Need a PST mod to allow focus for a camera?

[h0ughy]

in fact it needs to be simple and an off the shelf product - i cant machine, cut, mutilate, drill to save my life, so an adapter to replace the 1.25" holder would be great? Anyone done or found this type of thing?:question::help::screwy:

[Merlin66]

David,
As per the replies on the Solar Chat forum.....
adding a barlow lens to the nosepiece is the way to go.

(You can't replace the eyepiece holder section on the PST - this contains the critical blocking filter element to achieve the 0.7A bandwidth.)

[h0ughy]

would that be a short barlow?

[Merlin66]

Just unscrew the barlow lens from the end of the barlow (it doesn't matter if it's a x2 etc...) and screw it into the end of the camera nosepiece...drop this combo into the PST eyepiece holder and you should be able to reach focus...

[gbeal]

Which camera Dave? If a webcam, then a short nose-piece can do the business. If DSLR, forget it, or get the Barlow that Merlin suggests.
Gary

[h0ughy]

the zwo 120MM http://www.zwoptical.com/Eng/Cameras/ASI120/index.asp

[gbeal]

Well, it has a t T thread out the front, and a nose-piece included. Get a shorter nose-piece, as short as will allow the camera to touch the outer edge of the 1.25" ocular holder on the PST.
When I had a PST I actually removed the nosepiece of the Flea@, and made a spacer to take up the extra gap between the round section on the front of the camera and the inside of the PST ocular holder.
But before you splurge, take off the nose-piece and hold the camera against the PST and see if it will focus. I'm sure it will. Then work out where to get a short nose-piece.
Gary

[Merlin66]

David,
Did any of these suggestions resolve your problem????

[h0ughy]

wont be sure until I get some clear weather Ken, will try all the suggestions. I have ordered a shorty barlow to try that as well

[h0ughy]

that sounds helpfull Gary:thanx:

[gbeal]

Yeah, and after seeing Tornado's guider shot with it today I reckon it won't be too hard.
Gary

[h0ughy]

OK i mucked about late this afternoon and found that to get focus i need to crawled right up to the chip to get it to focus:sadeyes: but i excelled in the technical way i mounted the camera:rofl:

i don't know how i will be achieving that now. for the record i found i couldn't get focus with the 2x shorty barlow?

[2stroke]

I couldn't get focus with a next imager and a 2x screwed on the nose either, my wife had more luck with a dslr and barlow though it still wasn't in focus wasn't to far off. I'am thinking of trying some afocal till i can mod the PST for her.

[Poita]

I just replaced the black box with an SCT focuser, popped the blocking filter out of it's 1.25" holder and put it in the end of the camera. Worked a treat, plenty of back focus and a much much much better focuser than the PST stock one.

[asimov]

The EP holder in the PST is 2 piece. Unscrew the top section, throw it over your shoulder. drill, tap hole in the section left for the setscrew & go for it.

[Merlin66]

Caution:
In the current "blue" PST objective assembly, there are two filters in the eyepiece holder....
The section closest to the "black box" contains a "mini-erf" - an ITF to reduce the energy loading on the BF (and the CCD/eyepiece).
The top section (where the eyepiece fits) contains a small (5mm clear) "sorting" blocking filter (BF) element. This has a bandwidth of 8A to match the etalon finesse and is a mandatory part of the whole filter arrangement.
Removing the bottom section (ITF) without replacement can cause problems.....

[asimov]

Well warned Ken. I was assuming David had an older model but perhaps not.

[2stroke]

So i couldn't dich the top but i can the bottom for temp imaging? Might have to just mod a toucam and put the sensor right up front :(

[Merlin66]

Jay,
For occasional imaging ONLY the ITF can be removed.......