M42 Great Orion Nebula & NGC 1973 - 77

02/08/04

Canon 10D & Orion ED80 Refractor

Comparison with .8X & f/6.3 and f/5 Focal Reducers

by Gary Honis

The first two images below were first light for the Orion ED 80 refractor. I took images through the ED80 with a Canon 10D digital SLR before and as the 17 day old Moon was rising. The ED80 was piggy-backed on a 10 inch Meade LX200. A few manual guide corrections were made for the short exposures using a 9mm reticle eyepiece in the LX200. IMAGES PLUS was used to acquire the images. Images were taken from my backyard deck observatory in Conyngham, PA. Skies were slightly hazy and moderately light polluted. The ambient temperature was 15 degrees Fahrenheit.

The ED80 is 600mm and f/7.5

Images below were taken with the ED80 for comparison as follows:

1. ED80 - No Reducer............................................................f/7.5

2. ED80 with Televue 0.8X Photo Reducer / Flattener.........f/6.0

3. ED80 with Celestron f/6.3 Reducer / Corrector................f/4.7

4. ED80 with Celestron f/5 Telecompressor..........................f/3.8

NEAT IMAGE was used for noise reduction. All images are full frame.

Piggy-backed Orion ED80 on 10 inch LX200:

1. M42 & NGC 1973-77 (without .8X reducer)

Sum stack of 1 three minute, 6 two minute and 6 one minute exposures at ISO 1600:

2. M42 & NGC 1973-77 (with .8X reducer)

Sum stack of 2 three minute, 2 two minute, 6 one minute and 3 thirty second exposures at ISO 1600:

3. M42 & NGC 1973-77 (with f/6.3 reducer)

Sum stack of 12 thirty second exposures, 15 one minute exposures, 2 two minute exposures & 2 three minute exposures at ISO 1600:

4. EXPERIMENT: M42 & NGC 1973-77 (with .5X reducer)

Sum stack of 9 thirty second exposures at ISO 1600:

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