Seeing conditions of late (Sydney)

bigstretch (Nathan) · #1 03-07-2008, 11:08 PM

These last few weeks have been pretty average observing for me. As a noob I am wondering has this been due to poor seeing conditions or is it possibly my scope.

I've had my Meade 8" LX90GPS for 2 months now and planetary objects (Jupiter of late) seem a bit fuzzy and very hard to get a sharp image from. I've checked the collimation by defocusing and according to my Meade manual its pretty good. My 10mm Televue radian is furry and even the 26mm meade plossl isnt great (it shows Jupiter with a blue flare on one side and a yellow flare on the other).

So, have conditions been less than ideal this last fortnight in Sydney?

iceman (Mike) · #2 03-07-2008, 11:29 PM

Hey there and

to IIS!

The seeing conditions have been terrible around Sydney for the last fortnight - so don't worry, it's not you.

Last week, I got up every night with the hope of imaging Jupiter (it's been clear for 2 weeks), but every night without fail the seeing was horrible and Jupiter was a mess.. so I went back to bed.

Keep persisting!

bigstretch (Nathan) · #3 03-07-2008, 11:35 PM

Quote:

Originally Posted by iceman

Hey there and

to IIS!

The seeing conditions have been terrible around Sydney for the last fortnight - so don't worry, it's not you.

Last week, I got up every night with the hope of imaging Jupiter (it's been clear for 2 weeks), but every night without fail the seeing was horrible and Jupiter was a mess.. so I went back to bed.

Keep persisting!

Thanks Mike. Just to let you know your a bit of an astronomy hero of mine. The guys at bintel directed me towards some of your work when I asked them about a dmk.

Im glad to hear that. I thought collimation was pretty good and sure, my EP's could be a bit cleaner but its nothing that should affect it this much. Im only just learning that conditions in the first 2 weeks I got my scope are not always like that. Im learning to appreciate good seeing.

Chippy (Nick) · #4 04-07-2008, 12:53 AM

Seeing didn't seem too bad tonight (not that I'm an expert). But I had some pretty good views of Jupiter with my 8" dob.

bigstretch (Nathan) · #5 04-07-2008, 01:08 AM

Quote:

Originally Posted by Chippy

Seeing didn't seem too bad tonight (not that I'm an expert). But I had some pretty good views of Jupiter with my 8" dob.

Yes, earlier on it wasn't much chop but about 11:30 it seemed to get noticeably for me.

OneOfOne (Trevor) · #6 04-07-2008, 07:21 AM

I think the conditions on the east coast of Australia have been pretty ordinary for most of the YEAR! How come we get some much cloud and, in Melbourne at least, so little rain?

So you are not alone...

MikeyB (Michael) · #7 04-07-2008, 08:15 AM

Hi bs and welcome aboard. Another point worth noting is that you are using an excellent planetary scope, but your eyepieces aren't ideal ones for its long focal length (= high magnification), in average to poor seeing conditions. That Meade plossl won't be doing your scope's optics any favours even on a good night - Televue plossls are pretty much the gold standard in that eyepiece type and have never been cheaper after a recent price reduction! I'd especially recommend the 32mm TV plossl if you want to upgrade but have a tight budget.

Your 10mm Radian will be excellent for planetary use on a good seeing night (also for the moon and double stars), but as you are finding, its magnification is too much if the sky is unfavourable. An eyepiece in the high teens (a 19mm Panoptic is my favourite), will give you a crisper and more enjoyable view even on an average night, IMHO.

bigstretch (Nathan) · #8 04-07-2008, 10:42 AM

Thanks mikey. Im a quality over quantity kind of guy so with that in mind should I be looking at a plossl for low power or maybe something like a panoptic (or even something else)?

MikeyB (Michael) · #9 06-07-2008, 04:05 PM

That question's easier to ask than it is answer, Nathan

. Lower power plossl alternatives are all about wider fields of view, which necessitates more complex designs with more glass elements to correct distortion, hence higher costs.

Goto scopes don't get the same benefit from widefield eyepieces as manually tracked scopes, where targets continually drift out of sight, but one advantage of widefields is higher magnification with the same field of view. A 24mm Panoptic has pretty much the same AFOV as a 32mm TV plossl, but the greater magnification gives a darker sky background that helps fainter features such as nebulae and globular clusters to stand out a little better in a light-polluted sky.

But in the end, it all comes down to budget and personal choice!

bigstretch (Nathan) · #10 07-07-2008, 01:25 PM

Cheers, thanks Michael.