new EPs!

[janoskiss]

My pair of Antares Elite 25mm plossls have arrived!! :jump2:
I got these for the binoviewer. I also got a 2" Antares 1.6x barlow (another primarily BVer motivated purchase).
Clouds stay away! :prey:

[mickoking]

We look forward to a review :thumbsup: I hope you enjoy em.

Clear skies to ya.

[Starkler]

Gee and I thought you said you were going to buy some mediocre ep's for the binoviewer ;)

Look forward to seeing what you think of them :thumbsup:

[matt]

All the best to you Steve.

I hope the good seeing that's nowhere to be found around here has parked itself over you:)

[janoskiss]

Well, these cost just a bit more than Bintel's price for half of one of the two Panoptics I'm using in it at the moment. I still want another GS 25mm though for when kids (including grown-up ones) are around. (Mike is sending me his. ;))

Almost forgot. I also got a 15mm in this order. Its twin is coming next week. :) The twin is an Antares Ultima as opp. to Antares Elite. I just assumed they are the same thing.

These EPs look very well made. I can hardly wait to try them out. I'm also looking forward to comparing 15mm Plossls: televue vs ultima. On visual inspection, the Televue seems to have the darker coatings (reflections) but most of that is violet in colour, where the eye is least sensitive, so it may make little difference when observing through them. The inside of the barrel of the Ultima is blackened all the way to the end, while the TV has about 5-6mm of chrome at the end where filter threads would screw in.

There are clouds everywhere, of course. Rain is forecast for tonight and tomorrow.

[Starkler]

If your intention is binoviewing you want to be pretty sure they are the same thing :scared:

[iceman]

The GS 25mm is coming this week Steve, sorry for the delay.

[janoskiss]

Thanks Mike. No rush. :)

[janoskiss]

Just finished viewing a nice shadow transit on Jupiter. Seeing was getting really good just now, but I was getting too tired and packed up.

The 25mm Antares Elite plossls are a winner for the binoviewer. Easier to use than the Panos. The plossls have practically no pincushion (I never thought this mattered but for binoviewing it does), more comfortable eye relief for BVing and don't fog up so easily.

And they are very nice EPs on their own too. Sharp & excellent contrast. Less false colour than the Panos in the outer 20-30% of the field (this is very obvious on the Moon).

[Robert_T]

Hi Steve - who sells the Antares and what does "pincushion" mean?:shrug:

cheers mate,

[janoskiss]

scopestuff.com is where I got them.


See http://en.wikipedia.org/wiki/Pincushion_distortion

[Robert_T]

thanks Steve... ah so That's pincushion effect

[ausastronomer]

Robert,

As you have read in the link Steve provided, Pincushion Distortion is a form of rectilinear distortion. The other form is barrell distortion where the lines bend inwards at the EOF instead of outwards like with pincushion distortion. As I mentioned in a previous post (http://www.iceinspace.com.au/forum/showthread.php?t=8100) all eyepieces regardless of price have some aberrations, this is inevitable as the designer cannot correct for everything. In the case of Naglers and Panoptics a little distortion is left in the design to allow for correction of off-axis astigmatism and other EOF aberrations. The remaining distortion is not usually detectable to an observer viewing pinpoints of light or extended objects at night. This is what makes them such a good choice for astronomical viewing. You can detect the distortion at night by getting an eyepiece (eg: a Panoptic) in a dobsonian and dragging a middle magnitude star in a straight line in azimuth from one edge of the field to the other so the star basically traces a line across the FOV. If there is any rectilinear distortion in the eyepiece it will tend to scribe a slight curve rather than a dead straight line. This rectilinear distortion does cause issues to some observers using these eyepieces in a dobsonian while panning the sky at night. Rectilinear distortion is easy to detect in the day by observing reasonably distant targets, known to have straight edges. Example targets could be, a telegraph pole, bridge pylons or staunchions, the corners of tall buildings etc. Another test, is to observe the waterline of a distant ship at sea, on a calm day, and see if Neptune is sucking the sea down or pushing it up in the middle of the ship.

CS-John B

[johnno]

Hi John,

Thanks,for That
Very interesting reading on Pincushion distortion,

I have read somewhere,a LITTLE distortion is desirable in BINOCULARS,as it tends to reduce the "Seasickness effect",when Panning,especially on a LANDSCAPE.
I have found this to be the case,as I have some Binoculars,with almost NO distortion,and they DO produce a Rolling effect,When panning, which is a little unsettling.

Best Regards.
John