M100 shows it's beautiful arms with Night Vision

[alanjgreen]

I managed a couple of hours with the 20" big dob last night (11pm till 1am) minus some "cloud passovers".

My goal was to test M100 views (in Leo) with varying Televue eyepieces and Photonis Night Vision (PVS-14).

- (Any eyepiece longer than 27mm increase effective focal ratio of your scope. 35mm is like a x0.7 reducer. 55mm is like a x0.5 reducer).

 

With the sky darkening all the time, the views got better and better...

I was rewarded with my first sight of the complete arm structure of this galaxy (very happy).

- I found that the 55mm plossl (x38) showed the complete inner arm structure in direct vision, with the long outer arms coming with averted and "gain" adjustment.

- The 35mm Panoptic (x60) gave better image scale, but needed averted for the arm structure.

- The 27mm Panoptic (x77) gave great image scale but slightly less arm action than the other two.

 

I concluded that faster focal ratio really helps pull out the arms from face-on Galaxies, and I look forward to further experimentation in this area in the coming nights. My favourite view was with the Pan35 but it needed some proper observation techniques. Less experienced observers would probably prefer the "easier" view in the 55mm.

This really is a beautiful galaxy.

Alan

p.s. I will write up an explanation of "afocal" night vision theory and usage in a separate thread.

[celestron8g8]

Nice report , I've never seen M100 other than photos . Most my observing in the past was in the city late at night but now LP is so heavy I don't observe anymore at home .