585mc or a6000 for DSO with 8" F5 unguided?

[Michael_Bibby (Michael)]

I have a 8" F5 (1000mm) Newt on a belt modded Heq5 pro and am interested primarily in DSO.

Given the fact that I'm pushing the weight limits of my mount, and I aren't using a guidescope, I will be limited to short exposures (between 1 - 30 sec). Which camera will make the most of these limitations: the Zwo asi585mc/player one Uranus C or the Sony a6000? And why? I know the 585 has 2.9um pixels and the a6000 has 3.88um which would be more suited to my focal length, gather light faster and be more forgiving of tracking problems, but what other factors/specs should I consider?

[Michael_Bibby (Michael)]

I'll reply to myself: the a6000 desn't work with SharpCap, which is a problem...

[Startrek (Martin)]

The ZWO585MC is a planetary camera and not suitable for DSO imaging in your 8” newt
Some cooled OSC cameras suitable for your 8” Newt for DSO imaging are -

ZWOASI171MC

ZWOASI533MC

ZWOASI294MC

ZWOASI2600MC which I use in my 6” , 8” and 10 newts

Or alternative in QHY brand

The above cameras will work with most acquisition and capture software Sharpcap , APT , SGP and so on ……..

For selection of camera for your telescope you should calculate FOV and Image Scale for your proposed set up ( refer to “Astronomy Tools” to calculate FOV and image scale )

FOV refers to framing the object you want to capture in the field of view

Image scale refers to sampling ( ideally you should be between 0.60 to 1.20 arc sec per pixel or “oversampled” to take advantage of Binning )

Then there’s filters for Narrowband imaging

I strongly recommend you look into guiding ( PHD2 ) at some stage , it’s not that expensive or difficult to set up and do. You will soon get frustrated with short exposures especially if your located under darker skies ( outside City /suburban areas ) All you need is a guide camera , guide scope and cable , PHD2 is free software
Improving or tightening your polar alignment down to 1 arc min will only allow 50 or 60 sec max exposures with that 8” newt depending on your mount ?

If you have a tight budget then opt for a second hand Canon or Nikon DSLR camera with an APS C sized sensor ( not full frame ) for your 8” newt.I used a Canon 600D for 3 years
Capture software like BYEOS , BYNIKON or APT for DSLR’s are excellent

Hope the above is helpful

Cheers

[floyd_2 (Dean)]

Originally Posted by Michael_Bibby

I'll reply to myself: the a6000 desn't work with SharpCap, which is a problem...

Hi Michael. You can get the A6000 working with Sharpcap. That's how I started off down the slippery slope into AP. If you decide to use your A6000, PM me as I documented the full setup procedure and have all drivers etc needed to make it work.

[Michael_Bibby (Michael)]

Originally Posted by floyd_2

Hi Michael. You can get the A6000 working with Sharpcap. That's how I started off down the slippery slope into AP. If you decide to use your A6000, PM me as I documented the full setup procedure and have all drivers etc needed to make it work.

Thats interesting Floyd. I looked at a lot of forums and it seemed like no one could quite get it to work. I've decided on the 585 sensor which seems better suited to shorter exposures (EAA/EEVA etc.). Thanks for the offer!

[nikanj (Andy)]

The a6000 is listed as supported on this ASCOM driver. I got started with an a7II using this same driver though I was using NINA rather than SharpCap. It worked flawlessly for me.

https://github.com/dougforpres/ASCOM...ported-Cameras

To answer your question your a6000's APS-C is far better suited to DSO than the 1" sensor in the 585mc. The FOV on that camera with a 1000mm focal lenght scope would be extremely tight.

What I reccomend is downloading Stellarium and entering the details of all the sensors, scopes and reducers/extenders you want to compare. You can then simulate the framing of various target's you're interested in imaging.

[Michael_Bibby (Michael)]

Originally Posted by nikanj

The a6000 is listed as supported on this ASCOM driver. I got started with an a7II using this same driver though I was using NINA rather than SharpCap. It worked flawlessly for me.

https://github.com/dougforpres/ASCOM...ported-Cameras

To answer your question your a6000's APS-C is far better suited to DSO than the 1" sensor in the 585mc. The FOV on that camera with a 1000mm focal lenght scope would be extremely tight.

What I reccomend is downloading Stellarium and entering the details of all the sensors, scopes and reducers/extenders you want to compare. You can then simulate the framing of various target's you're interested in imaging.

Thanks Nikanj, yes, I've been using Stellarium and other online tools to simulate framing. I guess what I have learnt since asking this question is that what I am wanting to do is basically video astronomy/EAA/EEVA. I've opted for the 585 for its low noise and good dynamic range at gain's that should give me decent images at short exposures (between 1-30 seconds, depending on what my mount can bear). My main concern is oversampling with the 2.9um pixel size at bin1, and the read noise at bin2. I think this camera would be better for sub 750mm focal lengths under most seeing conditions, but I'm hoping though that I can get good results with this setup under very good seeing conditions.
I've already ordered the camera to throw myself in the deep end (having only had experience with visual astronomy). I will try and get a hold of a 150p in the near future too for doing more serious astrophotography, and I'm pretty confident that the 585 should pair well with that scope. But I'm looking forward to seeing what results I can achieve with my hulking 8" F5.

[Startrek (Martin)]

Michael,
I had no idea you were only interested in EAA as you made no mention of it ( only DSO ) , otherwise I wouldn’t have rambled on about long exposure AP
Also assumed you were totally new to Astro

All the best and good luck with your future set up

Clear Skies
Martin

[Michael_Bibby (Michael)]

Thanks for your info Martin, I'm throwing myself into the deep end and learning very quickly as I go.

[Camelopardalis (Dunk)]

Michael, the 585 is a cracking planetary sensor too…get yourself a 3x Barlow and point your scope at the bright planets we have on offer this Spring.

Your biggest challenge at 1000mm focal length IMO is going to be your polar alignment. There are software polar alignment routines these that can reduce the amount of time it takes to nail it, but you will want to nail it at that focal length…as that will be your limiting factor in practice.

[Michael_Bibby (Michael)]

Originally Posted by Camelopardalis

Michael, the 585 is a cracking planetary sensor too…get yourself a 3x Barlow and point your scope at the bright planets we have on offer this Spring.

Your biggest challenge at 1000mm focal length IMO is going to be your polar alignment. There are software polar alignment routines these that can reduce the amount of time it takes to nail it, but you will want to nail it at that focal length…as that will be your limiting factor in practice.

Thanks Camelopardalis, I'm just finishing off building a pier to attach my mount that should make polar alignment much easier, and with platesolving I should be able to get a consistently good alignment. And I already have a 2.5x barlow, which gives me pretty good views of the planets.

[Camelopardalis (Dunk)]

Going forwards, you could always add an OAG + guidecam to your rig, wouldn’t add much weight, and would open the door to longer exposures.

[Michael_Bibby (Michael)]

Yup, thats exactly my thinking at the moment too, OAG to keep the weight down and as I understand it, OAG would give me more precise guiding (assuming enough stars in the FOV) than with a guidescope.

[Camelopardalis (Dunk)]

Not necessarily. It gives a theoretically higher resolution view of the guide star. This has pros and cons. Ultimately it depends on how well your mount responds to guide pulses. This is where balance is key, more so than absolute payload.