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DSLR to CCD, what awaits me?


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I have tremendous fun with my DSLR but find time to be rather precious when it comes to imaging when considering weather, driving to a dark spot etc so I decided a while ago that a dedicated CCD could be beneficial.

I am waiting for a Starlight Xpress SXVR-M25C and hope to receive it in a couple of weeks time.

I wonder what immediate obstacles - if any - you guys encountered doing the jump from DSLR to Astro camera?

I have already been throught the PDF manual a few times and it looks slightly more complicated that using a DSLR but I reckon it's worth it!

Things like de-bayering, producing a colour picture, software control, focusing etc seem daunting to me compared to the joy of my EOS!

Any input appreciated!

/Jessun

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I have recently included an Atik 314L to my arsenal, I think my DSLR will get no use now! In preparation I read loads about how to process CCD images (alignment, stacking and channel integration). I also had to learn new capture software as well as a whole new way to focus - No live view on a CCD!! I've still to take a RGB image as I did Ha for my first image as it seemed easier!

It is a little daunting - But search around the net and read loads.

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I think you are in for a real treat making this jump. The M25C is so noisefree that you can pretty much forget about taking DARKS unless you have bad hot pixel issues but even these can be resolved by using the right stacking process (SD Mask works well).

De-Bayering often causes issues at the very start but once you have the right settings in your software this is a painless operation. A good start is to take a daytime image (perhaps using a camera lens instead of your telescope) and then adjust the settings in your de-Bayering software until the colour image matches what you see in real life. This will set a colour balance that suits you but it can be tweaked later.

Focusing will be easier than ever because you will be forced to use a PC as the CCD cannot be operated on its own - taking a series of short exposures of a bright star (4 - 6 seconds works well) and adjusting the focus until you get the smallest star image works well. A Bahtinov Mask makes this a trivial task.

What software will you be using for your camera control?

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What awaits you is a treat. I find DSLRs hideously daunting for astro because of all the work-arounds you have to do since they weren't designed for the job.

For OSC aquisition and processing I'd highly recommend AstroArt 5. Nobody uses SX software. I haven't used it for my OSC yet but Harry Page tells me it is even easier than with AA4 for OSC pre-processing. I always used AA4 for the OSC. Harry has a tutorial on his website - Google Harry's Astro Shed.

Olly

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Sometime in the future I was planning to buy something like a Canon D1100 and remove it's IR filter for astro dedicated user instead of using my Sony A200 DSLR, but this thread prompts me to wonder if I might be better saving up a few months longer and getting something like the Atik 320E.

Edited by Gina
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Go for the dedicated CCD anytime. I still use my DSLR for astro but the Atik 383L+ is my camera of choice now. Mine's a mono so colour images are built from separate filtered images.

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Go for the dedicated CCD anytime. I still use my DSLR for astro but the Atik 383L+ is my camera of choice now. Mine's a mono so colour images are built from separate filtered images.
Wish I could afford one of those :icon_confused: But I might go for a cheaper Atik camera. As for mono v colour, I know you can get much better results from a mono camera plus colour filter wheel. I could make a filter wheel so the extra cost would be just the filters. I'm thinking that if I was to spend that much money on a camera, I wouldn't want to change from colour to mono later on.

Anyway, all that is a fair way off, the next major purchase is planned to be a 10" Newt scope, I have various cameras I can play with.

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Thanks for your input everyone!

As to software, well I feel like a rabbit looking into two poorly collimated head lights... I don't know! I was hoping Nebulosity would do a good job, but following the AA tip for OSCs it looks like something I need to try out too.

No need for darks I hear, fantastic! That's a time saver :-)

I have a Rigel Systems focuser on the RC and a JMI for the SWs and it would be great to get all this hooked up to one program.

Steve your book is on the Xmas wish list!

Olly, good tutorials there, thanks for the tip!

I'm still waiting for this camera, but plenty to google and read up on here beforehand!

/Jesper

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Been looking at various CCD cameras on the FLO web site and the choice is quite bewildering. Obviously this needs very much more research. A case of "Yer pays yer money and yer takes yer choice" :icon_confused: More money - better camera. I might just be able to stretch to an Atik if I save up for a long time. Or there's the Imaging Source cameras at a fraction of the cost but no Peltier cooling and smallish sensors. I may well wish to take wide objects but I guess I could use an SLR camera lens for these with a smaller sensor rather than a "gert big" Newt.

I'm considering a dedicated CCD imaging camera rather than buying a Canon DSLR to dedicate to astro imaging.

Edited by Gina
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Been looking at the DMK_41AU02.AS_Mono at about 1.5 times the cost of a Canon 1100D, maybe a cheap set of filters at £73 and home made filter wheel. Sensor half inch, a bit smaller than the DSLR but no doubt a lot more sensitive.

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Sometime in the future I was planning to buy something like a Canon D1100 and remove it's IR filter for astro dedicated user instead of using my Sony A200 DSLR, but this thread prompts me to wonder if I might be better saving up a few months longer and getting something like the Atik 320E.

I'd be wary of the "E" range of Atik cameras. Sensitivity curves are quite poor in comparison to some of the other offerings out there due to the relatively small pixels. Someone at the astro imaging group I go to got the 314E and he's been less than impressed with it so far. If you want an Atik, I'd say the 314L+ is a far better cam for not much more money and worth saving and holding out for.

As for going for a Canon over the Sony.. The A200 uses the same SuperHAD CCD as the Pentax K10D I was using. This is also the same chip that can be found in one of the high-end Starlight Xpress cams (M26C). It's a great CCD sensor but could really do with cooling to get the best out of it for astro use as I found my darks were very temperature dependent. In the end, I left the camera's auto noise reduction feature switched on to ensure a perfect dark for each frame. Not ideal as this is at the expense of imaging time but did yield good results up to about 7 mins exposure time on a cold night. Beyond this the amp glow from the camera became too severe for it to deal with effectively.

In general though, a cooled astro cam is a massive step up from a DSLR. It's just a shame that the (relatively cheap and simple) cooling incurs a massive jump in price as well.

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Having spent some time with the Atik 314L now and having only done DSLR imaging before - I have to say that I am finding the CCD imaging as a whole really cumbersome and tricky. Not the imaging itself - that is absolutely fine, but the bit where you look at subs to check that you've exposed correctly. I find the .fits format very clunky and difficult to decide whether exposure is OK or if you could do with a few more / less minutes.

I am sure that it will come, all practice. Make sure you have something that will read .fits format and allow you to check exposures.

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Sara, good to hear you're enjoying the camera! I never worked with FITS so I wonder how tricky it will be. You say you want to check exposure? How do you mean. The reason I'm asking is that I was hoping to be able to just 'fire' away limited only by mount and guiding issues! You see people do 10 min subs and longer even, and exposure is no issue. Don't think I'd be able to make such long subs anyways.

Never used one though, do these cameras have all sorts of settings like ISO etc like a normal camera? Then I'd understand the problem!

/Jesper

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The CCD has no such ISO settings, you basically set the exposure and binning and off you go. Binning is a resolution thing if I understand it all correctly.

When I say exposure, I mean that for example with a DSLR I could take a 10min sub, look at the image in a raw processor and actually SEE what I had got regards to whether the image was under or over exposed. With the CCD format, unless I am being a complete twerp, it's not quite so simple.

I think now I have sorted it the following way. Take the image (10min for NB and 5 mins for RGB) and chack the brightest stars in Maxim to check that they are not saturated, hence losing star colour.

Edited by swag72
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Ok, hmm... Can't wait to start tinkering!

On another subject, I just got the SW reducer yesterday but clouds stopped me from trying it out. Are you pleased with it? Does it allow for APS size illumination like they say?

/Jesper

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In answer to the basic question 'DSLR to CCD, what awaits me?', I would say that for me, it has been regret and frustration.

Regret that even after spending spending £1000+ on a cam and filters, you are still only at the most basic entry-level with just 1392 x 1040 pixels to play with.

Frustration that, particularly with the British climate, you are so weather-dependent that you often don't complete a full Ha, OII or RGB set of images. And in any case the small sensor and my hopelessly inadequate processing skills means that the result isn't worth the effort anyway. Oh, for the simplicity and satisfaction of DSLR imaging. Obviously, though, not a problem with the bigger colour sensor of the SXVR-M25C.

Can you tell that I'm a bit disgruntled? Just had a huge income tax bill, which doesn't help, but I felt the need to vent my spleen.

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Luke, shame with the tax bill! I suppose I've taken some sort of median route here with perhaps a few more pixels and no filter trouble... But some argue that you can bin the RGB and do normal L - get a compromise - and in that way work faster than the OSC guys. Maybe you do that already!

Anyways I'll be slowest of the lot....

I've seen some of your work and it's worth it! Keep them coming!

/Jesper

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Oh you are going to enjoy your CCD :)

I went from DSLR to CCD and couldnt believe the difference in the depth of the image.

There are targets a plenty that will benefit from being OSC, not least of which M42 and M31 (I just had an M31 pic taken with a OSC camera chosen by Skywatcher to advertise their MN190 telescope:) ). Also clusters, globs, asterisms, comets, all these things are perfect for OSC.

And you can still use your OSC for narrowband if you wish. SteveL has had excellent results doing just that.

Can't wait to see your results!

Cheers

Tim

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