QHY8L + Brightside 2" FW + MPCC Mk iii

[Thalestris24]

Hi all

I'm looking at getting a filter wheel to go between my qhy8l and MPCC so was looking at the nice 'n cheap Brightside 4 x 2" wheel. Does anyone else have this combo by any chance? I've asked Bern at MA but he sounds a bit unsure... I currently have a 17-23mm M48 variable spacer between the qhy8l M48 adapter and the MPCC. So essentially a fw will have to fit in place of the spacer. The spacer is set to 21mm (as far as I can measure) so the fw may just fit or it may not! Bern is also saying the M48 thread at the front of the wheel may not be compatible with other M48 threads - huh?

If anyone has any experience with this combo, I'd be grateful to hear back

Thanks

Louise

[Earl]

some m48 thread pitches are not always the same, .62 and .75

what are you planning on doing?

[Thalestris24]

Hi Earl

Hmm... why would anyone make a filter wheel with a non-standard thread? Or, perhaps it is standard and Bern was referring to what the fw might be connecting to. I'm still waiting to hear back from Bern - he seems to be busy stock sorting today. I'm just planning on being able to switch the Baader 7nm Ha filter in for imaging emission nebulae. I know there may be focus issues but that's ok. The convenience of being able to dial a filter in would be very handy.

Louise

[Earl]

why not just pop a filter on the coma corrector.

Standards, there are no real standards just happy accidents This varience on M48 was discovered by an engineering mate of mine who was making adapters etc, m48 was not standard at all different threads on eyepiececes for filters and differnent threads on filters and other gear, its subtle but its there.

[Thalestris24]

Hi Earl

It's inconvenient, risky and time consuming to take everything out, put the filter on, put it all back. It potentially messes up my flats and risks inadvertent tilt being introduced. All in all, a pain! Ideally, I don't like to touch or move the camera at all. It would be much easier to use an Ha with a fw.

Strange about the M48 - to date, I've not come across any incompatibilities.

Louise

[Earl]

IIRC the qhy8l as a removable noise piece and t-thread infront of the built in IR filter, does that give you a few more MM to play with, getting the adapters a wheel in the right spacing could be a challenge, when i did ha with my qhy8l i pu the filter on the reducer it need seperate flats from without anyhow, i do seem to recall some reflection problems though, I ended up popping out the ir filter and used a t-cell astronomic cls ccd to get one less piece of glass.

it might be worth putting the filterwheel in front of the coma corrector, if it will thread directly into the filterwheel without a pushfit adpater so as to avoid spacing issues.

[Earl]

just had a look at that wheel, i used to use on with a reducer and 383L, Reducer adapted to m48 (ts adapter) then i sanded down the supplied m48 to t adapter to get the spacing..... i think, its been a while, the problem i found was the t to m48 adapters welding to the body of the wheel quite likly do to the threads not been identical, some adapters were smooth others not.

[Thalestris24]

Hi Earl

I don't quite understand the 'M48 to t-adapter' description of the fw - is that an optional connector? I don't think I want that - I just need M48 to M48, if possible.

Louise

[Thalestris24]

IIRC the qhy8l as a removable noise piece and t-thread infront of the built in IR filter, does that give you a few more MM to play with, getting the adapters a wheel in the right spacing could be a challenge, when i did ha with my qhy8l i pu the filter on the reducer it need seperate flats from without anyhow, i do seem to recall some reflection problems though, I ended up popping out the ir filter and used a t-cell astronomic cls ccd to get one less piece of glass.

it might be worth putting the filterwheel in front of the coma corrector, if it will thread directly into the filterwheel without a pushfit adpater so as to avoid spacing issues.

Hi

Earl - sorry, missed your previous post! The qhy8l does have a nosepiece but I'd rather leave it sealed and not undo it... At the moment I have an idas d1 on the front of the cc. I didn't get any reflections when I tried the Ha filter the other night and I put that in front of the d1. The cc is buried in the focus tube... So only the spacer and camera is visible outside. I'll have a scan on the net to see what's available. Plenty of people must use coma correctors and filter wheels in front of their cameras!

Cheers

Louise

[russellhq]

Hi Louise, I'm having the same issues as you. Different M48 threads.

So, for now, I've resigned to the fact that I will only capture 1 filter per night. Which kinda makes sense when you consider how much data you need to capture and how long an observing session you can get of an evening. You'll probably never capture more data than you need in one evening.

[Thalestris24]

Hi Russell

I don't think I actually have an M48 thread problem after all. I've been chatting to Bern at Modern Astronomy (he phoned me!) re: his Brightside filter wheel. It looks like it will fit in the imaging train ok. I just have to finalise the spacing situation. But I think I have enough M48 spacers so should be ok. I'll probably order the fw very soon - only £99.99 Well, lets call it a hundred quid, lol. I really only want it it for switching the Ha filter in and out. The rest I'll do in native colour. Well that's what I had in mind Presumably your problem is with the SW FR? I think Bern said that was a M48 thread mismatch. But I imagine there's a way around it?

Cheers

Louise

Edit: I'm limited because I image through a window so can only capture a particular target whilst it's crossing the window aperture (maybe an hour, if I'm lucky). After that, I have to find another target!