can you use refractor front lens on newtonian reflector?

[Timbo32]

Hi all,

i was wondering if you took the lens from the front of a bresser 700/70 telescope could you fit it to a celestron firstscope? or would this not be practical?

i know that there are alot of people that like to mod and would like to know other peoples opinions on if it could be done?

Tim

[Moonshane]

do you mean take out the mirrors from the latter and use the tube as a refractor tube to install the lens? if so then probably but I cannot see why you would. why not just leave it where it is? if you mean as well as the mirrors then no.

[Timbo32]

i mean take the lens out of the refractor and then mount it at the front of the newtonion refector?

[Gina]

No.

[ronin]

You could stick it on the front but the result would no longer be a telescope.

Curious what you were thinking would be the outcome.

[Timbo32]

lol i think it was a bit more fantasy than thinking!! i guess that the lens would focus the light then the mirror focus it more.... when i say it out loud!!! i'm going to stop typing now!!! lmao

silly idear

[Moonshane]

believe me there were lots of 'silly ideas' that went on to become world beaters. who on Earth would think that everyone would want to be contactable anywhere at any time. what's wrong with a phone at home, work and on a street corner??

unfortunately, this one would not work as the refractor would focus the light at a set point and so would the newtonian. in fairness, it might be possible with some shortening of the tube etc to get something that would work in a way but why bother wrecking two perfectly good scopes to make one bad on?. if you took the tyres off the car and put on rings of sausages, it might work for a while after a fashion but it's not a good idea.

[Timbo32]

thanks moonshane for the idear i'm off to the butcher's for some sausages!! lol

thnx for taking the time to reply all

Tim:)

[Earl]

You could view a maksutov newtonian as a concept of using a lens in front of a Newtonian.

It becomes a corrector plate, but still... yeah not a million miles away.

[Cath]

who on Earth would think that everyone would want to be contactable anywhere at any time.

ooooo noooo. I turn my phone off a lot of the time, especially when I leave the house. I only have one in case of emergencies.

[Gina]

I only use mine for emergencies too.

[Schorhr]

As the refracor's lens focuses the light to a point it won't work, but you can use the Firstscope as a neat finder scope ontop of the refractor with a 17€ 30mm plössl eyepiece ;-)

If you like tinkering get 1,5dpt reading glasses at a dolar store and a jeweler's magnification glass, that's what I made for a children's project and can work as 2€ scope for the firscopes wihout a finder scope...

(though then a 2.5dpt or more reading glass will be more suitable, as focal length (m) = 1/dpt = 40cm...)

[Chris]

Interesting out the box thinking Tim, I think I know where you where going with this before you thought about it some more as some scopes like SCT's and Maks do indeed have a combo of lenses and mirrors. However, if you draw a diagram of the light path in a Newt, then add a converging lens at the front it soon becomes clear that this will focus light on a tiny spot on the primary mirror which is designed itself to collect light over its entire service (minus the centre maybe) and that itself then focuses the collected light onto the secondary mirror. Not going to work but thanks for posting such an original topic, not come across this one before

Chris

[Timbo32]

i like that chris it was out of the box thinking although some might say i must have been out of my box to think that! lol

Tim

[IanL]

ooooo noooo. I turn my phone off a lot of the time, especially when I leave the house. I only have one in case of emergencies.

I only use mine for emergencies too.

Yep, that's my parents' thinking.  They too can't seem to get their heads around the fact that it might not be them having the emergency.

[Gina]

Mobile phone coverage round here is very patchy with all the hills.  We do have coverage at home though so it has come in useful on occasions when the land line has failed - to report the problem.