300p flextube budget eyepieces

[Astro_Dad]

I can vouch for the performance of the Baader zoom with an f/4.7. (In my case a 10” model). Recommended by the experienced members here when I first acquired it. BST’s also v good as most agree. I’ve had some superb views with the 5mm on lunar. I’m tending to use a 32mm GSO Plossl on the longer side - exit pupil creeping up but works fine for me. The OVL Aero ED’s review quite well  for the price range, but seem hard to get hold of - I’m looking out for the 30mm version but non available it seems. The ES 24mm 68 Deg is frequently praised for performance on fast scopes but higher price.  

[bosun21]

On 14/09/2021 at 07:16, Geoff Lister said:

"Budget" and "Baader Zoom" do not tend to fit well together. I like my 8-24mm Baader zoom, and, together with its companion 2.25x Barlow, gives me a 4mm to 24mm eyepiece range. I also have a "budget" 8-24mm zoom - it cost about a quarter of the price of the Baader, but is not far behind in performance.

With my 250PX flextube Skyliner, I tend to start with my 32mm Plossl, and then go to the zoom.

When I bought my Skymax 127, probably a couple of decades ago, the Skywatcher/Celestron importer for the UK, OVL, were offering a discount on the, cased, eyepiece and filter set. I am a glasses wearer, and the 6mm & 8mm Plossl eyepieces do not have enough eye relief, but the 13mm, 17mm & 32mm Plossls are fine. I also have the Svbony "ultrawide" (about 68 degrees) 6, 9, 15, & 20mm eyepice set, and these are worth considering.

But, as "Spile" suggests, give your existing eyepieces a proper evaluation, and then consider filling the gaps.

Geoff

What is your opinion on these SVbony UW 68 degree eyepieces? I keep hesitating to buy one to try, but they seem to tick all the right boxes. Thanks in advance 

[Ricochet]

10 hours ago, bosun21 said:

What is your opinion on these SVbony UW 68 degree eyepieces? I keep hesitating to buy one to try, but they seem to tick all the right boxes. Thanks in advance 

As far as I know they are the old 66° gold line eyepieces in a nicer housing. I had a 15mm gold line thrown in with a second hand scope and it was the worst eyepiece I've ever looked through. Apparently the other lengths are better though. 

[bosun21]

2 hours ago, Ricochet said:

As far as I know they are the old 66° gold line eyepieces in a nicer housing. I had a 15mm gold line thrown in with a second hand scope and it was the worst eyepiece I've ever looked through. Apparently the other lengths are better though. 

Are we talking about the same eyepiece?

[Ricochet]

3 hours ago, bosun21 said:

Are we talking about the same eyepiece?

Yes, that's the one. 

[Louis D]

6 hours ago, Ricochet said:

As far as I know they are the old 66° gold line eyepieces in a nicer housing. I had a 15mm gold line thrown in with a second hand scope and it was the worst eyepiece I've ever looked through. Apparently the other lengths are better though. 

At what f-ratio did you test it?  I've found the 20mm performs fine at f/18 in my Barlowed binoviewer and nearly as well in my f/12 Mak.  They do suffer at f/6, but the central part is no worse than a 20mm Plossl.  I would presume the 15mm to perform no worse since they're a scaled design.

Worst eyepiece I've looked through was a 20mm generic RK (Reversed Kellner?).  See below for an f/6 comparison with other eyepieces at this focal length.  The SVBONY 68 does quite well in comparison.  For the $20 I paid for it, it's hard to fault it.

[bosun21]

2 hours ago, Louis D said:

At what f-ratio did you test it?  I've found the 20mm performs fine at f/18 in my Barlowed binoviewer and nearly as well in my f/12 Mak.  They do suffer at f/6, but the central part is no worse than a 20mm Plossl.  I would presume the 15mm to perform no worse since they're a scaled design.

Worst eyepiece I've looked through was a 20mm generic RK (Reversed Kellner?).  See below for an f/6 comparison with other eyepieces at this focal length.  The SVBONY 68 does quite well in comparison.  For the $20 I paid for it, it's hard to fault it.

Thanks for your reply and was thinking about using in my 127 Maksutov. I have just bought a Baader Hyperion Zoom and the Baader Barlow with a 32mm Celestron Omni for finding targets. I have also bought several BST Starguider eyepieces. I don’t think that the SVbony 68’s deserve the stigma attached to them.

[Ricochet]

5 hours ago, Louis D said:

At what f-ratio did you test it?

F6. From what I recall, only the central 1/3 was useable. 

[Louis D]

4 hours ago, bosun21 said:

Thanks for your reply and was thinking about using in my 127 Maksutov. I have just bought a Baader Hyperion Zoom and the Baader Barlow with a 32mm Celestron Omni for finding targets. I have also bought several BST Starguider eyepieces. I don’t think that the SVbony 68’s deserve the stigma attached to them.

Here's how the 20mm SVBONY UWA looks in my 127 Mak from the same distance as the above comparison image:

I included the Orion Centering SWA for comparison because it performs more poorly at both f/6 and f/12.  It is a bit wider, but notice that the edge marks are less distinct.  To my eye, the SVBONY looked fine at f/12 while the Orion did not.

[Louis D]

5 hours ago, Ricochet said:

F6. From what I recall, only the central 1/3 was useable. 

Was it a flat field scope?  I've noticed field curvature in short f/6 refractors rather quickly ruins the field; thus, I use a TSFLAT2 with my 72ED.

If it was an 8" f/6 Dob, then it can basically be treated as flat field.  I'm sorry it didn't work out for you either way.

Edited November 12, 2021 by Louis D

[Geoff Lister]

On 10/11/2021 at 20:31, bosun21 said:

What is your opinion on these SVbony UW 68 degree eyepieces? I keep hesitating to buy one to try, but they seem to tick all the right boxes. Thanks in advance 

I think that the responses, above, are far more informative than anything that I could add.