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Pages: 1 MAURITS professor emeritus Reged: 09/22/09 Loc: Diksmuide (Belgium) Strange situation!       #5356338 - 08/07/12 11:37 AM Edit   Reply   Quote Quick Reply   This afternoon I used the 2" Lunt Herschel Wedge with in the front the Baader 2" UV/IR cut filter and the Ethos 6 mm with the Baader 2" Solar Continuum filter. So far so good, I saw clear the sunspots with the umbra and penumbra, it was a good view! Then I used the Ethos 13 mm with the Televue 2x powermate 2", and the view was "so much clearer" than with the above combination! Is this a normal situation, how is this possible (about the same magnification)? The scope is the TOA-150 and OK the seeing was not so good, but such difference in the view! Thanks! Post Extras:       brianb11213 Postmaster Reged: 02/25/09 Loc: 55.215N 6.554W Re: Strange situation! [Re: MAURITS]       #5356554 - 08/07/12 02:11 PM Edit   Reply   Quote Quick Reply   It doesn't make any sense to me, unless there was something wrong with the 6mm EP, perhaps being unable to cope with the focal ratio of the objective. I'll readily admit to not being a fan of the Ethos line but I really do not think that this is likely to be the case, any Ethos EP should cope with the native focal ratio of all except possibly the fastest Newtonians. Does the 6mm work OK at night, with an ordinary star diagonal or without a diagonal at all? If not, maybe it's been dismantled and an element has been put back the wrong way round. Post Extras:       highfnum Carpal Tunnel Reged: 09/06/06 Loc: NE USA Re: Strange situation! [Re: brianb11213]       #5356744 - 08/07/12 04:25 PM Edit   Reply   Quote Quick Reply   6mm vs effective 6.5mm (13/2) maybe that .5 mm made the differenece? or powermate gave more eye relief ? Post Extras:       brianb11213 Postmaster Reged: 02/25/09 Loc: 55.215N 6.554W Re: Strange situation! [Re: highfnum]       #5356776 - 08/07/12 04:55 PM Edit   Reply   Quote Quick Reply   Quote: 6mm vs effective 6.5mm (13/2) maybe that .5 mm made the differenece? or powermate gave more eye relief ? I doubt that you'd notice 10% difference, let alone it have a major effect. Actually a (nominally) 2x Powermate is more likely to give a magnification different to 2x anyway, with the Powermates (except the 5x which behaves more like a "normal" barlow) the magnification doesn't vary much with the extension distance but it does vary a bit. Eye relief - I was under the impression that the Ethos range were engineered to give (very nearly) the same eye relief across the range, and one of the selling points of Powermates is that the eye relief of the eyepiece is not affected by the insertion of the device. If the 6mm EP tests out fine I would suspect that it was just "unlucky with the seeing" - in my experience with solar observing, the seeing can vary quite quickly from being bad with better intervals to goodish with poor intervals. At my site when the sun is shining brightly the seeing usually becomes bad to awful if the wind falls calm; a gentle gust of wind improves the seeing for as long as it lasts, by breaking up the intense turbulence near the ground; when the gust dies away, the seeing gradually (over a period of a few seconds) goes bad again. Post Extras:       MAURITS professor emeritus Reged: 09/22/09 Loc: Diksmuide (Belgium) Re: Strange situation! [Re: brianb11213]       #5357443 - 08/08/12 12:59 AM Edit   Reply   Quote Quick Reply   Thanks brianb11213, thanks Jon for the quick answers! Post Extras:       simpleisbetter Carpal Tunnel Reged: 04/18/11 Re: Strange situation! [Re: MAURITS]       #5357449 - 08/08/12 01:06 AM Edit   Reply   Quote Quick Reply   My first thought is thermals and seeing fluctuation. I get this a lot when viewing the sun, especially in the summer. Views might be a P9 one minute, and the next drop to P3-4 due to thermals. Heat thermals play as much havoc on my solar viewing (especially summertime) as heat radiation does on my wintertime nighttime viewing. Post Extras:       Pages: 1

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