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Everything posted by John
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Pentax XW 10mm with Barlow vs Pentax XW 5mm
John replied to HollyHound's topic in Discussions - Eyepieces
Delites look delightful I'd like to try one someday. I tend to only use my barlow with my zoom as well and use either fixed short focal length eyepiece or the specialised 2-4 Nagler zoom. Good to have options at high power -
Double stars with under arcsecond separation
John replied to Armand Popa's topic in Observing - Reports
Another very impressive list Your skies, scope and eye must be excellent to be able to split all those sub-arc second pairs and some easily as well. What sort of 12 inch dobsonian are you using ? -
iOptron 150mm Rumak - first impressions
John replied to Mr Spock's topic in Discussions - Scopes / Whole setups
It looks a great scope Michael I agree with you re: photos of the actual instrument rather than boxes -
I think that is called "going the whole hog" ! I'm sure you will absolutely love those choices
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That all sounds very satisfying - nice report
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The 10mm claims to be 52 degrees and the 25mm 50 degrees. Not sure if those are accurate figures though - the ones I've used seemed a little narrower than that
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It's cloudy here now so I can't check on the current state of affairs but I figure early evening is the best time. The area which the dust storm seems to be affecting moves westwards as the planet rotates and could well be mostly out of sight over a couple of hours looking at the simulators. I've just read a report from early this evening on the CN forum which described a pale "finger" bisecting the darker areas diagonally from the SW limb, which sounds similar. These are dynamic things though so the shape / extent could well change over the coming hours and days.
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I've flipped Paul's drawing to get the refractor view here and arrowed the pale feature that I'm seeing:
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Just observing Mars again now with my Tak FC100. That brighter streak / corridor though the darker terrain in the SW quadrant of the planets disk that Paul Abel draws in his 1st drawing in Jeremy's link above seems to be quite visible just now. It divides off a chunk of the darker area to the W of it. Worth a look if you can get out, before that area rotates off the disk. I'm supposed to be cooking supper now so I'm just grabbing a few moments at the scope while my other half is on the phone
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The 1920's cigarette card thoughts on the Martian landscape have obviously been influenced by Schiaparelli and Lowell
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Minimum Useful Scope Aperture: Outdated concept ?
John replied to John's topic in Discussions - Scopes / Whole setups
Yes indeed ! -
Explore Scientific 12mm 92° has arrived
John replied to michael.h.f.wilkinson's topic in Discussions - Eyepieces
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Minimum Useful Scope Aperture: Outdated concept ?
John replied to John's topic in Discussions - Scopes / Whole setups
My original post was really concerned with observing. That's all I have any experience of. Aperture and it's relationship with imaging is likely to throw up a different sort of discussion I would have thought ? -
Explore Scientific 12mm 92° has arrived
John replied to michael.h.f.wilkinson's topic in Discussions - Eyepieces
The Antares 1.6x 2 inch barlow gained an excellent reputation for working pretty much seamlessly with the Ethos eyepieces. The newer designs of this barlow do have some issues if you have restricted focuser travel range though. Optically they have not changed. The older design of the Antares Barlow is worth looking out for - no compression ring or filter threads but it does reach focus in a wider range of scopes. The steel set screws can be swapped for nylon ones to protect eyepiece barrels. The other thing to watch for with all barlows is that they push the eye relief out a bit. With some eyepieces this can be an advantage but the ES 92's already have long eye relief so a barlow may cause some eye positioning challenges. With the ES 92's being such tall, heavy eyepieces, a lightweight, short barlow, as long as it performs well, is preferred I think. Sounds like using a barlow or focal extender is likely to be the only way to get a wider range of ES 92 degree eyepieces in the foreseeable future. -
Comet C/2020 M3 Atlas
John replied to John's topic in Observing - Widefield, Special Events and Comets
Well done Neil. I've got cloud and light rain here so I've given up for tonight and bought the scope in. -
Looks like my "brighter patch" is in the right area area but I could get nowhere near the detail that Paul has drawn there. The darker features on my sketch do seem to generally match what Paul has captured though, which I'm quite pleased about given the conditions here tonight.
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I've nearly given up here - so much cloud about and a gusty wind moving it around fast
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Yes - ctrl-shift-H reverses the chart horizontally and ctrl-shift-V does it vertically. You need to do both for a newtonian view, just the horizontal for the refractor / mak-cass / SCT view (assuming normal diagonal is being used).
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The problem is, even with a very large aperture scope, magnifications of 300x - 500x are not useful other than very rarely because of the effects that observing through our atmosphere has. As a device to observe very faint objects, at somewhat lower magnifications, 20 inches is an amazing amount of light gathering power.
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Yep, it's a bit wild out there
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Comet C/2020 M3 Atlas
John replied to John's topic in Observing - Widefield, Special Events and Comets
This comet is just above Orion's right "shoulder" tonight. Might get a chance later to have a look at it if the forecast is to be believed. I'd better watch out for "Attack ships on fire ....." as well -
Explore Scientific 12mm 92° has arrived
John replied to michael.h.f.wilkinson's topic in Discussions - Eyepieces
The Antares 2 inch 1.6x barlow works well with the Ethos's - perhaps it would well with the ES 92's as well ? -
It's a bit of an unfair comparison with the ES 30 being an 82 degree eyepiece @ £276 and the Stellalyra Superview 30mm a 68 degree eyepiece @ £69. There was some discussion on these on another forum. The Zhumell 30mm referred to is another branding of the Superview 30mm: https://www.cloudynights.com/topic/562728-zhumell-30mm-vs-es-82-30mm/
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SW 200P on a Skytee
John replied to WiltsStarGazer's topic in Getting Started Equipment Help and Advice
The problem with the stock clamps is that the threads on the tension knob of the clamp have a tendency to strip rather easily under load. The knobs are made of rather soft aluminum. They also used a steel threaded rod with a cross cut in the top which the knob screws onto to tighten the clamp. This cross cut has the effect of wearing away the threading within the knob rather effectively, being made of harder metal. Maybe the more recent versions of the mount have knobs which are made of harder metal and the threaded rod design altered ?