Invest in a 40mm eyepiece?

[kosmonaut9]

I Just bought a celestron astromaster 130EQ and I am still getting used to star hopping plus the red dot star pointer is a bit annoying.  Will it be beneficial to invest in a 40mm eyepiece to make star hopping easier ? Will the larger field of view provided by the 40mm eyepiece be worthwhile ?

[John]

Hello and welcome to the forum

I would go for a 32mm plossl rather than a 40mm. You will see the same amount of sky and the eyepiece will work more effectively with the F/5 focal ratio of your scope. If you wanted to put a better finder on the scope, the Rigel Quickfinder is a good alternative to the rather poor original one and mounts onto the tube using sticky (very sticky !) pads:

https://www.firstlightoptics.com/finders/rigel-quikfinder-compact-reflex-sight.html

 

[triton1]

As wot John said.

[Charic]

32 minutes ago, kosmonaut9 said:

Will it be beneficial to invest in a 40mm eyepiece to make star hopping easier ?

A low powered wide afov eyepiece may be beneficial for your needs, but as already stated, you don't need such a long focal length.

In my case, observing the galaxy, M31-Andromeda, there's nothing much to write home about, with it's small diminutive size when observed from my back yard, yet  fills my field of view if/when using the basic supplied 25mm eyepiece, observed from a darker site. It still felt I needed more so next came the BST 25mm with it's 60° afov, but still not wide enough for M31, ending up with the 32mm Skywatcher Panaview with  it's 70° afov. Now I'm happy. I've even used  a 72° afov but that's no longer in my collection.

If/when I'm secluded inside my Dob tent? I'll use this 32mm  eyepiece as my finder, rather than the standard finder scope, which is not actually useable, due to my screening?
The EP works very well for my needs, the only issue to consider, its weight & size due to its  2"  (51mm fitting)

[Red Dwarfer]

3 hours ago, kosmonaut9 said:

the red dot star pointer is a bit annoying

The finder should be adjustable so that the red dot does not outshine the target . As above , 32mm is recommended by FLO and others over 40mm , unless you want to do afocal photography . 

[Louis D]

Since it doesn't have a 2" focuser, the 32mm plossl is the better choice.  If it did have a 2" focuser, a 40mm 2" eyepiece would make some sense.

[kosmonaut9]

Thanks for the answers guys 

[ronin]

As already mentioned a 40mm plossl will deliver a simialr field to a 30/32mm plossl (I give it as 30/32 and never really sure there is a diffeence, they seem interchangeable).

Reason is simply that a 30mm is around 50 degree and a 40mm is around 40 degree. So wehat you gain on longer focal length/ lower magnification you lose on the field stop.

It also measn that a 25mm BST Starguider at 60 degrees has a filed the same as a 30mm at 50 degrees. So if finances and intentions make it plausable then a 25mm Starguider is now an option.

To the other side and the "problem" of a long plossl. This is really eye placement. The eye relief of a plossl is about 2/3 the focal length. So on a 30mm that mean the eye has to be some 20mm away, on a 40mm it would be around 26mm and oftan that means the eye/head is not in contact with anything so maintaining it at a given position is difficult. You will find a lot of people like their TV 32mm plossl and at least half also complain about the eye relief with it (too much), TV sell an extender for their long plossl's for this purpose.

Choosing eye pieces is not as easy as it first seems.

Where are you as there may be a person/club around where someone may let you use the items mentioned. At least that way you get a brief idea of them and the suitability.

[Charic]

I forgot to add, and  normally recommend  just taking the focal ratio of your scope and use it to multiply your dilated eye pupil size (mm), will provide you with a  guideline to the focal  length required, that best matches the scope-eye relation.

[LukeSkywatcher]

Cant go far wrong with a GSO 32mm. Great EP for star hopping. It only give a 50 degree FOV, but it feels like more. Best EP i have ever used.