Cure for Achroitis?

[Kaptain Klevtsov]

Tried this question in a different thread, probably the wrong place for it, so I'll put it on it's own.

How to pretend that your car is one's Bentley analogy.

If one were to obtain a very poorly corrected Achro. scope, one would expect the images to be poor. However if one were to install a filter that only allowed a small range of light wavelengths through, such as a Ha filter, one could focus all the available light on one's chip. One would then be solvent and have images.

Might it work?

Captain Chaos

[MartinB]

There might be some side effects CC like very dark images! Long exposures etc

[GordonCopestake]

Doing a RGBL set of exposures making sure you re-focus for each one apparently gives better results. You can use achro's for this as you only "see" one colour at a time so it doesn't matter if they are all focused or not

[Kaptain Klevtsov]

Presumably then, the L channel has to be Ha or similar?

Captain Chaos

[GordonCopestake]

im not 100% sure, but i guess people use "white", although im sure Ha would work fine. It's only luminecence theres no detail in the channel i think

[Ambermile]

Easier would be to stop the achro down CC

Arthur

[Kaptain Klevtsov]

As in put a doughnut shaped piece of card over the end?

Captain Chaos

[GordonCopestake]

I have it on good advice ( ) that the L channel can be either no filter at all, or an IR blocking filter.

[The Warthog]

There is, of course, a minus-violet filter, which helps with fringing. There is also a product called a Chromacorr, which corrects the colour correction issue, but is fairly expensive ($500 or so) but less expensive than buying an apo.

[Kaptain Klevtsov]

I've got a Baader "Fringe Killer" filter which does a good job, I was wondering about using a really bad system like a single 4" f/1.2 lens that's lying about in the garage really. If there was to be only a tight sliver of spectrum it might work rather well, or not at all. The current problem is a tube for it and how to get a wide enough nosepiece on the webcam. Next question will be what (not) on earth to point it at if it does work.

Captain Chaos