Don Pensack

6 hours ago, cajen2 said:

Is anyone else using a Clicklock and if so, how do you find it?

1) it's not adjustable and doesn't grab some slightly undersized eyepieces well and there is no way to tighten it.

2) it still binds with a thin brass split ring, not a long collet, and it can get hung up on some undercuts.

I'm not sure  I remember exactly the several hundred post thread on Cloudy Nights back in 2002-2005, but I don't think Zeiss actually produced the Astroplanokular.

It appeared after WWII as a product licensed to Ohi Optics (Masuyama).

As late as ten to 15 years ago Kasai Trading in Japan was selling the Kasai Astroplan eyepiece, also from Ohi Optics,

with the same internal design as the Astroplanokular of Zeiss.

15 hours ago, Voyager 3 said:

Mark,

https://www.cloudynights.com/topic/810970-astrotech-28mm-uwa/#entry11730857

How about waiting for a few reports? 

https://www.teleskop-express.de/shop/product_info.php/info/p2757_TS-Optics-2----28-mm-Ultraweitwinkel-Okular---82--Feld.htmlMark

This is the TS version of the same eyepiece. 

But maaaaybe a bit close in FOV to the 20mm 100°.

 

It's been around several years.  Just look for reports on the William Optics UWAN 28mm.

18 hours ago, Mr Spock said:

If you want to spent lots of money there's always the 21mm Ethos  Similar fov to the 31mm Nagler.

36.2mm field stop compared to 42mm.

The Nagler has a true field 16% wider.

If the magnification in the 31mm is too low for most purposes though, you're right--the 21 would get more use.

18 hours ago, cajen2 said:

I bought this some months ago as a stopgap till I could afford what I thought would be better-quality glass. It was hardly ever used as FLO did the Pentax sale and I took the opportunity to get myself a 5mm XW. Who'd use a Svbony when you've got a Pentax, right? Well, tonight, I was viewing parts of M42 with the Pentax and decided I wanted just slightly lower mag. So I put the Svbony in the focuser and was amazed at just how good the little EP was (it's about a quarter of the size and weight of the Pentax). The image was crisp and to be honest, hardly any worse than an EP five + times the price. The eye relief was very slightly shorter and the very edge of field slightly less controlled but that was it!

So the upshot is, if you're looking for a very cheap but good quality EP as an (even cheaper) alternative to a BST Starguider, you could do a lot worse than this Svbony. Do check models, though, as the company makes a huge range of EPs of varying quality.

I don't think Svbony is a manufacturer, but just a reseller of already existent Chinese products under private label.  Most of their products were available years before the Svbony label (which was formerly Vite).

But, you put your finger on the differences between inexpensive eyepieces and expensive ones:

Expensive eyepieces will have better corrected outer fields, both in terms of chromatic aberration and astigmatism, may have wider fields on top of that, and better control of light scatter on bright objects.

If all you're doing is looking at the center of the field, there is very little difference between eyepieces.

Here are the Japanese company's specs for the LVWs:

https://www.cloudynights.com/topic/445618-how-many-elements-in-a-vixen-lvw/?p=5767670

5,6,7, or 8 lenses.

5 hours ago, mikeDnight said:

I don't suppose you have any pic's Don?  I don't think I've ever seen the earlier version.

It was amusing at a local star party a good few years ago, when a fellow observer walked over to my FS128 to take a look at the double cluster. He'd used the scope many times and he'd seen the double cluster hundreds of times no doubt, but when he looked into the eyepiece he was momentarily wowed by the view. The double cluster looked as if it hung in free space right before his eye and he asked "what eyepiece is this?" How I wish I'd have had my wit's about me and said "it's a new line of TV eyepieces." Instead I blurted out the truth - "it's a 28mm RKE" I said. His interest was immediately lost, but his initial reaction was priceless and told the real story. It makes me wonder how many people lust over eyepieces merely because of a brand name, and conversely, dismiss them on the same basis?

 

Some information about it:

https://www.cloudynights.com/topic/363923-the-edmund-1-18-lens-description/

and a pic:

http://www.astrosurf.com/luxorion/Illustrations/edmund_scientific-catalog-astronomy-1962.pdf

See page 23 in the old catalog.  Edmund described it as a Kellner, but also mentions it has 2 achromatic lenses inside.

That is because Edmund called Plössls "Kellner Type III" eyepieces. [Kellner type I was the regular Kellner, Kellner Type II was what became RKE]

Here is a picture instead of a drawing (scan through the images to see--it's the all-black eyepiece) Click on any image to see it larger.:

https://astromart.com/classifieds/astromart-classifieds/eyepieces/show/rare-vintage-edmund-scientific-rke-plossl-set-excellent

Note: The barrel had no filter threads, there was no field stop (so it had a vary vague field stop and just faded out at the edge), and it worked only so-so below f/8.

I had one in the '60s with an f/10.5 scope and in the early '70s with an f/15 scope and it worked fine.

I bought one used in the '90s and even in my SCT of the time, it was not a good eyepiece.

2 hours ago, paul mc c said:

My RKE 28mm, apparently fairly rare first run Edmonds. Amazing floating views. 

I had an even older eyepiece than that early RKE--a 4 element Edmund eyepiece labeled 1-1/8" for the focal length.

Depends.

Just looking for a larger exit pupil?  A very cost-effective way would be the 30mm APM Ultra Flat Field or one of it's rebadged brothers.

Looking for a larger true field?  Then you want a larger field stop eyepiece, like the 31mm Nagler or 30mm ES 82°.

Of course, the second option also gives you the first.

I have, and extensively compared it with a 14mm Baader Morpheus and several other eyepieces at a dark site (m.21.4+ skies)

It has some issues:

1) It does not have 20mm of eye relief with the threaded-on eyecup provided.  That eyecup sticks up about 8mm above the lens, reducing the eye relief to about 12mm.

That would be fine if you don't use glasses at that focal length.  Unfortunately, I do, and it was inadequate for glasses use.

Removing the eyecup exposes your glasses to being scratched by the aluminum top of the eyepiece.  The thread is 50mm, so finding an eyecup to fit isn't going to be easy.

I stretched a smaller eyecup onto the eyepiece and folded the rubber inward to cover the aluminum top of the eyepiece with rubber about 0.5mm thick, and the eyepiece was usable with glasses at that point.

2) The eyepiece has some highly reflective surfaces inside the eyepiece and the eyepiece has some edge of field brightening I did not see in the Morpheus.

 I took the LHD eyepiece apart and blackened the internal spacers, lens edges and housing and this reduced, but did not eliminate, the edge of field brightening.

I communicated with LongPerng about it, but they admitted the eyepiece had a bit of a problem with scattered light but that they were "working on it to do better".

Other than those two issues (I kept the 14mm Morpheus and gave away the LHD), the eyepiece is nice and sharp to the edge.  Color rendition is good, and the eyepiece works fine

at f/4.5.  It's a very modern eyepiece, but I have to admit to being mystified why someone would design an eyepiece with enough eye relief for glasses and then put it in a housing that eliminates

its suitability for glasses, and that applies to the entire series.  I guess the outer shell designers paid no attention to the results of the optical designers.

An observation: the 12mm and 17mm ES92s are not free of SAEP either.

A lot of people have noticed this.

Long eye relief (long enough for glasses).  Comfortable observing (adjustable eyecups).  Wider field than Plössls, but no less sharp.

TeleVue Delites.  I bought 3.  Now I own all 9.  They are that good.

I'm just sayin'.

The 5X Powermate also has a significant change in magnification with distance from the lens.

See:

https://www.televue.com/engine/TV3b_page.asp?id=53&Tab=_app

I think it is unlikely it is the same optical confoguration as the other PowerMates.

Just now, ninjageezer said:

thanks don will get to test that out this week weather permitting ,if I can get focus buy doing that I'm guessing I need some kind of adapter to extend the focuser ?

Yes, it's called an Extension Tube.  FLO sells them, as do many other retailers.

4 hours ago, Louis D said:

I found that the only alignment problem I was having with my Arcturus BVs, which do have self centering holders, was due to eyepieces with undercuts tipping in the holder during the tightening process.  I have to cram them down while tightening to prevent them from popping up at an angle.  I should just fill the undercuts with pinstriping tape.

Which will solve the problem.  I use copper tape.

Don

Already responded to the same post on CN.  Can you achieve focus by pulling the eyepiece + PowerMate out of the focuser a bit?

How much.  For 1/4", don't sweat it, just do it and tighten it down.

For 1/2" or more, look into getting an extension tube (available everywhere).

On 11/02/2022 at 13:21, Louis D said:

So, 1.6mm off on the low side for the converted Tele Vue specified value of 40.6mm for the 13mm NT6.  The TV spec'ed 43.2mm value for the 19mm Pan and 16mm NT5 is off by 1.1mm on the low side for the former and 1mm off on the high side for the latter.  Even if TV had some rounding going on, I would have expected the 13mm NT6 and 16mm NT5 to have the same listed width.  My faith in Tele Vue spec accuracy has been shattered. 😱

LOL.  Their recommended setting for the 17mm Nagler was off by one setting, too.

ES has some wrong information in their eyepieces spec chart, Baader has some field stop errors in their eyepiece spec chart, APM has incorrect field stops listed for their UFF eyepieces.

I could go on and on.

As they say, Doveryai no proveryai: Trust, but verify.

some major links on filters:

Planetary:

https://www.cloudynights.com/topic/713148-planetary-filter-shootout/

https://www.cloudynights.com/topic/533147-spectroscopic-analysis-comparison-of-planetary-filters/

Nebula:

https://www.cloudynights.com/topic/527199-spectroscopic-analysis-comparison-of-nebula-filters/

https://www.cloudynights.com/topic/598011-nebula-filters-tested-over-a-2-year-period/#entry8205435

Comparative charts:

https://searchlight.semrock.com/?sid=a08a1af9-84ee-49d2-959d-153d7e7c0eb8#

Nebula filters increase contrast by reducing the light from the sky without dimming the nebula.

A narrowband, UHC-type, filter passes hydrogen emission line and the 2 O-III lines in the spectrum and little else.

Without knowing the spectrum of emission of the nebula, this is the 'universal' type of nebula filter.

[Nebula filters do not work on dark nebulae or reflection nebulae]

If the object has little hydrogen emission, but is strong in the O-III lines, narrowing the filter will increase the contrast even more.

So, narrowband--all nebulae, and especially the larger hydrogen gas clouds forming stars (M42/43, M8, M20, M17, M16)

O-III for planetary nebulae, supernova remnants, and Wolf-Rayet excitation nebulae.

Brands to look for: Astronomik UHC and O-III, TeleVue Nebustar and O-III, DGM NPB, Lumicon UHC and O-III, Chroma UHC and O-III, ICS UHC and O-III

2nd choice: Orion Ultrablock and O-III

For planets, the most effective filter I've used is the Baader Contrast Booster filter.  It is the one I reach for nearly every time.

The Baader Moon & Sky Glow is also good, but a bit less effective on Mars than the CB.

For the Moon, you really only need a filter at low powers--at high powers, the moon is kind of dim.  But a variable polarizing filter is most useful, though a 25% transmission neutral density filter also works well.

Well, I was wrong.  Meade brought the filter back in the late 2010s when they were owned by Sunny.

It's still available new from many suppliers.  It's $40 to $64 in the US, so you got a good price.

I hope it works in your scope.

The coatings on the X-Cel LX are better.  The old S4000 Japanese "Super Plössl" had excellent polish, but lesser coatings so more internal light scatter on very bright targets like planets and Moon.

Also, eye relief on the X-Cel LX will be consistent across the line, where the older "Super Plössls" will have an eye relief of approximately focal length x 0.7.

Only usable with glasses longer than 25mm.

The S4000 came in 3 Japanese versions:

1) 5 element, smooth side, no rubber eyecup, Japan stamped in the black aluminum

2) 5 element, with rubber eyecup, Japan stamped in the black aluminum

3) 4 element, with rubber eyecup, Japan stamped in the chrome barrel.

The S4000 have had multiple versions over the years, one from Taiwan, and several from China, but those 3 versions are the only ones I know of from Japan.

In a SkyWatcher Dob, I'd get the X-Cel LX:

--more comfortable eye relief, especially at high powers for planet viewing.

--more modern coatings

--more drift time before you need to move the scope because of a wider true field and wider apparent field.

Another competitor of the X-Cel LX you might look at is the BST Starguider eyepieces from FLO.  Might be a bit less expensive and pretty much equal.

Meade discontinued this filter 10+ years ago.  If you bought it new, it is new old stock, which is fine.

The issue with it is that it pulls the eyepiece back by a large amount and requires in travel at the focuser equal to its height.  Most people don't have that much additional travel available.

Most people simply thread a variable polarizing filter onto the eyepiece, but that is not as convenient as the Meade product you have.

If it works in your scope, it's a good find.

After your UHC filters, the next filters to get are O-III filters, which are useful on planetary nebulae, Wolf-Rayet excitation nebulae, and supernova remnants.

An H-ß filter has an even narrower bandwidth, making the field quite dark.   It does help make the large faint nebulae like the California Nebula more visible,

but it won't make the horsehead visible in that aperture.

I have held one up to the eye (it was mounted in a small tube to block all peripheral light) which allowed me, at a dark site, to see Barnard's Loop and the Lambda Orionis Complex with the naked eye.

So I would advise O-III filters first, then the H-ß filters last.  You have to be completely dark adapted to use them (45-60 minutes outside, away from lights), and use very low powers, like 3-5x/inch of aperture.

One additional comment: your Astronomik UHC filter passes the H-ß line.  If you cannot see an H-ß target in that filter at all, an H-ß filter won't make it visible.

All H-ß targets are visible in the UHC, albeit with a slightly lower contrast.  The H-ß filter helps, but doesn't make visible what was invisible through the UHC.

I might also add to the excellent summary above that the dark-adapted eye at night (scotopic vision) does not see the H-α line in the spectrum with more than a completely minimal sensitivity, if at all.

Whereas our photopic, daylight, vison might extend from 400nm to 750nm in the spectrum, our sensitivity at night changes to primarily 425-550nm with very little vision, if any, above 600nm.

That makes the 656nm emission of the H-α wavelength pretty much outside the range of our vision.

An H-α filter can be useful for a camera, whose sensitivity extends into the infrared, but it is not a visual filter.

So H-α is only useful for daylight viewing of the sun through a special solar scope that confines the light coming through to an extremely narrow bandwidth of H-α light.

The Cemax eyepieces are, therefore, aimed solely at solar viewing in special H-α solar scopes.  They have been marketed as accessories for the Coronado Solar telescopes, hence the gold coloring.

However, in the field they perform exactly the same for astronomy as other inexpensive GSO Plössls.

For use at night, lots of other eyepieces are their equals.

17 hours ago, LaurenceT said:

As a complete novice in astronomy, only started last year, I bought a 127Mak purely for lunar and planetary observation and photography with an Altair planetary camera.

I've used the Baader zoom eyepiece on the moon with the Baader moon filter and the views were wonderful and exquisitely detailed.

For a wider view I have a 130pds Newtonian and my new little baby an Orion ST80.

Well, as I said, a zoom can be a good choice when the narrow apparent fields of the zoom still yield wide true fields in the scope (like your short focal length scopes).

Or, I should have added, when narrow fields are preferred (Moon, planets, double stars).

It isn't the best choice for the Maksutov in question for general use, which is also on an undriven mount, where width of field is more important still.