6x30 finder orientation?

[Alastair Rae]

The Wikipedia entry for finderscope says under types, "Standard, Straight through, Upside down and reversed (i.e. rotated 180 degrees)". I thought straight finders were little refractors which are "normal" view?

[John]

My straight through finders (8x50 and 6x30) show an inverted view with left and right reversed. The same view that a newtonian scope shows.

[RichieP]

Astronomical Refractors give upside down images the same as reflectors, hence that's what you see from a standard finderscope.

Refractors meant for terrestrial viewing have extra lenses which flip the image the right way round.

Rich

[JamesM]

Refractors typically have diagonals attached which help correct the inverted view. Right angled finders also produce an upright corrected view (via a mirror) but still show an image back to front whereas a right angled erecting finderscope (via a prism) shows a corrected upright view. At the end of the day it's whether the finder works for you in actually helping you to find what it is you are looking for which is what matters in the end.

James

[cantharis]

Many right angle finders (including my Stellarvue finder) are correct image - the diagonal contains not a mirror but a prism.

[RichieP]

So to summarise:

- Straight through finder - image is upside down - matches what you see in a Newtonian or a refractor/SCT/MCT without any star diagonal.

- Right angled (RA) finder - Image is right way up but reversed left to right. Matches what you see with a refractor/SCT/MCT with a star diagonal.

- Right Angle Correct Image (RACI) finder - right way up and right way around.

Some people have strong opinions on which type is best but as James so rightly says, its really down to what works best for the individual! Personally I prefer a RACI finder (in conjunction with a red dot finder to put me roughly in the right region) as the view matches the start chart and I can spend as long as I want at the eyepiece. Straight through finders always seem to have me contorting my body in odd ways!

Regards

Rich

[wookie1965]

I have the 6x30 that came with cope which i think is left/right ive bought a Telrad which has made a difference but i am going to buy a (RACI) finder for the fainter stars.

[JamesM]

I think that many beginners find it tricky enough locating an object anyway without factoring in back to front and possible inverted views too - though to be honest a RACI finder is more intuitive to use but they don't come cheap unfortunately at about £65 and upwards depending on aperture. THough I confess to being a big fan of the Telrad to get you in close leaving the final adjustment via the optical finder ensuring the disorientation of some of these finders are kept to a minimum.

James

[jason.p]

I'm seriously thinking of the Skywatcher 9X50 RACI (if I can work out how to fit it!), if nothing else to avoid the contortions and neck twisting with the straight through. The Telrad will be next on the list then a couple more eyepieces, then.......Oh dear this is getting out of hand

[Alastair Rae]

Thanks all. I guess being used to terrestrial scopes I just assumed straight one gave a normal view. Actual the Wikipedia definition of spotting scope is "a small portable telescope with added optics to present an erect image," I guess the added optics are what's in the characteristic kink in a spotting scope which, in fact, aren't actually straight through.

I've been investigating replacing my RDF with a finder scope on the basis that with my light pollution I need all the help I can get.

[joe_coke]

I got the Skywatcher 9X50 RACI after never quite being able to force my brain to work upside down and left to right. So much easier now, especially without the neck strain.