Advice on next purchase

[pt130135]

Hi all,

I've just been given a Celestron C90 (Maksutov-Cassegrain, f/11, 1000 mm focal length, 3.55" aperture). I've got the 26 mm Plossl eyepiece that came with it and a Televue 10.5 mm Plossl which was about $80 in 1996 (I've no idea how good quality it is). I've also got an 8x20 finderscope.

I've had a bit of a play with it but I'm thinking I need to get some more eyepieces to really get going. I've looked at a longer eyepiece, maybe a Celestron Omni 32 mm Plossl. At the shorter end, I was thinking of either getting a Barlow to use with the 10.5mm eyepiece I've got or getting a new 5 mm.

Some initial questions:

• Any clue whether the Televue eyepiece is a decent one? It has no distingiushing marks, so I can only go on cost really.
  
• Is it better to get a Barlow or a short eyepiece?
  
• How much should I spend on a Barlow or an eyepiece in order to get a decent one? I was thinking of the Celestorn X-Cel range.
  
• Is there much point getting the 32 mm eyepiece?
  

I hope that's enough information to make sense. Thanks very much for any advice you can offer me!

Cheers,

Patrick

[Naemeth]

Don't worry about the TeleVue - it's as good as it gets .

Personally, I can't see you going wrong with a set of TeleVue plossls, you just won't need the 11mm as you already have the 10.5mm .

Yes - there is point in a 32mm eyepiece, and personally I wouldn't bother with a barlow (I, personally, am not a fan, others' are though).

HTH

[rowan46]

welcome to sgl other than that. What he says ^ ^ ^

[AlexB67]

Hello, welcome.

A cheapish sort of Barlow, like the one I have in my sig does the job okay, the quality will not be the same as it would be for an eyepiece giving the same magnification, contrast is noticeably reduced I find, but it is better than nothing. I've actually had pleasant views with it on the moon, and Saturn , On DSO objects I never use it these days, having bought another couple of extra eyepieces I already find I don't really need it so much.

I actually decided in the same direction as Jonathan, that is in the long run to fill out my eyepiece range enough not needing a Barlow. What I would consider however, if you plan on getting one, plan it so it works out that you magnifications spread out nicely with the Barlow and fall in between the magnifications your eyepieces do not provide. High quality Barlows or a powermate can give excellent results ( not that I have ever tried them, but this is pretty much what is said on the forum )

Another reason for a Barlow may be that for higher mags in a scope such as I have, a 3mm or less eyepiece is not really recommended for comfortable viewing, a Barlow and eyepiece combo may work out better in such cases.

Some more detailed info in this thread here

[AlexB67]

Sorry, I noticed that you have a long focal length scope there, I should have read that more carefully, the last point I made regarding short focal length eyepieces is not something you'll have to worry about I suspect, but others will chime in no doubt that have experience of the Maksutov-Cassegrain type scopes.

Good luck with the buying

[Schorhr]

The hr planetary start at around 45€/40£ and have a nice 60 degree wide apparent field of view, are available in 2.5, 3.2, 4, 5mm and up, eye relieve is good on all.

I have a 4mm Plossl and it is a pain to comfortably look through.

Else, especially on longer focal lengths, the UWA (ultra wide) eyepieces are nice, cost 30-40€/26£, have a even larger apparent field of view (66 degree), and are available in 6/9/15/20mm.

Fore those rarely used over magnifications a inexpensive 2x achromatic barlow, 16€, will do for starters.