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Upgrade a Pentax 65 scope? (1 Viewer)

Years back I bought my first scope, a Pentax 65 angled view (PF-65EDA). A budget-minded purchase, hoping to get a good quality scope at an entry-level price. I’ve enjoyed it greatly. It has definitely increased my ability to observe birds and I appreciate its smaller size and weight. Still, I’ve been intrigued for awhile with the possibility of improving the experience by upgrading the eyepiece. As many have noted, the XF zoom 6.5mm-19.5mm is very limited, best at its lowest magnification and quickly degrading at higher magnification. So…I’m looking for some advice. Is the body (being an older model) worth investing in? What eyepiece should I consider upgrading to? Initially I thought the Pentax smc 8-24mm zoom might be a good choice, to continue to have the versatility of a zoom with better optics. Now I’ve begun to think that a fixed e/p such as the Pentax xw14 might be the best choice. The wide fOV at higher magnification is very attractive. Thanks.
 
Hi,

first of all, welcome to birdforum!

Since the Pentax can take 1.25" astro EPs you do not have to use the Pentax XW series. They are good but also not cheap and they seem to be designed for use with glasses - not super wide and goot eye relief.

If you don't need a lot of eye relief due to no glasses, the Explore Scientific 14mm 82 deg EP has a wider field at 28x and costs about half of the XW14. You could spend the rest on an ES 8.8mm 82 deg for 44x or the 6.7mm from the same series for 58x...

Joachim
 
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Hi,

first of all, welcome to birdforum!

Since the Pentax can take 1.25" astro EPs you do not have to use the Pentax XW series. They are good but also not cheap and they seem to be designed for use with glasses - not super wide and goot eye relief.

If you don't need a lot of eye relief due to no glasses, the Explore Scientific 14mm 82 deg EP has a wider field at 28x and costs about half of the XW14. You could spend the rest on an ES 8.8mm 82 deg for 44x or the 6.7mm from the same series for 58x...

Joachim
Thanks, Joachim. Exactly the kind of feedback I’m looking for. Unfortunately, I do wear glasses, though I suppose taking them off while birding in locations where I am stationary is a possibility. If I do want that eye relief are there other options than the XW series? Also, how well can the 65 scope handle something as high as 6.7mm?
 
Thanks, Joachim. Exactly the kind of feedback I’m looking for. Unfortunately, I do wear glasses, though I suppose taking them off while birding in locations where I am stationary is a possibility. If I do want that eye relief are there other options than the XW series? Also, how well can the 65 scope handle something as high as 6.7mm?

Hi,

taking off the glasses is of course possible, if your prescription does not contain a big amount of cyl. (which means your eyes suffer from astigmatism). But it's a bit of a hassle... so maybe get other EPs.

The Baader Morpheus series is well regarded for use with glasses and still cheaper and wider than the XW. They also offer 14 and 9mm and work with the Pentax 65.


As for whether 60x will work in a 65mm scope - that depends on the available light (no problem in broad daylight - use 40x at the end of dusk) and of course whether the body is good... have you done a star test?

Joachim
 
Hi,

taking off the glasses is of course possible, if your prescription does not contain a big amount of cyl. (which means your eyes suffer from astigmatism). But it's a bit of a hassle... so maybe get other EPs.

The Baader Morpheus series is well regarded for use with glasses and still cheaper and wider than the XW. They also offer 14 and 9mm and work with the Pentax 65.


As for whether 60x will work in a 65mm scope - that depends on the available light (no problem in broad daylight - use 40x at the end of dusk) and of course whether the body is good... have you done a star test?

Joachim

I have used PF 65ED for stargazing and it works good at moderate magnifications.
The Plejades pretty much exactly fills up the entire FOV with 12,5mm Morpheus at 31x. That's an awesome view!
I have tried it with higher power but the result is not so good. Once I tried with 9mm Morpheus(43x) but as I could see it was not worth it compared to 31x. I could notice a sharpness loss, so dimmer image and narrower FOV with less sharpness is not much of a gain.
I also tried with a Vixen LV 5mm(78x) and the image was then not sharp at all.
The color correction was still good as I could see, though.
According to my experience, Pentax PF 65 ED handles CA well even at high magnification but not sharpness. At 31x it's very good but I think somewhere around or close to 40x the image degradation starts to be detecteable.
I am very pleased with it as a nature and astronomy scope at the magnifications I use.

BUT: I don't really know in what degree the limitation is in the objective or the ocular. Maybe a higher grade eyepiece will do it better at high magnification?
Baader offers great optical quality but I think Pentax XW and Televue are even higher quality.
 
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Actually this makes me wanting to find out if I can get a noticeable improvement with a more expensive eyepiece. Televue Delos series has 72deg AFOV and is very similar to Baader Morpheus. 10mm gives 39x and 8mm 49x. Will Televue raise the limit for magnification with remained sharpness? I have to find out it... 🤔
 
If the Morpheus is not delivering the views I’d point the finger at the objective. My astro 66mm works nicely up to 70x, view get dim as you would expect, but still sharp on the moon.

Peter
 
If the Morpheus is not delivering the views I’d point the finger at the objective. My astro 66mm works nicely up to 70x, view get dim as you would expect, but still sharp on the moon.

Peter

I think that the correct image prisms used in spottingscopes and binoculars set a limit far before mirror diagonals in astronomical telescopes.
But I just ordered a Televue Delos 10mm. I will give my report of my impression when I get it.
 
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I don’t notice a huge drop in quality between a prism diagonal and an amici prism, the diffraction spike from the amici prism is a edge being the most obvious. Do tell us how you get on.

Peter
 
I don’t notice a huge drop in quality between a prism diagonal and an amici prism, the diffraction spike from the amici prism is a edge being the most obvious. Do tell us how you get on.

Peter

I know there are high quality amici prisms, but I have only tried cheap models and they worsened the sharpness significantly compared to cheap 90deg prism.

My thought is: if Televue is just slightly better than Baader, that combined with 10% lower magnification(than with Morpheus 9mm, which didn't meet my requirement)
may result in my satisfaction. If Delos 10mm(39x) provides the same sharpness in my eyes, as Morpheus 12,5mm(31x), it's definitely worth it.
 
Hi,

yes, a star test of the body in question is recommended before getting higher mag eyepieces...

Joachim
I haven’t done a star test and don’t have a high enough magnification e/p for the test according to the article I read in Sky at Night (How to star test a telescope). Sounds like a good idea though to test the optical quality of the scope. In any case I like the idea shared of trying the Baader Morpheus 14mm e/p with its ample eye relief and ultra wide AFOV. The 9mm at 43x might be at the limit of the scope‘s ability if astro viewing is involved according to what was shared by Swedpat. As the primary use for the scope is birding, the optical limitations might be less noticeable in that kind of viewing. Anyway, the only advice I haven't heard is the value of a zoom such as the Pentax 8-24 mentioned above. I love the idea of a quality fixed eyepiece with wide field of view, but just don’t know how much I would be giving up with the need to switch lenses or not be able to just zoom. I do fine actually with the fixed lens binoculars. Maybe a single magnification scope with occasional swapping out for a higher magnification lens is a good solution. Opinions based on experience anyone?
 
Hi,

you can do a star test at lower magnification too... it will not be as sensitive as with higher magnification but strong aberrations can still be seen. And the aberrations need to be quite strong if a spotter is not sharp beyond 40x.

Joachim
 
I haven’t done a star test and don’t have a high enough magnification e/p for the test according to the article I read in Sky at Night (How to star test a telescope). Sounds like a good idea though to test the optical quality of the scope. In any case I like the idea shared of trying the Baader Morpheus 14mm e/p with its ample eye relief and ultra wide AFOV. The 9mm at 43x might be at the limit of the scope‘s ability if astro viewing is involved according to what was shared by Swedpat. As the primary use for the scope is birding, the optical limitations might be less noticeable in that kind of viewing. Anyway, the only advice I haven't heard is the value of a zoom such as the Pentax 8-24 mentioned above. I love the idea of a quality fixed eyepiece with wide field of view, but just don’t know how much I would be giving up with the need to switch lenses or not be able to just zoom. I do fine actually with the fixed lens binoculars. Maybe a single magnification scope with occasional swapping out for a higher magnification lens is a good solution. Opinions based on experience anyone?

Short answer:
===
Zoom for general use, fixed eyepiece for special cases.

I can recommend the 23mm aspheric or the 18mm UFF for your scope. The 23mm is unbeatable at its price point (US$10) and is an easy choice, the 18mm costs more (US$90 on AliExpress) but is very high quality.

Get the 23mm aspheric first and see whether you like a fixed power scope, if you do then you can consider spending more for better eyepieces like the UFF, Pentax XF, Pentax XW etc.

Long answer:
===
I wear eyeglasses and use a 80mm Svbony SV406P, f=432mm. It comes with a 7.2mm-21.6mm zoom (20-60x, 42-65 degrees FOV). It takes 1.25" astronomical eyepieces natively. My additional eyepieces:

23mm aspheric (62 deg, 57 measured)
18mm UFF (65 deg)
10mm UFF (60 deg)
9mm Svbony redline (70 deg)
4mm TMB clone (58 deg)

General Use:

I use the zoom for most of my birding (perched/walking birds 10-30m away). The ability to locate at low power, then view at mid/high power is a huge convenience. 60x is usable in bright light but usually the bird is already nicely framed around 30-40x. I use 60x more often for insects eg dragonflies.

Special Cases:

For birds in flight 50-100m up in the sky, the 23mm aspheric (19x) and 18mm UFF (24x) provide a wider FOV to find the bird, and 19/24x is fine for viewing. At higher power, the birds move too fast in the field of view for me to track anyway. For flying birds at close range, I use my 8x42 binoculars instead.

Other Notes:

I found the 10mm UFF redundant, the zoom covers the same magnification and FOV. The 9mm is wider than the zoom and very sharp, but suffers from SAEP/kidney beaning in the day, so I reserve it for night use where it gives nice views. The 4mm gives 108x, I have gotten amazing views of dragonflies from 6m away (minimum focus distance) and for larger birds further away eg storks I get close up views of the head/eyes etc. However, my tripod is not nearly stable enough, focusing at 108x causes vibrations so patience is needed. The view is also dimmer, so only good in bright light.

Conclusion:

When birding, 99% of the time I stick with the zoom. I bring the 23mm and 18mm but seldom use them. At night I bring everything out, and sometimes I stick with the zoom for convenience, other times I switch to the 18mm and 9mm and enjoy the views. For the 4mm, the stars/planets drift quite fast in the field of view, so it is not as fun to use.
 
Short answer:
===
Zoom for general use, fixed eyepiece for special cases.

I can recommend the 23mm aspheric or the 18mm UFF for your scope. The 23mm is unbeatable at its price point (US$10) and is an easy choice, the 18mm costs more (US$90 on AliExpress) but is very high quality.

Get the 23mm aspheric first and see whether you like a fixed power scope, if you do then you can consider spending more for better eyepieces like the UFF, Pentax XF, Pentax XW etc.

Long answer:
===
I wear eyeglasses and use a 80mm Svbony SV406P, f=432mm. It comes with a 7.2mm-21.6mm zoom (20-60x, 42-65 degrees FOV). It takes 1.25" astronomical eyepieces natively. My additional eyepieces:

23mm aspheric (62 deg, 57 measured)
18mm UFF (65 deg)
10mm UFF (60 deg)
9mm Svbony redline (70 deg)
4mm TMB clone (58 deg)

General Use:

I use the zoom for most of my birding (perched/walking birds 10-30m away). The ability to locate at low power, then view at mid/high power is a huge convenience. 60x is usable in bright light but usually the bird is already nicely framed around 30-40x. I use 60x more often for insects eg dragonflies.

Special Cases:

For birds in flight 50-100m up in the sky, the 23mm aspheric (19x) and 18mm UFF (24x) provide a wider FOV to find the bird, and 19/24x is fine for viewing. At higher power, the birds move too fast in the field of view for me to track anyway. For flying birds at close range, I use my 8x42 binoculars instead.

Other Notes:

I found the 10mm UFF redundant, the zoom covers the same magnification and FOV. The 9mm is wider than the zoom and very sharp, but suffers from SAEP/kidney beaning in the day, so I reserve it for night use where it gives nice views. The 4mm gives 108x, I have gotten amazing views of dragonflies from 6m away (minimum focus distance) and for larger birds further away eg storks I get close up views of the head/eyes etc. However, my tripod is not nearly stable enough, focusing at 108x causes vibrations so patience is needed. The view is also dimmer, so only good in bright light.

Conclusion:

When birding, 99% of the time I stick with the zoom. I bring the 23mm and 18mm but seldom use them. At night I bring everything out, and sometimes I stick with the zoom for convenience, other times I switch to the 18mm and 9mm and enjoy the views. For the 4mm, the stars/planets drift quite fast in the field of view, so it is not as fun to use.
Thanks for the detailed explanation and sharing when you find an eyepiece useful. Very helpful.
Hi,

you can do a star test at lower magnification too... it will not be as sensitive as with higher magnification but strong aberrations can still be seen. And the aberrations need to be quite strong if a spotter is not sharp beyond 40x.

Joachim
OK. Sounds good. I’ll work on it. Thanks.
 
We have been using both the Pentax 65mm and 80mm scopes for a while. One of us is nearsighted with a heavy perscription and can't use the scopes without glasses. Zooms for the Pentax aren't an option for us because the eye relief is too short. So we use fixed power astronomy eyepieces.

With the 65mm we like the TeleVue DeLite line. It is a nice size and weight for this scope. It is smaller and lighter than the Pentax XW line but the optics are extremely good. There is no CA. Images are crisp edge to edge. When seeing conditions are calm the view is stunning. When heatwaves start the view is stunning but wavy.

With this scope we don't go above 11mm focal length for the eyepiece. That is about 35x with the 65mm scope, and the FOV is about 90 ft at 1000 yds with this eyepiece. We live in an arid area with a lot of sun and heat. In our experience when pushing the magnification beyond 35/36x the image begins to breakdown enough (due to the combination of atmospheric conditions and optics) that we don't see a practical benefit in the field to any higher magnification.

The downside to this setup is the TeleVue eyepieces are not waterproof (like the Pentax XW line).

Chris
 
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Thanks everyone for the feedback about eyepieces. Based on the responses, I’ve ordered a basic 23mm aspheric as BKoh suggested and after I manage a star test will purchase a higher quality fixed eyepiece, such as the UFF, the Morpheus, the DeLite or the Pentax XW. Using the scope a bit with the fixed eyepiece should help me see where to go. Again, thanks.
 
I know there are high quality amici prisms, but I have only tried cheap models and they worsened the sharpness significantly compared to cheap 90deg prism.

My thought is: if Televue is just slightly better than Baader, that combined with 10% lower magnification(than with Morpheus 9mm, which didn't meet my requirement)
may result in my satisfaction. If Delos 10mm(39x) provides the same sharpness in my eyes, as Morpheus 12,5mm(31x), it's definitely worth it.

A few days ago I found this out with my straight scope PF-65ED II.
Delos 10mm compared to Morpheus 12,5mm indoors in a corridor:
The loss of sharpness was obvious and MAYBE I could see VERY VERY marginally more details due to the higher magnification. And that at the expense of brightness and field of view, of course.

In this case, I can draw the definitive conclusion that the limit is not set by the eyepiece but by the scope.

Pentax is an excellent spotting scope that works very well with 15-31x. But not with higher magnifications. Some other users find the performance good even with higher magnification, but this is my experience.

It is compact and with a perfect bag with handles easy to carry with you. It's water resistant even without an eyepiece inserted.
And not to forget: the color correction is excellent in my eyes.

So I am still very pleased with Pentax PF-65ED II and PF-65ED AII. I understand they are not in optical class like Zeiss, Leica or Swarovski. But neither is the price.
 
Had the 65 mm Pentax and it was nice at 32x with the BST Explorer 12 mm. Already at 43x, it began to struggle. Both my Nikon Fieldscopes (50 mm, 82 mm) appear sharper, and so does the Svbony 406P ED 20-60x80. Maybe the 406P ED 65 mm is an upgrade to the Pentax?

//L
 
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