Sky Watcher 200P EP's

[LukeSkywatcher]

MA = Modified Achromat - it's a variation on the kellner design. Don't know what the "super" part means .......

So they are NOT Plossl's.

That's interesting because they really are a LOT better then the Kellner EP's i got with my 90EQ. I would put them almost on par with the Plossl's i have in my Celestron EP kit. I think someone above mentioned that they can see a dark spot in the centre of the FOV of the SW EP's. I have experienced this also under certain conditions (too high of a magnification i seem to recall). It isnt a problem after a couple of mins. Perhaps the dark spot is the secondary mirror?

[alfingido]

This is from a website I found, I referred to it in my earlier post ( #9)

Eyepiece Types

Huygenian: The two-element Huygenian eyepiece was invented by Christiaan Huygens (pronounced “HOY-kens”) in the 1600s. This design is inferior to more recent designs, so it is now obsolete, except that some Huygenian (“H”) eyepieces are still supplied with cheap imported telescopes. Eye relief is extremely short and the apparent field is small. The 18th-century Ramsden design is much better, but still not up to today’s standards (though it is used on some microscopes that have very high f-ratios).

Kellner: The three-element Kellner, together with its close relatives the Achromatic Ramsden (“AR”) and Modified Achromatic (“MA”), is the least expensive eyepiece suitable for serious astronomy. It gives sharp, bright images at low to medium powers. Best used on small to medium-size telescopes, Kellners have apparent fields around 40° and reasonable eye relief, though short at higher powers. They’re good, low-cost performers, far superior to simpler Ramsden and Huygenian designs. A 40mm Kellner is an inexpensive way to get very low power on most telescopes.

Orthoscopic: The four-element “ortho” was once considered the best all-around eyepiece, but has lost some of its luster because of its narrow field compared to newer designs. Orthos have excellent sharpness, color correction, and contrast, and longer eye relief than Kellners. They are especially good for planetary and lunar observing.

Plossl: Today’s most popular design, the 4-element Plossl provides excellent image quality, good eye relief, and an apparent field of view around 50°. High-quality Plossls exhibit high contrast and good sharpness out to the edge. Ideal for all observing targets. Twenty years ago, these were considered “luxury” eyepieces for the well-heeled; today they are normal general-purpose eyepieces. Eyeglass wearers can generally use Orthoscopics and Plossls with focal lengths of 17mm or greater.

Erfle: The 5- or 6-element Erfle is optimized for a wide apparent field of 60° to 70°. At low powers, its big “picture window” viewing area provides impressive deep-sky views. At high powers, image sharpness suffers at the edges.

Ultrawides: Various improved designs incorporating 6 to 8 lens elements boast apparent fields up to 85° — so wide you have to move your eye around to take in the whole panorama (which some people like and others don’t). Light transmission is slightly diminished because of the additional lens elements, but otherwise the image quality in these eyepieces is very high. So, too, can be their price.

Allan

[LukeSkywatcher]

Ultrawides: Various improved designs incorporating 6 to 8 lens elements boast apparent fields up to 85° — so wide you have to move your eye around to take in the whole panorama (which some people like and others don’t).

My 32mm EP (my favourite EP) feels like that and it is not even an Ultrawide (that i know of). I find my eye wondering all around the FOV to take everything in. Not a bad thing because it is comfortable doing it even if i hold my eye away from the EP.

Interesting read there. Thanks for posting.

*footnote*

I wear glasses for driving,watching tv and when on the computer (out of habit for the last so many yrs i wear them full time though). I have never worn glasses while observing either with bins or scopes. I just cant seem to get used to observing through the EP with the rubber surround flipped up to allow observing with glasses as i feel my eye is too far away from the EP and i find my FOV is smaller. I'm pretty sure because of observing without glasses that i am losing optical quality.

Not sure what my point is here. Sorry.

[alfingido]

I'm pretty sure because of observing without glasses that i am losing optical quality.

Not sure what my point is here. Sorry.

I know what you mean about wearing glasses, I need them to read, but only because my arms are now too short to hold books far enough away!

I never wear them to observe, same problem as you, though I have to keep putting them on to read my handset, starmaps, books etc.

I dont think I am missing out on any seeing, I think the focuser compensates for any eyesight deficiency, certainly for me.

Allan

[LukeSkywatcher]

I know what you mean about wearing glasses, I need them to read, but only because my arms are now too short to hold books far enough away!

I never wear them to observe, same problem as you, though I have to keep putting them on to read my handset, starmaps, books etc.

I dont think I am missing out on any seeing, I think the focuser compensates for any eyesight deficiency, certainly for me.

Allan

Thats what i wonder about. When focusing without glasses i wonder if i am getting 100% focus either with my scopes,bins or camera.

I doubt it really.

I think observing WITH glasses is something that i am really just going to have to adapt to.

[kniclander]

i think that observing without glasses is fine - you just focus at a different point. but if you have astigmatisn then you need to wear your glasses at the e/p. I never wear my glasses at the e/p - i find it much more comfortable without.

[SkyExplorer]

I rang OVL and asked them about the Barlow, they said the delux one has a thread on it. I checked my barlow and it has the thread.

I'd like to try and see mars again tonight as it looks like it will be clear night.

[SkyExplorer]

Okay, so I have the 10mm and 25mm EP that came with the scope, when I looked at mars last week using the 10mm and 2x barlow it was a blurred and fairly small. Using the rule of thumb with my scope, I should be able to get to 400x.

Can anyone recommend a combination I should get? Maybe keep my 10mm ep and get a good quality 3x barlow so I can get to 300x. Or get a 6.4mm an keep my 2x barlow?

Help !

[alfingido]

Those ep's are really only for low to med powers. ( see my earlier post #9) You would be better to get at least a few good plossls and a good 2x barlow.

As I said before, Skywatcher Super Plossls ( try FLO for these) are good prices and you will be able to get higher magnification. Look at Tophouses previous post about the Antares eyepiece set. I think the difference between the eyepieces included with your 200p and the Antares are well explained, you would do well to follow his ( and others) advice.

Allan

[TopHouse]

@SkyExplorer, just checked my barlow that came with my 200P bought last week and no thread! are OVL the distributors for skywatchers?

[SkyExplorer]

Yep, OVL are UK distributor. The thread is on the large end, I guess its for attaching a camera to rather than a thread for screwing in a filter - If you see what I mean.

The one I have is on the left in the picture on this page

http://www.opticalvision.co.uk/astronomical_accessories/barlow_lenses/barlow_lenses

[SkyExplorer]

Okay, thanks for everyones advice.

[TopHouse]

Ahhh, I was looking on the small end, yep, mine has the thread, still seems pretty poor quality though, may invest in a tal or something similar in the future.