156 replies to this topic

[DRodrigues]

 

 

...

 

Do you feel the same about the 24mm? Would you say that it has two or three more degrees?

 

...

 

At https://www.cloudyni...flat-eyepieces/ is mentioned that the 24 has similar AFOV to the Pano 24 but that is because the Pano 24 is really 65º... I tested the Pano 24 in the past and had lower AFOV/FOV than the Hyperion 24. Tammy measurements confirmed my observations.

The UF 24 should be a good alternative to the Pano 24 and Vixen LVW 22 - I still didn't purchase these for my BV since would prefer a 1.25 ep with >22mm and >70 AFOV...

I have a XW20 and a pair of Meade 5000_60 26...

[Starman1]

 

 

 

...

 

Do you feel the same about the 24mm? Would you say that it has two or three more degrees?

 

...

 

At https://www.cloudyni...flat-eyepieces/ is mentioned that the 24 has similar AFOV to the Pano 24 but that is because the Pano 24 is really 65º... I tested the Pano 24 in the past and had lower AFOV/FOV than the Hyperion 24. Tammy measurements confirmed my observations.

The UF 24 should be a good alternative to the Pano 24 and Vixen LVW 22 - I still didn't purchase these for my BV since would prefer a 1.25 ep with >22mm and >70 AFOV...

I have a XW20 and a pair of Meade 5000_60 26...

 

The 24mm Panoptic has a 27mm field stop, quoted 68°

The 24mm Hyperion has a 28.5mm field stop, quoted 68°

The 24mm APM UFF has a 30.2mm field stop, quoted 65°, in the engineering diagram (though I question this for a 31.75mm O.D./28.5mm I.D. eyepiece barrel).

At that focal length, the apparent fields should be 65°, 68° and 72° respectively, assuming distortion of equal amount and parameter.

However, that is not likely to be the case.  It largely depends on the distortion amount and type as to what the actual apparent fields are.

Actual apparent fields need to be measured with, say, the flashlight test to get actual figures.

[ThomasM]

 

 

 

Meanwhile I could do a test under the sky, in a f/6.5 refractor the eyepiece is sharp to the edge, very nice. I compared it with a Baader Hyperion aspheric 36mm and Masyama 32 mm. No comparison, the egdge sharpness is very much better, the Masuyama on the other hand has a visibly larger field of view. Field stop of the APM UF 30 is very sharp. As you can see the size and weight ( 540 g) are similar to the Hyperion 36 mm. A key part of the UF 30 mm is the big entrance lens (40 mm diameter) of the reducer (it is not a Barlow type Smyth lens, it is a reducer!). In that sense the UF 30 differs from all other eyepiece on the market, it is a really new design. According to the designer, the first element is made of very high index glass, that might be the reason why it has a slight yellow cast.

All in all, a very nice eyepice, especially for binoviewing.

 

Thomas

 

When you describe the performance of the EP - is this in bino mode or mono? I ask because some binos use a tele extender etc. before coming to focus.

 

I am using the eyepieces mono as well as binocular, there is no tele extender used. A key advantage compared to other long focal length eyepiece that they are slim and rather light and at the same time sharp to the edge.

[rex-racer]

 

 

 

 

Meanwhile I could do a test under the sky, in a f/6.5 refractor the eyepiece is sharp to the edge, very nice. I compared it with a Baader Hyperion aspheric 36mm and Masyama 32 mm. No comparison, the egdge sharpness is very much better, the Masuyama on the other hand has a visibly larger field of view. Field stop of the APM UF 30 is very sharp. As you can see the size and weight ( 540 g) are similar to the Hyperion 36 mm. A key part of the UF 30 mm is the big entrance lens (40 mm diameter) of the reducer (it is not a Barlow type Smyth lens, it is a reducer!). In that sense the UF 30 differs from all other eyepiece on the market, it is a really new design. According to the designer, the first element is made of very high index glass, that might be the reason why it has a slight yellow cast.

All in all, a very nice eyepice, especially for binoviewing.

 

Thomas

 

When you describe the performance of the EP - is this in bino mode or mono? I ask because some binos use a tele extender etc. before coming to focus.

 

I am using the eyepieces mono as well as binocular, there is no tele extender used. A key advantage compared to other long focal length eyepiece that they are slim and rather light and at the same time sharp to the edge.

 

Thanks for the report etc. This EP fits right in between the Vixen 22mm LVW and the 42mm LVW so I might pick one up in the future if user reports are positive.

[Tamiji Homma]

 

 

 

What binoscope for 2" are you using?

 

Hi Thomas,

 

It is 95mm Swarovski spotting scope objective lens with EMS, compact, lightweight binoscope built by Matsumoto-san.

It is inward focus challenged and it has short 2" sleeve so long 2" nose piece eyepiece may not come to focus to infinity.

 

Tammy

 

Hi Tammy,

 

I saw the pictures, a very nice instrument. If the Baader Hyperion 36 gets into focus you should have no problem with the APM UFF 30 mm.

 

Thomas

 

 

Hi Thomas,

 

I received APM UF 30 today.  I tried it on my Swarovski binoscope.  I had 0.5mm left to go when I focused to 1.5 miles away.

I guess it was no go for the binoscope since I won't be able to use any filter with the thin margin.

 

I'll save them for coming new binoscope.

 

Tammy

[ThomasM]

 

 

 

 

What binoscope for 2" are you using?

 

Hi Thomas,

 

It is 95mm Swarovski spotting scope objective lens with EMS, compact, lightweight binoscope built by Matsumoto-san.

It is inward focus challenged and it has short 2" sleeve so long 2" nose piece eyepiece may not come to focus to infinity.

 

Tammy

 

Hi Tammy,

 

I saw the pictures, a very nice instrument. If the Baader Hyperion 36 gets into focus you should have no problem with the APM UFF 30 mm.

 

Thomas

 

 

Hi Thomas,

 

I received APM UF 30 today.  I tried it on my Swarovski binoscope.  I had 0.5mm left to go when I focused to 1.5 miles away.

I guess it was no go for the binoscope since I won't be able to use any filter with the thin margin.

 

I'll save them for coming new binoscope.

 

Tammy

 

Hi Tammy,

 

this is a pitty, I am sorry for that. I think the UFF 30 mm has 4 mm more extra travel than the Hyperion  36 mm, but I understand, if you want to combine it with filters this will not be enough. So your coming new binoscope is a TEC 140 instrument?

 

 

best regards

 

Thomas

Edited by ThomasM, 07 January 2018 - 12:01 PM.

[Tamiji Homma]

 

this is a pitty, I am sorry for that. I think the UFF 30 mm has 4 mm more extra travel than the Hyperion  36 mm, but I understand, if you want to combine it with filters this will not be enough. So your coming new binoscope is a TEC 140 instrument?

 

Hi Thomas,

 

As you can see below, APM 30 UFF 2" nosepiece is long so that it hits the bottom.

That's why...  Oh well, I can use Panoptics 27 with the scope.  

 

Yes, new binoscope is Yuri's new offering, a pair of TEC-140s.

 

 

 

Tammy

[DRodrigues]

Tammy,

 

Can you please confirm if the 24 UFF has similar FOV to the Pano 24? What do you prefer, within the UFF and Pano 24?

 

Thank you.

[Tamiji Homma]

Tammy,

 

Can you please confirm if the 24 UFF has similar FOV to the Pano 24? What do you prefer, within the UFF and Pano 24?

 

Thank you.

 

Here is from my measurement log.  APM UFF 24 has slightly larger  field stop than Panoptic 24.

Since I measured it just once, it may have some errors

 

fs 27.03 pafov  64.5 adv_afv  68.0 ratio  -5.1% Televue Panoptic 24
fs 27.05 pafov  64.6 adv_afv  68.0 ratio  -5.1% Televue Panoptic 24
fs 27.09 pafov  64.7 adv_afv  68.0 ratio  -4.9% Televue Panoptic 24
fs 27.15 pafov  64.8 adv_afv  68.0 ratio  -4.7% Televue Panoptic 24
fs 27.32 pafov  65.2 adv_afv  65.0 ratio   0.3% APM UFF 24
fs 27.49 pafov  92.6 adv_afv  92.0 ratio   0.7% Explore Scientific ES17-92
fs 28.51 pafov  68.1 adv_afv  68.0 ratio   0.1% Baader Hyperion 24
fs 28.51 pafov  68.1 adv_afv  68.0 ratio   0.1% Baader Hyperion 24 2"
fs 28.51 pafov  68.1 adv_afv  68.0 ratio   0.1% Baader Hyperion 24 T2

 

fs: field stop in millimeters

 

Tammy

[ThomasM]

 

 

this is a pitty, I am sorry for that. I think the UFF 30 mm has 4 mm more extra travel than the Hyperion  36 mm, but I understand, if you want to combine it with filters this will not be enough. So your coming new binoscope is a TEC 140 instrument?

 

Hi Thomas,

 

As you can see below, APM 30 UFF 2" nosepiece is long so that it hits the bottom.

That's why...  Oh well, I can use Panoptics 27 with the scope.  

 

Yes, new binoscope is Yuri's new offering, a pair of TEC-140s.

 

 

 

Tammy

 

Hi Tammy,

 

now I understand, it is the length of the eyepiece nose making trouble. Actually, I was also a little bit afraid of that because the first element is a reducer and not a barlow.

 

But you will enjoy the TEC bino with the UFF 30 mm

 

Thomas

[Tamiji Homma]

 

 

now I understand, it is the length of the eyepiece nose making trouble. Actually, I was also a little bit afraid of that because the first element is a reducer and not a barlow.

But you will enjoy the TEC bino with the UFF 30 mm

 

It was a few millimeters short for the binoscope.  

 

Anyway, I did indoor tests, measured field stop of APM 30 UFF.

It has the same field stop, 36.2mm as Pentax XW 30.  They show pretty much the same TFOV.

 

fs 27.32 pafov  65.2 adv_afv  65.0 ratio   0.3% APM UFF 24
fs 27.35 pafov  65.3 adv_afv  65.0 ratio   0.4% APM UFF 24
fs 36.20 pafov  69.1 adv_afv  70.0 ratio  -1.2% APM UFF 30
fs 36.20 pafov  69.1 adv_afv  70.0 ratio  -1.2% Pentax XW 30
fs 36.25 pafov  69.2 adv_afv  70.0 ratio  -1.1% Pentax XW 30

 

APM 30 UFF weights 549 grams, XW 30 weights 696 grams.  

As advertised, APM 30 UFF shows flatter image than XW 30.

 

APM 30 UFF is probably the best 30mm 2" eyepiece for binoviewing fans.

I would love to view star field

 

Tammy

[Starman1]

36.2mm?  I calculated 36.7mm for a 70° field, though, as you know, apparent field and field stop are only loosely linked due to distortion.

That isn't very close to the 38.0mm that is claimed, however.

[ThomasM]

 

 

 

now I understand, it is the length of the eyepiece nose making trouble. Actually, I was also a little bit afraid of that because the first element is a reducer and not a barlow.

But you will enjoy the TEC bino with the UFF 30 mm

 

It was a few millimeters short for the binoscope.  

 

Anyway, I did indoor tests, measured field stop of APM 30 UFF.

It has the same field stop, 36.2mm as Pentax XW 30.  They show pretty much the same TFOV.

 

fs 27.32 pafov  65.2 adv_afv  65.0 ratio   0.3% APM UFF 24
fs 27.35 pafov  65.3 adv_afv  65.0 ratio   0.4% APM UFF 24
fs 36.20 pafov  69.1 adv_afv  70.0 ratio  -1.2% APM UFF 30
fs 36.20 pafov  69.1 adv_afv  70.0 ratio  -1.2% Pentax XW 30
fs 36.25 pafov  69.2 adv_afv  70.0 ratio  -1.1% Pentax XW 30

 

APM 30 UFF weights 549 grams, XW 30 weights 696 grams.  

As advertised, APM 30 UFF shows flatter image than XW 30.

 

APM 30 UFF is probably the best 30mm 2" eyepiece for binoviewing fans.

I would love to view star field

 

Tammy

 

Hi Tammy,

 

this is very interesting, so the field stóp is 36,2 mm, a little bit smaller than specified (38 mm). By the way, Marcus Ludes provided an illustration of the light rays propagating through the eyepiece ( in a german forum, but now the image is gone...) and the measured acceptance was 36 mm ( not 38) so it make sense.

 

Yes, the UFF 30 mm is  extremely nice for binoviewing but I will still keep my Masuamya 32 mm eyepieces, not sharp to the edge but 47 mm field stop!

 

best regards

 

Thomas

[ThomasM]

A small update, I did measure the transmission,  at 530 nm wavelength  it is 85 %, at 405 nm only 58 %. This is in line with a small yellow cast. For comparison the Masuyama 32 mm, 93 % at 530 nm, 82,5% at 405 nm. I would say that in direct comparison you see the difference, the brigth OB stars in Orion look brighter and more bluish in the Masuayma. But I think you will only notice this in a direct comparison.

[Starman1]

For comparison of the curves, do you also have the figures at 600nm?

[jeffmac]

A small update, I did measure the transmission,  at 530 nm wavelength  it is 85 %, at 405 nm only 58 %. This is in line with a small yellow cast. For comparison the Masuyama 32 mm, 93 % at 530 nm, 82,5% at 405 nm. I would say that in direct comparison you see the difference, the brigth OB stars in Orion look brighter and more bluish in the Masuayma. But I think you will only notice this in a direct comparison.

 

Due to the four less elements, no doubt.

[Starman1]

 

A small update, I did measure the transmission,  at 530 nm wavelength  it is 85 %, at 405 nm only 58 %. This is in line with a small yellow cast. For comparison the Masuyama 32 mm, 93 % at 530 nm, 82,5% at 405 nm. I would say that in direct comparison you see the difference, the brigth OB stars in Orion look brighter and more bluish in the Masuayma. But I think you will only notice this in a direct comparison.

 

Due to the four less elements, no doubt.

 

Element count won't explain it, since there are some 8-9 element eyepieces that reach about 96% at 550nm.

What will explain it is the use of ED glass which, in my opinion, yields a "warm" image compared to its absence.

There could also be a difference in coatings as well.

[lylver]

I love my classics for deep sky. Some useful filters for nebulae are the Hbeta, OIII high in the range and Halpha, NII at the other side.

It is the classical rays for the achromatic design.

Giving transmission at ray F(486),C(656) and the max. or near e-Hg (546nm)

Perhaps giving something at the 435nm wave length (as a drop check) because of night sensitivity at 450nm (eye's rods), for colorless/faint object

85% is not exceptionnal, as example panoptic 15 was an outdated EP and had around 90%. Eye has logarithmic sensitivity, so keeping over 85% in the achromatic range may be enough at our time for complex EP. You will loose more if the color focus is not good. Better to have pinpoint stars on all field than visible dots with same distributed energy. (fewer cone/rod stimulated will be better to reach the sensitivity threshold). So for deep sky, i'll prefer to plan a flat range than to up the max at 550-600nm. For planetary EP, I would have another thought (copying what was done for the TV plössl should be good : the 550/600. Anyway, it was good widely )

Anyway, they could do a 90% now, with proper FMC quality, should be re-checked on the main range points.

Mean population eye sensitivity (photopic), rod sensitivity not shown

[Starman1]

This is dated, but I laud the transmission testing at 5 wavelengths.

The curves can tell you easily if an eyepiece will appear "warm" or "neutral":

http://www.amateuras.../tips/tips3.htm

 

Note the shape of the scotopic vision curve:

http://www.bluugnome...eye-meter-4.jpg

and http://hyperphysics....gvis/lumeff.gif

and: http://webvision.med...eswv/Kall4.jpeg

Note the difference in eye sensitivity below 500nm.  The scotopic sensitivity at 450nm is slightly higher than the daytime

sensitivity at 550nm.  If an eyepiece rolls off a lot at 450nm, we can see it.

 

The question is, can we see it on the Moon or planets, where our vision becomes mesopic and sensitivity begins to resemble daytime curves?

Because seeing a "warm" or "neutral" color tint when looking at a nebula isn't going to happen.

[lylver]

The question is, can we see it on the Moon or planets, where our vision becomes mesopic and sensitivity begins to resemble daytime curves?

Because seeing a "warm" or "neutral" color tint when looking at a nebula isn't going to happen.

Yeap, we don't have cones everywhere : this is the color field of the retina. It is about 30° left and right (density of cone decreases past 20° : adverted vision)

Activated cones are supposed to cut the rods around (a not really sharp threshold).

There is a effect known as the Purkinje color effect during the transition (the constitution of some chemical substances stock is involved), it changes you color perception : so it depends much on individual sensitivity, health...

[jeffmac]

 

 

A small update, I did measure the transmission,  at 530 nm wavelength  it is 85 %, at 405 nm only 58 %. This is in line with a small yellow cast. For comparison the Masuyama 32 mm, 93 % at 530 nm, 82,5% at 405 nm. I would say that in direct comparison you see the difference, the brigth OB stars in Orion look brighter and more bluish in the Masuayma. But I think you will only notice this in a direct comparison.

 

Due to the four less elements, no doubt.

 

Element count won't explain it, since there are some 8-9 element eyepieces that reach about 96% at 550nm.

What will explain it is the use of ED glass which, in my opinion, yields a "warm" image compared to its absence.

There could also be a difference in coatings as well.

 

Yes. Forgot about the ED factor. It seems that all well corrected, multi-element, wide field eyepieces, necessarily use ED glass of some sort in their design.  

[range88]

This eyepiece is a no-brainier keeper for binoviewing.

The only defect is the yellowish tint.

[ThomasM]

For comparison of the curves, do you also have the figures at 600nm?

Sorry for the late reply, no, I havn't done that, I could but, it was a lack of time. I would expect that the transmission is higher than that at 530 nm since the low transmission is due to an extra high dispersion element ( the first lens) wich have low transmission in the UV, blue but are ok at long wavelength. I could do the measurement if you are interested.

 

Thomas

[ThomasM]

This eyepiece is a no-brainier keeper for binoviewing.

The only defect is the yellowish tint.

Yes, I agree. Personally, I find the yellow cast not so distracting, you only see it in comparison with a neutral or cool tone eyepiece.

Edited by ThomasM, 26 January 2018 - 04:01 PM.

[elstargazer12]

Hi All,

 

I just got my APM Ultraflat 30 mm a couple of weeks ago.  Mainly I was motivated by the very positive comments about it on this thread!

 

I had a Kohki 30 mm Widescan II, which has a huge AFOV (a little bigger than a Nagler), but a lot of astigmatism in my f/6.3 triplet apochromat  The astigmatism was visible but not too intrusive in an f/8 refractor.  I held off buying a 31 mm Nagler mainly due to the weight and size.  I hate having to lock everything down just to be able to change the eyepiece without losing the target!

 

In short, the Utraflat 30 mm is FANTASTIC!  I've used it now over several clear nights.  It really is pretty much aberration-free at the edge of field!  No comparison to the Widescan.  Pinpoint?  Well, no, but no eyepiece is really literally pinpoint at the edge of a large FOV like that, even the Panoptics and Naglers.  There is a tiny amount of field curvature (i.e., different focal points as a function of position from center), but really very tolerable.  I can't compare with a 31 Nagler, but for what it's worth, compared to higher power Naglers and Panoptics I have, the edge of field in the ultraflat is just a tiny bit less sharp, but that may well have to do with the larger true field bringing out field curvature in my refractor.  

 

I didn't measure the AFOV or TFOV directly, and that has been discussed at length earlier in this thread.  But just sticking the the Ultraflat and another eyepiece up to both eyes like a binocular, it's clear that the AFOV is about halfway between a panoptic and nagler, maybe a bit less.  So like 73˚-75˚?  Definitely more than the 70˚ written on the barrel. 

 

Anyways, I very enthusiastically recommende this eyepiece!  It's really the only option for a wide field 30 mm that is so sharp to the edge AND that comes in a manageable size.  At $260 or so, the price is surprisingly low. 

 

Roger