Filter wheel, is it really worth it?

[emadmoussa]

This might not be the right section for such a question, it is multi-dimensional and difficult to categorize precisely...

Anyway, I'm thinking about getting a filter wheel to include at least 3 filters: lunar, contrast and light pollution. Is it really worth throwing money on it? They seem quite over priced...

P.S the wheel will be hooked to a 152mm doublet refractor...

SW LP filter can act as a lunar dimming and contrast filter?

[SnakeyJ]

I found a nice cheap one via Amazon back in Feb, but think these are also being listed on ebay at the moment -

Works a treat and the quality excellent for the price, but you may want to replace the grub screw with nylon one to use with expensive EPs. It does add some 25mm plus extension, so be wary of infocus limits - though not a problem for me imaging as I use barlow - filter wheel - camera, so this acts as about +1 on my barlows.

[bomberbaz]

I don't actually fully get how these work and the benefit they give. Excuse my total naivety but are these mainly for astro photography?

[emadmoussa]

I don't actually fully get how these work and the benefit they give. Excuse my total naivety but are these mainly for astro photography?

In principle, they're used for both. Instead of getting your observation obstructed by removing an eyepiece, unscrewing the filter and then screwing in another one, the wheel simply contains a number of filters that sit between the focuser and the eyepiece allowing you to jump between different filters. So if you want to change the filter, you spin the wheel without having to remove the eyepiece. I'm uncertain of the practicality of this piece of kit though. I mostly use one filter for lunar and almost none for DSO...so I'm not sure if should go for it. Then again, my collection of filters is likely to grow and will need a method to swap between them quickly and effortlessly.

[bomberbaz]

How do they fit though, they must have a gap between focussing tube and EP so they can slide between it, or am i missing something.

[emadmoussa]

This will give you an idea

P.S. I'm not advertising Orion, quite the opposite really...I

[Macavity]

I have a Brightstar (now £70 at Modern Astronomy). Hardly essential for visual astronomy, imaging-dabblers or Random colour or contrast filter experiments. Rather essential for stacking RGB images. For casual users (me!), a slide-type filter holder might create fewer balance issues. Not quite as easy to find, but...

[bomberbaz]

Hmm handy but one thing to be aware of in my case with an SCT is that it will alter the focal length of your scope. Funnily enough I started a thread the other day about changing focal lengths due to add ons with Maks and SCT's. But from an imaging perspective, I think this would be quite handy.

[SnakeyJ]

Apart from the LP and coloured visual filters, there are also visual nebula filters that are useful for DSO - though not sure at what aperture these come in to their own. As Macavity says the weight of a loaded filter wheel may unbalance some rigs, though this is probably an advantage with a big doublet refractor in shifting the COM back towards the centre of the OTA.

[emadmoussa]

Apart from the LP and coloured visual filters, there are also visual nebula filters that are useful for DSO - though not sure at what aperture these come in to their own. As Macavity says the weight of a loaded filter wheel may unbalance some rigs, though this is probably an advantage with a big doublet refractor in shifting the COM back towards the centre of the OTA.

Totally!

[sparkyjon]

Can you got these computer controlled though imad or is this just for your visual set up.

I think ive seen electronic ones but not sure if they can hook up to a lappy and they seemed very expensive as you said ..

[SnakeyJ]

Can you got these computer controlled though imad or is this just for your visual set up.

I think ive seen electronic ones but not sure if they can hook up to a lappy and they seemed very expensive as you said ..

you almost certainly could motorise this - there's quite a good article at AstronomyMark on converting the orion 5 position 1.25" filter wheel (which is the same as my unit- unbranded).

Ideally, for imaging you would want an ascom driver, so that it could be controlled via your capture software.

On a second look, I think this conversion could be improved with a simple position sensor (optical or pressure) to correctly locate and preferably identify the filters - might have a look at this myself after the arduino focuser is completed.

[emadmoussa]

Like Jake said, that's an available thing. Either you modify an existing non-motorized one or pay significantly extra and get a readily made USB filter wheel.

[emadmoussa]

Something like this http://www.firstlightoptics.com/starlight-xpress-accessories/starlight-xpress-usb-filter-wheel.html

[cathalferris]

If I ever get a larger Dob, I'll be putting in a filter slide, with UHC, OIII, Moon and clear filters. Not a filter wheel but as a slide either between the focuser and tube or just inside the tube, moving longitudinally along the scope axis.

I would certainly use a computer-controlled one with parfocal filters if I were doing more astrophotography though. I'm not that fond of the idea of a filter wheel for visual use - I just don't change between the filters enough.

[Astrobits]

If I ever get a larger Dob, I'll be putting in a filter slide, with UHC, OIII, Moon and clear filters. Not a filter wheel but as a slide either between the focuser and tube or just inside the tube, moving longitudinally along the scope axis.

I would certainly use a computer-controlled one with parfocal filters if I were doing more astrophotography though. I'm not that fond of the idea of a filter wheel for visual use - I just don't change between the filters enough.

That is the question. If you use filters enough to get tired of continually removing the eyepiece, unscrew the filter, screw in another one, replace the eyepiece, in the dark with cold fingers then a filter wheel/slide might just be what you want. If you only do it occasionally then it might be an expensive accessory. Alternatively, you could buy several identical eyepieces and fit each one with a different filter, then it is just change the eyepiece. Just a thought

Nigel

[SnakeyJ]

One advantage to consider that the filter wheel has over strips, is that the filters are reasonably protected from dust/contamination within the body of the wheel. With a strip I imagine it is possible to fumble and touch the filters inadvertantly or easier to pick up airborne contaminents. Against the filter wheel is the weight factor (mine is 480gms fully loaded) - though perhaps this is more of an issue for the dobs?

I do recall seeing a thread here in the last 3-4 months about a DIY filter strip - just found it

Unfortunately the media seems to be unlinked so might be worth a PM to GazK if interested.

[emadmoussa]

Mm...OK, having to swap between several filters had to some extent interrupted my observing session. If I'm going for a filter wheel I'd rather think of it as a keeper solution. Meaning, I'd like one that will serve me visually and astro-photography-y.

Here's the deal, my aim is to get only the most necessary filters:

- UHC or O-III ( not sure which one is best of r a 152mm refractor, any advice? I hear the O-III is effective against AC... )

- Skywatcher LP filter

- Moon filter (neutral density)

I might also consider a ''contract boost'' filter. But not sure what difference it'll make to the UHC or O-III...is it worth it?

I'd like to think that at some point I will be able to connect my DSLR (EOS 1100D) to the filter wheel. Is it possible with the 1.25" wheel? Or do I need a 2" one? Then again, if I use the 2" wheel, will I still be able to use it for 1.25" eyepieces and cameras??

Thanks!!