Whats the best eyepieces for viewing.

[cjroberts792]

Hello All, 

firstly thanks for all your help on my previous questions and thanks in advance for clearing things up for me here.

So, i brought a load of eyepieces the other day, BST Starguider ED in sizes 25,15,12 and 5mm. Already had a 28mm that came with the scope and i brought a 9mm Sky-Watcher UWA Planetary EP. I was out the other night having a look at Jupiter and as i was going though the EP's, Jupiter became just a big blob when i got down to the 9 and 5mm,  Is this normal? Obviously i did try to focus but coulnd't get Jupiter looking as good as with the 12mm. I did also try with the Barlow ( i think - 3 inch tube that goes between the Ep and focuser). what size lenses are best for planets and whats best for DSO like Andromeda Galaxy and Pleiades.

My setup is SKY WATCHER 200pds on HEQ5

Cheers for taking timeout for helping me.

Newbie chris

 

[Buzzard75]

There are a lot of variables. The focal length of telescope and eyepiece, aperture, seeing conditions, etc. and even the individual observer. As for scale, with my own equipment, I find that 150x is a good magnification that gives enough detail on Jupiter and Saturn's rings. If you increase magnification too much though, you'll start to lose detail as your seeing conditions begin to have more of an effect. Starizona has a great article on magnification and the various effects of all the variables.

https://starizona.com/tutorial/understanding-magnification/

EDIT: And if you REALLY want to get into the details, there's another great article on Observing Theory. Note, the above magnification is specific for my equipment. Yours may differ.

https://starizona.com/tutorial/observing-theory/

 

Edited June 6, 2019 by Buzzard75

[John]

Broadly, for the moon, planets and double stars, eyepieces that give a range of magnifications between 140x and 250x are useful so eyepieces that range from 7mm down to 4mm in focal length. Jupiter tends to look sharper and more contrasty at the lower end of that range. Saturn, Mars and the Moon can bear more power so you can press on with the shorter focal length eyepieces. There are provisios though - the seeing conditions need to be stable for good viewing and with the planets being so low currently that poses a problem because we view them through more of our unstable atmosphere. Having the scope in good collimaion is also a key to good high power planetary performance.

For the large targets such as the Andromeda Galaxy and the Pleiades the lowest power and widest views are what you need so, with your scope, eyepieces in the 30mm - 25mm range in focal lengths.

The eyepieces you have are actually pretty good. My suspicions are that unsatisfactory planetary views will be the result of non-eyepiece related factors, maybe a combination of them ?

 

[paulastro]

Chris.  Yes, John is quite right.  I looked at Jupiter last night with my 120ED refractor and struggled to get a good image at x120, and didn't bother even attempting to go any higher.  The seeing was so bad at times it was like looking at Jupiter at the bottom of a fast moving stream.  Alas this isn't unusual when the planets are low in the sky.

So, take heart and don't be put off, when the seeing cooperates your telescope and eyepieces will give you wonderful views of the planets. 

Something to look forward to is Mars which is favourably placed, close to earth and higher in the sky than it's been for a while late next Autumn.  I promise you, it will blow you away!

Edited June 7, 2019 by paulastro