Evening and Morning Light on the Crater Petavius
By Frank McCabe
On the 6th day of March 2007, I sketched crater Petavius in the evening light
close to the time of sunset at Petavius. This large rather circular floor
fractured crater appeared elongated and ellipsoidal because of its proximity to
the limb and in a somewhat unfavorable libration. I was hoping on Wednesday
evening during the next lunation to catch the crater again just after sunrise but
I was thwarted by clouds and rain 16 days after the first drawing. However the
next evening had some breaks in the cloud cover before the rains reappeared and I
was able to sketch Petavius in the lunar morning sunlight and also at a more
favorable libration which explains its more circular appearance. Upon completion
of the second drawing I rotated and resized it using Microsoft paint and placed it
with the earlier sketch. Seeing the same features in the morning and evening light
adds to the endless enjoyment of lunar observing any time during a lunation or
between lunations as occurred here. The March 6th sketch (evening at the crater)
was posted at this site March 17, 2007. The March 23rd sketch (morning at the crater)
made 17 days later is posted second. I used the same telescope and eyepiece to
sketch both drawings.
Sketching: 1st Sketch
For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’
pastel pencils and a soft blending stump.
Telesccope: 10 inch f/ 5.7 Dobsonian and 6 mm eyepiece
Date: 3-6-2007 2:45-3:30 UT
Temperature: -6°C (21°F)
Clear, calm
Seeing: Antoniadi IV
Colongitude 113.5°
Lunation 16.5 days
Illumination 95%
Sketching: 2nd Sketch
For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’
pastel pencils and a soft blending stump.
Telesccope: 10 inch f/ 5.7 Dobsonian and 6 mm eyepiece
Date: 3-23-2007 1:10-2:20 UT
Temperature: 17°C (62°F)
Partly and at times mostly cloudy, variable winds
Seeing: Antoniadi III- IV
Colongitude 320°
Lunation 4 days
Illumination 22 %
Frank McCabe
Wow Frank, not only is that an amazing comparison, but both sketches are beautifully done. Morning/Evening comparisons of various Lunar features sounds like a great sketching project =D
Jeremy,
Thank you. I have wanted to do this with other craters as well.
Frank