184 replies to this topic

[Neanderthal]

Thank you Don! 

[Houdini]

Has the 20mm Houdini been drift-timed to verify the 86°? Or some other measuring method (other than a computer design theoretical)?

Note that you would measure the field stop diameter, theoretically 30.0 mm, with the drift-timing method, not the 86° AFOV.

 

I remember observing the moon through the 25" F/5 telescope during the Saturn occultation on January 4th of this year. The eyepiece provides 159x magnification and a theoretical field of view of 32.4'. The Moon, with a diameter of 32.5', fit nearly perfectly within the field of view. I found it quite striking how well its size matched that of the field.

 

If you were to measure the AFOV, you might find it to be 87° instead of 86°. The field stop is not razor-sharp; there is a transition zone of about 1° where the field illumination drops to zero. Theoretically, you have 80% illumination at 43°, 50% at 43.5°, and 15% at 43.8°. The partial illumination consists mostly of blue rays, which explains why objects at the field stop appear colored.

Edited by Houdini, 16 May 2025 - 11:28 PM.

[Tangerman]

Hope to be able to contribute to the conversation soon. Ordered yesterday, though Visa didn't like it and it took a couple of calls to my credit union to get the order to go through. International purchases from Belgium are not the norm for me, so I understand why Visa thought it could be fraud, but I got the order confirmation in the end, and it looks like a shipping label has already been created (not sure if that's an automatic thing or if Robert decided to work this weekend). 

 

I definitely fall into the target audience: someone who's gotten by with minimal eyepieces and no coma corrector. One of the appeals is that these should work with the sort of fast Dobsonian that I dream of getting, so this should be a lifetime eyepiece. Another appeal, and this is really a big factor, is these are some of the widest AFOV eyepieces that I should be able to use with my glasses.

Edited by Tangerman, 17 May 2025 - 07:36 AM.

[Neanderthal]

Hope to be able to contribute to the conversation soon. Ordered yesterday, though Visa didn't like it and it took a couple of calls to my credit union to get the order to go through. International purchases from Belgium are not the norm for me, so I understand why Visa thought it could be fraud, but I got the order confirmation in the end, and it looks like a shipping label has already been created (not sure if that's an automatic thing or if Robert decided to work this weekend). 

 

I definitely fall into the target audience: someone who's gotten by with minimal eyepieces and no coma corrector. One of the appeals is that these should work with the sort of fast Dobsonian that I dream of getting, so this should be a lifetime eyepiece. Another appeal, and this is really a big factor, is these are some of the widest AFOV eyepieces that I should be able to use with my glasses.

I placed an order for the 20mm yesterday and had a hiccup with the credit card as well, but after backing out and re-trying a few times it finally took. Got the confirmation text from the credit card company as well. The ability to pay with PayPal would have been my preference.

 

I am thrilled with the Morpheus eyepieces but the only complaint I have is how coma correction robs you of the FOV you paid for. So now I would have to acquire a 14mm Morpheus to get back the same FOV I had with the 12.5mm prior to correction. The other EP's didn't have that simple of a solution (within the Morpheus line). I can easily live with this but the Houdini option might be simpler and cheaper. My only concerns with the Houdini are how comfortable it will be compared to the Morpheus and the eye relief for my wife who needs to wear glasses (I will as well someday, sooner than later).

 

Robert - please don't send clouds with the H20.  

[astrophile]

... The ability to pay with PayPal would have been my preference.

...

Problem there is PayPal will hammer you with a ridiculous exchange rate, unless you specifically tell the PP transaction to use your credit card...in which case you're back to confirming legitimacy with the CC company.  Which isn't that big a deal if you're expecting it.

 

This should all alleviated when Agena and any other US retailers start carrying the Houdinis.  Might even save on shipping costs as well.

Edited by astrophile, 17 May 2025 - 12:53 PM.

[Neanderthal]

Yep, my PayPay automatically pulls from a credit card, which still would've required a text verification. It's all good. Got a shipping notice this morning.

I see the Houdini EP's are now shown on AgenaAstro's website. Glad I ordered yesterday, lol.

[arg0s]

I've now used it several nights in between storms we've received.

 

Admittedly, it's a bit of a weird buy for me; I have a couple fast Newts, but they're small and 1.25" only, and my largest Dob is f/7. However, it seems to stand on its own pretty decently as a general widefield eyepiece. Views were very sharp in my Dob across the field. I wasn't sure how things would look in my AT72 given its F/6, but it still performed well. I've been meaning to look through a Classical Cas, but haven't had a chance yet.

 

So, for me, the 20mm's role in correcting coma is mostly speculative on maybe eventually getting or borrowing a faster Dob in the future, but as someone otherwise relatively uninvested in 2" widefield EP's, the value proposition seems decently strong regardless.

 

The 12mm will be a different story when it comes out; I've invested in 1.25" around that focal length already, but correcting them natively in a 1.25" format would be unwieldy at best. A correcting eyepiece that doesn't have weight/focuser travel issues would be far better suited for tiny fast Newts for G&G.

[Sarkikos]

Three Houdini eyepieces are listed at Agena Astro:  7mm, 12mm and 20mm.  The 7mm and 12mm are 1.25".  The 20mm is 2".  (They are not yet on the Astronomics store website.)

 

Listed.  Unfortunately, they are all "Out of Stock."  If you drill down to each eyepiece, they show "Coming Soon."  I've put all three in my Wish List and subscribed to back-in-stock notifications.  The complete set would cost $1219.

 

If I had all three, I could do without the Paracorr ... at least for those three eyepieces.  Also, I could do without a 2" Barlow lens assembly for the 20mm-only scenario. 

 

Could these three replace my 6 or 8mm Ethos, 12.5mm Docter and 20mm XWA? 

 

Mike

Attached Thumbnails

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Edited by Sarkikos, 18 May 2025 - 08:10 AM.

[Bob4BVM]

Three Houdini eyepieces are listed at Agena Astro:  7mm, 12mm and 20mm.  The 7mm and 12mm are 1.25".  The 20mm is 2".  (They are not yet on the Astronomics store website.)

 

Listed.  Unfortunately, they are all "Out of Stock."  If you drill down to each eyepiece, they show "Coming Soon."  I've put all three in my Wish List and subscribed to back-in-stock notifications.  The complete set would cost $1219.

 

If I had all three, I could do without the Paracorr ... at least for those three eyepieces.  Also, I could do without a 2" Barlow lens assembly for the 20mm-only scenario. 

 

Could these three replace my 6 or 8mm Ethos, 12.5mm Docter and 20mm XWA? 

 

Mike

Glad to see these are hitting the market and make sense for some of you.

Unfortunately for me, the "set of three" would cost me $2438.00, not $1219.

 

Stuff like this keeps making a pair of Leica ASPH zooms at $1800 look more and more reasonable.

 

CS
Bob

[Houdini]

Stuff like this keeps making a pair of Leica ASPH zooms at $1800 look more and more reasonable.

You would also need to add two coma correctors to your 17.5" F/4.5 bino.

The whole point of the 86° coma-correcting eyepieces is to provide built-in coma correction and sharp images right away.

[Sarkikos]

Glad to see these are hitting the market and make sense for some of you.

Unfortunately for me, the "set of three" would cost me $2438.00, not $1219.

 

Stuff like this keeps making a pair of Leica ASPH zooms at $1800 look more and more reasonable.

 

CS
Bob

Although you could sell your coma correctors to make up the difference.

 

I have one Leica Zoom and several other zooms.  The main reason I use zooms is to avoid switching eyepieces. 

 

Mike

Edited by Sarkikos, 23 May 2025 - 06:38 AM.

[Bob4BVM]

Although you could sell your coma correctors to make up the difference.

 

I have one Leica Zoom and several other zooms.  The main reason I use zooms is to avoid switching eyepieces. 

 

Mike

So far i have learned to live without coma correctors by keeping targets center field, so did not design them into the BT.  Still my preferred instrument by a large margin. Something about the natural 2-eyed view seems to make up for any drawbacks.

 

I use a host of fixed EP pairs, as well as a couple of zoom pairs sometimes.  Avoiding switching EPs is my main reason for zooms, it gets to be a much bigger deal on those cold nights. when you are dealing with 4 EPs and 4x filter swapping for each EP change,

 

That said, I'd be very interested to see how a Houdini Zoom would stack up against the ASPH, performance and pricewise. A true 80* 3:1 zoom at under $800 would get my attention. The APM SZ story leaves me thinking "I'll believe it when I see it"

Edited by Bob4BVM, 23 May 2025 - 01:31 PM.

[Neanderthal]

The Houdini 20mm arrived a little while ago - unfortunately our weather here in southern Missouri is absolutely craptastic and no chance to give it a try for a few days.    Gave it a cursory trial outside in the daylight before it started raining. Here are a few first-thoughts:

 

Ordered on Friday, May 16 @ 6 pm, arrived today, Friday, May 23 about 4:30 pm

So right at 1 week from Belgium to southern Missouri, pretty good. 

 

Here's a side-by-side view of the Houdini 20mm with the APM 30mm UFF:

 

Eye lens view:

 

This could easily be labeled an APM, lol.

 

My first impression is that it was like looking through the Astro-Tech UWA 28mm. With no eyeglasses and the rubber guard up - I could not see the field stop without rolling my head quite a bit. With the rubber folded down, I still had to roll my head, but just a tad. While wearing my readers, the rubber def had to be folded down, I could barely catch the field stop with rolling my head, but was more difficult than without glasses. Note that my readers are less-than-optimal for astronomy service, I'd get something more svelt, these are the thick-framed Wal-Mart $8 readers. The real test will be at night, with my wife using her glasses.

 

Agree about the rubber eye guard complaints. Robert - if you read this, I think it would be a smart plan to pursue a different eye guard asap. What is the thread specification at the top? I'd get a Baader Morpheus eye guard to the manufacturer and tell them to mimic that design.

 

 

[Starman1]

The Houdini 20mm arrived a little while ago - unfortunately our weather here in southern Missouri is absolutely craptastic and no chance to give it a try for a few days.    Gave it a cursory trial outside in the daylight before it started raining. Here are a few first-thoughts:

 

Ordered on Friday, May 16 @ 6 pm, arrived today, Friday, May 23 about 4:30 pm

So right at 1 week from Belgium to southern Missouri, pretty good. 

 

Here's a side-by-side view of the Houdini 20mm with the APM 30mm UFF:

Houdini 20 & APM 30 side-by-side.jpeg

 

Eye lens view:

Houdini 20 & APM 30 eye lens.jpeg

 

This could easily be labeled an APM, lol.

 

My first impression is that it was like looking through the Astro-Tech UWA 28mm. With no eyeglasses and the rubber guard up - I could not see the field stop without rolling my head quite a bit. With the rubber folded down, I still had to roll my head, but just a tad. While wearing my readers, the rubber def had to be folded down, I could barely catch the field stop with rolling my head, but was more difficult than without glasses. Note that my readers are less-than-optimal for astronomy service, I'd get something more svelt, these are the thick-framed Wal-Mart $8 readers. The real test will be at night, with my wife using her glasses.

 

Agree about the rubber eye guard complaints. Robert - if you read this, I think it would be a smart plan to pursue a different eye guard asap. What is the thread specification at the top? I'd get a Baader Morpheus eye guard to the manufacturer and tell them to mimic that design.

The Houdini takes a 55mm eyepiece cap if you store it with the eyecup flipped down.

The APM UFF takes a 2" eyepiece cap if you store it with the eyecup flipped down.

[Tangerman]

I spent some time the past two nights trying out my new Houdini 20mm. The first night I compared it to my Astro-tech UWAs in my 10" f/5 telescope. These are 28mm, 10mm, and 4mm focal lengths, so the comparisons weren't direct but rather just looking at how the stars were at the edges of the field. I do not own any sort of coma corrector, so the Houdini line of eyepieces should be a great way to expand my collection and get higher quality eyepieces. 

 

I compared using Spica and Arcturus and placing them at various positions in the FOV, as well as general observing. In the Houdini, some chromatic smearing (not sure of the technical term for it), just as the spot diagrams show, is visible towards the edges of the FOV on bright stars, more pronounced on Spica than Arcturus because it's much bluer. In the UWAs, this chromatic smearing was combined with coma. I didn't notice any chromatic smearing for fainter stars. That's not to say it isn't there, but it doesn't distract from the view unless you've got a really bright star in the field.

 

The second night I tested with an 18" f/3.5 dob that I will most likely be purchasing. This was equipped with a SIPS unit, which I took out for using the Houdini and had in for my other eyepieces. This makes the telescope operate at f/4 for the non-Houdini eyepieces. At f/4, the astigmatism in the 28mm UWA was more readily apparent. I didn't notice as much of it in the 10mm UWA, so it seemed to me that the 10mm is better corrected at the edges. With the Houdini, the field looked really good. I didn't notice any coma, and any chromatic smearing didn't seem much worse than the f/5. The star images at the edge were definitely better than with the UWAs. Very pleased with the eyepiece, and with it cheaper than a Nagler, I think it's a great option for someone moving into fast scopes.

 

As for ergonomics, the 28mm UWA and Houdini handle similarly and are similarly sized. I have to press my glasses against the eyecup to access the whole field of view in either one, but an 86° field of view is worth it. I look forward to not needing to take off my glasses to use higher magnifications, because the shorter focal length UWAs have significantly less eye relief (though still comfortable without my glasses on). I also tested the Houdini without my glasses to see how easy it was to view through. I found this configuration very nice, very easy to see the entire FOV.

 

Thank you, Robert, for the new line of eyepieces! Looking forward to the others to round out my magnification gaps!

[nkoiza]

An 86 degree, long eye relief, light weight coma correcting eyepiece - quite a feat!! It's about time that someone took on this challenge and delighted to learn about this breakthrough!

 

The early reports seem to indicate very good sharpness across the field in fast dobs, but I would be interested to receive comments on the transmission and contrast characteristics of the 20mm Houdini?

 

I have been considering buying a 23mm Pentax XW, although the 16.5 XW is slightly better. With Paracorr at F/4.4 in the 16", the magnification would be identical to the 20mm Houdini (89x and 4.5mm exit pupil). If contrast and transmission also impress in the Houdini, I might be tempted to abandon the idea of the 23XW, which I was thinking of as a longer term purchase.

 

I don't know whether contrast and transmission would be right up there, i.e., KUO vs Ricoh (Pentax XW), but I would certainly be interested in any feedback and comparisons between the 23 Pentax XW and 20 Houdini.

[Houdini]

I spent some time the past two nights trying out my new Houdini 20mm. The first night I compared it to my Astro-tech UWAs in my 10" f/5 telescope. These are 28mm, 10mm, and 4mm focal lengths, so the comparisons weren't direct but rather just looking at how the stars were at the edges of the field. I do not own any sort of coma corrector, so the Houdini line of eyepieces should be a great way to expand my collection and get higher quality eyepieces. 

 

I compared using Spica and Arcturus and placing them at various positions in the FOV, as well as general observing. In the Houdini, some chromatic smearing (not sure of the technical term for it), just as the spot diagrams show, is visible towards the edges of the FOV on bright stars, more pronounced on Spica than Arcturus because it's much bluer. In the UWAs, this chromatic smearing was combined with coma. I didn't notice any chromatic smearing for fainter stars. That's not to say it isn't there, but it doesn't distract from the view unless you've got a really bright star in the field.

 

The second night I tested with an 18" f/3.5 dob that I will most likely be purchasing. This was equipped with a SIPS unit, which I took out for using the Houdini and had in for my other eyepieces. This makes the telescope operate at f/4 for the non-Houdini eyepieces. At f/4, the astigmatism in the 28mm UWA was more readily apparent. I didn't notice as much of it in the 10mm UWA, so it seemed to me that the 10mm is better corrected at the edges. With the Houdini, the field looked really good. I didn't notice any coma, and any chromatic smearing didn't seem much worse than the f/5. The star images at the edge were definitely better than with the UWAs. Very pleased with the eyepiece, and with it cheaper than a Nagler, I think it's a great option for someone moving into fast scopes.

 

As for ergonomics, the 28mm UWA and Houdini handle similarly and are similarly sized. I have to press my glasses against the eyecup to access the whole field of view in either one, but an 86° field of view is worth it. I look forward to not needing to take off my glasses to use higher magnifications, because the shorter focal length UWAs have significantly less eye relief (though still comfortable without my glasses on). I also tested the Houdini without my glasses to see how easy it was to view through. I found this configuration very nice, very easy to see the entire FOV.

 

Thank you, Robert, for the new line of eyepieces! Looking forward to the others to round out my magnification gaps!

Thank you for the detailed report.

The "chromatic smearing" of bright stars near the edge of the field is called lateral color. Your observation is correct, it does not change with the focal ratio.

[Houdini]

An 86 degree, long eye relief, light weight coma correcting eyepiece - quite a feat!! It's about time that someone took on this challenge and delighted to learn about this breakthrough!

 

The early reports seem to indicate very good sharpness across the field in fast dobs, but I would be interested to receive comments on the transmission and contrast characteristics of the 20mm Houdini?

 

I have been considering buying a 23mm Pentax XW, although the 16.5 XW is slightly better. With Paracorr at F/4.4 in the 16", the magnification would be identical to the 20mm Houdini (89x and 4.5mm exit pupil). If contrast and transmission also impress in the Houdini, I might be tempted to abandon the idea of the 23XW, which I was thinking of as a longer term purchase.

 

I don't know whether contrast and transmission would be right up there, i.e., KUO vs Ricoh (Pentax XW), but I would certainly be interested in any feedback and comparisons between the 23 Pentax XW and 20 Houdini.

Higher in this thread CrazyPanda compared the transmission with the Ethos 21. See post #29.

 

At the French Astrosurf user "maire" made the comparison between the Houdini 20 and the Pentax 23 in Paracorr 2, in a 300 mm F/4 telescope.

He could not detect any difference between the views - the power and field match nearly perfectly.

See post #23 above which also has the link to Astrosurf. After the test the user put his Pentax 23 and Paracorr for sale on the French forum .

 

With the 1100 mm F/3.6 I extensively compared the Houdini 20 with the Ethos 21 in Paracorr 2, on deep-sky and Jupiter (back in December). I did not see anything in one of the two eyepieces that I could not see in the other.

Edited by Houdini, 24 May 2025 - 02:12 PM.

[Houdini]

Agree about the rubber eye guard complaints. Robert - if you read this, I think it would be a smart plan to pursue a different eye guard asap. What is the thread specification at the top? I'd get a Baader Morpheus eye guard to the manufacturer and tell them to mimic that design.

I agree, the eye guard is not the best ever. Unfortunately, the prototypes did not have the final eye guard, so I could not validate it. 

However, I have now managed to convince the KUO engineers that there is indeed an issue, so we can work from there.

I'll suggest to the KUO engineers that they take a look at the Baader Morpheus eyeguard.

If we decide to create an improved version, we will definitely send it to all current Houdini 20 users. Luckily, it's a part that can easily be swapped.

 

For what it's worth, the Houdini 12 and Houdini 7 have an eyeguard that sits much tighter around the eyepiece body — it's a lot better.

[Neanderthal]

That's good news! It's really nice to see a provider that is this responsive to customer feedback.

The true beauty behind the Baader screw-on design, is that it permits a thin, low profile rubber cup that has a couple mm's of eye relief adjustment just by screwing/unscrewing tighter or looser. I dont remember if there's enough thread on the H20 to pull that off, but if so, yhatd be awesome.

[nkoiza]

Higher in this thread CrazyPanda compared the transmission with the Ethos 21. See post #29.

 

At the French Astrosurf user "maire" made the comparison between the Houdini 20 and the Pentax 23 in Paracorr 2, in a 300 mm F/4 telescope.

He could not detect any difference between the views - the power and field match nearly perfectly.

See post #23 above which also has the link to Astrosurf. After the test the user put his Pentax 23 and Paracorr for sale on the French forum .

 

With the 1100 mm F/3.6 I extensively compared the Houdini 20 with the Ethos 21 in Paracorr 2, on deep-sky and Jupiter (back in December). I did not see anything in one of the two eyepieces that I could not see in the other.

Thank you for this additional information. I'm very impressed and would love to give the 20 Houdini a try!

Edited by nkoiza, 24 May 2025 - 04:07 PM.

[star drop]

If your proposed 30 mm eyepiece is made will it be possible to attach a Dioptrix to it?

[Tangerman]

Robert, 

Your Cruxis site has ray traces of coma-corrected eyepieces with focal length 20mm and longer. Have you posted any spot diagrams for the upcoming 12mm and 7mm eyepieces? Perhaps you could link the spot diagrams at f/4 on your website (or maybe it's already there and I just couldn't find it).

[Houdini]

If your proposed 30 mm eyepiece is made will it be possible to attach a Dioptrix to it?

Like the Houdini 20, the Houdini 30 will have 42 mm diameter lenses in the top part, and that is too big for Dioptrix.

It might be possible to 3D print an adapter, I guess, the Houdini 20 has some 48 mm threading at the top that could be used for this.

[Houdini]

Robert, 

Your Cruxis site has ray traces of coma-corrected eyepieces with focal length 20mm and longer. Have you posted any spot diagrams for the upcoming 12mm and 7mm eyepieces? Perhaps you could link the spot diagrams at f/4 on your website (or maybe it's already there and I just couldn't find it).

The designs on the Cruxis web site are just for illustration, they're not "production" quality, these pages were made about a year ago - before our collaboration with KUO.

 

But yes, it's a good idea to have a comparison chart for the Houdini eyepieces with the spot diagrams at F/4. I'll prepare a chart and post it on the Houdini Telescopes web site.

 

EDIT: Below the Houdini 20-12-7 Comparison Chart at F/4.

The Houdini 12 and 7 are very sharp!

 

Edited by Houdini, 25 May 2025 - 06:17 AM.