Virgo Core

(fritz kleinhans)


The Virgo Galaxy Cluster Core, M84 and M86, are a popular target, as is the chain of galaxies leading away from here (Markarian's Chain).


Virgo Core:
May 16-17, 2015; Casitas de Gila, NM.

TEC 140 prime focus, TEC field flattener, AstroPhysics Mach1 GTO mount, 50 mm f5 Borg guide scope, Lodestar, PhD2 autoguiding.  Canon-Griffin 600D @ ISO 800, 14 x 8 min subs = 112 minutes, four darks, two flats;T~44F; intermittent sneaker clouds.  Full resolution = 0.905 arcsec/pixel. Acquistion and processing with Image Plus.  Additional processing with Picture Window Pro 7.

This shot is longer, utilizes improved processing skills, and goes deeper than the 2012 shot below; however it is not as sharp.  This probably reflect seeing.  The shot here was taken with high haze drifting in and out.  Auto grade was used in Image Plus, which eliminated 7 of 21 shots.

 

 

Virgo Core:
Black and White negative print of above, labeled.  Well, almost!  I reprocessed the above image and this is the B&W negative of a previous effort.  Pictures are never done!


 

Limiting Magnitude:
200% scaling: Using Sky Tools Pro 3 and Ned, I chased down some magnitudes. S = star, G = galaxy, decimal points omitted.
I'm willing to say that the stars go to m = 19+ and the galaxies go to m = 18+.  It's hard to be sure of the identification of the faintest galaxies.

 

Markarian's Chain, Virgo Core:
May 14-15 and 16-17, 2009, Albireo West Observatory, CO.

500 mm f4.0 AIS manual focus Nikkor at f4.8 on Losmandy GM-8 with SBIG-STV & efinder autoguiding.

Canon Hutech 400D @ ISO 800, 16 x 8 min subs = 2hr 8 min, several darks. (temperatures were in the 30's and 40's F; sky clear, seeing poor)

Cropped, full resolution 2.4 arcsec/pixel.  For a regular camera lens, the 500 mm Nikkor is very sharp.  That makes it just good enough for astrophotography.  Typical of camera lenses, the corners are not all the same.  The lower left corner here has more aberrations.  Not near as good as the TAK 85 mm Baby Q.  Comparable prices, but the TAK is designed for a single purpose and it shows.


Virgo Core:
April 21-22, 2012; Casitas de Gila, NM.

TEC 140 prime focus, AT2FF field flattener, AstroPhysics Mach1 GTO mount, 50 mm f5 guide scope, Lodestar, PhD autoguiding.  Canon-Griffin 600D @ ISO 800, 5 x 15 min subs = 75 minutes, two darks, two flats; cold.  Full resolution = 0.905 arcsec/pixel.

 

 

 


 

Virgo Core Finder Chart (Guide 8)