Planetary Observation - new EP or new Scope?

[GarethA]

As a beginner who's started out with a 6" reflector - what would folks recommendations be for the next stage in planetary (primarily Jupiter) observation?

Would it be to spend money on more advanced EPs for the same scope, or look at something like a 127 mak which at < 250 for the SW OTA is cheaper than some of the more advanced EPs?

[Ags]

Full marks for lateral thinking!

I would at least try a planetary EP with the current scope. Assuming your scope has an F5 focal ratio, try a 5mm EP giving 150x. You can get a TMB clone for 36 pounds from Skies The Limit. If it works out you can buy another at an even shorter focal length. I think STL even let you send back EPs that don't work out with no quibbles.

Of course, collimation of a newt is very important when viewing planets.

[John]

What 6" reflector have you got ?.

I'm not confident that reducing aperture is the way to see more.

"Advanced" eyepieces will show things very nicely but are not a substitute for more aperture which I suspect might be what you require.

[nicnac]

aperture is good, more the better, if your reflector is an F5 i would say a decent quality barlow and some nice EPs

i am using a 6 inch reflector with a TAL X2 barlow with X-Cel LX EPs, and i am getting some fine views

i am pretty sure you havnt maxed out your telescope yet, i havnt but soon...... hello 10 inch newt!!

[GarethA]

Yes it's an f5 SW 150p.

Collimation is pretty spot on.

I have tried a cheapish barlowed 6mm NPL EP but frankly it doesn't give any better results than the standard 10mm plossl. This has put me off looking at shorter FL EPs - maybe I just need more aperture...

I don't really want to go to an 8" newt (yet) at this stage...

Would a mak give better views or should I go for higher quality EPs?

[GarethA]

Cheers Nick - yes, the 8mm X-Cel is on the christmas list!

[magic612]

Something to keep in mind is that the idea of "more aperture means more detail" applies with the caveat of "all things being equal." That's an important point to remember, because a 10" mirror will take far longer to cool off to ambient (equal) temperature with your surroundings compared to a 6" mirror. Also, a 10" mirror is looking through a larger column of air, which can actually pick up more disturbances of poor seeing than a 6" scope.

I'd suggest more / better / different eyepieces first. The beauty of having them is is if/when you do upgrade to a larger scope, you can use all of them in it as well. Despite enjoying the heck out of my 10" Dobsonian reflector (and recalling a superb night last year of looking at Mars around 480x), on most nights I get nearly as good views with the 5" f/9 refractor, because of seeing and cooling issues.

Just a few things to consider. Hope that helps.

[Ags]

The 6mm + barlow will give 250x which may be too much for the viewing conditions. Also, what barlow are you using - the poor view might be due to a poor barlow?

[GarethA]

Thanks Magic - good points!

I keep my scope in the shed so no real cooling issues. (though if I were to upgrade to a 10" newt I'd have to get rid of a few bikes + lawnmower etc :-) ... or build a bigger shed!)

I do take the point re eyepieces being reusable on my next scope - I'm just wondering what the best investment is now re getting better planetary views.

[John]

Would a mak give better views or should I go for higher quality EPs?

I think the answer for both is maybe, but only slightly, if at all. At the end of the day it's aperture that captures the light and the more of it you have, the more detail there is to see.

Actually one thing that will improve your views, and it's free, is time. Spend lots of time observing Jupiter or Saturn and you will gradually be able to make out more details and more subtle contrast. I typically spend a couple of hours viewing just the one object and by the end of the session I'm invariably seeing details that I did not pick out at the start. My planetary scope is a 120mm refractor and I see plenty of detail with that under decent conditions.

[GarethA]

@ags - am using the standard SW x2 barlow

[GarethA]

@jahmanson - yes I think you're totally right, there's no substitute for time at the eyepiece! Took me hours (over several nights) to see the cassini division with this scope but I got there!

I'm just looking at the next small step -- without buying a 1000 pound ED 120 refractor (maybe next year

[magic612]

Time at the eyepiece does matter. The difference between a 6" scope and a 10" scope, on the vast majority of nights, is subtle at best (and on bad nights of seeing, can be much WORSE in the larger scope!). Yes, more aperture does provide more resolution - but again, all things being equal, which they often are not. And another thing - very good 6" mirror will likely outperform an "average" 10" mirror as well. Size doesn't necessarily mean more resolution - a well-figured 10" mirror makes a difference - there's that "all things being equal" again.

Spend time with the 6" scope. You will appreciate the subtle differences that much more when you do move up to a larger scope, and they will seem to be greater differences then as well.

[Ags]

I've read that the standard SW barlow is quite poor, although I have no experience of it myself.