What camera to buy for my scope

[Al8819]

Hello everyone!

I'm very new to the hobby and need some advice. I have a celestron nexstar 127 slt and plan on mostly doing planetary and solar imaging. What are some good ccd or cmos cameras that would pair well with my scope and intended targets? My budget would be less than $500. All advice is appreciated.

[vlaiv]

Hi and welcome to SGL.

Depends on your priorities.

If you are going to shoot H-alpha solar, go with mono sensors, otherwise, you might find that OSC sensors (one shot color) are far easier to use.

You need low read noise, good quantum efficiency and fast download rate CMOS sensor for best results.

Best color sensor for the job is currently ASI385 (or other vendors with same sensor - I know ZWO cameras, so I'll list ASI models, but other vendors have cameras with these chips as well), followed by ASI224.

If you plan doing Lunar and Solar, then size of chip matters - for planets all sensor sizes will be good enough since planets fit on even smallest sensors.

In mono variety, you have following choices: ASI290 and ASI178.

Choose one with USB 3.0 connection rather than USB 2.0 since it will provide you with needed download rates for high fps.

[Al8819]

Hello Vlaiv,

Thank you for the warm welcome and suggestions. Could I still take color photos of the planets using planetary filters with a monochrome camera? Or would I basically be stuck capturing monochrome planetary photos? If I can use a monochrome to take color planetary photos using planetary filters then maybe I would go with monochrome and take h-alpha solar photos too. If not, then perhaps ASI385 color option would be a better choice?

[vlaiv]

Just now, Al8819 said:

Hello Vlaiv,

Thank you for the warm welcome and suggestions. Could I still take color photos of the planets using planetary filters with a monochrome camera? Or would I basically be stuck capturing monochrome planetary photos? If I can use a monochrome to take color planetary photos using planetary filters then maybe I would go with monochrome and take h-alpha solar photos too. If not, then perhaps ASI385 color option would be a better choice?

Yes of course, you can take LRGB / RGB type of images with mono camera and filters / filter wheel.

It is however much more expensive and involved option. Having two cameras could actually be alternative - one mono for solar H alpha / lunar (sometimes lunar imaging can benefit from mono camera as there is no much color on the moon) and one color for the planets.

When doing planetary imaging you have limited time window - like 4-5 minutes to do single session. This means that shooting with filters / mono you will have something like 1 minute per filter, or that you will have to switch filters every minute until you cycle them all.

If you have manual filter wheel - that means a lot of wasted time. If filters are not par focal - again more wasted time.

This is because when you want to switch filter, you need to. Stop your capture, manually turn filter wheel, wait for scope shake to settle, adjust focus if your filters are not par focal, then start another recording run. You need to repeat this procedure 2-3 times depending on whether you are shooting RGB or LRGB image.

All of that can be avoided if you purchase par focal filters and automatic filter wheel - but for that sort of money, you can get a color camera instead (even simple filter wheel and set of basic interference filters will cost something like $200-$250, and color camera is not going to cost much more - you can get ASI224 for $250 from ZWO - not sure about shipping and import duty though).

If you are really tight on cash - just go with color camera instead. You will still be able to shoot Ha with it. It will only use about 1/4 of camera's pixels (only red channel) - so you will need to barlow it a bit more than you would mono to get to critical sampling rate.

[Owmuchonomy]

In addition to @vlaivexcellent response above, many solar imagers (me included) primarily use the ZWO ASI 174MM for this purpose (and the ZWO ASI 290 MM for solar and particularly lunar).  If I were to choose a colour camera for planetary imaging then I would personally go for the ZWO ASI 224.  Examples of images taken with 2 of these cameras on my Flickr page.

[Al8819]

You make some good points about the filter wheels. It does seem like buying two seperate camera's is ideal in the long run. I think I will just go with the color camera for now and get a monochrome later. Thanks again for the informative response, very helpful.

[Andy R]

2 hours ago, Owmuchonomy said:

Examples of images taken with 2 of these cameras on my Flickr page

Some cracking images there indeed.

[Al8819]

Owmuchonomy,

 Those cameras are definitely capable of some incredible pictures. Very Nice work! I want to take solar photos like that for sure.

[Science562h]

One of my 'scopes is an Orion 127 mm MAK-CASS on a Celestron SLT & I have a few CAMs but here is my very first planetary test, with the Neximge 5, from many years ago. 1 min recording, no barlow & no drizzling. The Neximage 10 is way better & the ZWO ASI178MC is even faster but costs more. Planets don't require expensive cameras at all but the ZWO 178 & 183 really are superior performing CAMs. Depends on, how much $500 means to you. Worth a CAM?  

For your 127 mm, you will, eventually need atleast a 0.5x barlow for planets, unless you drizzle, during processing & 0.5x focal reducer for the Moon & Sun. The prospectus for the Neximage 5 & your combo is very good, you will beat that linked Jupiter pic very easily, with a color CAM.

Just record once in color & don't worry about debayering & alignment problems later, like he had.  Contrasting is, about likeness. His Jupiter turned out blurry. You can always contrast the color later. Remember, our alt-az mounts suffer from field rotation, which will mess up your captures (Look in-to Celestron's new autoguider for a bit more). You might not actually have time to capture in all LRGB colors & then make darks, due to Jupiter's rotation. You can caputure for a bit more & equal the light, all at once. CAPTURING TECHNIQUE & PROCESS EDITING. I'm perfectly round, no blurring & no misalignments. This is with a MAK-CASS though.   

Image. Absolute first test, with defauts. 90 mm MAK-CASS & 1 min. Neximage 5. 

 

[vlaiv]

3 hours ago, Science562h said:

Remember, our alt-az mounts suffer from field rotation, which will mess up your captures

You really don't need to worry a bit about field rotation. For all intents and purposes - in duration of single sub, there simply is no field rotation that we can speak of. Any field rotation that accumulates over recording session is dealt with in alignment / stacking phase.

 

[Al8819]

This thread has been very informative. For now I decided to go with the ASI224mc for planetary imaging. I will save up my money and get a monochrome with a larger sensor later for solar imaging.  

Edited January 27, 2020 by Al8819

[Arshad Wali Muhammad]

How’s neximage 5 vs ZWO ASI385 ? I have both and I have keep one. Can anyone guide me ?

[SgtBunny]

On 09/07/2020 at 20:41, Arshad Wali Muhammad said:

How’s neximage 5 vs ZWO ASI385 ? I have both and I have keep one. Can anyone guide me ?

So what did you decide to use?  I am looking at the ASI224 and ASI385 and not sure if the 385 is worth the extra $100.