Which Planetary EP?

[JodieH]

Hey everyone 

I have a Celestron Starsense Explorer DX 102AZ on the way. 

https://www.celestron.com/products/starsense-explorer-dx-102az

660mm

F6.5

I was wondering if someone could please recommend which size EP to buy for viewing planets and the moon? 

https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-uwa-planetary-eyepieces.html#faq

Sky watcher ULA Planetary (my budget is £40)

I've read on another thread that sometimes 9mm can outperform a 4mm with a fast telescope as more magnification can make the viewing duller? I was hoping for the best magnification that is also crisp. 

Thank you for your help. 

Edited August 10, 2020 by JodieH

[Waddensky]

Hi, and welcome!

Yes, to see details on the planets and the Moon you'll need quite a bit of magnification. The angular resolution of your telescope (smallest details that can be resolved by the scope) is about 1.15 arcseconds. To magnify that so it can be discerned by someone with a decent eyesight, you'll need a magnification of about 100x. In your case, that's an eyepiece of 6 mm. You can always magnify more, but this won't resolve more details - resulting in a larger but more blurry and also darker view. In some cases this is helpful, for example to see some subtle contrast differences or to split very close double stars, but I personally mostly enjoy the sharper, lighter views.

I'm not familiar with the Sky-Watcher eyepieces from your link, but I'm pretty sure there are some decent 4-6 mm eyepieces available for your budget. Good luck, and above all, enjoy your views!

[Geoff Barnes]

Hi @JodieH and welcome to the forum.

I have both the 4mm and 5mm SW Planetary eyepieces and I rate them very highly indeed. For their price I think they are unbeatable. The planets will look small in any telescope so high magnifications are needed to see a lot of detail within the limits of your equipment and the seeing conditions on any given night. Also the planets are low down from the UK at the moment which doesn't help in getting clear and sharp views of them. I would think the SW 5mm Planetary will be a great first purchase for your scope for both planets and lunar viewing. 😄

[Dippy]

56 minutes ago, JodieH said:

Hey everyone 

I have a Celestron Starsense Explorer DX 102AZ on the way. 

https://www.celestron.com/products/starsense-explorer-dx-102az

660mm

F6.5

I was wondering if someone could please recommend which size EP to buy for viewing planets and the moon? 

https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-uwa-planetary-eyepieces.html#faq

Sky watcher ULA Planetary (my budget is £40)

I've read on another thread that sometimes 9mm can outperform a 4mm with a fast telescope as more magnification can make the viewing duller? I was hoping for the best magnification that is also crisp. 

Thank you for your help. 

I have several expensive planetary (high power) eyepieces, but value for my money I have not seen anything better than TMB Planetary II eyepieces from China. They cost about £23 and have focal lengths from 9mm to 2.5mm. I have the Vixen HR 2.4mm and Pentax XW 3.5mm and my TMB 2.5mm (to my eye ) looks equal to them in sharpness and image quality. I kind of regret buying Vixen HR 2.4mm because it cost me ten times more than the TMB 2.5mm. I think a 6mm or 7mm will be enough for your needs, and you can always Barlow them for higher magnification. 

[Starwatcher2001]

Welcome aboard Jodie. Hope you enjoy using your new telescope.

[JodieH]

Thank you for the clarification @Waddensky. It's interesting to learn about all the factors to consider for the best viewing. 

@Geoff Barnes thanks for providing a review of the EPs. 

Based on what has been said, I think I'm going to stick with that range and get the 6mm.

I have been stuck in a cloud of sea mist for a few days now! Fingers crossed it will shift soon as I am eager to look up

 

 

[Waddensky]

21 hours ago, JodieH said:

Based on what has been said, I think I'm going to stick with that range and get the 6mm

Great, enjoy! Remember that even at 100x the planets are quite small and need a steady atmosphere and some experience to discern all the subtle details. But you'll gain this experience very fast 😊