Eyepiece advice for Tal-1 needed please

[Neil M]

Hi - I set up my Tal-1 for the first time last night. Got my first proper view of Jupiter even though it's very low at the moment, and almost directly underneath my nearest street light. I was amazed at the quality of the image using the supplied 25mm plossl and 15mm Kellner eyepieces. The four moons were pin sharp but couldn't make out any detail on the planet itself so I increased the magnification using the 3x barlow. Once I managed to re-aquire Jupiter (this took a while as I'm totally new to this, at one stage I thought the barlow may have been defective!) I could make out two bands of colour and was again suitably impressed.

The combination of the 3x barlow and 15mm Kellner gives me (I think) approx 160x magnification, the focal length of the Tal being 805mm or so. At this magnification the image was very bright, I'd assumed that it would fade under the higher power.

Apologies for the long winded ramble but my thoughts went straight to how best to achieve higher magnification. Looking at FLO's website I was drawn to the William Optics SPL eyepiece:

William Optics - William Optics SPL eyepiece

As I'm interested in planetary and lunar observation this looks like possibly a good bet at £67.

If I went for the 3mm eyepiece I would achieve approx 270x magnification. I realise this would require very good seeing conditions but I'm inspired by my excellent views last night. I've also read much about the relative quality of the Tal's optics.

Guidance would be most appreciated, could I even take the magnification higher?

Thanks!

[Whippy]

Neil, the general rule of thumb for maximum magnification for a given scope is roughly double the aperture in millimetres so in your case that would be x220 (110mm x 2). However atmospheric conditions won't allow you to reach this maximum unless you have one of those rare nights where it's perfect.

Another thing to take into account is that Jupiter is low in the sky which again is adversely affected by our atmosphere. Not sounding too good so far is it!

The good news is that because your scope is a bit 'slower' than some, you can use eyepieces that might otherwise not perform as well in a 'faster' scope.

I have a TAL1 and have used my old Baader Hyperions in them and they work really well, but they're not cheap. I think if you're on a bit of a budget, some plossls might be a good choice or if Lunar and Planetary observing are you bag, then maybe some Orthoscopics would give you a really nice view.

HTH

Tony..

[Neil M]

Thanks Tony. What makes Orthoscopics better for planetary viewing?

[Whippy]

Orthoscopics are essentially a simple design of eyepiece that doesn't require several pieces of glass to make it work. In theory, the less glass you have in the eyepiece, the more light gets through which enables you to get a brighter image and more detail. The big downside is that they do have a narrow field of view and eye relief isn't great either. I have a couple and I like them but I use other eyepieces for viewing objects like nebulae and open clusters that demand a wider field. If you can put up with their weaknesses, they're really nice but I reckon Plossls are a better bet as an all round eyepiece.

Tony..

[Neil M]

Thanks again Tony, very helpful.

[AndyH]

Try a 5mm ortho, giving approx 150x mag. That's what i used on my Tal 1. Great sharp views on the moon and planets. Fine as long as you dont wear specs.

Great scope, the Tal 1 .

Andy.