PST problem?

[moriniboy]

Not sure if my PST has a problem.

I can view the sun ok but I have to keep my eye in exactly the same place,1 to 2 mm either side and the view disappears.

Are all PST's critical like this, I have tried various ep's

[hunterknox]

Sounds like an eyepiece issue rather than a PST one. What are you using?

[Peter Drew]

The standard PST has a blocking filter only 5mm diameter so you do have to be a little more carefull with your eye position. Some eyepieces are better than others in this respect. IMO, the supplied 20mm eyepiece does the PST no favours, it gives too low a magnification and is prone to the effect you describe.

[keithatrochdale]

Try using a zoom eyepiece, I was impressed the other day when I did.

[moriniboy]

Not had a great amount of time using the PST yet so I may be crying wolf.

The ep's used so far range from 5, 6 & 7 mm BGO's, 12.5mm circle t ortho and 17mm Hyperion.

Really need a good clear day so I can investigate further.

Been looking at a zoom but want to confirm scope is ok before going down that route yet.

[NGC 1502]

Been looking at a zoom but want to confirm scope is ok before going down that route yet.

The PST and the Lunt 35 (in my sig) produce a tiny exit pupil.

It's not a fault, just an optical fact. It means you have to place your eye in exactly the right place to see the view.

If I let my eye wander a fraction to one side, the view is lost.

A friend bought me an inexpensive zoom eyepiece. It performs poorly with my other scopes (only sharp in the centre of the field of view) but works very well in my Lunt 35 due to the long focal ratio and the restricted field of that scope.

Regards, Ed.

[Merlin66]

Use a 10 to 13mm eyepiece (or a zoom set at 10mm or above) - you should find a workable image. Practise, practise, practise

[kev]

Wonderful thing about Ha observing, you can use an eyepeice that is good but suffers Chromatic Abbreation cos the single wavelength completely negates it.

Best eyepeice I have used on my Solarscope is a kellner!

[jimmyjamjoejoe]

Sounds like blackouts caused by a small exit pupil, and small pupils due to daylight. Had a similar problem with a pair of binos.

[garethmob]

When I had mine I used a zoom as I found the supplied kellner rubbish. I had it off astro boot for £10 and worked perfectly

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