prom with open slit method

[highfnum]

sin adjusted and raw

Capture 2022-11-03T11_47_17arslitadj.jpg (65.91 KiB) Viewed 1234 times

Capture 2022-11-03T11_47_17arslitsm.jpg (129.61 KiB) Viewed 1234 times

[marktownley]

Good image John!

[Montana]

That's a lovely prom!!

Alexandra

[Alun_H]

Nice,going to have to sort out adjustable slit for my SHG and have a go at this method.

Alun

[highfnum]

Alun_H
my prom rig is separate from SHG
why?

1) you need a larger scope i use 60mm F12
2) you need ability to rotate rig to make tangent line to prom
3) grating should be 600lpmm or 1200lpmm max or else you get doppler distortion - SHG uses 2400lpmm

[thesmiths]

1) you need a larger scope I use 60mm F12
2) you need ability to rotate rig to make tangent line to prom
3) grating should be 600lpmm or 1200lpmm max or else you get doppler distortion - SHG uses 2400lpmm

Doesn't it also work better with a quite large slit (wider than the typical 10 micron SHG slit)?

[highfnum]

oh yes
this has variable slit with a knob 0 - 3mm range in width

[Alun_H]

Alun_H
my prom rig is separate from SHG
why?

1) you need a larger scope i use 60mm F12
2) you need ability to rotate rig to make tangent line to prom
3) grating should be 600lpmm or 1200lpmm max or else you get doppler distortion - SHG uses 2400lpmm

Thank you for the information,I am thinking of using my rough n ready SHG which has a 1200/mm grating and will exchange the Alpy slit plate I have in place at the moment for a Surplus Shed adjustable slit. In regards to the telescope,I will use a 90mm f/10 achromat and have it mounted side by side along with the 72ED and Sol'Ex.

Alun