Tal 100rs : big deception

[KaStern_Former_Member]

Hi folks,

Hi folks,

-chromatism : at 120x, there's no false colours on moon (first quarte) and saturn. For an achro it's very good.

no false colour? For an achro this is impossible. Better get your eyes checked.

When it comes to the 4"f/10 TAL achromat some people seem to loose the ground contact...

Or whatever it is. That thing got lots of chromatism at 120x on the moon.

You even do not need 120x. 50x is enough to see it.

If have seen it with my own eyes.

Cheers Karsten

[RobH]

Hi folks,

Hi folks,

no false colour? For an achro this is impossible. Better get your eyes checked.

When it comes to the 4"f/10 TAL achromat some people seem to loose the ground contact...

Or whatever it is. That thing got lots of chromatism at 120x on the moon.

You even do not need 120x. 50x is enough to see it.

If have seen it with my own eyes.

Cheers Karsten

I think that the OP is quite capable of making his own judgement on his own telescope Karsten, certainly more capable than you are of making a judgement on his telescope for him.

My Tal shows very little CA also....not none, but an acceptable amount. Certainly not lots.

Do you have anything positive to add to this thread, or are you simply determined to try to ruin the OP's enjoyment of his new telescope?

[Erathostene]

No problem There's a little chromatism of course (an achromatic is an achromatic, not an apo), but at this magnification it's very discret, and we must concentrate on it to note this aberration. It does start to become a little annoying to twice the diameter (not so bad for an achromatic). At f/10 for 100mm for a very good optical construction it's not so surprising.

[haitch]

Well said Rob. Btw KaStern I just clocked your profile pic. You might want to change it, as whilst I have no issue with your sentiment I think you might find the following in the Code of Conduct on SGL...

The “not allowed” list is pretty short, but it should be remembered that what can seem to be light-hearted comments and fun to one person, can be offensive to another. This is especially true in politics and religion. Therefore:

• No politics

• No religion

[F15Rules]

Hi Kastern,

I'd second RobH's last post.

It's one thing to have an opinion (good or bad) of a particular scope, that's everyone's right. It's another to appear to be determined to denigrate a scope, in this case the Tal 100RS, (which the vast majority of people who have used one agree is a great scope for the price paid) just to make a point.

I've owned 5 or 6 tal refractors and at x120 the CA is negligible on the Moon - unless you only look at the limb, where you wiil see a little yellow/green tint. Me? I'd rather look at the craters, mountains, rills and valleys - with very little CA visible!

Good luck to you Erathostene!

regards

Dave

[michael.h.f.wilkinson]

Gentlemen, shall we just enjoy the scopes we have and not get needlessly hot under the collar.

[Mapk]

Salut, Erathostene!

Very happy that you found the problem with the TAL. I also own a TAL-100RS, have had it for two years now, and am very happy with it. The optics are outstanding, but did you know that by improvements to the tube assembly, viewing can be made even better?

My 100RS came with internal baffling (didn't bother to carefully check for several months after delivery, didn't want to ruin anything after a glorious first light!) that had eight large, noticeable holes along the edges, due to the baffles being octagonal in shape. When looking through the focuser end, I could easily see how all of that stray light might reduce contrast and cause odd internal reflections.

I removed the lens cell and focuser, and spread epoxy over every hole along the edges of the baffles. It was a messy and difficult task, but it worked perfectly. I then spray painted the interior with matt-black paint, and let dry. Viewing from the focuser end revealed a completely black interior, with no stray light penetrating along the edges, and no reflections at all.

Another internal reflection problem, that I have not yet fixed, is the interior of the focuser tube itself. I detect a fair amount of reflection from it. There are probably other focusers that kill this reflection, and am considering one day buying one.

Bonne chance!

Mapk

TAL-100RS

TAL eyepieces

Baader eyepiece

[nightfisher]

Salut, Erathostene!

Very happy that you found the problem with the TAL. I also own a TAL-100RS, have had it for two years now, and am very happy with it. The optics are outstanding, but did you know that by improvements to the tube assembly, viewing can be made even better?

My 100RS came with internal baffling (didn't bother to carefully check for several months after delivery, didn't want to ruin anything after a glorious first light!) that had eight large, noticeable holes along the edges, due to the baffles being octagonal in shape. When looking through the focuser end, I could easily see how all of that stray light might reduce contrast and cause odd internal reflections.

I removed the lens cell and focuser, and spread epoxy over every hole along the edges of the baffles. It was a messy and difficult task, but it worked perfectly. I then spray painted the interior with matt-black paint, and let dry. Viewing from the focuser end revealed a completely black interior, with no stray light penetrating along the edges, and no reflections at all.

Another internal reflection problem, that I have not yet fixed, is the interior of the focuser tube itself. I detect a fair amount of reflection from it. There are probably other focusers that kill this reflection, and am considering one day buying one.

Bonne chance!

Mapk

TAL-100RS

TAL eyepieces

Baader eyepiece

The fosus draw tube is very reflective, i used flocking on the inside of my 100rs,  big improvement