crazy abuses. From what I can see, someone is holding the reins, but it isn't Congress or the President.
Meet the new boss
Same as the old boss...
Funding Member
