Watec vs CCD

[Andrew]

I’m thinking of getting into video astronomy to assist my observing (and combat light pollution) and I’d be grateful if anyone can advise me...

I’m trying to choose between getting a Watec 120n+ or a CCD camera (not really video astronomy I know) and I’m wondering which would work best? I realise the Watec would give more of a ‘live’ feeling to viewing (with the CCD I guess I would look at the image with zero/minimal processing). What I’m particularly interested in is the difference between a Watec and a CCD like an Atik in terms of image quality and image brightness. I assume that the Atik would give a better quality image (e.g., with something like the 314L+), but I’m wondering if the CCD would require a longer exposure time compared to the integration time used with the Watec. Does anyone have any experience of both CCD and Watec that would allow them to comment on this?

[steelfixer]

have you had a look at the Samsung series.

only around the £100 mark.

I have an SBC2000 and it is brilliant.

With its special features you get DSO's live and in colour.

just a thought.

graham

[Andrew]

Thanks Graham. I'll take a look at them.

[riklaunim]

Machine vision cameras like analog Watec or digital TIS DMK/DBK/DFK planetary cameras use low dynamic range and high framerate. DS cameras like Atik use high dynamic range and low framerate - minimalising noise.

Assuming TIS DMK or a Watec with high end frame grabber the difference in final image would be like "standard" M27 from DMK/Watec, and M27 with outer shell and not overburned core from a DS camera (like so: Astro Anarchy: M27, the "Dumbbell Nebula", reprocessed ones again)

[Andrew]

Thanks Riklaunim (very nice web site by the way).

Sorry if I have misinterpreted what you said - but does this mean that on bright DSO you would expect a DS camera to give less noisy and more detailed images than a Watec for similar exposure times, while on very faint objects the Watec would require shorter exposure times than a DS camera to be able to see the object at all?

[Ben Ritchie]

have you had a look at the Samsung series.

only around the £100 mark.

I have an SBC2000 and it is brilliant.

I have one too, and it's excellent value for money - and a very good way to try out video astronomy to see if it's for you without spending a lot (and, if it isn't, I suspect a SBC-2000 would be snapped up pretty quickly on the for-sale board!).

[riklaunim]

Sorry if I have misinterpreted what you said - but does this mean that on bright DSO you would expect a DS camera to give less noisy and more detailed images than a Watec for similar exposure times, while on very faint objects the Watec would require shorter exposure times than a DS camera to be able to see the object at all?

Nope. DS camera will always require long exposures to fill the 16-bit histogram. 8-bit histogram in machine vision cameras is "smaller" and can be filled with short exposures. High gain and short exposures of 8-bit cameras will give more noisy (lower SNR) frames than those from 16-bit DS cameras. Partialy it may be solved by stacking a lot more frames from a 8-bit camera, but some differences will still remain (due to noise or dynamic range).

[bhuvfe]

I have a watec 120n+ and lodestar C. The watec is great for astrovideo, you don't need a laptop, there's no processing involved but you may miss the color with some objects.

The lodestar is light and is connected directly to a laptop and you have a lot less wiring (no remote, no power cable, analog cable). The "live view" image is in BW and you can convert it to color later.

The processing involved takes less than few minutes. It has auto-dark/flat subtraction (something very nice if you don't want to look at too many hot pixels). There's this guy in UK with plenty of info about it astroman.org

For the moment, I don't feel there's a big difference in sensitivity between the two even if the monochrome watec should be intrinsically more sensitive.

But I got the lodestar last August and I still have to evaluate them on the same scope/conditions.

I use the lodestar when I want to record what I see or when color is important. The watec is mainly for visually assisted astronomy also because the image generally looks better live then when is converted to digital (probably because I have a cheap frame grabber).

The samsungs are very nice and great for starters on bright objects (I was bitten by the astrovideo-bug with a SCB-4000 looking at M 42). Unfortunately, after a while you will probably miss the unlimited integration for faint objects.

Clear skies,

Ant

[West End Wendy]

The watec is great for astrovideo, you don't need a laptop, there's no processing involved but you may miss the color with some objects.

When I bought my Watec one of the things it was sold to me on was that "you don't need a laptop". At the time I didn't really see any great advantage in this as I was using a laptop and a frame grabber anyway as my monitor. However I now see the ability to ditch the computer and use a dedicated monitor as a major plus. It makes the setup much simpler and takes the experience away from imaging and towards straight observing.

Tim

[Andrew]

Thanks everyone - I will take a look at the Samsung and the Lodestar C.

Do those of you with a watec use a guide camera as well or is that not necessary?

[West End Wendy]

Do those of you with a watec use a guide camera as well or is that not necessary?

Not necessary. The maximum preset integration time is 10.24 secs and for that duration even the most basic polar alignment will do.

If you're using the unlimited integration mode then you're more dependent on good polar alignment of course, but 30secs to a minute is certainly possible without guiding.

Ditto the Samsung but that cam does have a noise reduction system which would benefit from guiding if you wanted to go down that route.

Tim

[Ben Ritchie]

The Samsung with NR mode appears to be fine at 1040mm focal length with my reasonably well aligned but unguided EQ6 (...assuming i've turned NR on correctly...!).

Having to actually guide would reduce most of the attraction for me, if i'm going to do that then I might was well integrate for 5 minutes and start conventional imaging. It's a plus side of video though that the immediacy of it all rather compensates for any imperfections in tracking, noise etc. that might spoil conventional images.

[Psychobilly]

I chucked my CPC back on the pier/wedge in the obs last night and after a 3 star align the wedge align routine reckoned it was -4mins out in azm and +6 in Alt seemed fine unguided...

Seeign as the scopes will be back off again at the begining of November I didn't se the point of fine tuning the alignment...

Peter...

[West End Wendy]

The Samsung with NR mode appears to be fine at 1040mm focal length with my reasonably well aligned but unguided EQ6 (...assuming i've turned NR on correctly...!).

That's interesting. I have an EQ-5 with a simple RA drive and it definitely doesn't track well enough to give good results with the Samsung NR.

I assume the EQ-6 has some sort of periodic error correction, is that the difference?

Tim

[Ben Ritchie]

The EQ6 has PEC, I think, but I've never used it - just standard tracking in sidereal mode.

Sent from my iPhone using Tapatalk

[West End Wendy]

Maybe the EQ-6 has inherently better tracking than the EQ-5. I'll try that NR again next time I get an opportunity.

(Sorry to hijack your thread Andrew)

[Andrew]

(Sorry to hijack your thread Andrew)

Don't worry - it's all interesting to me since I know nothing about either the cameras or mounts yet (up to now I've been strictly a dob user)