Filters for an Atik 314L - Which ones?

[swag72]

OK, getting closer now to the Holy Grail!!

So what filters do you use in your Atik 314L?

I want a complete RGB and NB setup. I've been quoted for Baader ones. Looking on here, these seem OK.

Do I need anything else - such as a L filter, IR filter?

Sorry, a bit clueless in this new venture!!

[shaunster]

Baader ones are good yes.

If you get LRGB baader set then get the good ones and not the cheaper ones which are not anywhere near as good. Then get the baader NB set which personally I find great, not many halo's which is something you cant say about other NB filter sets, particulary astronomiks.

You wont need a IR block filter with these filters as they are IR blocking, the cheaper sets arent which is when you would need to use an IR block as well.

[riklaunim]

RGB filters usually come as LRGB and the L may be used for luminance shots (L or L + light pollution filter, or light pollution filter substituting L). L filters are IR/UV cut, as well all good RGB filters are IR/UV cut.

IR passing filters aren't that much needed in DS imaging (but sometimes may be used if you want something different).

[swag72]

If you get LRGB baader set then get the good ones and not the cheaper ones which are not anywhere near as good.

These here being the cheap ones?

Thanks for the info so far folks.

[shaunster]

These here being the cheap ones?

Thanks for the info so far folks.

Indeed avoid those and get these First Light Optics - Baader LRGB CCD Filter set

[AndyUK]

Hi Sara - I concur with this also... Although not mentioned here, the "posh" baader set and the associated NB set are all (allegedly) parfocal, so, in theory, once in focus with the first filter then you'll be in focus with all (in theory... )

(I don't trust it myself though, and always refocus after each change!)

[swag72]

Excellent - These are the ones that Green Witch quoted me for - Not the cheap ones, so that's OK. Just working on some spacing at the moment, then need to wait for my Dad and his credit card - Happy 40th to me!! (albeit it 9 months earlier!!) But I can't wait!!

[Uranium235]

Yep, youve chosen some good filters there (Baader), they're the same ones as ive got.... but, they are not quite parfocal as they claim. The red/green channels are close(ish) but the blue is always way out. In fact, it is best practice to always refocus after changing a filter - including narrowband filters.

Though a question this throws up is: are the differences in focal position between filters purely down to the telescope optics or does the filter being used have any impact on that?

[riklaunim]

With achro Barlow or standard f/6.3 SCT reducer I can see on screen focus shift with a Bahtinov mask and RGB filters (Orion). With APO Barlow or no reducer the Bahtinov spikes don't move (for the eye). Also if the object is on low alt focus will always shift due to atmospheric dispersion.

BTW. I'm also switching filters to Baader

[ollypenrice]

I use the 'posh' Baaders at F3.9 and consider them parfocal to a high order of precision. Certainly they are more parfocal, so to speak, than the sky, during the course of the night. At F7 in the TEC I have stopped bothering to check them at all. Scandalous! And I am the ultimate focus fusspot, or so I thought.

Olly

[Whippy]

Though a question this throws up is: are the differences in focal position between filters purely down to the telescope optics or does the filter being used have any impact on that?

If it's a refractor and your filters are supposed to be parfocal, it'll almost definately be the scope. Some APO's are more APO than others .

A reflector doesn't refract light so there is no chromatic abberation while the corrector plates on SCT's and Maksutovs only do so to a miniscule amount, you might as well say they don't suffer from CA either.

Personally, I'd recommend refocusing between each filter regardless anyway as other factors like temperature change could alter the focus point.

Tony..

[Uranium235]

Thanks Tony, its just as I thought. The ED80 is not, and never will be anywhere near a TEC - now I know what the big price tag is all about

I could go back to the newt, but when I use it I start thinking "I wish I had more contrast!" - which then takes me back to the refractor. Checking focus as the temperature drops is something I normally do, usually after about an hour into the session. And in the winter, its after 30 min (esp if its -20 outside!)

Rob

[Whippy]

In fairness Rob, we're talking a quid difference though! Although it'd be interesting how good a 80mm TEC f7.5 doublet would be though.

IMO, that's one of the advantages of mono/RGB imaging. You can re-focus between filters which largely cancels out any CA in the scope, something you can't do with a colour camera.

Tony..

[antimorris]

Although you certainly couldn't go wrong with Baader, I have never had halo problems (as someone mentioned above) with my Astronomik set and my 314L+. I have LRGB, Ha, OIII, & SII and have been quite pleased with them.

[swag72]

Cheers Anna. It's the Baader one's I am getting and they are low profile, so won't cause any problems with the filter wheel.

[antimorris]

I am sure you will enjoy them greatly! I only went with Astronomik vs Baader as I got them for a steal and haven't had any problems with them so haven't ever upgraded.