Best eyepiece for when jupiters moons are in front

[Jemmo (Adrian)]

I finally got a clear night to use my 10" dob I just got 2nd hand. I only have cheap eyepieces at the moment. By cheap I mean came in the box with a $150 scope but it's all I got for now.
I used a 12.5mm ep last night and got a good shot of Jupiter and 4 moons I could make out the bands around Jupiter.
I'm just wondering what eyepiece I would need to see Jupiter filling up the eyepiece I read in the next few days 4 of its moons will be infront of Jupiter I won't see them with my current lense I doubt.
What ep would allow me to get really close? A 9mm with Barlow? Sorry if noob question I am a noob lol

[Dboots (Duncan)]

Hi Jemmo,

Congratulations on your choice of scope. A 10" dob is a great telescope. With a bit of patience and clear skies, you will get years of enjoyment out it.

When I started with astronomy, I wanted to push the magnification envelope and quickly learned that bigger is not better. Pushing magnification too far generally results in duller, blurrier images. This is because all telescopes have a theoretical magnification limit (around 500x for a 10" scope) and atmospheric disturbances make the air "wavy", limiting any scope to around 250 - 300x on an average night.

It is all about getting the best our of your telescope. I find that I can pick up an amazing amount of detail if I just give myself time to really look at an object for 1-5 minutes. I have a 14" dob and my most used eyepiece is a 14mm ES 82. It gives 114x magnification which seems to be a sweet spot for the scope.

If you are interested in the calculation for your scope, below are some useful links:

http://www.stargazing.net/naa/scopemath.htm
https://www.astronomics.com/eyepiece...ication_t.aspx

Duncan

[Jemmo (Adrian)]

Thanks mate. Yeah I did try my cheap 9mm ep but wasn't too good I used a 3x Barlow and my cheap 12.5mm ep but still not great the 12.5mm alone was good I could make out bands. I've got a decent 9mm on its way do you think I'd get a good shot with a pretty good 9mm ep? I've seen some photos of Jupiter through a 10" dob and you can make out the lines and big storm very easy and jupiter looks huge. I understand the eps would be very good quality. I just wanna know if I can get anywhere close to those pics with my gear

[Wavytone]

Adrian, an eyepiece in the range 5-7mm will be optimal. A single short eyepiece with good eye relief is generally better than a longer one with a Barlow.

For high power views of small targets (planets) contrast, sharpness, perfect colour correction and lack of ghost images are high priorities. Minimising the number of optical surfaces in the light path is a very significant way to achieve this.

For this reason modern variants of simple eyepieces such as plossl, orthoscopic, RKE or monocentric remain popular. The only real advantages of more complex eyepieces (such as LVW, Pentax, Nikon, Radian, Ethos, Nagler, the ES range...) are more eye relief and wider field of view, at the expense of more glass in the path.

[rustigsmed (Russell)]

Hi Adrian,

with planets in particular it comes down a lot to 'the seeing'. you may have noticed Jupiter kind of going from sharp to blurry randomly due to the atmosphere, lastnight was very windy so i'm sure you'll get a better view with better conditions. the better the seeing the more of the sharp view you will get and less the blurry.

when it comes to the photos they are usually done by videoing the planet and then passed through a computer program to remove the blurry moments and then the sharp ones are stacked to reduce noise.

[Jemmo (Adrian)]

Yes it did go a bit blurry everynow and then and I did expect it was due to conditions. So say with a half decent 6mm ep could I expect this on a good night or is this a lot of money down the track. I'll attach a pic below. I don't expect to see Jupiter like this I was already amazed with what I saw last night.

[dannat (Daniel)]

i agree with wavy , an ortho is the clearest & cheapest [<100}option to render fine details...after that you are looking for delos/pentax

[MortonH]

At Katoomba on Saturday I viewed Jupiter with my 8" f/5 Newtonian. The seeing wasn't great and the best view I could get was with a 12mm Pentax XF eyepiece giving only 83x magnification. It was possible to push the magnification higher but then I was hardly ever getting a sharp image. With planetary observation sharpness is more important than magnification, and sometimes the seeing conditions just don't allow high magnification.

[MortonH]

I find my ES eyepieces are pretty good for planetary viewing without breaking the bank. The 6.7mm model is one of their best.

http://www.vtioptics.com.au/premium-...fic-eyepieces/

I also have the 4.7mm but it needs good seeing conditions. The 6.7mm gets used a lot more.

[AstralTraveller (David)]

I have a UO 7mm HD ortho and it is the best planetary ep I have for my 10". I was so happy with it that I bought the 5mm version but I find that the seeing is rarely (perhaps never around here ) good enough to support the extra magnification. I suspect a 6mm might get some use but it is very close to the 7mm so I think I'll save my money. Beware; orthos have very short eye relief, which not all people can handle. I find the 7mm to be tolerable but with the 5mm I tend to wind up with my eye on the glass of the ep, which isn't as painful as it sounds - just uncomfortable and it gets the ep dirty.

[Suzy]

Hi Adrian,

I'm just wondering what eyepiece I would need to see Jupiter filling up the eyepiece I read in the next few days 4 of its moons will be infront of Jupiter

Would you be referring to this article?
http://www.space.com/16149-night-sky.html

"Friday–Saturday, Jan. 23–24, 11:35 p.m.–03:00 a.m. EST. The shadows of Io, Europa, and Callisto will fall simultaneously on Jupiter; this is an extremely rare event, which will not occur again until 2032.
Credit: Starry Night software".

If so, this event will not be observable from Australia.
See thread here


Regarding eyepieces......

I too have a 10" dob but I found it a real pain observing planets with plossl eyepieces because of their small field of view (I think around 50 degrees?), the planet just zoomed across to quickly. This was my experience with plossls under 10mm. So I bought myself widefield eyepieces which gave a lot more time for me to view it.

The sweet spot I found - as Wavytone suggested - is in the 5mm to 7mm range. Use of the 5mm will be dependent on the seeing conditions but I can often use it. 7mm is the one I regularly reach for with success and the 10mm never lets me down unless the seeing is really quite bad. If it's bad in the 10mm, don't even bother reaching for higher magnification.

In general, the 10mm XW is my most used eyepiece on general objects (galaxies, globular clusters, nebulae & planetary nebulae). My 15mm is the one I reach for comet observing as that range hits the spot for observing them the best through my 10" dob., and sometimes galaxies. And my 22mm for star clusters (but I often observe clusters in my 10mm & 15mm as well- it just depends on their size and brightness).
It's often interesting & I do it often, observing star clusters across all the eyepieces.

Anyhow, that's just my experience of what works for me using the same equipment as yours .

[Jemmo (Adrian)]

Yeah that's what I was referring to.
Bugger I was excited for that. I might try find a decent 2nd hand 6 ep soon I got a 9mm and 26mm wide angle on the way

[Suzy]

Aaargh! I found out this morning at 1.30am AEST my time (21st) , right when it was happening - but was too cloudy , there where two shadow transits; Io and Europa!
I keep telling myself, it really pays to check the Astronomy Australia 2015 book more regularly grrrrrrr because if it was clear this would've been a great opportunity to catch a double shadow transit. It was visible all across Australia.

That's great that you're able to get a 6mm. And those wide angled eyepieces you ordered will make observing much easier with a dob. You will also really enjoy the high magnification views of that 9mm wide angle ep when you take a look at the two biggest and brightest globular clusters in the sky- Omega Centauri and 47 Tuc. In the 10mm plossl that comes with the dob, the field of view is so narrow that it doesn't show all of Omega Centauri, it's not a pleasing view and you're just looking into the middle of it really. A little trick- when you're observing globular clusters, don't keep staring at them. Roll your eye ball just away from it and then back to it and you will see many stars sparkle and come to life. The change in contrast of the sky to the object helps our eyes to see things a bit better. Like giving the scope a bit of tap with really faint things. Using averted vision is another very useful observing technique which can allow better views of deep sky objects (DSOs) in general.

And expect lots of rain your way with all those eyepieces you have ordered! It's the way things go.....

When funds allow, see if you can fill in that gap with either a 14 or a 15mm eyepiece.