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First Light test image - QSI 683 WSG8


steppenwolf
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The first clear night for weeks gave me an opportunity to run some test shots through the Quantum Scientific Imaging 683 CCD camera.

Camera: QSI 683 WSG8

Filters: Astronomik 12nm Ha and 12nm OIII

Mount: Mesu 200

Telescope: William Optics FLT98

Guiding: SX Lodestar with QSI integrated OAG

4 x 600sec Ha

2 x 600sec OIII

Subject: NGC 6888 (Caldwell 27, Sharpless 105, Crescent Nebula)

Including: PN G75.5+1.7 (The Soap Bubble Nebula)

NGC 6888 is an emission nebula in Cygnus and contains the Wolf-Rayet star, WR 136. This massive hot star is responsible for energising the shell of gas it is ejecting as it reaches the end of its life, causing it to emit light in Hydrogen Alpha and Oxygen III wavelengths. At some time in the future, WR 136 will let go in an explosive supernova event.

Also (just!!) captured in this image is the Soap Bubble Nebula (see inside red box) discovered by amateur astronomer Dave Jurasevich on July 6th, 2008. This very dim planetary nebula is almost perfectly circular and my rough test image hardly does it justice but I was surprised to have captured it at all with so few subframes.

Only two filters were used to produce this image with Ha mapped to red, OIII mapped to blue and a mix of Ha and OIII mapped to green to produce the final false colour image. This is very much a camera test image and, therefore, a work in progress but I am pleased to note that the camera works!

post-1029-0-98656300-1372976113_thumb.pn

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Wonderfully framed Steve! Given the short exposure time that image looks really good to me and it's great to see the soap bubble. What were the proportions of Ha and Oiii in G? Did you strech Ha and Oiii separately or after combining them?

cheers

E.

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Super image Steve and this is only a test image........

You are going to have fun using the QSI 683 WSG8.

Can't wait until you post your real images.

On another note. How are you getting on with the Mesu mount?

cheers

Steve

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Hello Steve,

I think you will be very pleased with the 683.

I meant to mail you an apology after your previous post when you were considering the 683 as I had given some incorrect information.

I had to re-read the QSI manual while searching for some data and found that the 683 does have a desiccant plug, I don't know why I thought it didn't.

The desiccant chamber is hidden behind the serial/model number plate....but...should not be opened until it is absolutely necessary to re-charge the plug as the factory fill of dry Argon will escape.

I'm looking forward to seeing your first completed images...I'm not having much luck with my observatory at the moment, my neighbours seem to have gone away...their outside floodlights have been on all day and all night for the last three weeks and no reply when I called round to see if they were ok...no cars outside so I assume they on on holiday.

I feel really sorry for the next generation of amateur astronomers, despite the best efforts of the CfDS the way things are going they won't be able to see anything dimmer than the moon or sun in a few years time!

Regards,

William.

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What were the proportions of Ha and Oiii in G? Did you strech Ha and Oiii separately or after combining them?

I used a totally unscientific approach here as it was just a test series - I stretched the Ha and OIII separately and then combined them 50 - 50 for the green channel.

On another note. How are you getting on with the Mesu mount?

I am really pleased with it as it has performed faultlessly. The only issue I have had so far is that the centring routine in MaxIm DL that I use a lot, does not work that well with the axis encoders enabled which is a little bizarre! In all other respects, I am delighted with my choice.

and found that the 683 does have a desiccant plug, I don't know why I thought it didn't.

Thanks, William, I discovered this in the manual too so it is good that there is a long-term solution to avoiding icing.

Sorry to hear about your LP woes, I too feel sorry for the next generation in both this and many other regards!

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QSI cameras do have a reptutation for working, so I'm not going to profess surprize! I've seen a good few in action but only played with one of them hands on. I thought it was very classy on all counts.

Clearly it's a sensitive camera because the SB is faint, all right, but you have it. Nice and deep in the background, too.

I'd really recommend hammering away on the OIII layer, which gets more and more fascinating the more you collect.

Olly

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Utterly fabulous Steve! :)

Just to sanity check, that picture is just HA and OIII? Nothing else? Not LRGB or anything? Starting to study this a whole a lot more now that I have a CCD :)

And I always understood you did a stretch *after* combining? Boy, I have a lot to learn.

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I'd really recommend hammering away on the OIII layer, which gets more and more fascinating the more you collect.

Absolutely agree, Olly - my problem that night was serving the needs of a review first and I ran out of time with the Sun coming up after only two OIII subframes! This is a fabulous region of the sky if you enjoy nebulae and OIII has a very important roll to play here.

that picture is just HA and OIII? Nothing else? Not LRGB or anything?

Quite so, only the two filters. Remember that OIII sits right on the cusp of 'green' and 'blue' in terms of wavelength so it can be used and re-used in a variety of ways, including using exactly the same OIII data for both the green and blue channels to create quite realistic colour images approximating those of LRGB data.

And I always understood you did a stretch *after* combining?

So much depends on how well matched the data is - in this region of the sky the Ha is very dominant and in addition, I had more Ha data than the already weaker OIII

Good luck with the photon hunt! They all count you know! :tongue:

I recognise some of those words but just can't place them :grin: :grin:

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