[mental4astro (Alexander)]

Hi all,

One of my favourite DSO's is Eta Carina. It has so much to offer for all apertures, large and small. It is also one DSO where, if viewed from a dark site, a small aperture can actually show just about as much extensive nebulosity as seen in photographs.

I have recently completed my fifth sketch of Eta Carina. Curiously enough, it is also my first sketch of Eta Carina from a dark site. I have been surprised by the extent of the visible nebulosity, which would be typically seen in deep photos.

I've thought it would be a good opportunity to post all five sketches together. This way a comparison can be made of the effects not only of aperture, but also of urban vs dark skies.

I've placed the sketches in order of aperture from smallest to largest, and noted where each sketch was done. All these sketches, other than the first one done with binos, were done with the added use of an OIII filter.

1, 11X70 binos, from my home in Sydney. The enormous open cluster NGC 3532 is also in the same field of view.

2, 4" f/5 refractor at 17X, from dark site

3, 8" f/4 reflector, at 27X, from my home in Sydney

4, 17.5" reflector, at 57X, from Oval at Randwick Girls' High School

5, 17.5" reflector, at 153X, from my home in Sydney

I hope this series of sketches serves as a good guide to the capabilities of different apertures. I also hope it demonstrates that having a smaller aperture can have its advantages over larger ones too.