CCD and filters

[Shelster1973]

Realise that most of the imaging done with CCDs and filters involve the use of a filter wheel, but is it possible to have filters that screw onto the CCD in a similar way that you can screw filters onto EP's

Am contemplating going down the CCD route soon and was looking at a way of getting into it with the minimum of cost at first. Will eventally head for a filter wheel, but not just to start with

[MattJenko]

Have a look at second hand manual ones. They can be had for a small % of an LRGB filter set.

If you want to use a filter on its own, you will need to find a T-adaptor which allows the filter (presuming 1.25" ones) to screw into it as the filters are not T-threaded.

[PeterCPC]

You can screw some filters into the nosepiece of CCDs but you wouldn't want to keep taking it out to change filter because you would need to re-focus each time. It's not unusual to use Light Pollution Filters like this.

Peter

[Stargazer33]

I believe that most, if not all, CCDs have a thread which will allow you to fit filters directly or onto a nose piece.

[MattJenko]

http://www.scopestuff.com/ss_tfa1.htm

this is the kind of thing I was thinking about, although these are US based. Teleskop Express in Germany do a decent range of these kinds of things as well.

(Peter is right, you could screw the filter into the nosepiece supplied with some CCDs if it is threaded.)

[daz]

You would also need to take flats before you change the filter - otherwise the camera will rotate with respect to the optics...

You could look at filter drawers - http://www.teleskop-express.de/shop/product_info.php/language/en/info/p2159_Filter-Quick-Changer-incl--1x-2--filter-drawer---low-profile.html

[ollypenrice]

I believe that most, if not all, CCDs have a thread which will allow you to fit filters directly or onto a nose piece.

You can always put a filter onto a I.25 nosepiece but it will be a long way from the chip and will be very likely to vignette. There would be no point in buying a 2 inch filter to put on a 2 inch nosepiece because it would be cheaper to buy a wheel and smaller filters! This assumes a reasonable size of CCD chip. You can get away with 1.25 filters on webcam nosepieces because the chips are so tiny. As Matt says, a second hand manual wheel would be cheap as chips and easy to find. I only switched to electric a couple of years ago. They are far from essential.

Olly

[D4N]

I use filter drawers, mainly to keep the weight and size down though as I have a very portable imaging setup.

I have the filter drawer attached to the camera, this has the added benefit of not filtering the light to the oag.

Sent from my iPad using Tapatalk

[Shelster1973]

Cheers all...all great advice and poins as expected.

Have never heard of flter drawers.  They do look like a very practical solution to my 'problem'.  Would possibly go for a 2" option, althoug I do have a rather cheap and cheerful set of 1.25" filters that came in the yepiceaccessory box I bought with the scope.

Still, this is all a long way of coming to fruition as am no where near ready in the funding department to purchase the CCD.......plus there is the decision of which CCD to go for to match my setup........

[Shelster1973]

.which I am thinkng along the lines of the Starlight Trius SX-674 as do like the not having to take any darks and also the built in hub appeals to me as I am not a big fan of trailing cables.  Can then have guidecam plugged into image cam and get down to one cable comng down

[daz]

Cheers all...all great advice and poins as expected.

Have never heard of flter drawers.  They do look like a very practical solution to my 'problem'.  Would possibly go for a 2" option, althoug I do have a rather cheap and cheerful set of 1.25" filters that came in the yepiceaccessory box I bought with the scope.

Still, this is all a long way of coming to fruition as am no where near ready in the funding department to purchase the CCD.......plus there is the decision of which CCD to go for to match my setup........

Those filters will be visual, not photographic

[Shelster1973]

Those filters will be visual, not photographic

A very good point there Daz.....scrubbing the existing fiters out of my mind now

[ollypenrice]

Don't buy 2 inch filters if you don't need them. The price difference is staggering.

With set point cooled CCD darks are a total non-issue. You take them any old time at temp 'x' and keep them for a year or so.

Olly

[silios]

I would buy just an Ha filter for starters and a motorized filterwheel to have something to gather data in the meantime and then save up for the rest of the filters.

The expenses and the hassle from going down the route of filters in nosepieces, then a drawer, then a manual fw and then a motorized fw will add to a "proper" fw.

[Shelster1973]

Yeah..it all does seem to add up....

Have norrowed my choices of CCD down to either the ATIK 460EX or the Starlight SX-694. As these both have same chip and basic 'under the hood' specs, just need to decide whether the USB hub and sensor adjustment you get on the SX are worth the extra £300 over the 460EX. That £300 would get me a wheel......oh the decisions....