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How far to go with imaging?


ianpwilliams
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I've only done four unguided imaging sessions so far (Andromeda and Pleiades twice), and I'm trying to work out how deep I can afford to go with imaging. I was hoping that I could start out by getting as many targets as possible unguided, and then move to a guided setup later. But now I'm wondering.

I had to get help from here with processing my Andromeda and Pleiades stacks, and now I've downloaded the PixInsight demo, and I'm trying to process them myself while following Harry's tutorials. But I'm now told that really I need a 64-bit PC rather than a 32-bit one, otherwise I'm running the "obsolete" 32-bit version of PixInsight. So that's £175 for PixInsight, plus maybe £500 for a 64-bit laptop.

Then there's the guiding issue. If I wanted to upgrade to a guided setup, then I estimate I would be looking at about £500 for a guide cam and scope. But the question is, would it be worth me going guided, bearing in mind that I can't have a permanent setup (shared garden), I have light pollution, I'm restricted to the garden (no car), and I'm restricted to battery power rather than mains?

I need to think ahead, because if I can't go guided later, then maybe buying PixInsight and a 64-bit machine might not be worth it either, and maybe I would be better off buying an Astrotec or similar and doing wide field images instead. I would prefer that not to be the case now that I have my HEQ5 and 130PDS, but maybe I have to consider it.

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Suppose it comes down to what do you want to produce.

If you re looking at the semi-professional astrophotography level then you will need to go up.

Would it not be possible to improve by a different route?

Being sort of "blunt" a good imager that gave a talk around here simply pointed out that a DSLR was for holiday snaps not astrophotography. The person he said this to was not overly pleased but Canon make cameras for hoilidays, Atik make cameras for astrophotography.

It may be that you sit down and identify the weakest item in your imaging setup then improve that. If the DSLR were the weakest then new software is not going to suddenly make that a brilliant astroimaging camera.

How good is the scope, is another question.

Any other imagers around that you can talk with, and discuss everything - immaterial of how painful.

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IMHO, guiding is one of those things that make a MASSIVE difference (the next is using a CCD). You will lose far fewer subs to trailing, and the subs you collect will be of better quality. Both of these things are vital when having to set up each night as it maximises your imaging time. You can drastically increase your sub exposure length, which means higher quality data as there is more signal to noise. Finally, guiding is virtually compulsory if you get into narrowband imaging as the sub-length is normally 10+ minutes (20 minutes is the minimum that I use).

You can make a finderguider quite cheaply. £30 for an adapter and £100 for a 2nd hand QHY5 (if you can find one). The software is free (PHD).

Yes, a CCD will give better results, but DSLRs can give excellent results too. They work best with dark skies and a fast focal ratio (f4 or better) to ensure that lots of signal gets through. But it'd be wrong to dismiss DSLR imaging out of hand.

Edited by Zakalwe
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Guiding need not cost you £500...

QHY5LII (Colour) from Modern Astronomy for £184

BST Finder Guider from 'SkiesUnlimited' on ebay for £75 (http://www.ebay.co.uk/itm/BST-Starguider-50mm-Mini-Guide-Scope-Set-/380988676194?pt=UK_Telescope_Eyepieces&hash=item58b4b1d862)

I guide with this combo and can get 1-1.5" RMS errors regularly.

Unless you are dead set on PixInsight, consider using APT, DeepSkyStacker, Gimp, etc - all free or cheap and should be Ok on your 32 bit laptop (as long as you have 3 or 4gb of ram).

cheers,

Robin

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If it's any help in your decision making I have posted a DSLR image here http://stargazerslounge.com/topic/232850-heart-with-modded-canon-1200d/

which will give you some idea what to expect with a guided DSLR. It's not great but I am happy with it. It depends how good you want it to be. I should point out that the DSLR is Astro Modded. I guide with a QHY5 and an Orion mini guide scope.

Peter

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So it seems that upgrading to guided might be cheaper than I thought. And with a finderguider I reckong that not being a permanent setup might be doable. I did worry that guiding might not be worth it with having light pollution, but I have seen what can be done with processing.

When it comes to processing, I have got GIMP, but I never seemed to be able to get results with it, because although GIMP has histogram, colour curves etc, it doesn't have DBE etc, so I'm not sure if I could produce anything with that (I don't have Photoshop with Gradient Exterminator either). But seeing as upgrading to guiding is cheaper than I thought, I would be prepared to pay for PixInsight (although the 32/64 bit issue still remains).

So it looks like upgrading to guided might still be worth driving towards after all.

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If it's any help in your decision making I have posted a DSLR image here http://stargazerslounge.com/topic/232850-heart-with-modded-canon-1200d/

which will give you some idea what to expect with a guided DSLR. It's not great but I am happy with it. It depends how good you want it to be. I should point out that the DSLR is Astro Modded. I guide with a QHY5 and an Orion mini guide scope.

Peter

That's a lovely image. I was never expecting hubble-standard images from my setup, and what you've got there is probably higher than what I would be aiming for. More than anything I know that my choice of targets is very limited with an unguided setup, but that a guided setup could open up a whole new world of targets to go for. Edited by ianpwilliams
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Have a look also at AstroArt V5, I think it was £125 from FLO.

Regarding the shared garden, could you (Would you be allowed to) sink three small paver blocks into the lawn (if there is one) so that it's a little below the level of the grass? Then you could put three dimples in it that you can locate the tripod legs of your HEQ.? It Would make setting up a whole lot quicker.

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I've actually got blocks out there already, with masonry paint marks for the feet based on pointing to Polaris, and marks on the weight bar etc too, so I can set up a level and balanced mount quite quickly. I'm also hopefully going to be able to store the mount in my landlord's shed soon, which will also help greatly.

And thanks, I'll give AstroArt a look.

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I started guiding with a QHY5, a copy of PHD, and a finder scope adapter (£28 from Modern Astronomy) to convert the finderscope I already had to a guide scope.  I can still use the finderscope as a visual finderscope as the beauty of the adapter is you can just unscrew it and screw the eyepiece back in when you need to.

I used an old laptop to guide with and can get 10 mins subs now with my setup.

I recently upgraded my laptop to a 64-bit Lenovo T420, which came with 1600x800 screen, 8gb ram and i5 processor for £260.  It was a refurbished laptop, but you would not know it, so you can get a decent spec laptop for way less than £500 if you need to.  http://www.scan.co.uk/products/141-lenovo-4180a32-b-intel-core-i5-2520m-25ghz-8gb-320gb-hdd-dvdrw-bluetooth-windows-7-professional-

So potentially you could be all set up for £175 PixInsight, £260 laptop, £210 for guide scope and adapter, so er £645 for everything......

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I can use gradient exterminator with paintshop pro and also that hldv plugin also talked about and it has adjustment layers and masking.

I know nothing about this but if you have that much light pollution then is it realistic to use 20 minute guided subs? Won't that just be one wash out image with no data left in it to actually process?

Why not look at Louise's threads as Louise had lots of lp in Glasgow and see what Louise is doing.

Edited by happy-kat
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I think guiding is more important than new laptop / Pixinsight, I managed perfectly OK with old laptop Win XP and star shoot autoguider for years, Pixinsight is a step too far for me, if you have money to chuck at the hobby then all well and good otherwise you can manage quite well without it.

Dave

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I know nothing about this but if you have that much light pollution then is it realistic to use 20 minute guided subs? Won't that just be one wash out image with no data left in it to actually process?

I use 20 minute subs, but only with narrowband imaging. Imaging in H-a (and ideally with a mono camera) is a great way to co through light pollution. Because narrowband filters block so much light, 20 minutes subs are necessary to get a decent signal.

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It's a relief to hear that there are people even more 'hard line pro-CCD' than I am! While I do think CCD is the way to go I can easily concede that you get a lot of chip for a low cost with a DSLR. I wouldn't worry about 32 bit or the latest Pixinsight. These are refinements but in an entry level setup surely guiding is the first step. I spent the first years working with an 8 bit Photoshop and nobody said anything.  I would also describe the transition to 16 bit as mildly underwhelming. 

Keeping to short focal lengths makes the tracking issue so much easier. There's a lot you can do with camera lenses which are also often nice and fast.

Olly

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Yeah, 230 euros is about £180 now due to the weakening euro.

On the website it says:

"Users from Eurozone member countries must pay an additional 21% VAT rate. The final price for Eurozone users is 278.3 Euros, taxes included."

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