observations,questions and suggestions..

[nickdud]

so tonight i hit the garden (after a few beers i admit) and had an hour or 2 with Jupitor, Pleiades and Andromeda.

Andromeda was very high and confirmed my thoughts that i need a counter-balance weight on my scope/mount setup(more later elsewhere, i have a plan in hand which will be posted at a later date).

Pleiades was ..........errr.......... yes...........i'm sorry......... spotted,briefly looked at and passed by, but to my credit, i do find it by eye/scope very easily....(i know, slap me and send me back for the night!!!!)

and so to Jupitor. i have found that if i put the apperture cover on my scope but remove the middle cap, i can see/define more of the bands, so, if i make a smaller hole(drill a smaller hole in the mid cap), will i get more contrast/see more band detail while removing the overall brightness or should i just buy(the painfull word that goes hand in hand with this obsession) some filters?

and finally to suggestion............

big warm coats really dont come bigger and warmer than this....

http://www.surplusan...ket-494018.html

i've had mine longer than my scope and i've slept loads in my garden in the winter in it so nuff said....

and you will be nice and toasty with some big warm toasty boots, my new ones are well comfy......

http://www.polimil.c...esert-boot.html

i have no connection with these companies other than i have the jacket and the boots...... and i'm toasty;)

cheers astro peeps;)

[nickdud]

so? better contrast by smaller apperture or filters? any ideas please?

[John]

By viewing Jupiter through the small hole in the aperture cover you are reducing the aperture of your scope. Thats why the brightness decreases. So making an even smaller hole means reducing the aperture even further - you effectively have a very small aperture scope, which means, while the image of Jupiter will seem less bright, the amount of detail to be seen will be much less as well. It's not a good solution to be honest.

If you study Jupiter for quite a while, your eye will adjust to the brightness, and you will start to see more details. As Jupiter rises in the sky the details will become clearer as well. Filters may help a little though I don't find I need them to see good details once my eye has adjusted.

So, to answer your question, better contrast by spending more time observing the planet and allowing your eye to adjust. The details will come.

You don't say what eyepiece you were using. I find 120x - 180x gives good results with Jupiter. More magnification than that does not seem to make the details any clearer - often the opposite.

[nickdud]

thanks john:)

i think i had a 6 or 10mm ep, so 60-100x mag

[Ags]

Check your collimation - tha might be why you get a much sharper image with the aperture reduced - it would also reduce the effects of poor collimation.

[John]

Check your collimation - tha might be why you get a much sharper image with the aperture reduced - it would also reduce the effects of poor collimation.

Good suggestion but don't think the OP's F/5 120 refractor has collimation adjustment ?

[nickdud]

tis just a simple frac, no col required:)

[Ags]

Doh... Sorry, for some reason I thought you had a reflector....

The chromatic aberation on startravels is very bad indeed. This gets a lot better as you stop the scope down as you have noticed. Perhaps you should look at getting a baader fringe killer filter, which will filter out a lot of the false color.

I own an ST80 and only use it for low power viewing of DSOs and star fields - these short tube fracs are not really designed for high power planetary observation.