Multiple eyepiece

[Ignoro]

Today I looked at Jupiter for a short while and at one moment I thought why not try to put another eyepiece on top of the current. So on top of a x2 barlow with a Tv plossl 11mm I put a BST Starguider 8mm and after some focusing I have managed to see a clear image of Jupiter. The whole thing isn't very practical as it's difficult to hold an eyepiece on top and have nice and steady focus, but still it worked somehow... 

And the most interesting thing was that the image wasn't upside down anymore, but it was normally aligned... So now I'm wondering, why isn't there a product which can flip the image in reflectors (or there is one I don't know about)?

I've read somewhere online that reflectors cannot have a normally aligned image...

[Louis D]

I'm guessing the exit pupil of the 2x11mm TV Plossl was magnified and brought into focus by the 8mm BST SG.  Inverting the image seems to follow from this diagram I found online:

[Stu]

There are things called erecting prisms which correct the view for newts apparently. I've never tried one, but doubt they improve the view! This one also adds a x1.5 Barlow, presumably to allow you to focus still.

Visionking 1.25" Erecting Prism For Newtonian Reflector Astronomical Telescope https://www.amazon.co.uk/dp/B014QNEXRC/ref=cm_sw_r_cp_apa_i_McYdDbQA8BNM4

[Ignoro]

So it does exist, that's what I thought... 😎🤔

I just might order a piece to see how it works...

[Ricochet]

Given the size of the top lens, there will be vignetting issues with wide FoV eyepieces. 

[Geoff Barnes]

Hi Ignoro, I think this might be what you're after..... https://global.vixen.co.jp/en/product/3847_09/.

[Ignoro]

This could be used for star hopping also. 💡then later remove it and put good eyepiece... Very useful accessory 

[Stu]

5 hours ago, Geoff Barnes said:

Hi Ignoro, I think this might be what you're after..... https://global.vixen.co.jp/en/product/3847_09/.

Pretty pricey from what I understand Geoff, but in sure the quality is excellent. I think it works using lenses not a prism.

[Geoff Barnes]

Yes Stu, has just 3 lenses apparently.

Vixen quality optics though, I've seen a couple of reviews that were favorable.

I can get it here for around  $115 .....

https://www.myastroshop.com.au/products/details.asp?id=MAS-014K.

 

[timwetherell]

On 23/06/2019 at 07:56, Stu said:

There are things called erecting prisms which correct the view for newts apparently. I've never tried one, but doubt they improve the view!

I have a nice WO 1.25" erecting prism - it's outstanding for low magnification terrestrial use but does degrade the image somewhat above about 100x. The biggest problem using it for astronomy is that you get a really big diffraction spike from the cemented joint between the prism components. And of course the extra glass and surfaces drops the contrast a little. Great for looking at ships at sea though  

[Peter Drew]

If you can see ships at sea from here I'd definitely buy one!     😀