Advice on mono camera

[billyharris72]

Hi all:

I've been thinking about investing in a mono camera, but am struggling to identify the best option (not even sure there is one). I'm currently using a Nikon D3300. It needs to meet the following requirements:

1) It needs to be mono (obviously)

2) It needs a reasonably sized sensor (I'd be using it for a combination of Ha DSO imaging and differential photometry, so needs to be large enough to get the comparison stars in the field of view.

3) Be reasonably inexpensive (definitely under £1k, not including filters).

My eye keeps being drawn to the ZWO CMOS cameras. Would one of these (maybe the ASI 174) be up to the job? If so, how big a performance difference are we talking between the cooled and uncooled models? Obviously the latter will have more noise, but how would they perform with subs of 2-3 minutes?

Another though is are these CMOS cameras okay for photometry? They mostly have 12 bit ADU and I don't know over how wide a range they show a linear response.

Any advice very gratefully received.

Billy.

 

 

 

 

[wimvb]

For accurate photometry, ccd may be a better choice. Mainly because it is proven technology in this field. Cmos generally have more on chip dataprocessing that can interfere with photometry.

The ASI 178 has a 14 bit ADC, but the difference between 12 bit and 14 bit gets less important with stacking.

For DSO, you'd want a bigger sensor, unless you're mainly interested in galaxies and planetary nebulas, which benefit from small pixels in combination with a larger focal length scope.

QHY have the same type of cameras as ZWO, with a few benefits: improved amp glow reduction, and internal dew heater for the window.

For DSO imaging, you should definitely choose a cooled camera. DSO imaging is very much about getting noise under control, and cooled cameras will outperform uncooled cameras any time.

Since you're on a budget: check out the used gear ads here and on other sites.

[SonnyE]

To my knowledge, Billy, CMOS are better suited to Planetary and Solar.

Deep Space wants for a CCD.

As an owner of a less expensive CCD, I really, really wish for a better camera.

I quickly outgrew 'Cheap'.

BTW, my other camera is a D3300...

[billyharris72]

Thanks for the advice. I get the impression it's possible to do DSOs with some of the higher end mono CMOS cameras, but that the workflow is quite different (more subs, shorter). Which is both a bad thing and a good thing (e.g. easier guiding).

If I was to look at the CCD option is there a good camera in the price range I'm thinking of?

[swag72]

There's a whole host of mono CCD's out there and their prices do very much depend on sensor size. Use this FOV calculator to pump in popular CCD's alongside your scope http://astronomy.tools/calculators/field_of_view/ it will give you a really good feel for what the different sensors offer in terms of size. It will cement your thinking about what size you really do want and whether your budget can stretch to it!

I would say that the first thing to decide on is sensor size then after that which manufacturer you want to trust with your ££'s

Hope that helps

[SonnyE]

46 minutes ago, billyharris72 said:

Thanks for the advice. I get the impression it's possible to do DSOs with some of the higher end mono CMOS cameras, but that the workflow is quite different (more subs, shorter). Which is both a bad thing and a good thing (e.g. easier guiding).

If I was to look at the CCD option is there a good camera in the price range I'm thinking of?

That I don't know Billy. Yes, some of the CMOS cameras are showing promise for deeper objects. But I don't think (my opinion is) they are not quite where I would like to see them. Based on results from friends I've seen.

As for cooling of the sensor, if you have it, you don't have to use it. But if you do not have cooling, you can't try it. That said, I do always run cooling on my camera, even though it only is rated for a 10 degree C drop in temperature. Quite mediocre. But I'll take anything I can get. I'm not 'Mr. Moneybags' so I'm careful how I invest, as it were. I think my current CCD burned me, so I'm being much more careful before dumping money on the next try.

Some day the ad writers might even be perfectly honest, but don't hold your breath waiting for that.

 

[DaveS]

I may be wrong here but I think that for research grade photometry you'll need a camera without an Anti-Booming Gate, as that provides a "leak" to stop the spikes you sometimes see above and below bright stars. Not to be confused with diffraction spikes.

[billyharris72]

That's a good point about an anti blooming gate. I don't know that I'll ever be doing "research grade" photometry (any step up from DSLR would suit me) but while I'm looking it wouldn't hurt to bear that in mind.

[ollypenrice]

On a fairly recent post I suggested that photometry required a non anti blooming gate camera but a photometrist corrected me, saying that, within the mainstream brightness range, blooming gated cameras were pretty linear. On the other hand Marc Breton, who runs the nearby Observatoire des Baronnies, uses a non anti blooming gate camera for his exoplanet searches etc. So I don't know!

If you can find a decent sized mono sensor of good sensitivity for under £1000 please tell us because you will become the favourite son of SGL. I don't think it can be done, alas.

Olly

[Davey-T]

1 hour ago, ollypenrice said:

If you can find a decent sized mono sensor of good sensitivity for under £1000 please tell us because you will become the favourite son of SGL. I don't think it can be done, alas.

Olly

Don't suppose it would be under £1000.00 but I don't see why they can't mount 4 sensors as one in a CCD camera to make one big sensor.

Just need to process out the cross in the middle 

Shouldn't be a problem given the marvels of modern technology.

Dave

[wimvb]

1 minute ago, Davey-T said:

Don't suppose it would be under £1000.00 but I don't see why they can't mount 4 sensors as one in a CCD camera to make one big sensor.

Just need to process out the cross in the middle 

Shouldn't be a problem given the marvels of modern technology.

Dave

Given the problems some have with the Sony A7S, which has two sensors next to each other, I think it's waaaay easier to do a mosaic with a smaller single sensor.

[Davey-T]

2 minutes ago, wimvb said:

Given the problems some have with the Sony A7S, which has two sensors next to each other, I think it's waaaay easier to do a mosaic with a smaller single sensor.

Not if you only get a few clear nights a year 

I'm presently working on a triple imaging rig to combat the problem.

Dave

[London_David]

If you have a look in the EEA forums here and on cloudy nights you can find some great examples of DSO imagery using the mono ASI290 which is relatively inexpensive, ultra low noise and very sensitive. As someone mentioned above you can shoot lots of short subs and get some amazing results. With CMOS you don't need to rely on longer subs so much -- if your interested check this post out:

It's a slightly different thing to typical CCD photography but definitely something to consider. I have one and really like it. It's a good option particularly on a budget.

Check these out:

https://www.cloudynights.com/topic/567930-m87-relativistic-jet-and-other-galaxies-using-short-exposures/

https://www.flickr.com/photos/abbeyroadobservatory/sets/72157668589828735/with/26830497230/

Also, the Atik infinity and ASI1600 are worth checking out in your price range but I have no personal experience with them. There are some great videos on YouTube reviewing them, and images in astrobin.

 

 

[SonnyE]

23 hours ago, Davey-T said:

Not if you only get a few clear nights a year 

I'm presently working on a triple imaging rig to combat the problem.

Dave

Lord! If I only got a few clear nights a year, Astronomy would be far back in my hobbies.

Multiple Imaging Rig? How about this? Focus that.

 

https://petapixel.com/assets/uploads/2015/05/differentarrangement.jpg

[Davey-T]

10 minutes ago, SonnyE said:

Lord! If I only got a few clear nights a year, Astronomy would be far back in my hobbies.

Multiple Imaging Rig? How about this? Focus that.

 

https://petapixel.com/assets/uploads/2015/05/differentarrangement.jpg

By the time I'd got that working it would have clouded over 

Dave

[wimvb]

1 hour ago, SonnyE said:

Lord! If I only got a few clear nights a year, Astronomy would be far back in my hobbies.

Multiple Imaging Rig? How about this? Focus that.

 

https://petapixel.com/assets/uploads/2015/05/differentarrangement.jpg

... or get a filter wheel

[SonnyE]

1 hour ago, wimvb said:

... or get a filter wheel

Naw, no wheel needed wim,

Just put a different filter on each and fire them all at once.

Poof! Got it!

[billyharris72]

Thanks for the advice all - worth a try but it's pretty obvious there is no "perfect" option out there, especially not on my budget. Thinking I might go for the ZWO CMOS option and experiment to see what it can do.

Billy.