CCD and filter wheel question

[Catanonia]

Just got my 1st CCD and filter combination QHY9 Mono and wheel with 2inch filters from Modern.

So my first of many questions.

Will the focus shift between the filters, ie will I have to refocus when moving between LRGB?

They were bought together as a QHY LRGB set.

I also assume that I will need flats for each filter combination during the processing. Is this correct ?

Thanks

[Euan]

Will the focus shift between the filters, ie will I have to refocus when moving between LRGB?

No, the QHY LRGB are parfocal, but if you use any other filters like Astronomik or Baader, they will be at a different focal point. They are talking about bringing out narrowband filters via OB Optics and these will be parfocal with the LRGB, but no word yet if they have arrived at QHY for testing:

OB narrow filters

I also assume that I will need flats for each filter combination during the processing

Yes, as far as I know (although never done it)

The flats may be slightly different for each colour

[Catanonia]

Thanks Euan

[roundycat]

Your filters may be parfocal but that does not mean that you can focus once and forget it. Your scope may not be fully corrected from red to blue so there may be some focus shift plus after a time there will be a temperature drop that will make your scope shorter.

You will need flats for each filter if the filters are dirty. If the filters are fairly clean one flat may do the job but it might depend on your pre-processing software. If it reads the FITS header to find out what filter was used it might not be able to flat green and blue frames if your flat insists it was a red one.

Dennis

[Catanonia]

All setup with laptop in the living room with MaximDL 5 so now the task of transfering it to the obs and cabling / balancing it all up.

The day gets better, got CS5 Master Edition today, on Friday wifey gives me a WO66 new scope as a birthday present and tonight looks crystal clear

Yippee..... There is a god and the wife is working late too

Thanks RoundyCat, will bear this in mind and keep checking the Bahnitov masks to figure it all out.

Intend to use LRGB individual flats. Going to cool to -25 celcuis, so hopefully won't need darks.

[Catanonia]

All cabled / routed and tested. Now awaiting dark to align and get my 1st lights.

Got to work out how to foucs this thing now without live view

LOL should be fun.

Wish me luck.

Cat

[Catanonia]

Well focusing was easy with MaximDL and LRGB are all parfocal that is good. Cooling to -40 celcius

Aligned and tracking on M51 now

Waiting for dark now to give this beast a go