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Galaxies and smaller DSO's


Phillyo

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Afternoon all,

Well so far I've only imaged nebula and wide field stuff using my gear (which I'll list below), however I'd really like to get some pictures of some Galaxies and smaller/more distant DSOs and for that I'm going to need some new gear. However, what gear? That is my question.

Current setup:

Avalon Linear Fast Reverse

Star71

QSI583wsg

Astrodon 3nm Ha and Astronomik 12nm OIII and SII.

Lodestar X2 guiding

Software, I think is immaterial.

So does anyone have any suggestions? I'm going to say the mount is fine, as is the guide camera. I know I'm going to need some LRGB filters, but will I need a new camera or will the 5.4um pixel size be ok with the 583?

I guess the first question people will ask is budget.

Lets keep it under a grand if possible?

Thanks,

Phil.

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Another vote from me on an RC. I picked up a nice carbon fibre 8" with feathertouch focuser, losmandy bar and a reducer for well under £1000.

If you are thinking of dual mounting though, I'd say think again. Been there, done it on the Avalon and decided that a single mounting was better all round.

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Pixel size in another where there seems no "solid" rule.

Recall trhat on the SBIG site they said 1 arc second = 1 pixel.

So one that basis the Star71 (350mm) means a pixel size of 1.7um. Now that is small. Smallest I have listed is the Atik 450L at 3.54um.

Next is that then lots of people say bigger and if you use 1 pixel = 2 arc sec the the Atik 450L just suits the Star71, but they cost over the budget. The Atik 420 and 320 are 4,4um and fall in below £1000. The 450L is around the £1400 price

I could see you wanting a smaller pixel size but how about just using the setup as you have and see what comes out of it. Lets face it if it works then it works and you can take time to decide based on the images obtained.

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Thank you all. I have had a look at the 6" and 8" RC but wasn't really sure what I was looking at. Are they fast enough? I'm guessing a FF/FR is required anyway so that'll speed things up a bit. I'll head on over to 12D string and look at some targets to get an idea on FoV.

Sara, no probably not dual mounting, at least not side by side. I saw on your website that you'd tried that but decided against it. Perhaps one on top of t'other? Not sure yet but that's a worry for another day. I set up each night anyway so setting up one scope is the same as another (within reason).

Phil

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Thank you all. I have had a look at the 6" and 8" RC but wasn't really sure what I was looking at. Are they fast enough? I'm guessing a FF/FR is required anyway so that'll speed things up a bit. I'll head on over to 12D string and look at some targets to get an idea on FoV.

Sara, no probably not dual mounting, at least not side by side. I saw on your website that you'd tried that but decided against it. Perhaps one on top of t'other? Not sure yet but that's a worry for another day. I set up each night anyway so setting up one scope is the same as another (within reason).

Phil

Focal reducers for RCs can be hard to get. APM does still have one suitable for the GSO 6" and 8":

http://www.apm-telescopes.de/en/optical-accessories/flattener-reducer-correctors/astro-physics-ccdt67-0-67x-reducer-2-e-g-gso.html?info=3430

This would yield F/6 in the 6" and F/5.36 in the 8" model. Not bad at all

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Dare I mention the ubiquitous 190 mak-newt? 1000 mm fl and f/5.3. FLO have it for just under the £1k mark, though I suspect you'll need a better focuser. This is from what I've read on these forums, I don't yet have one, and won't until I get a better mount.

Oh, and no nasty spikes as you'd get from a RC design.

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Purely on a personal note I would think long and hard before jumping to an MN190. Don't get me wrong, people love them and there's some great pictures, but for me, when I had a focal length of 975mm (I think it was on an ED120) it just wasn't long enough for the smaller DSO's and galaxies that I wanted.

A field of view calculator is your friend! Along with many hours looking at all different combinations.

The 8" RC is slower compared to what I am used to. I am using it native at 1600mm - A most pleasing focal length for me and I love it. I've got the reducer for it, but can't image that I will ever put it on.

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Afternoon all,

Well so far I've only imaged nebula and wide field stuff using my gear (which I'll list below), however I'd really like to get some pictures of some Galaxies and smaller/more distant DSOs and for that I'm going to need some new gear. However, what gear? That is my question.

Current setup:

Avalon Linear Fast Reverse

Star71

QSI583wsg

Astrodon 3nm Ha and Astronomik 12nm OIII and SII.

Lodestar X2 guiding

Software, I think is immaterial.

So does anyone have any suggestions? I'm going to say the mount is fine, as is the guide camera. I know I'm going to need some LRGB filters, but will I need a new camera or will the 5.4um pixel size be ok with the 583?

I guess the first question people will ask is budget.

Lets keep it under a grand if possible?

Thanks,

Phil.

With the exception of M31 and perhaps M33 the rest of the more popular galaxies are far too small for any scope of less than 700mm FL. To go deep on the more popular ones you'd need something in the region of 1000 mm of FL and with this you'd be imaging at roughly 1 arcsec/pixel with your present camera which is ideal as with galaxies as you'd have the option of binning the RGB and then L @ 1X1 or just doing long subs in RGB @ 1X1 and ditching the L but using a synthetic L  ( derived from unbinned RGB ) in the mix and I believe that this method gives a slightly less noisy final image. So in short you do not need a new camera but perhaps a fast scope of about 1000mm of FL. The choice depends on how deep your pocket is.

Regards,

A.G

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