Correction. That should be: The PPMXL catalog combines USNO B1.0 and 2MASS.
Type: Posts; User: Carter Scholz; Keyword(s):
Correction. That should be: The PPMXL catalog combines USNO B1.0 and 2MASS.
There is good information about photometry here:
http://brucegary.net/dummies/x.htm
including a method for converting J- and K-band magnitudes into Vmag.
Some theory here:
...
Jones 1 ( = PK104-29.1)
A few nights ago, in 16" under SQM 21.3 skies, and 3/5 seeing, I could hold 3 galaxies reliably. Might have glimpsed one or two others. Nice target, thanks Alvin.
Just as another data point, I've observed Pals 7 (=IC 1276), 8, and 9 (=NGC 6717) with an 8" f/6 Dob from very good skies. To my eye, those three are the easiest, and of similar difficulty. With a...