This blog is part observation, part scope comparison, and part equipment test.

What can I say my time is limited I had to squeeze it all in to one session :)

All-nighter

Friday night started poorly - I missed the boat home (I was the last car not to get on). I left work at 4.15pm and finally got home at 9.15pm. So I thought, I'm not losing my Friday night. I decided to pull an all-nighter and finally get Jupiter under a clear sky. I had dinner, took a shower and delayed until Jupiter was high enough. I setup up at 1.00 am.

Refractor first

Jupiter was now well up and looked steady to the naked eye. I setup my Celestron CG5-ASGT and Put The Explore Scientific 152mm (Achro') Refractor on the Mount. Jupiter looked nice at 121x so I pushed up to 197x. One of the moons was closing towards Jupiter but I was too busy looking for detail on Jupiter's cloud decks to think ahead. After 30 minutes or so, I realised the close in moon had disappeared and its shadow was now transiting Jupiter.

I studied the shadow and shortly after it began, I noticed a dark feature in the North Equatorial Belt - I thought it was a double shadow transit.

Astro-Tech 8" Reflector

I took the Refractor off the mount and switched to the 8" reflector - I wanted to find which was sharper. I used the same eyepieces on both scopes - a Celestron Ultima LX 5mm 2" - with Antares 1.6x Barlow 2". This gave me 256x on the Astro-Tech and 317x on the Refractor - a significant difference but Jupiter did not offer any less detail down at 200x. First look and surprisingly I could not see the shadow with the 8". Jupiter was steady but show low contrast in both scopes - I think high haze was responible as the stars were dim.

I moved the focuser back and forth back and forth trying to pull in that dark feature I knew was there - but I could not see it.

This scope has really good optics - I have seen a perfect diffraction ring pattern around bright stars at high power - and for imaging it is superb. But the oversize secondary (wonderful for photography) is 35% by area and that's enough to reduce contrast visually.

Fringe Killer

I switched back to the Refractor and again the shadow transit was visible - I shot lots of video with a pocket digital and snapped many stills with a Nikon DSLR at Prime plus Barlow. The big Achro' was throwing up a strong purple halo around Jupiter - bigger and purpler (is that legal) at 317x than at lower power. I added a Baader Fringe Killer. If I trust any company to know what they are doing, its Baader. The fringe was reduced and now appeared more crimson than purple but the view was no sharper than before.

It was only the second time I had seen Jupiter all year and the first time seeing it high up in the sky. I was a little underwhelmed at how low contrast the view was - I have seen a shadow transit more obvious in a 4" Refractor. But it was great to be under the stars and have an unexpected shadow transit of Io for a scope comparison.

Summary

The Refractor - despite the fringing was able to show more detail. Jupiter appeared as though I was looking through haze - so I have no doubt under transparent skies the Astro-Tech would also have shown the transit.

The Fringe Killer - not effective is all I can say - perhaps the haze reduced its effect? I still want to have the option of using it though - perhaps it will prove itself as I use it more.

Feel like a got my Friday night back - thanks Jupiter!