Eyepiece Selection

Hey All,
So it is likely that this has been covered to exhaustion but I am trying to select an eyepeice for planet observing.
The scope I have is a 10" f/4.8 reflector. I don't have any issue with the magnification i'd like, I suspect a 10mm or little lower would be ok for viewing planets. I would also take it that the Nagler eyepeices are going to provide the best veiw or at least I can't go wrong.

What i don't have experience of with the scope is:

1. Do I need to use the coma corrector (I have a MPCC Coma corrector) for a <10mm eyepeice? Coma to the best of my knowledge effects the outer portions of the FOV, but can it also affect finer detail that should be seen on a planet disc?

2. I have a Televue 4x powermate, should I just go for a lower powered eyepeice and use the powermate? The powermate is used for photography with a CCD camera and thats why I purchased it. I am leaning towards leaving out the powermate for visual observing because it is quiet large and heavy, so coupling an eyepeice on to this could easily become a cumbersome setup.

I would appreciate opinions or suggestions on what to watch out for particularly with the f/4.8 scope?


Regards,
Mike

Ha funny you should say that Michio, because I have it in my room and I am trying to do the initial setup for collimation...square this than sqaure that, it will be a good square kick into the dump if it doesn't work out for me this time, this is its last chance though because I am at my wits end with this!! :laugh:

And yep your right it really is an imaging scope and everything I have around is for imaging (not that I have been overly succesful thus far). So I really don't have decent eyepeices, 2 kelleners 25mm and 6mm and 1 10mm plossl.

Iam not in Dublin but what brand are the eyepeices?

Cheers
Mike

Hi mike,

In my very little experience:

1. You shouldn't need your mpcc. The coma, I think, only comes out to play on the lower powered eyepieces. Although, I'm sure you know, any f ratio equal to or less than 5 will show it more. Still, shouldn't effect you on a 10mm ep. As always, there are people here far more knowledgeable than me, so they could say different. And I'd believe them!!!

2. I've never used a powermate. I think they are a very impressive, but 'just' a Barlow. As far as I know, it's used to limit the amount of eyepieces you need. But, I think using an eyepiece on its own, for the mag you want, will generally give better views. Again, not really sure. But I'm guessing adding more glass is just going to highlight any problems with eyepiece (dust, fingerprints, eyelash marks, etc..)

So, to sum up- I haven't a clue. Wait for the experts

Oh, I'm looking for an mpcc at the moment. Not easy to come by on the used market. What's your experience with it?

Good luck.

Sean

I haven't had an opportunity to try many eyepieces, but my setup (200 mm f/5 reflector, MPCC) is similar to yours so my experience may be helpful.

First, the MPCC is great for reducing coma at the edges of the field, but has little impact on the viewing near the centre. It's a must for wide field imaging, but less important for visual observing, especially for small targets like planets.

I got a Baader 5 mm orthoscopic eyepiece for higher magnification observing and am very pleased with it. The field of view is small, the front element is tiny and the eye relief is small, but I don't find those issues to be a problem (I do wear specs but take them off for viewing). It gives very clean bright images and I find it significantly better than Plossls. I've not had a chance to compare with short focal length Televue eyepieces, but it's worth bearing in mind that orthoscopics are much cheaper. A 5 - 7 mm eyepiece will give you as much magnification as you need, given that the seeing in Ireland is rarely conducive to high magnification observing. The Powermate will be useful for imaging, but I think you are right to consider an alternative lighter, simpler setup for visual work.

Finally, don't worry about the difficulties of collimation. It is essential and it does take a little time to get the hang of the technique, but once you've got it right you'll find it quite easy.

Just my tuppence worth.

Mike

michiokakurules wrote: you mean you dont live in dublin i take it because
paypal locked my account after some little crook
tried to say i didnt sent him the item it was the
old cash back paypal scam after i got it unlocked
i said i wont use it again for selling only buying
my own things.

You know...You're eventually going to run out of Internet service providers (ISP's), Internet Cafes and Wifi Hotpots Gliese, as each reregged IP address is banned by the mods

Thanks for the answers. Few things clearer now. I am reviewing a link that compares the Baader 5mm to a Pentax 5mm XO which had caught my interest.

www.wlcastleman.com/equip/reviews/5mm_EP/5mm_ep.html

The Baader is within my budget so will check it out.

Indeed the mpcc was for coma correction for astrophotography (with canon350), and the Powermate was for increasing the magnification of my current set of eyepeices and also for attaching a tracking camera.

Need to finish the collimation, but yes its proving very tricky. I don't think I have come across something that from one view appears absolutely perfect but from another view appears as though it couldn't be more wrong. Anyway for another thread!

Regards,
Mike