markse68
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Posts posted by markse68
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10 hours ago, Louis D said:
Yes, there were equivalent XL diagrams and specs, but I can't locate them online anywhere.
strange that isn’t it🤷♂️ like they’ve been erased from history. Do you know what year they were released?
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Nice catch and something to keep an eye out for next time round. Thanks for the link too- could come in very useful
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16 minutes ago, Dippy said:
Thank you for sharing this nice idea. Would you mind if I ask whether the magnet is easy to slide during observation in the dark and if it stays in place when changing the angle of your telescope’s tube? I am asking because I found something similar in a web site, but like the one you have shared the picture of, it looks like normal magnets, not neodymium ones. So I am wondering are they strong enough to hold on to the tube. Thank you again for giving link and sharing this brilliant idea.
you wouldn’t want a neodymium that size- it’d lift a car! (or cause you serious damage if you got on the wrong side of it!) Pot magnets like this increase the field strength by diverting the flux lines from the other pole round close to the centre pole- they’re probably just ferrite magnets like used in speakers i’d guess. Smaller ones can be alnico but a bit spendy.
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26 minutes ago, John said:
My dob is in tube rings so could be shifted up and down as well but that would not be enough and also the travel downwards I have is limited because of the way I have the scope setup for my eye height. I have a number of eyepieces that weigh well over 1kg so they do need counterbalancing when the scope is pointing below around 60 degrees. Its become second nature for me now
Whatever works for you though. I just thought I'd post the pic to show one fairly easy way to do it
Sorry John, didn’t mean it to sound so contradictory 😬 I think if I were observing from home or somewhere more permanent then having the ease of just adding weights would be more convenient for sure and of course for some scopes there just isn’t enough tube travel. As it happens I’ve also just removed my motor focuser as after initial enthusiasm for it waned I just resorted to manual focusing and it became dead weight 😂. So now my scope is rather bottom heavy so i have lots of rearward free travel to play with. does mean that at zenith i’m on tip toes though....🤦♂️ It’s a delicate balancing act!
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11 minutes ago, John said:
That's a great counterweight solution for a steel tubed scope
My Orion Optics 12 inch has an aluminum tube so I've gone for a knife rack, some screws through it to create little shelves in 2 positions along the rack, and a couple of old TAL counter weights of 750g and 1500g.
Gives me lots of "quick change" weight options depending what I have hanging out of the other end and also depending on the angle that the scope is pointing at
i had similar but just removed it as I couldn’t be bothered to carry weights around with the scope and with the way my tube is held inside a sort of cradle it’s easier just to shift the tube up or down if balance is too far out to maintain set altitude.
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3 hours ago, Dippy said:
Good evening Alan, I like reading the subject material of your reviews, but most of the time I find it difficult to understand or follow what you are writing. Would it be possible before posting just edit, add punctuation and finally trim at least two thirds of the writing. I can understand probably English is not a first language for most of the people, but really it is difficult to understand this really useful review.
How rude! 😳🤦♂️ Shame there isn’t a flabbergasted emoji in the “likes” palette!
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just had another look at Mu Ceph and I don’t know if it’s my light polluted skies but it’s a deep orange to me 🤷♂️ I remember looking at it through a uhc in the past and it was very red though. Antares was spectacularly boiling tonight through I assume the jet stream 😂 and i’ve never seen Jupiter and Saturn look so bad- they had a lot more horizontal stripes than normal 🤦♂️ Not the best seeing but thankful for a brief glimpse through my scope at the start of what looks to be a dismal week 😞
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52 minutes ago, Louis D said:
I dug around Pentax Japan with the Wayback Machine archives and located this eyepiece PDF that seems to have vector diagrams of the lenses that can be increased in size at will.
That one's on the current Ricoh website too: http://www.ricoh-imaging.co.jp/japan/products/catalog/pdf/xo-xw.pdf#page=2
Ever seen an XL brochure? I guess there must have been one...
I tried to get the ZAO brochure from Company 7 lol. funny company
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1 hour ago, Barry-W-Fenner said:
Antares is a good shout John. I don't think it is in a very good position until about 2am here 😂
I think it’s reaching peak altitude around 11.30 at the moment Baz- at least that’s when it started dipping when i was tracking it a few nights ago. the trouble is it never gets very high so tends to be a boiling mess of atmospherics but i will persevere and one day i will see the b star- might have to take my scope on a trip (a lot) further south though 😉
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4 minutes ago, Louis D said:
And these:
Where the DS line indicates sagittal field curvature and the DM line indicates meridional field curvature. The origin is on axis performance and the vertical axis indicates performance trending toward the edge at the top. As the two lines diverge, it indicates increasing levels of astigmatism. The 5mm should have almost none with field curvature canceling that of most telescopes.
any idea where to get a higher res version of that first image Louis? I’ve seen it posted a few times but not found a higher res version- checked ricoh japan site too.
Mark
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if you don’t buy it, can I? 😉
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what diameter is the hole and width of the bracket? could you bend something from stainless steel strip?
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that looks excellent Peter- thanks for the heads up- will try it out when next at a pc. I love that they have added historical maps too- should make for some fascinating cross referencing. I love those ancient moon maps- my dream is to do a full moon sketch inspired by Cassini 😉...one day
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14 minutes ago, Stardaze said:
Perfect, that’s what I’m after Mark. Maybe the metric search would have found them?
yes maybe- the PE is soft enough to give a bit and fit the 50.8 barrel but in the field it’s too tight for comfort but cutting them down makes them more usable.
Of course there are 1.25” versions too which actually fit pretty perfect- tight but not too tight 👍 and cheap 😉
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for the barrel or the eye end? barrel caps are quite easy to find on ebay- i used these ones- they’re a tight fit- maybe annoyingly tight so i cut them down to half height
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24 minutes ago, Ricochet said:
What about if you use the 14 with a 2x barlow? Do you see a similar effect then?
i’ll try that- good idea
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1 hour ago, jetstream said:
My 24" and the Delos do not produce eye reflections for me- YKSE, a respected member here mentioned lens cleaning in that CN thread- have you tried cleaning this eyepiece?
i think the conclusion was that was for a different issue- a haze around bright objects? Yes the eye lens is spotless on mine.
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7 minutes ago, jetstream said:
I have tried piles of eyepieces and the Delos has never done this eye reflection- my 10mm Luminos was famous for it. Do you have a link to the CN thread?
it’s an interesting thread that Don participated in- he must have the patience of a saint 😉 The conclusion i’m coming to is this can happen to any ep but especially those with long er and wide afov but seems to depend also on scope and eye characteristics combination 🤷♂️ Larger aperture (brighter image) seem to make it worse too.
https://www.cloudynights.com/topic/572187-corneal-reflections-on-jupiter/
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1 minute ago, John said:
Only one way to find out .....
I like mine 😂 But i haven't compared them to any other fancy equivalents...
The 7xw performs superbly btw- the quality of image of Jupiter is just as good as my ortho and this corneal reflection has only manifested itself on Jupiter so i’m not displeased with it generally and won’t be getting rid of it just yet.
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11 minutes ago, John said:
So orthos might be better choices for you than wide fields with long eye relief and large curved optical elements ?
like i said John, i don’t have this issue with my other xws so no- not generally but yes perhaps for the 7 when looking at Jupiter with this scope😉
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16 minutes ago, bomberbaz said:
Good point well made John. When I see people cooing over ortho's I am thinking, noooh, don't like that, couldn't be doing with the tight er and small fov. Some of those same people might think 100 degrees fov, so what. It's all very subjective.
well my 7mm ortho didn’t have this issue 😉 Nice to have the extra fov and er though for sure.
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has the sharpening caused the moire pattern? Shame about the conditions last night- i watched Io appear off the limb closely followed by tack sharp Ganymede shadow which should have been followed by GRS! but thin hazy cloud swept in obliterating Antares first then the planets so i packed in. something nasty has been eating my feet out there so the change in weather is actually a welcome relief!
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5 hours ago, jetstream said:
Delos...
yes. it happens with those too apparently 😂🤪
”Yes, it happens to me too and last night I was really thinking about it. I was using Delos eyepieces but it happens with others as well. I think it might depend on the curvature or lack of curvature of the eyepiece top lens. It may also matter if your eyeball is too dry or too wet. I forget which. “ from an interesting thread on it on CN.
several people suggested moving eye closer to eye lens than normal er helped- seems to be common issue with long er eps with large eye lenses more so than eps with smaller lenses.
actually reading that thread made me feel a bit better- i had been thinking there must be something wrong with my particular xw7 and that i should have bought a new one but now i’m reassured that it happens with a LOT of eps from all makers and seems to be fairly inherent in long er widefield eps so i’ll just tolerate it... or get fitted with some expensive multi-coated contact lenses which surely must be the next big thing for visual astronomy! 🤔
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17 minutes ago, Don Pensack said:
Different eye lens shapes reflect back at the eye bright images that reflect from your eye. You're seeing the reflection of Jupiter from your eye, reflected back at you from the eyepiece. It will go all over the place if your head moves back and forth.
Other eyepieces, with different curves, may not have the same effect.
is there a solution Don? would it be scope specific?
Pentax XW 5mm
in Discussions - Eyepieces
Posted
I have the 40 as my finder ep- it’s very light weight for its size- seems to have much less glass than an XW- i guess a much simpler design? Would be really interesting to find optical diagrams of the XLs to see how they differ internally