Questions around camera

[steveinhants]

After dusting off the equipment I'm now looking to move from a DSLR to a cooled astrophotography camera. It's a minefield to say the least and I'm taking in as much info as I can. My love is narrowband imaging but being realistic, I don't have the time or funds to pursue that just yet. So, I want to go down the route of a colour camera. I've been looking at the ASI533 and comparing it to the 294 and various other models. I was originally put off by the square sensor but actually, I'm past that and figue that on most images I could look at cropping in post processing if I really needed to.
My current set up is an SW Evostar 80ED DS Pro with a .85 reducer to the DSLR.
First question is can this reducer be used on a dedicated cooled camera?
Also, after reading it seems that people aim for a resolution of 2" per pixel and using astro tools I can see that my setup is around 1.5" (assuming the reducer stays). Is this a problem?
Appreciate there are many threads on topics about which camera etc but I think for my needs, the time I can dedicate to the hobby and the budget I can comfortably assign, this camera fits. Would welcome some clarity - not just in the sky!
Steve

[vlaiv]

6 minutes ago, steveinhants said:

First question is can this reducer be used on a dedicated cooled camera?

No reason not to use it. It is optical element - it does not care what comes after it (if it is DSLR or some other type of sensor).

Only thing you have to worry about is size of corrected field and most dedicated cameras are either same size of DSLR or smaller (there are only few full frame dedicated astro cameras and they cost an arm and a leg).

8 minutes ago, steveinhants said:

Also, after reading it seems that people aim for a resolution of 2" per pixel and using astro tools I can see that my setup is around 1.5" (assuming the reducer stays). Is this a problem?

No, it won't be much of a problem. Even if you are over sampled - it will be by small amount.

[steveinhants]

25 minutes ago, vlaiv said:

No reason not to use it. It is optical element - it does not care what comes after it (if it is DSLR or some other type of sensor).

Only thing you have to worry about is size of corrected field and most dedicated cameras are either same size of DSLR or smaller (there are only few full frame dedicated astro cameras and they cost an arm and a leg).

No, it won't be much of a problem. Even if you are over sampled - it will be by small amount.

Thanks a lot for a quick reply. I’ve looked at a lot of targets on Astro tools with the setup and most seem pretty decent in respect of the field of view 

[Clarkey]

Assuming your 0.85 reducer is the standard SW flattener/ reducer, it with readily combine with your image train.

Also, the 294 is known to be a bit temperamental with flats, so the 533 I'd probably a better option.

[steveinhants]

3 minutes ago, Clarkey said:

Assuming your 0.85 reducer is the standard SW flattener/ reducer, it with readily combine with your image train.

Also, the 294 is known to be a bit temperamental with flats, so the 533 I'd probably a better option.

Yes, it's the SW 0.85 reducer. Am I correct in thinking that ZWO will provide the correct accessories in the box to achieve back focus with this reducer? I'm aware they don't provide power but not sure about the accessories.

[Clarkey]

With my ZWO camera it came with the correct spacers to give the 55mm back focus required. As far as I know this it still the case.

Unfortunately, I sold my ED80 which I have come to regret. It is a great all-rounder for visual and imaging.

[steveinhants]

6 minutes ago, Clarkey said:

With my ZWO camera it came with the correct spacers to give the 55mm back focus required. As far as I know this it still the case.

Unfortunately, I sold my ED80 which I have come to regret. It is a great all-rounder for visual and imaging.

Yep, I really like the ED80 but I also have nothing to compare that to! Regarding filters, I am in a Bortle class 4 sky - would I need anything like the L-extreme?

[Clarkey]

You won't need anything, but a dual band filter will allow you to image HOO with a colour sensor. Also, helps if imaging during a full moon.

You don't say what mount you are using. At the end of the day, it's the most important part of the set up.

[steveinhants]

2 minutes ago, Clarkey said:

You won't need anything, but a dual band filter will allow you to image HOO with a colour sensor. Also, helps if imaging during a full moon.

You don't say what mount you are using. At the end of the day, it's the most important part of the set up.

Ah yes. I use a HEQ5 that was stellar tuned by Dave from Dark Frame. Had some fantastic results from it in the past with exposure times of up to 4 mins unguided. I've just sorted the guiding set up too.

[Fegato]

I have the 294MC and it's a good camera, but as above, it's not consistent at very short exposures and therefore flats need to be calibrated with flat darks (rather than bias) which can be a bit of a pain. It also has amp glow and definitely requires darks as a result.

The 533 has a slightly more modern sensor and like the other newer ZWOs - no amp glow, and generally better performance (lower read noise etc.). Having said that - you can take brilliant images with the 294 and awful ones with the 533 of course, so I wouldn't argue against a 294 if the sensor size suits you better.

[Elp]

From my experience I would avoid the 294MC at all costs, it'll just be an unnecessary exercise in frustration trying to get a decently calibrated image out of it. I've owned at least five other ZWO cameras, all have worked as expected and calibrated as expected even planetary cameras not designed for DSO I've used for long exposure DSO imaging, the 294MC however is something else entirely. Sure the FOV it offers due to the sensor size is alluring, but not at the frustration it causes. I'd rather just mosaic with the 533 knowing that the square sensor will be more evenly illuminated within the image circle and that it produces a nice clean result every time.

Edited October 20, 2023 by Elp

[ollypenrice]

Given that an image circle is - ahem - a circle, the best non-circular chip is a square one.

lly

[vlaiv]

42 minutes ago, ollypenrice said:

Given that an image circle is - ahem - a circle, the best non-circular chip is a square one.

lly

That is a bit loose statement

How about hexagonal or maybe octagonal sensor?

In fact, best non circular sensor having all straight edges would be N-tagonal regular polygon where N -> infinity

[Anne S]

I have an ASI533 colour camera which I use for starparties etc. I use mono ccd cameras and broadband and narrowband filters at home. Below is an image from Kelling star party last week when I used my 4nm ultranarrowband filters for the first time. 130minutes exposure with mostly 5 minute subs. Cmos is very close to ccd cameras now. Only calibrated with bias and flats. I'm really pleased I bought this camera! I love the square chip.

Anne

 

[uhb1966]

@Anne Simpressive... most impressive !