Looking for Eyepieces

[sixsix]

Hello,

My first post here...

I purchased a Starblast EQ-1 ( 450mm FL / F4 ) a few months ago. My wife and I are very pleased with it and the neighbors and our friends are equally impressed – most of us had never seen Saturn or Jupiter before.

Our scope was well collimated right out of the box, easy to assemble and we were looking at stuff within the hour.

We are primarily interested at lunar and planetary views, but would like to also look at, for example, the Orion and Andromeda nebula(e)s.

I have some questions about eyepieces:

- What ‘kind’ or 'type' of ( Plossl, MA, Kellner or what ) category do the eyepieces that came with the scope fall into?
- They ‘seem’ pretty good – they are a 6mm and a 15mm –

- Wanting to upgrade the EPs, We bought an Orion ‘Shorty Plus’ Barlow and were not at all pleased with the lack of focus, bad light, etc, etc.

- We also tried a Meade 15mm QX lens – it was highly recommended by stargazers and by online reviews.

- We were NOT impressed with the Meade lens either – To Orion’s credit, the 15mm lens that came with the scope had as good a view, clarity, eye relief, FOV, etc, etc. The Meade was a ‘tad’ sharper at the edges, but not $80 worth of better.

- Our main question is this: With a ‘fast’ ( F4 ) scope and and short focal length ( 450mm ), should we be looking for a ‘certain’ ‘style’ of lens – are some types – as opposed to manufactures – more appropriate for this scope?


Thank You very much again and My wife and I look forward to hearing an answer soon – the sooner we can spend some more money.


Mike & Jeannie Karwath

ps: we sent the Barlow and the lens back

[redshifter]

I"d recommend a low power eyepiece with a wide feild of view, that's best for deep sky panning and larger objects such as the Andromeda galaxy and the Pleiades. I'd also recommend a medium and a high power eyepiece. If you like the 15mm, then that would be fine as a low/medium power. I'd also recommend a barlow of some type for higher power observing. I like this line of Orion eyepeices: http://www.telescope.com/shopping/pr...iProductID=212

I have the 25mm and the 9.5mm. They're not much more than good plossl eyepeices, but they're much more comfortable to look through, as they have longer eye relief (the distance your eyeball has to be from the lens to see the whole field) and a nice big lens to look through, even at higher powers. I'd recommend the 22mm and the 5.1 mm. With those, plus your 15mm and a barlow, you'd have a nice range of magnifications available, albeit a bit cluttered at lower powers. However, the nights where you'll be able to use the 5.1 with a barlow will be rare due to atmospheric limitations, as that'll really push the limits of that scope. 5.1 + a barlow in your scope will put you at 180X, which is 40x per inch of aperature in your scope. It should be fine on a really good night, which can be rare.

[Dave Mitsky]

Unfortunately, fast f/ratio telescopes, and f/4 is very fast indeed, require very well corrected wide-field eyepiece designs such as Tele Vue Naglers and Panoptics to avoid astigmatism at the field edge. Each one of these eyepieces will cost a lot more than your StarBlast did. However, you can certainly use ordinary 50 degree AFOV Ploessls or learn to live with the astigmatic images at the outer third or fourth of the FOV that far less expensive wide-field eyepieces will produce.

According to this review, the supplied oculars are Kellners.

You may want to refer to these sites for information on choosing eyepieces:

http://www.actonastro.com/eyepieces.htm

http://www.chuckhawks.com/ocular_basics.htm


Dave Mitsky

[sixsix]

Thank you for the speedy response, redshifter.

Yes I have looked at those Lenses - not physically, just online and in their catalogs, reviews, etc.

It's just that they do not specify what style or speed scope they would be most usefull to. And I realize some are better for eyeglass wearers - eye relief - namely.

I have done quite a bit of searching - here for a couple of days and elsewhere online for months - before buying and now after. Not much on 'Fast Scopes' or 'Short Scopes'.

And you also mentioned a Barlow - well, we tried that - got a supposedly good one. Better glass, better construction, etc, etc. did not see much diff. at all between it and a 'cheapie' $24 dollar model.

Can you or anyone elaborate?


Thanks again,

Mike & Jeannie

[Dave Mitsky]

Mike,

A mass-produced f/4 mirror should not be expected to be a good performer at higher magnifications. Telescopes like the StarBlast are best suited to be used as low power, rich-field instruments.

However, for higher magnifications you might want to consider a long eye-relief Burgess/TMB Planetary Eyepiece. They are extremely good oculars, especially when considering their price.

Dave Mitsky

[sixsix]

Thank You, Dave

That's one review that I did not see. Our scope came w/ a 15mm and a 6mm - if these are Kellners, I am a bit surprised. While I am not at all experienced with many types of eyepieces - I was somewhat surprised at the quality of our '15mm Kellner as compared to a Meade 15mm QX Super Wide Angle.

Mike

[Dave Mitsky]

Mike,

As I mentioned earlier, fast telescopes (i.e., those with f/ratios below f/6) are not forgiving of uncorrected eyepieces with wide apparent fields of view. A Kellner is a three lens-element design and has a small AFOV of about 40 degrees. A five lens-element Meade QX has an AFOV of 70 degrees. I have very little experience with the QX but I have read some pretty negative reviews.

Dave Mitsky

[sixsix]

Dave,

I understand what you are saying about fast scopes and now why that Meade QX wouldn't work well. Do you have experience w/ these lenses ( Burgess/TMB ) personally or about them in a technical sense?

The only reason I ask is... after looking at info on them, I find a few of them ( we are interested in the 6mm ) mention being ideal for 'long' focal lgth. scopes and the description has them at 60 deg FOV. But like you said, there is ( or must be ? ) some 'correction' going on.

Thanks again Dave and all


Mike

[aurora]

What sort of upgrade are you looking for? Since the scope is best for low power wide field views, are you looking for an eyepiece that would give you a wider field? Dave mentioned Panoptics, and I have a couple of them and like them very much. In my short tube refractor I often use a 19mm one, or sometimes use a 15mm Orion ultrascopic. Heck, even a 25mm plossl would probably give good low power views in your scope, and it would be cheaper.

Or are you trying to push the seeing and get a higher power (which is why you went to the Barlow) -- but that would run up against the light gathering ability of the scope and seeing conditions.

Maybe the best thing to do would be to take your scope to a local star party (see if a local club has regular events) and ask to borrow some different eyepieces and try them in your scope on several different objects.

[sixsix]

I had my wife look at the lenses we got w/ the Astroblast:

66 Ultra Wide Multicoated Long Eye Relief 15mm - under 'not so good' viewing conditions, this lens looked every bit as good as the QX

66 Ultra Wide Multicoated Long Eye Relief 6mm - can just pick up red spot on Jupiter ( averted view slightly ), Saturn is crisp & can see a division in the rings - we have been following them for several months now.

We also have a new 25mm Meade MA that we got for $9.99 w/ free shipping from Meade's closeout stuff - looks fine for a med power - good clarity, no complaints.


Mike

[sixsix]

Aurora,

You bring up some great points ( and you are not alone ).

I thought the eyepieces that came w/ the scope were junk too. That's all I read: "so, I tossed out the Kellners and slipped my $200... ( you fill in the blank ) in there and wowee... or "We tried out a buddies 15mm Meade QX" and same reaction. Same scope or similar speed and size.

So... we thought, even though we were impressed with the views we got - we thought, hmmm, for about the same cost as the telescope we could get a lens and a Barlow and be set for quite a few EP mags and get some "OUTSTANDING" ( my wording ) views.

I think I should be able to do pretty good with a 'STD' Orion Shorty and a lens under $99 like the Burgess.

No, I am not trying to push the scope - I think my wife and I know what it's limitations are. We would like to get the best that we can and stay reasonable.

Should we ever get a larger scope ( I know we will ), we will be happy, I'm sure.

A star party in Cincinnati is scheduled soon. Thanks alot for the sage advice.


Mke n' Jeannie

[Dave Mitsky]

Dave,

I understand what you are saying about fast scopes and now why that Meade QX wouldn't work well. Do you have experience w/ these lenses ( Burgess/TMB ) personally or about them in a technical sense?

The only reason I ask is... after looking at info on them, I find a few of them ( we are interested in the 6mm ) mention being ideal for 'long' focal lgth. scopes and the description has them at 60 deg FOV. But like you said, there is ( or must be ? ) some 'correction' going on.

Thanks again Dave and all


Mike

Mike,

I own a 4mm that I won as a star party raffle prize. I have been very pleasantly surprised at how well it performs in the variety of scopes with which I've used it. I've also used several of the other focal lengths when observing with friends.

Astigmatism is not much of a problem at higher magnifications. I'm not sure what you're trying to say about long focal length telescopes other than the obvious fact that only the longer focal length eyepieces in that line would produce useable high magnifications with long focal length telescopes.

Dave Mitsky

[sixsix]

Dave,

Sorry I took so long to get back to your staement:

"I'm not sure what you're trying to say about long focal length telescopes other than the obvious fact that only the longer focal length eyepieces in that line would produce useable high magnifications with long focal length telescopes".

I went looking around for Burgess/TMB eyepieces and the site that I got quite a bit of info at was Astronomics - and this is a brief outline of what they said about a few of the EPs:

2.5mm - short focal length/fast focal ratio refractors and reflectors
3.2mm - short focal length/fast focal ratio refractors and reflectors
4mm - long focal length refractors, reflectors, or catadioptric scopes
5mm - short to medium focal length refractors and reflectors
7mm - wide variety of telescope types and focal ratios
9mm - long focal length refractors, reflectors, or catadioptric scopes, nearly ideal for an f/10 Schmidt-Cassegrain

They mentioned a few other attributes, but these stuck out.

Sorry 'bout the confusion.


Mike