38 replies to this topic

[Princess Leah]

Focussed on infinity with a 20/68 .Very little room to play with. But the optics seem very good.

 

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Edited by Princess Leah, 06 January 2025 - 10:55 AM.

[Princess Leah]

Found more info on the second one. It's useless as it converts the other way. So it's back to the DIY.

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[Astrokg]

That mirror diagonal from Aliexpress is very low quality, I turned mine into a prism here is thread ...
https://www.cloudyni...l/?fromsearch=1

[Princess Leah]

With a 3.2mm EP a flashlight reveals the baffle in the centre of the OTA vignettes the aperture to 50mm

 

Would that still be the case with a 0.965 eyepiece?. Cant think any reason why not.

 

Thanks Leah 

[andycknight]

I can't see a 965 eyepiece making any difference either...

"As long as you focussed to infinity before you did the test"

 

Note my dodgy department store 60mm frac had a baffel fitted to close to the main lens and stopped it down to around 40mm. But that was in an attempt to improve a bad lens. Can't believe the same for your frac though.

 

It could be its been accidently moved or put back in the wrong position... If it's not welded in place could easily be moved a few inches closer to the focuser and see how the scope performs??

 

Edit: There is one other possibility... Is there a baffel in the focus tube?? If so could this be the cause... In theory if the focus tube is too far inward (due to too much BF on the diagonal/eyepiece) the end of the focus tube (or an internal baffel) might clip the light cone.

 

Regards

 

Andy.

Edited by andycknight, 07 January 2025 - 09:56 AM.

[Princess Leah]

Thanks Andy.

 

I removed the welded baffle in the focus drawtube . It had a tiny aperture. I had to saw off the end of the drawtube with the baffle. Then I tested the aperture.

 

I then positioned the main baffle so the telescope now functions at full aperture. However tomorrow I will need to flock the focuser tube etc.

 

I take your point about more inward travel required. I wish I checked that previously. However there is so little focus depth that my feeling is it was operating originally about 50mm. I remember using it previously with a 0.965 to 1.25 hybrid and being surprised how dim the image was. I also tried it with the original prism.

There was actually originally only one position for the baffle, due to screws etc on the OTA. What was for sure, was that the baffle was in the original position. Only the objective side of the tube interior was painted black.

 

Others have reported how little CA this scope has. I think that is because it originally functions at 50/700mm.  An F14 50mm!

[Princess Leah]

Not had time to flock, but was very impressed by the image of the moon last night. The scope displayed a very 'white' moon.

 

On another post, another CN user suggested I used my Svbony finder rings to get it mounted.

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Edited by Princess Leah, 08 January 2025 - 07:40 AM.

[Jon Isaacs]

Here’s what you need, a hybrid diagonal. They ship to the UK/Ireland/Germany etc.: https://www.ebay.com/itm/235634073332

 

The vendor is Bill Vorce at the Telescope-Warehouse.com

 

He may have a prism hybrid diagonal in stock.

 

Another possible source is Sheldon Farowski. He was the proprietor of Apogee Inc and he still has a great deal of new old stock that he sells off. He actually had quite a bit of Carton stuff.

 

https://www.cloudyni.../25634-masilmw/

 

Jon

[Princess Leah]

Thanks Jon.

 

Bill doesn't seem to have any prisms.

I will message Sheldon.

[Princess Leah]

Did a quick flock of the tube/focuser.

 

Very sharp telescope terrestrially. There is a tiny spacer that separates the doublet. The elements appear to have the most basic coatings ; virtually invisible.

 

During the day light happily bounces around the two elements - making it pretty useless as a spotter.

 

This didn't happen with the moon last night. Again it makes me wonder how much less light the moon emits when you focus on it. Or is that because the moon has more of a spot light effect, compared to the scatter of daytime viewing?

I now find it hard to believe my exit pupil during the day is similar to that when viewing a bright/full moon.

Edited by Princess Leah, 08 January 2025 - 09:54 AM.

[grif 678]

Rather than an adapter, which may or may not allow you to focus, I would suggest a .965 to 1.25 diagonal where the nose piece is .965 and the eyepiece barrel is 1.25.

 

That is the way to go. You can still get the Parks .965 to 1.25 diagonal . but you can google to find out where. These are top quality, Japan made, not the cheap plastic ones made today.

[Princess Leah]

Nothing showing here in the UK. Sheldon doesn't have any either.

 

I was using the scope tonight. It's good on the moon and Jupiter - not sure if it is useful for any other purposes. Light throughput is quite low.

 

Curiously it seemed to prefer shorter focal length EPs. It didn't like anything longer than 17mm. Too much scatter with a 24mm 68.

There was no scatter with the 17mm Hyperion. No matter how much I increased the magnification the moon didn't seem to get any dimmer, or softer. There was no yellow cast, very white hard image. I'm not quite sure how good it is on the moon, it was certainly an interesting and very realistic view, then the clouds rolled in.

[Princess Leah]

Further note.

 

The cirro cumulus clouds briefly cleared and so did the scatter/flare. The views of Orion/Pleiades etc were quite mpressive with a 24/68. However I did feel the scope was somewhat out of it's comfort zone. Returning to Jupiter and the moon it did 110X no problem. Then the clouds rolled in again.

[izar187]

Not a recommendation, just shared just as an FYI.

https://www.sieberto...-eyepieces.html