Entry level DSO ccd recommendations?

[icebergahed]

Hi

I have been using a dslr for a while now and have started to look at dedicated cameras.

I have a Nexstar 6SE alt/az which i know is the wrong mount for astrophotography however ive been quite happy with my dslr results. I would just like to bring it to the next level.

I plan on getting a wedge and guide camera which is the bit i can figure out. But when it comes to the imaging camera i have no idea. Prices range from £100-£3000 with tech specs that only a scientist would understand. Some cameras are labelled "planetary" imagers?????

There seems to be no clear guide and scale of what you are getting.

So if i have a budget of around £300 what would be your recomendations?

 

[Pieter]

I just read a good article about the typical question "monochromatic vs colour"-ccd:

https://photographingspace.com/colour-vs-mono-camera

Could come in handy when making that decision. No exp on the rest, sorry.

[kens]

If you are stepping up from a DSLR you should aim for a cooled camera as that will be the major difference from a DSLR. If you are imaging with light pollution consider a mono camera as it will let you do narrrowband imaging. 

Planetary cameras are oriented towards taking videos at high frame rates for lucky imaging. DSO oriented cameras are cooled to reduce noise on long exposures. 

Given your budget, you'll find you can only get a camera with a much smaller sensor than your DSLR so it wont have as big a field of view. Infact, looking at ZWO's offerings their cheapest cooled camera (colour) is over GBP 600

You are probably better off making the changes you mentioned and just stick woth your DSLR till you can spend a bit more. Even then, a solid mount would be a better next step. Or maybe look around for a second hand HEQ5.

[Adam J]

Sorry to say this but at 300 pounds the DSLR is your best bet for astro-photography. Your 6SE on an alt az mount is not s good combination for astro-photography and I suspect that it is more the limiting factor for you as opposed to the camera. You should look for a second hand HEQ5 mount and SW ED80 as suggested above, if imaging is the direction you want to go in then I would sell the 6SE to fund this.

[London_David]

A lot depends on what you want to see and do. 

As you say, your setup is not the right mount for astrophotography. With an alt/az mount you are closed off from long exposure photography. However, new low noise sensors and stacking get around some of that. You should get up to 30 second exposure okay on your mount. You just need a sensitive low noise camera. 

The wedge and guide cam can also help with that, but then that’s expensive equipment when you only are leaving 300 for the camera — if you want to buy the new camera. The wedge and guider will help with the dslr imaging.

I’d be thinking the other way around. What do you want to image with your upgrades. figuring out the right camera for that, then worrying about what else you need to get the best out of it. You can also practice easier things with the right camera while saving up for the other stuff.

First, I’d go to http://astronomy.tools and use the field of view calculator to see what kind of things you can image with a new camera and your DSLR for reference. You can pick various objects to get a sense of what you might see with your combination  

Your scope is 1500mm @ f/10, that’s pretty slow for everything except planets. I’d look at a focal reducer or even a hyperstar to get your speed up. Since your just starting I’d look at a ts optics 0.5 reducer for about £50 which will get you to f5. 

So I suggest putting in your scope and a focal reducer into astronomy.tools and playing around.

But what camera? As mentioned it’s worth checking out if you’re interested in mono and filters or colour. Also, what is the reason for upgrading... I know you say take it to the next level but that can mean many things!

From my experience I really like the zwo cameras. They’re very good value and have the latest tech.

In the lower cost budget range with your scope I think the ASI224, ASI385, and ASI294Pro are the best colour cameras around right now, and the ASI290 is the best mono.

The 224 is a small sensor, the 385 is a bit bigger and the 294Pro bigger still - getting similar in size to a dslr (its pretty much a micro 4/3 size).

The 294Pro is cooled and is really great. It has a very low noise, meaning the sensor doesn’t create a false signal, it has very high sensitivity meaning that if a photon hits the sensor it will detect it, and has an extremely high full well capacity meaning that it has a high dynamic range. It’s also cooled so the noise is lowered even further. I’d strongly recommend that camera even if it is outside your budget, it’s the best bang for buck around right now. Especially if you are used to a dslr it will really feel like a upgrade.

The only thing I wonder about the 294is if the nexstar 6 can fill the sensor without vignetting. However, if you’ve been having no problems on a dslr (I assume it’s an aps-c) the 290pro should be fine,  though — you’d have to check for this. 

Going back to sensor specs and how to read them — The key specs to look at in a camera are read noise, qe and full well capacity. Read noise is a measure of how clean the signal is from the sensor, so if it is 1e then on average 1 electron gets fired off as a false signal per unit of reference. Qe is a measure of how sensitive the sensor is to photons that hit it, eg. If qe is 80%, 80% of photons that hit the sensor create a signal. Full Well Capacity is how much dynamic range there is before the sensor overexposed. You want the biggest full well capacity, the highest qe, and the lowest read noise.

But also remember never to just trust specs when you’re buying!

I fear that if you’re happy with your dslr you may find most £300 astronomy cameras a little disappointing. At that price point the one thing they have is higher sensitivity than a dslr but at the expense of a smaller sensor. They are however, far more sensitive than your dslr (unless you have a Sony a7r then nothing will impress you in this price bracket). The 224 and the 385 are similar in performance. Using short exposures and stacking even on your altaz you will be able to see galaxies and other dso’s. The 290 is more sensitive but again it’s a small sensor and mono. Search Flickr and astrobin for these cameras an you will see the kinds of thing you can get. 

There are other manufactures than ZWO with some great cameras, and other things that might make you purchase - atik has great software, as does Starlight xpress. But ZWO currently seems to be in front on camera tech and SharpCap is great software to use too. 

So the quick answer to your question is, for £300, I’d buy an ASI224 and a focal reducer, but while you’ll see an improvement in how deep you can see, and the ease of use and speed of seeing it, you may be disappointed with the actual images. With a little more money the focal reducer and the 385 for a bit more field of view. 

However, I’d suggest the asi294pro is where you’ll really notice a big upgrade from a dslr all round, and if you can put together the money, I’d wait to buy that. 

[ollypenrice]

I would start the entire thought process again and not put cash into the 6SE. You will be very lucky to get it to guide well enough, it will be an indifferent performer on deep sky even if you do and wedges are expensive, with low residual values because the trend away from them is one way. (I have never heard of anyone going from German Equatorial to wedge, the the other direction being commonplace.) The alt-az SCTs are great scopes for visual. We have one here - but there are no plans to fork mount it for AP. I made that mistake once before!

Second hand kit is the great way to save. 

Olly

[happy-kat]

Change your budget from £300 to £30 buy a dove tail or similar mounting bar, take that 6SE off that mount and fit the DSLR using a camera lens straight to the mount. A great length lens is say 135mm or just use the kit lens you already have. That is the cheapest way I think to further improve what you are doing before you decide how big a jump you want to make into imaging.

[Tangoringo]

I was in a similar boat about a year ago with only a small etx 105 for visual viewing so can empathise with your predicament. After asking a few questions on here and doing some research I came to the conclusion that ( as Olly mentions above ) I would be throwing my money away pursuing this route. Patience ( and a bit of luck ) is definitely required if you are looking on the second hand market but it is worth going down this track. I was fortunate to find a used WO Megrez 90 and an HEQ5 pro for £400 at an auction in the West Country. That was then followed up by an ST 80 guidescope from the classifieds here ( for about £70 ) and a second hand SBIG 8300cfrom astromart ( around £500 ) This was my big investment but flogging a load of junk from the attic on flea bay got me most of the way there. Chuck in a qhy II guide came and my entire imaging kit cost only a smidge over a grand. 

Sticking with a DSLR will still give good images and it will take you a while to sort out   Getting to grips with your eq mount and guiding. Then you can save a bit more cash and start improving your imager. Baby steps as they say.

The point of this is to say that you don’t have to buy new and you do need to be patient but don’t throw your hard earned money away to buy the newest or latest gizmo or continuing down a dead end alley can be costly. You can get stunning images ( not mine btw! ....yet ) for relatively small amounts especially if slowly built up.

All this being said, youve started on the correct route. Keep asking questions on here. There is a wealth of knowledge and experience ( and bruised wallets ) to guide you down this route and help you avoid the pitfalls. I’m still in a similar position to you, being on the first rung of a very tall ladder, but it helps to have people alongside you to guide you up. Just keep taking those little steps and good luck.

[SteveNickolls]

Hi icebergahed, thanks for your post. From what you say you have already got the imaging bug using your Alt-Az mount so are prepared to expand horizons. As you know imaging can absorb any amount of money and you could still be left wanting something better/newer etc. In some ways your lack of money to go on a spending spree is a useful check allowing you to decide where you next really want to venture into as much as that is possible.

You are doing right getting advice.

I would say a new camera is the wrong way to go right now, use your existing camera and as happy-kat says use it with whatever lenses you already have.

I am in the same circumstance to you and have found the jump from Alt-Az to a SkyWatcher Star Adventurer (SA) mount via a home made barn door tracker has been a fascinating experience and given me, for modest outlay, a big jump in imaging. Have a look on SGL at what others have produced using this little cracking mount. It costs £269 from our sponsors for the SA astro-bundle, so within your budget. The mount needs a suitable tripod but the mount is lightweight and portable. You will be free from the constraints of Alt-Az in terms of field rotation and what direction and altitude you can perform reasonable exposures to. I don't know what your local light pollution is like. If you have dark skies you will love the improved images from the SA, if you have to contend with light pollution at some point a filter, even going to a Ha filter will open up longer exposures. I bought my SA last April and after acquiring an Astronomik clip-in Ha 12nm filter for Christmas have been taking exposures of up to 15 minutes with nice results on some nebulae.

Over time as you amass savings for the hobby you can decide where to travel on to the imaging adventure. 

If you do go down the route of mount + DSLR camera and lens have a look at these sites for inspiration and reassurance over future lenses purchases-

http://www.astropix.com/html/i_astrop/lenses.html

https://www.lenstip.com/lenses_reviews.html

Good luck whichever way you decide to venture into.

Best Regards,
Steve