Thoughts on which imaging rigs to concentrate on

[Gina]

Thought I'd just rotate it and crop it and upload that.

[Gina]

Took some more bias and dark frames tonight but at -24°C to -25°C rather than -30°C as a compromise in the hope of improving on no calibration at all.  It has worked to a large extent.  Not removed all the noise of course as it doesn't really fit but it's certainly an improvement and shows that the data has promise.

This is the result of running the CPP script.  This is all the image, full size, histogram stretched and saved as PNG.

[Gina]

Processed the Cygnus Loop with the new master bias and dark plus the Ha flat with CPP then had a play in Ps - rotating and cropping and saving full size image as PNG.

[wimvb]

In PI batch preprocessing you can check the radiobox to scale the master dark. It works when darks are taken at another exposure time, but it might also work for a different temperature. Worth a try at least.

[Gina]

That's interesting - thanks Wim

[Gina]

The SX mini filter wheel with OAG has arrived and looks very nice   Since I'm waiting for the Astrodon 3nm SII filter from Ian King (getting more in) and not yet managed to capture RGB M31 subs, I think I'll set it up with Ha, OIII, R, G, B as the five filters.  OTOH I could do the RGB before changing filter wheels - I'll see how I feel this afternoon.  I think I'd really like to get the new wheel installed and tested   I'm thinking of adding Ha to the RGB image of M31 so to be able to add longer Ha subs would be useful.

Edited September 12, 2016 by Gina

[Demonperformer]

It does pose a problem, doesn't it? I wonder if SX will make spare carousels available separately, which would mean you could have a broadband wheel and a narrowband wheel.

[Gina]

I have a serious problem!   The SX filter wheel is 15mm thicker than the Atik EFW2!   I could save 11mm by buying an extra female SX adaptor plate and dispense with the ASI1600MM gender changer but that would still mean I need an extra 4mm travel on the lens focus and it just isn't there.  I think the same would apply to the field flattener for the Esprit scope and it's adapter

Edited September 12, 2016 by Gina

[Demonperformer]

On 04/09/2016 at 15:58, Gina said:

Interesting but I can see no mention of the built-in USB2 hub that the latest version of this camera has and is the version sold by FLO.  Maybe the 365Astronomy one doesn't have the USB Hub and that's why there's 10% off!

Good news, Gina ...

USB2 hub is included [phew!]

[Gina]

That's good then You're having more luck than me!

Been looking at other filter wheels on FLO's web site.  The ZWO one looked just the job at first - very narrow and designed for their 1600 camera meaning that I would have room for the OAG I have.  BUT the spec says " Important Note: 1.25" filters require threads shorter than 3mm and the height without threads must be less than 7mm. "  The thread length is fine at about 2mm but the height without threads is 7.5mm for the Astrodon filters!   So it seems the ZWO filter wheel cannot take Astrodon filters   Bummer!!    (excuse my "french"!)

Really don't know what to do now!   I guess email to FLO for suggestions.

Edited September 12, 2016 by Gina

[Gina]

I feel like the robot in HHGTTG now

[Demonperformer]

'Brain the size of a planet' you mean?

[Gina]

Maybe but "I'm depressed" is what I really meant.   Or something like that - I forget now - long time ago...

Edited September 12, 2016 by Gina

[Gina]

The FW problem is my fault I guess - I forgot to check the optical length before I bought it    Just checked now and the measurements are there on the web site

[SilverAstro]

Oh crumbs ( hope the filter wont object to that word but I can think of others ! ) how weak can one find barlow elements ( negative lenses) to extend the focal length a wee bit ?

Oh ding ! remember tele-extenders? didnt always do wonders for the fidelity but with that sensitive chip an f-stop could be sacrificed perhaps ?? EDIT nope brain took leave for a mo. the focal plane did remain the same sorry

 

Edited September 12, 2016 by SilverAstro

[SilverAstro]

19 minutes ago, Gina said:

Maybe but "I'm depressed" is what I really meant.   Or something like that - I forget now - long time ago...

Marvin - the paranoid android

Ohhh I dont know why I bovver hhaaahhhhhh

 

[Gina]

Ah yes - that's it!  I guess I should have guessed the delight with the new camera and imaging rig couldn't last - I'm just not that lucky!!!!

[Gina]

I really don't want a separate guide scope!  I wonder if the ZWO filter wheel could be modified to get that extra half millimetre room for the filters.

[SilverAstro]

Hang on I'm having another idea, just need to fetch one of my old lenses ,,,,ah I wonder, they came with rings on their backs to suit different camera mounts / threads, remove that and I wonder what thread is under ?

Yes, held on with three little grubs to my 135mm

Edited September 12, 2016 by SilverAstro

[SilverAstro]

Is there 4mm in it though ? and is yours the same

 

[Gina]

I'm doing more measuring...  I'm not sure the guide camera can be brought into focus with the camera sensor being 11mm or so nearer with the adjustment available on the guide camera stalk.

[Gina]

Hmm...  Things are not looking good.  Checked the measurements again and yes, I do need 4mm more back focus from the camera.  Also the adjustment for the guide camera is way less than the extra 11mm required.  This filter wheel will simply not work with camera lenses, all of which have a back focus of about 45mm.

I think there may be another problem too - the rear element of the lens is only 28mm and looks like it will only cover about half of the prism when this is far enough out to clear the camera sensor.

So it's looking like an OAG isn't going to be possible with a camera lens after all Not sure yet about the Esprit scope.  Drat!!  Looks like I shall have to work out how to use another lens for the guide camera and mount it...

[SilverAstro]

Oh dear, sorry to hear of the other probs.   I was thinking - that the lens mount ring is probably sat round a v groove and is the way the base lens is lined up so the index and lettering is in the right position as well as it carrying the right thread/mount for the SLR camera, does that make sense. So removing that and fabricating something might have won you a few mm, but to no avail by the sound of the other complications

So, I'll leave it with you cos I cant help any more  ( I would have said all that earlier but I just unexpectedly lost 2hrs out of my life - swmbo phoned - stranded - lost car keys - had to go rescue  with the spare ! grrr )

Edited September 12, 2016 by SilverAstro

[Gina]

Thanks for your reply   I'm going to have to give all this some more thought.  I've put a question on FLO about using Astrodon 5.25" filters in the ZWO filter wheel (in the Q&A section of the ZWO FW page) as they apparently won't fit.  Probably get a reply tomorrow.  The ZWO filter wheel in small and light and designed specially for the ASI1600 camera - ideal for a lightweight WF imaging rig that could go on a lightweight mount. 

[Gina]

I've put the rig back together and back on the EQ8, connected everything up and run all the software to check it all works still - which it does.  So I'm all set up for next time we get a hour or so of clear night sky.  Focussed on tree on distant hill which gives a good starting point for star focus.  Weather forecast looks good for 2am tomorrow morning but I'm not staying up that late just in case they're right!  

Edited September 12, 2016 by Gina