Solar viewing question

[pastiche]

I have a Meade ETX 105 and want to know if it is OK to use it for viewing the Sun using the projection method without risking damage to the telescope.

Any advice would be most welcome....

Thanks,

Paul

[rightguard]

i dont know much but i assum ethe projection method is where you hold a piece of card up to the eyepiece and look at the 'projected' image?

if so then i wouldnt do that. solar filters are made for a reason. do you really want all that energy being thrown around inside your scope?

[ronin]

Wouldn't like to say Yes.

The front aperture collects the light and the main mirror bounces it back up to the reflector on the front plate.

At this secondary mirror you will be concentrating the light and heat, not as much as at the focal plane, but sufficent I would say to start heating things up.

So the actual reflecting surface could get damaged, and in the worst case the corrector plate could crack.

That is I think the worst case and the reason for it. So I would not try it. You wouldn't get a second chance.

Could you not buy a full aperure solar filter for the scope? Astro Engineering did one for the ETX70 and ETX90, so they might have one for the ETX105. Otherwise you could buy another or make one for yourself.

[johninderby]

Unfortunately a Mak like yours is totally unsuitable for solar projection. You'll have to use a full aperture solar filter on the front. The primary mirror can cause excessive heat to be generated inside the scope, particularly if everything is not 100% perfectly aligned. It might work briefly but you'd probably end up with scorch marks inside the scope and a ruined eyepiece.

A small refractor is ideal for this purpose or you could try making a pinhole projector. Just Google solar pin hole projector.

John

[Bizibilder]

No. Don't use it for the projection method. The reason is theat you will be collecting the Sun's light and heat and reflecting it back down the telescope tube to the back of the corrector lens (where it will reflect again back to the eyepiece). The problem is that it will almost certainly cause the corrector lens to crack or shatter.

The only way to observe the Sun with this type of scope is to use a "front end" filter like Baader Solar film in either a commercial or home made mounting. This cuts out the heat and light before it enters the telescope tube and thus no damage can occur.

[superjody]

DONT DONT DONT DONT x 1 million point your scope at the sun without solar filters

it will damage your scope and probalby set something on fire.......i made the mistake of taking my solar filter off to put to the finder on the scope so i could line it up, i took the eyepiece out and covered the end with the cap not thinking anything of it, after about 5 seconds of the mirror being exposed to the sun, the scope was smoking and the eyepiece cover was bubbling......luckily the only damage was to the eyepiece cover.

Im no expert but please be carefull with the sun, do your homework first....your vision is unrepairable

[pastiche]

Thank you all for your prompt replies.

Rest assured I will in no way go anywhere near the sun with this scope.

I thought that might be the case, but thought it worth checking out.

[Bizibilder]

You CAN use the scope for the Sun! But with the correct front end filters. If you don't fancy making them then:

First Light Optics - AstroZap Baader Solar Filter

have them for £38. Just be careful and sensible (as you obviously are by asking your question in the first place).

[pastiche]

You CAN use the scope for the Sun! But with the correct front end filters. If you don't fancy making them then:

First Light Optics - AstroZap Baader Solar Filter

have them for £38. Just be careful and sensible (as you obviously are by asking your question in the first place).

Thanks for the advice Bizibilder. I will go and take a look.