5x Powermate on a PST with a webcam?

[Kaptain Klevtsov]

Wondering if this will reach focus as Anthony has one for sale, and Starman (Pete Lawrence) has used one to stunning effect with a different camera. Mine's an SC3 from Astronomiser if that helps.

Reason for the question, PSTs are a pain when it comes to getting stuff to focus. Using an eyepiece works great, but a webcam like mine (and a DSLR) will only work with a Barlow. From the Televue website, it appears that the Powermate doesn't change the focus point like a conventional Barlow lens, so it might not work. Anybody had a go yet?

Might need one anyway when some big planets come around again, but it will need to do double duty to justify the cost in the short term.

TIA

Captain Chaos

[Ambermile]

You may need to remove the spacer in the ep holder CC, this will also remove your warranty though

[Kaptain Klevtsov]

I have been reading about that Arthur, and putting the etalon in an expensive APO (how much spectrum spread are they expecting?), and other high stake gambling. Rumour has it that newer models have a really important filter in the bit you wrestle off though, so I don't wan't to risk messing it all up. Mine works with a normal (Skywatcher) Barlow ATM so if I got a 5X and had to use it with another Barlow, it would be too much I fear. Better then to go for a 2.5X plus the one I have.

Captain Chaos

[Ambermile]

No - I think you are referring to a different mod CC. I mean the EP holder (the 1.25" bit) sits on top of a spacer about 25 mm high. This unscrews (but it's loctited so needs a bit of a tug) and then you screw the EP holder back in. Bingo - an instant 25mm more in-travel.

The other mod involves ditching the pointy end and screwing in a 2" adapter to the etalon/diagonal assembly and using a suitable refractor, fitting an ERF over the cell. However, these ERF's are hard to come by... :nono:

arthur

[Kaptain Klevtsov]

I noticed the "suitable" mentioned on certain websites were quite exotic APO 'scopes. Surely any old Achro. would do as there is no false colour at all with anything to do with a bandpass filter such as the PST has?

Off to check on the unscrewyness of the spacer bit.

Thanks for that Arthur.

Captain Chaos

[Ambermile]

Ah - the posh apo bit is a misnomer. You have to cut nearly 90mm off the tube anyway to maintain focus travel! Current thinking seems to be (and I do know, trust me) that the WO 80mm clones are ideal.

Arthur

[Kaptain Klevtsov]

But my point is, Arthur, they aren't cheap. Any old Achro should do, like a Synta ST80 or similar. Why do they go for a sexy 'scope to saw up?

Captain Chaos