Which filters for my CCD?

[OzDave]

I've just bought a QSI 683wsg camera (a belated Christmas present to self) and now I'm trying to decide which brand of filters to buy for it. The choices are Astrodon, Astronomik, or Baader.

I would want to buy a set of LRGB and also a set of narrowband.

Are the scopes that I'll use to image with a factor in deciding which filters to buy? If so, the scopes I have available are MN190, Equinox 80, and SkyMax 127. I tend to image only with the MN190 and EQ80.

When thinking about narrowband and how narrow the band should be (e.g. 12nm, 3nm, 6nm, etc), does the focal ratio or aperture of the scope come into consideration? If so, what should I be looking at for my scopes?

If we assume that price isn't that important, should I just go for the Astrodons, or are there more factors to consider?

Any advice you can give would be great. I've spent quite a lot of money on the camera so I would like to get something that will allow it to perform well with the scopes I have.

Regards,

David

[NickK]

I've just bought a QSI 683wsg camera (a belated Christmas present to self) and now I'm trying to decide which brand of filters to buy for it. The choices are Astrodon, Astronomik, or Baader.

I would want to buy a set of LRGB and also a set of narrowband.

When thinking about narrowband and how narrow the band should be (e.g. 12nm, 3nm, 6nm, etc), does the focal ratio or aperture of the scope come into consideration? If so, what should I be looking at for my scopes?

I have the par focal Baader 2" LRGB to fit a 2" imaging train onto the 8300 chip. Originally there was a large discussion about 1.25" and 36mm and vingetting so I plumbed for the 2" to remove any issue.

The problem with the smaller 1.25" is that it has to be mounted virtually on top of the sensor. I know the QSI have a 36mm camera+filterwheel combined but I think that model is a straight camera so you're looking at possibly large 2" filter.

The Astrodon are better but you're looking at £700-800 compared to the £300ish Baaders. Given the weather conditions and time I have - colour seems to be the icing on the cake but Mono is easier for me.

[FrankieValley]

I have a set of Baader LRGB filters. They are parfocal and come with (or without, I think) an IR cut coating. Not sure of the competition, but parfocal and negating the need for an IR cut filter was important for me.

I don't think the type of scope affects the filters or vice versa.

[OzDave]

The model of camera I have takes 1.25" filters in a wheel that sits directly in front of the sensor. I think vignetting has been designed out here.

I am more wondering about things such as how narrow the narrowband filters should be. Maybe there is no point buying the narrowest of filters with the scopes I have?

What about the parfocality of the different brands? Does this make a difference with my scopes?

And what about general difference in spectra between the brands? I've read that Astrodon is considered better here, but what about the other factors mentioned above?

David

[ollypenrice]

The Astrodons are certainly the best, I'm sure, though I haven't used them myself, I have the good Baader LRGB set and like them. An imaging neighbour with very high end kit, Karel Teuwen, reckons the Astrodon RGB are significantly better. That said, the Baaders are great.

Astonomik are supposedly better than they were but I have not been wowed by my Astronomik NB filters. Earlier ones gave haloes and later ones give... haloes, albeit smaller! I'd go for Baader.

The narrower the bandpass the better they are for contrast, beating LP and beating the moon. I have a Baader 7Nm and an Astronomik 13Nm for Ha. I always use the Baader. I'd love an Astrodon. The relationship between exp time and bandpass defeats me. I don't understand it. But... it seems that a narrower bandpass may not be necessarily slower. I'll let an expert come in on that one.

There is an intermediate size between 1.25 inch and 2 inch since the 8300 came along. Sorry, can't remember what the exact size is!

All things considered the Baaders are very good and in balance, price wise, with the rest of your kit. If you were imaging with a 20 inch Plane Wave and FLI 36mm square chip on a Paramount then it would very obviously be Astrodon...

Olly

[Gina]

The Baader ones come in 1.25" and 2" mounted and 36mm unmounted.

[OzDave]

I think I will go for the full set of Baaders.

Astronomik seems to almost universally get slated for having halos, and Astrodon is quite expensive and still some people say they have problems.

Baader seems to have a reasonable price point and I suspect that my imaging skills will need to improve a lot before I notice issues with the filters.

Regards

David

[Gina]

I plan to go for the Baader parfocal ones when I get to that stage.

[BlueAstra]

I have the Baader 2" LRGB and narrowband, very happy with them. Reasonable cost and par focal. I have the 7nm Ha.

[ollypenrice]

Good choice.

Olly