Image of the day

Captured by
Douglas Rollain

M20 Trifid Nebula in LRGBHa

My Account

New to Astromart?

Register an account...

Need Help?

Moon and its Negative image

Moon and its Negative


Acquisition Details
  • Number of frames:
  • FPS:
  • Focal length:
  • CMI/CMII/CMIII:
Description

Breaking all the rules - single image taken indoors through a window. Scope is a home-made refractor using a Jaegers 128mm diameter 590mm fl oil-spaced doublet objective. Camera is Canon digital rebel with IR cut filter removed at prime focus to the objective. Registax 6 wavelet processing and Photoshop used to invert for negative. Oil-spacing using castor oil makes a large difference in performance for this doublet objective. This lens is supposed to be f/5 with 640mm fl, so perhaps the oil spacing affected the fl and speed. This is unusually good performance from such a fast f/4.6 achromat. It is interesting to study the image and its negative side by side.

  • User details
  • Ron Masters
  • Ron Masters
  • November 8, 2015