First Light with Dual Imaging Setup - Now with Images!

[steppenwolf]

My first attempt at posting this at around 03:00 this morning was thwarted by the simple issue of my website being down so the links to the images wouldn't work - hopefully this has now been resolved!

This is in fact a double first light in more ways than one! First there is the first light image from my William Optics Megrez 72FD which until tonight has only ever been used for guiding and secondly it is the first light pair of images from my dual imaging system. I don't have perfectly matched camera orientation yet but I know how I am going to achieve this in the future.

The mono image is 'The Wall' in NGC7000 (The North America Nebula) taken with my WO Megrez 72D, WO FR III, SXVF-H9 mono CCD camera and Astronomik 12nm Ha filter. This telescope also had the off axis guider installed on it.

The colour image is the same region of sky taken at the same time with my WO FLT98, Hotech SCA Field Flattener, SXVF-M25C one shot colour (OSC) CCD and Hutech IDAS LP filter.

Both sets of images are made up of 10 x 300 second subs. with no calibration frames for the colour and BIAS subtraction only for the mono. The reason that there are no flats is that I was still imaging when I processed the first 10 frames because I was impatient to see if the project was working OK!

To run both cameras at the same time, I needed to use Starlight Xpress' own software with the colour camera and the FITS data from this software is not compatible with my existing MaximDL bias library so I have some issues to resolve here.

[Gina]

Great Steve A very interesting project

[Black Knight]

Looks an extremely interesting project great images as well!

[Quatermass]

Looking very good there and a very cool project

[Spikey]

Great little project Steve.

[steppenwolf]

Having plate solved the two images, I am reasonably happy with the pointing accuracy of the two telescopes bearing in mind that the only adjustment available is the two Allen keys and slippage of the ADM saddle plate on the side by side bar - Currently I am 22.5 arcseconds out in RA and 2.3 arcseconds in Dec. The H9 was almost spot on 90 degrees rotation (just 0.88 of a degree out) but as expected, the M25C was 9.18 degrees out but I can fix that in future.

I have now had an opportunity of producing a trial combination of the two images. The one on the left is the original OSC colour version and the one on the right was combined by blending the Ha data with the Red data - note the triangular cut-out at the bottom left hand corner caused by rotating the colour image to compensate for the orientation error mentioned above.

[fwm891]

Lots of subtle detail there Steve. I think you will get lots out of that set-up!

[Jessun]

A very interesting project there, Steve! Shame really to guide with a WO ;-) I'd swap you for a finder scope setup!

Nice work. You say you know how to deal with the pointing, does that involve the ADM adjustable saddle by any chance? Which IDAS version are you using btw?

[Uranium235]

Very interesting Steve, much along the lines of what im working on at the moment (except using DSLR colour). It seems that more people are deciding to go for the dual shooter option, perhaps in response to the dire lack of clear sky over the past few months. But its a great way to take advantage of situations where the sky is perfect, better to grab it all at the same time while the going is good, rather than waiting to finish it another day when conditions are poorer.

[Guest]

Sounds like a cool setup Steve - just off to your website to hopefully see some pics of it "in action"

Good images of this nebula too - I'm thinking of having a go at Ha this year but need to establish what the highlights and benefits are - should probably break down and buy your book while I'm at it! :-)

David

[steppenwolf]

You say you know how to deal with the pointing, does that involve the ADM adjustable saddle by any chance? Which IDAS version are you using btw?

I have no direct experience of the ADM adjustable saddle but I am not too keen to add any additional component that could introduce flexure, much as the ADM unit looks very tempting! I am happy enough with the actual pointing of the two telescopes, it is the orientation of the camera that I was referring to and for that I'm going to add a set of alignment marks on each component in the light path with a 180 degree graduated band at the rotating part of each focuser.

I believe that my Hutech IDAS filter is the version II (MPT ?) bought in late 2008.

[Jessun]

I see what you mean, but that ADM unit does look like a spare part from a heavy tank... I don't use one due to the sheer weight of it. I have the v4 IDAS I believe but didn't feel successful in mating that to the M25. I need to work on that obviously.

A project to follow!

[RobH]

That's working out very nicely Steve.

Are you using the smaller 16HR image as your reference for scaling ? I assume so or I would expect you'd have a problem with the 16HR/WO72 combination at full scale if you upscaled that image to the osc image size.

Hopefully I'll be going down the same route using a m25c and SX H18 this summer while we're away camping (or being rained on!)

Cheers

Rob

[Anweniel]

Very nice Steve you demonstrate well the subtleties of trying to get precision from what at first seems a simple idea but then becomes a bit more complex when you look into the contributing factors to the final work!

Love the Ha blend. What made you change the WO scope from a guider to imager?

[Auntystatic]

If you stare at the 2 images (like you did with the magic eye posters a few years ago), a third one appears in the middle and looks almost 3D, very cool indeed.

[steppenwolf]

But its a great way to take advantage of situations where the sky is perfect, better to grab it all at the same time while the going is good, rather than waiting to finish it another day when conditions are poorer. (Uranium 235)

This has always been my argument for using an OSC camera but it is so nice to collect this additional data, especially Ha as this makes for a worthwhile photograph (albeit in mono) in its own right.

I'm thinking of having a go at Ha this year but need to establish what the highlights and benefits are (Sand Dune)

Ha is present in emission nebulae including planetary nebulae and using an Ha filter will release some of the minute detail missed by a standard RGB filtered image. There are, of course, other narrowband filters that also release otherwise hidden detail, like for example OIII filters but Ha is so common that it is the most rewarding.

I have the v4 IDAS I believe but didn't feel successful in mating that to the M25. I need to work on that obviously.(Jesper)

Not sure why you are not getting good results with your IDAS filter with the M25C - my filter has transformed the light pollution problems that I have at my location. I hope you find a solution - have you tried calibrating your de-Bayering algorithm to give an accurate daytime image with the LP filter in place? I have done this to ensure that I have a good base point to start my post processing from.

Are you using the smaller 16HR image as your reference for scaling ? (ROBH)

I am indeed, Rob - this is a limitation to the system as it means that as a best case, my combined images will be at the lower pixel count of the H9 but, as you know, the colour can be compromised to a great extent without losing final image fidelity provided the Luminance channel data remains intact! However, I have to work with the components that I have available so I can work with the limitation. I will be very interested to see how your own dual system works out.

What made you change the WO scope from a guider to imager? (Anweniel)

( a ) it seemed a terrible waste of a potentially good astrograph

( b ) I decided to overcome the spacing issues of using a filter wheel, OAG and focal reducer or coma corrector by producing my own hybrid ATIK/SX solution which allowed me to move over to off axis guiding and the advantages thereof!

If you stare at the 2 images (like you did with the magic eye posters a few years ago),a third one appears in the middle and looks almost 3D, very cool indeed.

I must give that a try - thanks for the head up!

[nytecam]

Great images Steve - makes a lot of sense to run two cams on same target for those rare clear UK nights

[earth titan]

Yeeks...

I have enough trouble with just one camera!

[Coco]

Looks great Steve, those little Meggys are fabulous..

[steppenwolf]

If you stare at the 2 images (like you did with the magic eye posters a few years ago), a third one appears in the middle and looks almost 3D, very cool indeed.

Just for you Danielle, here IS a 3D version:-

[todd8137]

They looked 3D before super images

[Auntystatic]

Just for you Danielle, here IS a 3D version:-

Oh my goodness that's absolutely brilliant, the way the stars pop out at you really gives a fantastic depth of field, well done, we should have more of these there grrrrreat!

[Guest]

Oh my goodness that's absolutely brilliant, the way the stars pop out at you really gives a fantastic depth of field, well done, we should have more of these there grrrrreat!

That is absolutely fantastic! :-) I can see that I now have to try this with some of the images I've captured. I was really surprised at how well it works.

David

[mgirdwood]

Very Nice Steve, puts my attempt at the weekend in to perspective

[steppenwolf]

What I should have done, of course, was find out the relative distances of each star from the Earth and set them correctly spaced but it was great fun doing it - my eyes are still crossed though from all the testing!