Best Night in Ages last night!!

The large glatter 45 degree face barlow target that goes in the end of the drawtube is even easier to use with a truss Dob.

Thats what I do, its the only way to go with a truss, mine's from kendrick, not glatter.

Ahh, When you said, you must check it out I thought maybe you were a diehard Cheshire, Autocollimator and/or CatsEye user and weren't familar with the premium lasers like the Kendrick, Farpoint and Glatter.

Did you see Kendrick have come out with a switchable Barlow Target. Just press a lever or switch (cant remember which) and the barlow lense is moved in and out of the lightpath for Secondary and then Primary barlow collimation. No more inserting and removing the whole target. It can be purchased as an upgrade for existing Kendricks afaik.

Just catching your reports now Keith. Very long, with lots of detail - and a great read as well. Nice to read about newbies exploits in to the hobby like yours.

Seanie.

I knew Virgo would be well placed for me last night, due south at the time I would be observing. Its a pity transparancy wasn't great with moisture in the air meaning skyglow extended up to about 40-50 degrees.

Why is it when there is a lot of moisture in the air that transparancy seems to be worse then usual?

I know i mentioned the pollution "skyglow" one night reached about 60 degrees upwards and Keith told me it was all to do with the level of moisture in the air.

I guess water droplets act as magnifying glasses and magnify the light pollution at street level?

Paul --

It's not so much that they act like magnifying glasses, but just that they scatter the light around. So some of the light pollution that was headed off into space ends up coming back to your eyes/equipment.

Some of it is also due to extinction (where the light from the target hits the water droplet and gets knocked off course). But this effect is more relevant when at a dark site -- at a light polluted site the scattered light pollution will be a much bigger factor.

Dust will also reduce transparency, but I think in that case the scatter and extinction are more evenly matched.

-- Jeff.