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Astro eyepieces with Kowa 883 (1 Viewer)

Gypa

Member
Hello again. I still have the idea of using an astro eyepiece on the Kowa 883 to achieve 150-160x. I have thought that perhaps using the Kowa extender 1.6x in combination with the external screw astro adapter, a greater number of astronomical eyepieces may be compatible. This is so?
Thanks again.
 

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jring

Well-known member
Hi,

you might be lucky as a barlow lens will generally put your focus plane farther out.

Btw, 333x on a 3.5" refractor is just a bit over the top - even if we assume you have seeing which would support this magnification (usual rule of thumb is 50 or 60x per inch of aperture). Sth. around 200x will be nice on a very good example of the 883.

Joachim
 

Gypa

Member
Thank you very much Joachim. The photo that I attach is from a website. I don't have 1.6x extender or eyepiece yet. I would like advice for an eyepiece between 4-5 mm, medium price and that works with this system. I had thought of some Vixen slv or Baader Hyperion. Does anyone have experience?
I hope not to bother too much with the matter
Thank you very much again, health and good birding
Pedro
 

BoldenEagle

Well-known member
Hi,

I have tried Baader Morpheus 12.5mm eyepiece with Kowa 883 and using the adapter with external screws, it didn't reach focus over about 50 meters.

But it worked fine with the 1.6x extender.

I got the other adapter with socket screws which gets the eyepiece deeper in the scope mount and one can reach focus to infinity without any problems.

So if you get the other adapter (costs about 30€), I think you can have more eyepiece options without having the 1.6x extender.

Baader Morpheus seems to be quite good eyepiece and not very expensive (about 200€). Haven't tried other than 12.5mm (which gives about 41x mag. with Kowa 883). IMO only obvious drawback with Morpheus is it's lousy eyecup of which one must deal.

Best regards,

Juhani
 

jring

Well-known member
Hi,

yes, there are two adapters available - one with an external screw and one with a grub screw which goes in deeper and thus allows for a millimeter or two of backfocus - which might be the difference between coming to focus at infinity or not.
Handling is obviously easier with the external screw.

As for eyepieces, I would not recommend either of the two mentioned. The Baader Hyperion fixed mag series (not the zoom!) are known to perform not great on fast instruments - and your f5.5 certainly qualifies...

The Vixen SLV series might be ok on it (at least one reviewer used it on a 12" f5.5 dobsonian and didn't complain) but the 50 degree afov will not be great - this is a nice planetary EP for people needing good eye relief but for general observation not so much.

The Baader Morpheus series are known to perform well on fast instruments, same goes for all the 82 deg afov Nagler clones. I personally like the Explore Scientific 82 deg series a lot as they offer 95% or more of the performance of a Nagler at half the price. But there's others out there from Teleskop Express (82 deg series) or Celestron (Luminos) which are probably also Nagler clones.

Btw. will you wear glasses while observing? In that case ER is an issue to think about.

Joachim
 

Tringa45

Well-known member
Europe
Hi,

I have a Kowa 883 with the thumbscrew adapter and a variety of astro eyepieces.
Infinity focus can be achieved with a 28 mm Edmund RKE, a 19 mm TV Panoptic, an 11 mm TV Plössl and a 3,5 mm TV Nagler Type 6. Neither a 6 mm Vixen NLV nor a 7,5 mm Baader Eudiascopic can be focussed to infinity with this adapter.

John
 

Gypa

Member
Thank you very much for your help. I'll try to get hold of the internal screw adapter.
Juhani says that the Baader Morpheus does work with it.
I would like more advice from those who use this adapter and the eyepieces with which it works well.
Thanks and regards.
(a question: could a barlow lens be used instead of the kowa 1.6x extender by placing the astro adapter first, then the barlow and finally the eyepiece?)
 

BoldenEagle

Well-known member
I have used only 12.5 mm Morpheus and the standard TE-11WZ zoom eyepiece with my 883.

If I would have more astro eyepieces, I probably would buy more of those adapters with internal screws since it would be easier to swap eyepieces without using screwdriver every time and because those adapters are not that expensive. But it depends on your needs will you need more than one adapter.

As I mentioned, Morpheus has very lousy eyecup but I solved the problem by using spare Leica 25-50 zoom eyecup which I had from my previous scope. It was fairly easy to attach to the eyepiece and it can be even adjusted to different heights.

Below is a picture of my set.

Juhani
 

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BoldenEagle

Well-known member
Hi Juhani,
What is the current mag you reached with your Morpheus eyepiece (41x mag?, with or without extender?)
Thanks in advance
Regards
Yves

Hi Yves,

I believe 12.5mm eyepiece has about 41x mag with Kowa 883 (scope focal lenght 510mm divided by 12.5mm is 40,8x) and so with 1.6x extender mag will be around 65x.

I use my Morpheus 12.5mm exclusively without the extender because it is good compromise (for my needs) between enough exit pupil, magnification and wide field of view and has plenty of eye relief even with eyeglasses. Sometimes the (generally excellent) TE-11WZ zoom is better option and if I really need high mags, I use the zoom with extender.

I wish I could sometime have Docter 12.5mm UWA...

Juhani
 

PCreed

Member
I have the opposite issue--a Kowa eyepiece (TE11WZ) for astro-use. I only have a modded version of this eyepiece that works great for astro with 2"-eyepieces.

I can say the TE11WZ is VERY sharp off-axis even in fast scopes. The 883 is an 88mm f/5.8 scope. I've used the TE11WZ in an 8" f/4.9 Newtonian, both with and without any coma corrector.

I'm new here, but one of the older members of Cloudy Nights (astro forum). Numerous people have vouched for the Morpheus eyepieces ("Morphi"?). The eyecup issue has vexed it, but most describe them as way, WAY better than their Hyperion predecessors.

--Phil
 

Gypa

Member
Hi. My intention is to take advantage of the Kowa 883 for observation mainly of the Moon.
* What maximum magnifications do you think the Kowa can withstand for a luminous object such as the moon and operating a conventional tripod?
Thank you
Pedro
 

PCreed

Member
Hi. My intention is to take advantage of the Kowa 883 for observation mainly of the Moon.
* What maximum magnifications do you think the Kowa can withstand for a luminous object such as the moon and operating a conventional tripod?
Thank you
Pedro

General rule of thumb for astro resolution is about 50X/inch or 2X/mm of aperture (look up Dawes' Limit for more on this)

The Kowa 883 has an 88mm aperture, so 176X is where you'd max out. If you use a 3mm eyepiece, you're at 170X. The 1.6X will get you up to 96X and a 2.5X barlow would get you down to 150X using just the zoom, assuming they could be used in conjunction with the Kowa.

The Baader Morpheus series offers a 4.5mm 76° eyepiece, good for 113X. There's also the 3mm, 4mm and 5mm Televue Radians (170X, 128X and 102X on the 883) which, though discontinued, often pop up on Astromart. Great contrast and eye relief, 62°.

I think your hunch is correct in that the limiting factor is likely to be the tripod, not the scope. Magnification...magnifies. Everything. Including vibrations.

What are the dampening times at 60X? Good rule of thumb is if you're using twice the power, expect twice the dampening time before the image is still. If it's >5 seconds at 60X, it will be really, REALLY frustrating over 100X.

--Phil
 

dothedr3w

Member
Canada
Hey everyone,

I'm new to the forums and this thread is exactly what I was after. I just recently purchased a Kowa 883 and have some answers to questions here, as well as some questions of my own. I figured it was better to revive an old thread rather than start a freshy. Turns out my reply had become rather lengthy so hold on

I have the Kowa 883 with TE-11WZ eyepiece, as well as the Kowa 1.6x adapter...which I highly recommend. I also have an astro eyepiece; the TeleVue Nagler 3-6mm zoom. As for the astro adapters, I have the Kowa adapter with thumb screws, and the Baader with grub screws and brass compression ring.

Here are my observations so far which will hopefully help some of you:

- yes, 176x is the recommended maximum for this scope, but I have taken it to 276x (Nagler zoom @ 3mm with 1.6x) both terrestrially and looking at the moon. The moon is so big, and so bright that I don't know what the maximum zoom is while looking through this scope, but the max is certainly beyond 276x; atmospheric conditions will be your limiting factor. I've also taken the 276x terrestrially and it's equally as impressive. Again, limited by atmospheric conditions. I had it outside in about -15C mid day while testing this and could, albeit with some difficulty, correctly discern words on a pedestrian sign about 700 meters away. I'll confirm the distance if anyone is interested.

- the Nagler 3-6mm Zoom is an awesome companion to the TE-11WZ; between the two of them they cover a pretty impressive range, especially when the 1.6x extender is in the mix. The Nagler is not without its faults however...it's only functional with the extender, which I'll explain.

- The Nagler zoom has a longer barrel than other 1.25" eyepieces which will cause it to bottom out before the eyepiece 'astro adapter' hits the 'shoulder' of the eyepiece. What does this mean... It turns your Kowa into a microscope instead of a telescope. Continue below:

- Scenario 1: Nagler 3-6mm Zoom WITHOUT 1.6x Kowa extender. Focus range is from 13ft to about 150ft. I performed a series of tests to figure out wtf the problem is, and the result is this...the eyepiece will not seat far enough into the scope's receiver to achieve infinity focus.

- Scenario 2: Nagler 3-6mm Zoom WITH 1.6x Kowa extender. Focus range minimum was not tested, however it was able to achieve focus on the moon (I'm not sure if this constitutes infinity focus). As previously mentioned, I could also read the really far away sign (read above). Why the difference you ask?? The 1.6x extender allows the astro eyepieces to be seated 1-2mm deeper into the socket so-to-speak. I roughly measured this by scribbling pencil onto the barrel of the eyepiece.

- With a fixed focal length eyepiece I don't think you'll have the issues I've experienced as they have a 'normal' length barrel; any 1.25" astro eyepiece SHOULD work with or without the extender...but then again that's what I thought.

- I can't offer any advice over which astro adapter to buy (the Nagler zoom bottoms out so this is irrelevant for me). However, don't forget the issue I've experienced...I can't achieve infinity focus because the eyepiece will not seat deep enough; the thumb screw variant of the astro adapter may present this problem in exchange for it's convenience. To clarify, the thumb screw variant of the astro eyepiece adapter may not allow the eyepiece to seat to it's fullest potential. If in doubt, buy both. You've already spent thousands of dollars, what's another $30.

Here's my question:

How do I "trick" my Nagler zoom think it's closer to the scope than it actually is? Is there an optical device or filter I can place between the eyepiece and the scope itself, keeping in mind it's already bottomed out. The best solution I can think of so far is a focal reducer, but I'm too much of a noob to know if it'd actually work (albeit robbing me of zoom).
 
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia

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