Orthoscopics?

[chiltonstar]

As well as twilight, sometimes looking through thin cloud seems to enhance detail; seems illogical but there you go....

Chris

[Mak the Night]

1 hour ago, chiltonstar said:

As well as twilight, sometimes looking through thin cloud seems to enhance detail; seems illogical but there you go....

Chris

I guess it acts as a filter. Too much filter most nights lol.

[Mak the Night]

On 24/01/2016 at 18:47, Mr Spock said:

If you can tollerate the small field of view they are as crisp, clean and detailed as anything out there.

At first I thought the more limited FOV would be a problem, but surprisingly, it isn't.

[Mr Spock]

By comparison planets are really small, even at high magnification. I know some people say the view is 'cramped' but, you just don't need all that real estate. I find the small FOV concentrates you on what you should be looking at

[Mak the Night]

I think that's true especially at high magnifications. A lot depends on the field stop size as well. The ortho's weren't drastically smaller than the Plossls in that respect.

[RT65CB-SWL]

I have two 6mm Ortho's.

One is a 1.25" Circle-T and the other one is an unknown 0.965" that I use with an 1.25" adaptor. I did a quick comparison test late last year with my ETX105. Both are very good performers on Lunar/Moon and planetary targets.

[Mak the Night]

2 hours ago, Philip R said:

I have two 6mm Ortho's.

One is a 1.25" Circle-T and the other one is an unknown 0.965" that I use with an 1.25" adaptor. I did a quick comparison test late last year with my ETX105. Both are very good performers on Lunar/Moon and planetary targets.

What magnification do they give you on your Meade? I think anything below 6.25mm will give me less than a 0.5mm exit pupil on my 102mm (f/12.7) Mak.

[Mak the Night]

I finally got to use the 25mm Hutech ortho's in the bino on M42. The seeing wasn't what I had hoped even though the nebulae was visible with the naked eye and I soon settled on a magnification of 52x (no Barlow). I experimented with the 15mm TV Plossl pair (87x) and the 20mm WO SWAN's (65x) with and without the Neodymium filter. Before finally settling on the AH 25's plus filter.  I found that with the nebula cloud it was comparatively easy to combine the bino images than with Jupiter and settled down to some very good viewing for around an hour. Whether this was because without the Barlow the eye relief was shorter (22.2mm) or that the target was larger in area I'm not sure. Either way, the ortho's delivered a mesmerising 3D-type view of the Orion Nebula. I'm impressed!

[RT65CB-SWL]

On 6 February 2016 at 16:32, Mak the Night said:

What magnification do they give you on your Meade? I think anything below 6.25mm will give me less than a 0.5mm exit pupil on my 102mm (f/12.7) Mak.

It works out at 245X with the ETX 105 (f/14) and 250X with the C6 (f/10). The downsides are eye-relief & exit pupil are 'tight', (pushing my 'scopes and eyes to the maximum limits), and the field of view is narrowed compared to a 6mm Plossl e/p.

With the TeleVue Ranger (f/6.8) it is 80X.

[Dave In Vermont]

If a telescope can handle 245X at 105mm aperture, which works out as a hair over 60X/Inch, that speaks very highly of the quality of the optics. And the 'seeing' conditions must have also been excellent.

These little Maksutov-Cassegrains never cease to amaze me!

Dave

[Mak the Night]

19 minutes ago, Philip R said:

It works out at 245X with the ETX 105 (f/14) and 250X with the C6 (f/10). Eye-relief and exit pupil are 'tight', (I cannot remember what they are). The field of view is slightly narrower, compared to a 6mm Plossl e/p.

With the TeleVue Ranger (f/6.8) it is 80X.

OK, if my maths is right, you should get an 0.47mm exit pupil on your ETX 105, 0.6mm on your C6 and 0.88mm on your TV Ranger. I think you should be able to get away with 0.47mm on the ETX. I can get a 0.47mm exit pupil on a 6mm EP for approx 217x on my Mak. It can be done and it's only technically a gnat's member under 0.5mm!

I have a 9mm WO SWAN that I can reduce to 5.625mm with a 1.6x Barlow to give me 231x giving me an 0.44mm exit pupil. I think that's pushing it a bit though lol.