filter size for Dagor 6"?

**Keith Fleming** · 15-Oct-2007, 21:21

I use 1.25-inch filters from the Orion telescope catalog. The eyepieces for amateur astronomy scopes come in 1.25 and 2.0 inch sizes, and Orion provides filters in various colors for these scopes. The disadvantage is that Orion sellls the filters in sets rather than individually. However, I've been able to "borrow" a yellow filter from an unused set that belongs to my wife (who no longer has a scope).

Keith Fleming

**rippo** · 15-Oct-2007, 23:43

wow, yeah robert, that helps a lot. very clear now, thanks! i can see how the lens is going to have a lot of stuff dangling off the front end. could be dangerous, as you say.

rather than go to a 67mm thread, which is what my 'classy' filters are, could i do just a series 6 and then buy a cokin 'A' adapter ring to fit it? that would save on weight and let me use what i've already got. is the retaining-ring thread size standard on series filters, or just the lens-end of the filter holder?

pictures too! wow, full service. thanks again.

**rippo** · 15-Oct-2007, 23:46

keith: i saw you mention those in an earlier post (see, i did do some research before postin!

). however i didn't understand whether it pertained to me or not. will the 1.25" filters fit? do they slip on, screw in, or what? if they slip on, i just get to use one at a time i would think.

thanks!

i'd like to have the ability to use my grad filter from time to time, even if it's the cokin A series one. although i can live without if necessary.

**Robert A. Zeichner** · 16-Oct-2007, 04:24

Originally Posted by rippo

wow, yeah robert, that helps a lot. very clear now, thanks! i can see how the lens is going to have a lot of stuff dangling off the front end. could be dangerous, as you say.

rather than go to a 67mm thread, which is what my 'classy' filters are, could i do just a series 6 and then buy a cokin 'A' adapter ring to fit it? that would save on weight and let me use what i've already got. is the retaining-ring thread size standard on series filters, or just the lens-end of the filter holder?

pictures too! wow, full service. thanks again.

Series size threads are not really the equivalent to any modern screw-in filter sizes except the series 8, which is very, very close to 67mm. So, much so, that 67mm screw-in filters almost with out exception, fit right in. For series 6, I don't think you will find an off-the-shelf Cokin ring that will fit. But, there is Gorilla Glue. You can get a 46mm Cokin adapter ring if they make one, remove the retaining ring on a 31.5mm push-on adapter and glue one to the other with the aforementioned adhesive or some other epoxy. If you find that a 46mm is only available in the Cokin A size, I think you could get an A to P adapter, but Cokin is not my forte, so perhaps others can guide you in that.

**Keith Fleming** · 16-Oct-2007, 11:05

Rippo,

The Orion filter I'm using screws into the 6-inch Dagor.

Having read comments elsewhere today by Sandy King, I am mindful that many variations of Dagors exist as they were manufactured by various entities over a long time. While the Orion filters screw into mine, such filters may not fit other 6-inch Dagors. For clarity, I have a coated version, serial number 77XXXX, in a Copal O shutter, by C. P. Goerz Am. Opt. Co.

Keith Fleming

**rippo** · 16-Oct-2007, 15:19

robert: i'd probably go the glue route, otherwise i'd have a lot of things hanging off the front. must think on this a bit.

keith: thanks for the heads up. 31.5 would definitely have to be the outer diameter on this lens. perhaps i have a smaller one. i seem to recall the serial started wit 784, but i'm at work now and can't check it.

the easiest thing might be for me to get a 28mm filter and just try it. i think that's a vidcam standard, and they're cheap on ebay. i'll check around locally and see if i can find something to try first. if that works, i know i can step up to 47mm, then get a cokin adapter for the P. but i don't think your 1.25 filters are going to work here.

thanks.