60 replies to this topic

[davidgmd]

Interesting. Like Dave said, in Europe I never noticed any change in supply.

 

Has Orion closed completely?

  
It’s my understanding that Orion and Meade are no more. At least for now. No idea if there is any possibility that someone restarts either brand.

[Jon Isaacs]

You are correct.  I bought that Vixen A80Mf (the lowercase "f" identifies it as being made in China by Synta) four years ago, right before Vixen went out of business.  As far as I understand, the Japanese-made Vixen A80M and A81M scopes had much better optical quality.  One CN member has commented about having been familiar with the older Vixen A80M and the Chinese-made A80Mf, and there is no comparison.

 

I have owned more 80 mm F/11 achromats than I can remember, I once owned seven simultaneously. They've included Celestron/Vixens, Mizar Meade's, Towa Meade's, Synta Vixens and Synta Celestrons. 

 

The optics were all very similar, none of them had flawed optics and none of them were significantly better than the others.

 

The scope that was significantly better was the 80 mm F/7 William Optics Megrez 2 FD, an FPL-53 doublet. It would split more difficult doubles and provide crisper, sharper planetary views 

 

An 80 mm F/11 achromat does show visible chromatic aberration, the color blur is significant, about 3x the diameter of the Airy disk.

 

Jon

[Princess Leah]

The lens cell on mine is plastic , but the doublet is very heavy, lead glass? I'm not seeing the CA I would expect. Certainly no fringing on Saturn.

[davidgmd]

Jon, don’t slower scopes typically have less chromatic aberration than faster scopes? Was it the FPL-53 that set the WO Megrez doublet apart, despite it being faster?

[Jon Isaacs]

Jon, don’t slower scopes typically have less chromatic aberration than faster scopes? Was it the FPL-53 that set the WO Megrez doublet apart, despite it being faster?

 

Most definitely.  An 80 mm achromat would have to be about F/40 to have the color correction of an 80 mm F/7 FPL-53 doublet.

 

Jon

Edited by Jon Isaacs, 13 October 2024 - 09:53 AM.

[Princess Leah]

I think I've made a basic error here. I mistakenly used a prism instead of a mirror diagonal with the fast (F6) ED scopes.

When I checked today terrestrially the views were much improved with the mirror.

Will await a clear night to check on Saturn.

[Oldfracguy]

Most definitely.  An 80 mm achromat would have to be about F/40 to have the color correction of an 80 mm F/7 FPL-53 doublet.

 

Jon

Absolutely right.  

 

I have one of those 80mm f/7 FPL-53 doublets now as it turns out.  Last night I had it up to 224x on the Moon.  The problem was not with the lack of detail still visible on the lunar surface at 71x per inch of aperture with this scope, it was with floaters and other problems with this observer's eye at that small 0.36 mm Exit Pupil.

[Princess Leah]

Most definitely.  An 80 mm achromat would have to be about F/40 to have the color correction of an 80 mm F/7 FPL-53 doublet.

 

Jon

What about spherochromatism?

[Jon Isaacs]

What about spherochromatism?

 

The colors have to come to focus. In a 80 mm F/11, the don't come to focus.

 

Jon

[STEEL]

Does the Planetary 3.2mm ED incorporate a Barlow lens in its configuration?

It would not be news that inside it there are two elements similar to a Barlow. Other brands of prestigious eyepieces also use or have used an optical scheme with Barlow elements (see Pentax XO or Vixen HR).

[Oldfracguy]

I think I've made a basic error here. I mistakenly used a prism instead of a mirror diagonal with the fast (F6) ED scopes.

When I checked today terrestrially the views were much improved with the mirror.

Will await a clear night to check on Saturn.

I've been able to use the Baader T2 Prisms in f/6 scopes (AT60ED and AT72EDII) successfully.  It will be interesting to hear how Saturn looks using one of your ED scopes with both the prism and the mirror diagonals.

Edited by Oldfracguy, 13 October 2024 - 03:32 PM.

[Oldfracguy]

Does the Planetary 3.2mm ED incorporate a Barlow lens in its configuration?

Yes.  Here are some photos I took recently when I was taking apart a BST 4mm Planetary eyepiece.  These eyepieces have 5 elements in 3 groups.  The upper part has a single lens, below which is a metal spacer, followed by a cemented doublet lens:

 

 

 

 

 

The lower portion contains a Barlow section:

 

Edited by Oldfracguy, 13 October 2024 - 03:31 PM.

[Princess Leah]

Great replies, thanks again.

My 2 inch Baader prism also seemed fine last time I used it at F6. But here I was using the Celestron 1.25 inch prism. I will compare them terrestrially tomorrow and then again on Saturn, next clear night.

What I meant about spherochromatism is I believe it is more of a problem with a short fast ED scope, so the difference colour-wise betweens the F6 ED scope and the F11 achromat may not be so massive.

[Jon Isaacs]

Great replies, thanks again.

My 2 inch Baader prism also seemed fine last time I used it at F6. But here I was using the Celestron 1.25 inch prism. I will compare them terrestrially tomorrow and then again on Saturn, next clear night.

 

What I meant about spherochromatism is I believe it is more of a problem with a short fast ED scope, so the difference colour-wise betweens the F6 ED scope and the F11 achromat may not be so massive.

 

The chromatic blur of an 80 mm F/11 achromat is about 3x the Airy disk. That means the red and blue are badly out of focus. 

 

Check out this scope:

 

https://www.cloudyni...ge-wo-80fd-f69/

 

I believe Spherochromatism would show up in the red and blue . Looks pretty good to me.

 

(If you read enough of that thread, you will see that it was my scope that was tested.)

 

Jon

Edited by Jon Isaacs, 14 October 2024 - 02:47 AM.

[Princess Leah]

I agree that my achromat scientifically should produce violet halos at 160X, but it doesn't, not on Saturn at at least. I'm having to go looking for CA which is a good sign. At 100X on tree branches on the horizon I can see some faint violet encroachment (a bit more than the Equinox shows)- but none on Saturn....yet. A couple of friends at my club were impressed and surprised.

However its not a particularly bright scope and I hope the Equinox will be better.

I've read several reviews of cheaper ED scopes by famous brand names on 'CloodyNights' that show considerable false colour.

One review I remember involved the father showing his son the planet Saturn, only for his son to ask, 'what are the two violet blobs on either side of the planet?'

I'm sure on paper these scopes should perform better than my achromat, but in reality they don't.

 

I'm not insensitive to CA. The Equinox 80 has a little, but it's a very bright, sharp scope which has very little light scatter. It's a little similar to a Televue Pronto with less false colour. I prefer it to my CF 80 triplet, which takes longer to cool and image wise seems a little dull, even though it appears 'optically perfect.' Unless for imaging, I probably wouldn't buy another triplet. Although I should mention the triplet is much better at splitting doubles (there's a joke or riddle there somewhere).

 

Like your friend I'm trying to reduce the amount of refractors I have. I want a simple life!

Tonight looks set to be clear, hopefully the Equinox will win with a mirror!

[Jon Isaacs]

 

I agree that my achromat scientifically should produce violet halos at 160X, but it doesn't, not on Saturn at at least. I'm having to go looking for CA which is a good sign.

 

Keep this in mind:

 

Chromatic aberration means that the colors are not in common focus.  Just because you do not see the false color, it can still affect the crispness and contrast of the image.

 

 

 

One review I remember involved the father showing his son the planet Saturn, only for his son to ask, 'what are the two violet blobs on either side of the planet?'

I'm sure on paper these scopes should perform better than my achromat, but in reality they don't.

 

That has not been my experience. Something wasn't right, it sounds like the son was inexperienced and did not understand how to focus properly. 

 

Even an ST-80 does not produce violet blobs when viewing the rings of Saturn.

 

I read reviews sometimes but do not believe everything I read.

 

Jon

[Princess Leah]

Was testing out the prism and mirror terrestrially today. Very sunny, looking at tree branches again.

Curiously the 1.25;inch prism produced false colour with the Equinox when using the Baader zoom , but not with any other eyepiece. With a mirror the Baader zoom exceeded my expectations. Previous I thought it was a somewhat overrated zoom.

With the Orion 80 CF it didn't matter, prism or mirror, I couldn't detect a difference, no false colour. The image actually looked better with the prism/more contrast.

 

I managed to collimate/align the Orion CF focuser by adjusting the three hex screws. It seemed to take forever, but I finally got it alligned. When I was doing this I flocked the draw-tube. These two changes have made a big difference. I perhaps prefer it now to the Equinox.

Will try Saturn tonight.

I agree with Jon, there is a lot of nonsense written online.

[Oldfracguy]

Keep this in mind:

 

Chromatic aberration means that the colors are not in common focus.  Just because you do not see the false color, it can still affect the crispness and contrast of the image.

 

 

Jon

That's it in a nutshell.

 

The image produced in a refractor is 3-dimensional.  It has width and height, but it also has depth.  That depth is along the optical axis of the telescope, and results from the different wavelengths of light coming to focus at slightly different distances away from the objective lens in the front of the scope.  Ideally, the image would be perfectly flat, 2-dimensional, with no depth at all.  The better a refractor's objective is the smaller that longitudinal depth, and the better the image quality becomes.  Not only does that color fringing shrink to a practically invisible level. the sharpness of the image increases, as do fine details that can be seen.

[Princess Leah]

I have no problem with the theory.

 

It's putting the theory into action that I sometimes see inconsistencies!

[Princess Leah]

Had a grand night. 

 

What I noticed was this.

 

When seeing was initially poor, and/or dispersion was poor due to a fine layer of Cirrostratus, a prism can play having in my F6 Equinox. It introduced flare/glare and annoying reflections. I'm not sure why that is, but changing to a mirror made a great improvement.

A prism also magnifies any CA introduced by the Baader zoom. The zoom works great with a mirror and even Barlowed.

 

With the mirror in place the Celestron X-cel LX Barlow worked very well indeed.

 

However later in the night when the seeing improved and the thin icy clouds departed, I was actually able to see more detail on the moon and it's current 'satellite Saturn' with the prism in place.

The views indeed were excellent, using a 5.5mm ES 62 Barlowed.

Unfortunately I hadn't the time to compare the views with the F11 achromat.

Edited by Princess Leah, 15 October 2024 - 02:23 AM.

[Lookitup]

I have the Tecnosky Planetary ED 3.2mm and if we leave out the extreme edge of the field and consider only 50° of field (maybe more), this is a very sharp eyepiece. I have done several tests with Zeiss abbe II, Pentax ortho, Takahashi TOE, and Televue DeLite. In the tests I have done I also used the Zeiss Barlow (on the 6mm of Zeiss abbe II and Pentax or 7). The Tecnosky Planetary ED 3.2mm are absolutely very sharp and it is possible to do very serious astronomy even by combining them with very expensive telescopes. The Televue DeLite and Tecnosky Planetary ED have remained in my equipment and are absolutely wonderful. If hypothetically you could diaphragm a Tecnosky Planetary ED 3.2mm and reduce it 52° like the Takahashi TOE 3.3, I don't know who would come out on top (ED 3.2mm is a big step forward in dispersion containment).

 

I can reassure you that the Tecnosky (Paradigm, BST) are excellent quality eyepieces at a reasonable price, but be careful with the 18mm and the 25mm, these are not to everyone's taste (I returned the 18mm

The BST 12 mm were my fav. before the 11mm Delite's. But I do like more FOV now so it's the Morpheus 12.5 and 17.5's with binoviewer's. They do have more reflection on Jupiter in my setup but they feel like using giant binoculars with the SM 125ED.

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[Princess Leah]

I purchased a used 3.2mm Starguider ED. It might be clear tonight. I will try it with the little Equinox against the Omcon.

[eblanken]

Hi to OP & All,

 

I'm following with interest this thread. Thanks to Princess Leah (OP) for starting the thread and for the integrity & honesty of admitting to a simple error that uncovered some things that were helpful for me to know and/or be reminded of . . . 

 

Very Best Regards to All,

 

Ed

Edited by eblanken, 09 November 2024 - 02:48 AM.

[Princess Leah]

Thanks Ed.

Unfortunately remained cloudy again! Will update when clear skies return.

[Princess Leah]

Last night I observed Saturn with my 80mm Equinox (F.25).

Curiously I got a better view of Saturn, Barlowing a 7mm Xcel LX, compared to using a 3.2mm Starguider. The difference was very noticeable. Much sharper using the Barlow.

 

It also resulted in more magnification than the 3.2mm EP. I believe the 7mm Xcel is actually 6mm. And the X-cel LX Barlow is about 2.2X.

 

I believe I have ascertained the problem is not the Barlow. I will have another look with my 80/900 achromat. I will make sure it's the same height of the ground when comparing with the Equinox.

Edited by Princess Leah, 13 November 2024 - 06:06 AM.