Recting Prism ?? Are they worth getting....

[Daveb3650]

I was trying to get the kids to try the scope, but as they are youngish and I want them in bed before it's too late I tried them during the day on my Skywatcher 130....

"Everything upside down dad"..... "how do you make it the right way up" they asked.....

welll.... i've heard of,but not used one of the erecting prisms so dont know what to expect.....

and....

anyone got one going cheap.

Thanks

Dave

[Daveb3650]

this looks cheap and cheerful.... but is it rubbish.?????.. anyone got one ????

Newtonian Reflector Telescope Erecting Prism 1.25" 1.5x on eBay (end time 21-Jan-10 23:00:09 GMT)

Thanks

Dave

[crepitis]

I havent used one Dave, but anything Ive read about them seems fairly negative, extra glass in the light-path degrading the image etc,.

[Capricorn]

If you are using one for the kids during the day then light loss isn't going to be a problem, there is a lot of it running around in daylight.

One may make the image less sharp, up to you to decide how much of a problem this is but you say you are trying to introduce them to the scope so I would say not overly important.

When viewing stars it is irrelevant as the things are points anyway. If you want the kids to view stars then pick colourful doubles. A google search of "colourful double stars" turns up a list somewhere that has about 40 in it.

If viewing the moon then I would say for kids one could be useful and that a reasonable one would be worth it. The moon is big and usually bright enough that kids would find it useful the have up, down, left and right as expected. Again light loss shouldn't be a factor but sharpness may be.

[crepitis]

If you are using one for the kids during the day then light loss isn't going to be a problem, there is a lot of it running around in daylight.

.

Thanks for the heads up about the amount of light around in daytime Capricorn, , I was talking about the effects of viewing through more glass than is necessary, not about loss of light .

[brianb]

Must admit I use an erecting prism most of the time - but it's a good one (William Optics 2"). Makes reference to charts easier. IMO less damage to the image than the degradation caused by eyepieces with too much glass in them.

Cheapo erectors are generally speaking Not A Good Thing. Also I'm using an SCT, with a Newtonian the extra back focus requirement of an erector prism set is likely to be a big problem.

[Daveb3650]

Thanks for the info...

I think i'll get one.... it's not a lot too spend on what basically will be something that I can use just to satisfy the kids needs.

I dont think will know anything about the the pitfalls of using them, I think they will be more impressed that James dad's car is now the right way up.

I've had them at the moon, they loved it...... well they did til they rememberred that it was -2 degrees and that mam was making mugs of hot chocolate...... then it was "bye dad"...... and then it was me.... spotting solo!

Thanks again...

[Daveb3650]

Must admit I use an erecting prism most of the time - but it's a good one (William Optics 2"). Makes reference to charts easier. IMO less damage to the image than the degradation caused by eyepieces with too much glass in them.

Cheapo erectors are generally speaking Not A Good Thing. Also I'm using an SCT, with a Newtonian the extra back focus requirement of an erector prism set is likely to be a big problem.

I had a look for the Williams Optics eyepiece...... what a price, but then again.... you are obviously getting what you pay for....

Thanks again..

[Capricorn]

Crepitis sorry but the question seemed to be that Daveb's kids were partially interested in using his scope, and him in showing them.

If they would find an erecting prism better then get one for them, even a cheapy, if it gets them interested and involved. After that I didn't really care, but lets not put kids off of astronomy for what amounts to purchasing a simpe erecting prism.

These days most optical items are of decent quality, so I wouldn't expect an erecting prism to degrade the image that much irrespective of the source. A small drop in the transmitted light isn't going make a great deal of difference except on faint DSO's.

By the way I have no idea how much even a cheapo one is. DaveB may have to sell one of the kids to fund it for all I know.

[Daveb3650]

Sell one of the kids ???? got twins so it's all or nothing....

Any offers,,,,,