Yet another question

[nephilim]

Apologies for the overwhelming amount of questions recently but I'm in the process of researching for a new AP setup.I tried my hand at AP a few yrs ago but made some bad kit choices, hence the amount of research I'm doing this time around.

Mount & scope-I've decided on the HEQ5 & Skywatcher 80ED, the camera on the other hand is taking time. My budget is £1000 for the actual camera & I'm wanting a OSC, I'm not interested in a dslr (I'd only end up wanting a dedicated camera further down the line) & I'm not ready for mono/fiters etc (yet)

I'd pretty much decided on the QHY8L until a fellow SGL member mentioned the ZWOasi 294. It's a new camera & well within budget. I've seen some very good images taken with it but as it's so new I'm struggling to find any first hand user reviews. Has anyone used one of these & if so i'd be grateful of their opinion (pros/con's etc) or does anyone have a link to an in depth review as I've tried searching online  but come up with very little.

Regards

Steve

[geordie85]

Maybe send a pm?

 

[LightBucket]

There was a secondhand SX-M26c on here recently for about £700, which in my opinion was a bargain, as they are one of if not the best OSC CCD Camera around, and yes they are Sony CCD not Panasonic CMOS like the QHY and ZWO offerings....if you want a OSC then go for the best available, the SX-M25 or 26c.....

I have the SX-M25c and it superb...trust me

[newbie alert]

A friend uses the same scope and mount..but uses a 1600 cool..amazing images..not sure on a price on them..and again I think his is mono..

[vlaiv]

I would vote ZWO ASI294 but I've just looked its specs, and there is something that kind of worries me.

Not sure what it really means, but if you look at the specs, there seems to be a sudden jump in read noise around unity gain. I would be much happier if unity gain was in low read noise region rather than in high read noise region.

If you end up deciding to go with ZWO camera, I do recommend you using it as 13bit camera rather than 14bit, or lower gain, so ADU of 0.5, or gain setting around 175. From graphs that looks like best setting with enough dynamic range.

Oh, pros being:

- shorter exposure needed, so less strain on guiding / non guided exposures

- less read noise

Cons on the other hand:

- a lot of subs - this means a lot of data to process and store

- won't work the best with DSS, so you will probably need another software to make most of it.

[nephilim]

23 hours ago, vlaiv said:

I would vote ZWO ASI294 but I've just looked its specs, and there is something that kind of worries me.

Not sure what it really means, but if you look at the specs, there seems to be a sudden jump in read noise around unity gain. I would be much happier if unity gain was in low read noise region rather than in high read noise region.

If you end up deciding to go with ZWO camera, I do recommend you using it as 13bit camera rather than 14bit, or lower gain, so ADU of 0.5, or gain setting around 175. From graphs that looks like best setting with enough dynamic range.

Oh, pros being:

- shorter exposure needed, so less strain on guiding / non guided exposures

- less read noise

Cons on the other hand:

- a lot of subs - this means a lot of data to process and store

- won't work the best with DSS, so you will probably need another software to make most of it.

Thanks for the info Vlaiv, I see you point but I do like what im seeing about it so far, its a very new camera & there's not many hands on reviews yet. I wont be buying until around June so hopefully there will be more people reviewing it over the next few months. Although ive never used any stacking software ive read a lot of recommendations for Nebulosity but again, still in the research stage.

Thanks for your help

Steve

[ollypenrice]

I realize that this response is entirely out of order but I owe it to you to tell you the truth as I see it.  You ARE ready for mono and filters. On a learning curve a metre long, about one mm separates OSC from mono and filters. What does mono involve? You shoot a set of red, green and blue. You stack them separately. (No need to fret about debayering.) 99% of the time the same flat will work for all filters. Ssshhh, I do it all the time.) You open your three colour images (in AstroArt in my case) you click once to 'Align All images' and then you open 'Trichromy' and asign red to red, green to green and blue to blue (rocket science?), you check 'white balance' and, pop, you get your RGB image.

Don't turn this into a problem. It just isn't.

Olly

[Bukko]

Olly, you are right, mono and filters are not a big problem to manage and it opens the doors for narrow band work.

But the problem would be the £1,000 budget...

Even second hand, this would be very difficult to acheive.. If there would be more money available later, then going for mono camera would be good and then invest in the other bits as funds allow would get the OP there. My choice would be to look for a cooled CCD and build on the system from there.

For sure, this opens up another load of questions; what to prioritise next, but when I look back at my purchasing history, there is a lot of money consumed with intermediate steps...

Gordon.

[nephilim]

2 hours ago, Bukko said:

Olly, you are right, mono and filters are not a big problem to manage and it opens the doors for narrow band work.

But the problem would be the £1,000 budget...

Even second hand, this would be very difficult to acheive.. If there would be more money available later, then going for mono camera would be good and then invest in the other bits as funds allow would get the OP there. My choice would be to look for a cooled CCD and build on the system from there.

For sure, this opens up another load of questions; what to prioritise next, but when I look back at my purchasing history, there is a lot of money consumed with intermediate steps...

Gordon.

You've hit the nail on the head there Gordon.

Money is the big hurdle. I'm going from visual to imaging & non of my visual equipment will cross over (EQ5 200p newt) so I'll be taking a very big hit in one go money wise (HEQ5, 80ED, camera,new laptop, power tank,  future guide scope/camera, software etc) 

I didn't want a dslr so a OSC makes sense to me, I've seen some great images taken with them & if I can even get near that standard I'll be happy. If a couple of years down the line I decide I want to take my images that next step further then I'll cross that bridge but for now a OSC will keep me busy for quite a while.

Regards

Steve

[rigradio]

SGP + Plate Solve2, you can find and framing the object you want, then start imaging in just a few minutes.

If you are not ready for PI yet, try APP.

Sara can tell you how good the program is

Good luck!

Ketut

[nephilim]

23 minutes ago, rigradio said:

SGP + Plate Solve2, you can find and framing the object you want, then start imaging in just a few minutes.

If you are not ready for PI yet, try APP.

Sara can tell you how good the program is

Good luck!

Ketut

Thanks Ketut, these are good to know about.

Steve

[nephilim]

15 hours ago, ollypenrice said:

I realize that this response is entirely out of order but I owe it to you to tell you the truth as I see it.  You ARE ready for mono and filters. On a learning curve a metre long, about one mm separates OSC from mono and filters. What does mono involve? You shoot a set of red, green and blue. You stack them separately. (No need to fret about debayering.) 99% of the time the same flat will work for all filters. Ssshhh, I do it all the time.) You open your three colour images (in AstroArt in my case) you click once to 'Align All images' and then you open 'Trichromy' and asign red to red, green to green and blue to blue (rocket science?), you check 'white balance' and, pop, you get your RGB image.

Don't turn this into a problem. It just isn't.

Olly

The main problem Olly is money, if I could afford to pick & choose I'd be buying a Tak & a Mesu 200  so the realistic options I've got are the HEQ5, 80ED & OSC camera. I've seen some very good images taken with this type of set up & would be very happy to be able to get anywhere near the quality these images.

Also, I live in the Lake District & fortunate to have some very dark skies. But because of the mountains & valleys, cloud (and lots of it for many days) is a big problem here. I don't like the thought of spending an evening imaging red then waiting days/weeks then onto green etc. I like the thought of getting enough data in 1 night to be able to spend those cloud infested periods getting my processing skills (of which I have none at the moment) bang on .

As I've mentioned, if further down the line I want better images/detail etc then mono would be the option

Steve

[LightBucket]

9 minutes ago, nephilim said:

The main problem Olly is money, if I could afford to pick & choose I'd be buying a Tak & a Mesu 200  so the realistic options I've got are the HEQ5, 80ED & OSC camera. I've seen some very good images taken with this type of set up & would be very happy to be able to get anywhere near the quality these images.

Also, I live in the Lake District & fortunate to have some very dark skies. But because of the mountains & valleys, cloud (and lots of it for many days) is a big problem here. I don't like the thought of spending an evening imaging red then waiting days/weeks then onto green etc. I like the thought of getting enough data in 1 night to be able to spend those cloud infested periods getting my processing skills (of which I have none at the moment) bang on .

As I've mentioned, if further down the line I want better images/detail etc then mono would be the option

Steve

Totally agree, i was the same I had a mono camera and sold and bought a OSC for the same reasons, and have never looked back, it’s ok for those who are retired and have got all night to sit up and image, one filter after another, and live in an area with over 200 clear nights a year....Olly..

But some of us don’t have that luxury...well not yet anyway....

[spillage]

I dont want to start world war 3 here but mono cameras are in no way slower than a osc (should I say mono is quicker). I find with my asi1600 I can get much more done that my previous cannon. From what has been said the op will be running a pc, so platesolving comes into play if imaging over several sessions.

I am sure you will be fine using a mono and I think the results would be better for you as they can be better customized. You can just by rgb filter and later on a Ha filter which will allow imaging in moon light.

There have been a few asi1600 cameras for around £700 and I have seen some cheap filters and usb wheels go through. This may be just over your budget but if you can wait a bit it should be achievable.

Have you considered a permanent set up as this will help even further.

I decided to hold out updating my canon until I had enough funds for the kit that I had settled on rather than buy kit that I would want to change in 6 months.

 

 

 

[ollypenrice]

I don't want to hijack this thread into an OSC/mono debate and I do understand the frustration factor with UK weather, which I endured for fifty years before escaping! However, mono is remarkably fast, certainly faster than OSC. A while back I did this 2 hour Heart Nebula image by way of demonstration. 20 minutes each of red, green and blue and an hour of Ha. I don't believe that, on this target, an OSC would be faster.

UK weather sufferers might reflect on the power of the Ha filter on moonlit nights, too. However, enough on this and back to the main topic...

Olly

[wimvb]

7 hours ago, nephilim said:

I don't like the thought of spending an evening imaging red then waiting days/weeks then onto green etc. I like the thought of getting enough data in 1 night to be able to spend those cloud infested periods getting my processing skills (of which I have none at the moment) bang on .

Exactly my thought. So I got an ASI174 mono with an electronic filter wheel. Cmos allows me to adjust the gain. I can either take guided, long exposures at low gain (higher dynamic range), or unguided short exposures at high gain. Either way, switching filters after 5 exposures allows to capture all channels in one night. Any additional night allows extra data for noise reduction.

Like you, I'm on a tight budget, so I used my antique box brownie (aka pentax k20d) until I had the funds to buy what I wanted. And I don't regret going mono, even with an average of only about two imaging nights per month.

[nephilim]

7 hours ago, ollypenrice said:

I don't want to hijack this thread into an OSC/mono debate and I do understand the frustration factor with UK weather, which I endured for fifty years before escaping! However, mono is remarkably fast, certainly faster than OSC. A while back I did this 2 hour Heart Nebula image by way of demonstration. 20 minutes each of red, green and blue and an hour of Ha. I don't believe that, on this target, an OSC would be faster.

UK weather sufferers might reflect on the power of the Ha filter on moonlit nights, too. However, enough on this and back to the main topic...

Olly

Stunning image Olly especially as it's just 2hrs worth only .

I've spent the evening researching mono as the idea of been able to image on moonlit nights is very appealing.

As mentioned, I've a few months until I can start making purchases & after opening my mind up to mono I think i'll be looking at both options now (OSC & Mono). Budget will still be the deciding factor but with a lot of good quality 2nd hand equipment available then mono could become an option.

As for a permanent set up, unfortunately that isn't possible, North is completely blocked by the house & I'm on top of a hill so South I have all the lights in Penrith. There's plenty of good dark sites within a 20mins drive though which is where I travel to for visual sessions.

Steve

[nephilim]

8 hours ago, spillage said:

I dont want to start world war 3 here but mono cameras are in no way slower than a osc (should I say mono is quicker). I find with my asi1600 I can get much more done that my previous cannon. From what has been said the op will be running a pc, so platesolving comes into play if imaging over several sessions.

I am sure you will be fine using a mono and I think the results would be better for you as they can be better customized. You can just by rgb filter and later on a Ha filter which will allow imaging in moon light.

There have been a few asi1600 cameras for around £700 and I have seen some cheap filters and usb wheels go through. This may be just over your budget but if you can wait a bit it should be achievable.

Have you considered a permanent set up as this will help even further.

I decided to hold out updating my canon until I had enough funds for the kit that I had settled on rather than buy kit that I would want to change in 6 months.

 

 

 

After reading up a bit about mono imaging this evening I was surprised that mono is actually faster, replied to further down on your next post.

Steve

[wimvb]

5 hours ago, nephilim said:

As for a permanent set up, unfortunately that isn't possible, North is completely blocked by the house & I'm on top of a hill so South I have all the lights in Penrith. There's plenty of good dark sites within a 20mins drive though which is where I travel to for visual sessions.

Steve

In that case, you should definitely consider cooled cmos. It will enable you to choose a high gain and short exposures, and take guiding out of the equation. This will make the imaging process much easier.

[nephilim]

12 hours ago, wimvb said:

In that case, you should definitely consider cooled cmos. It will enable you to choose a high gain and short exposures, and take guiding out of the equation. This will make the imaging process much easier.

Excuse the 'newbie' questions (I still have a great deal to learn) but wouldnt losing the ability to guide greatly affect the quality of potential images?

I was intending to use stellarium rather than the HEQ5's goto feature to quickly locate targets & Nebulosity or APP to frame the target & will be using my laptop 'out in the field' (quite literally ) hooked up to a power tank.

my main dark sky site is very sheltered from the elements , it's in the middle of a Lakeland fell accessed by a track which is car friendly 'ish' & I have access to a gamekeepers tea hut so my plan is to set up by the hut (sheltered from the wind so I'll have a couple of planned targets dependent on wind direction if that makes sense?) I can then set up an imaging run & sit in the hut with a book while the camera does its job. I can't use this as a permanent setup but it's close.

Id obviously prefer not to guide (the simpler the procces is the less that can go wrong) but not to the detriment of potential images. Do you know the approx exposure length unguided & isnt upping the gain to shorten sub Length  the same as increasing iso on a dslr therefore introducing more noise? (Again, as a total beginner these are all things I'm unsure of & I'm grateful for you taking your time to read this 'essay' )

Steve

[alexbb]

32 minutes ago, nephilim said:

Do you know the approx exposure length unguided & isnt upping the gain to shorten sub Length  the same as increasing iso on a dslr therefore introducing more noise?

Due to the periodic error of the mount, you will most probably lose even a couple of 30s exposures when the movement is the least uniform in one complete rotation of the gears. That's 8min for the heq5 if I remember well.

And yes, increasing the gain is about the same thing, just that you can increase it in smaller increments.

On another note: what's more expensive than a camera? 2 cameras. You still have enough time to think until June. Btw, do you have astronomical darkness in June?

[wimvb]

2 hours ago, nephilim said:

Excuse the 'newbie' questions (I still have a great deal to learn) but wouldnt losing the ability to guide greatly affect the quality of potential images?

Almost any mount can handle exposures up to about 30 - 60 seconds without any visible degradation in tracking. If you have the ability to correct the periodic error of the gear (worm wheel), you can probably get even longer exposures. If you don't overload the mount, balance your scope, and have a good polar alignment, this will all improve the tracking. Due to the very low read noise of cooled cmos cameras, you can get good images with short (less than 60 seconds) exposures. And since the total integration time should be kept the same as with long exposure AP, you will collect a lot more frames, and can afford to lose a few.

Here's a recent image I took with only 30 and 45 second exposures, unguided:

 

2 hours ago, nephilim said:

Do you know the approx exposure length unguided & isnt upping the gain to shorten sub Length  the same as increasing iso on a dslr therefore introducing more noise? (Again, as a total beginner these are all things I'm unsure of & I'm grateful for you taking your time to read this 'essay' )

You should be able to get exposures up to about 60 seconds without too much trouble. Yes, increasing gain is equivalent to increasing ISO in dslr cameras, but the read noise (which is the ultimate limiting noise contribution from the camera) is so low, that this isn't really a problem. Unless of course you want to chase VERY faint signal, in which case there's no shortcut but to use long exposures.

The ability to "go deep", and image faint nebulae depends more on the darkness of the sky, than the length of your exposures. But there is no shortcut: the total time on target (total integration time) determines the qualitiy of the stacked image. So, fewer long exposures, or lots more shorter exposures.

Btw, your imaging site seems almost ideal. Dark skies and sheltered. If you can also park the car where you want near that hut, you can use that as a wind screen.

[nephilim]

2 hours ago, moise212 said:

Due to the periodic error of the mount, you will most probably lose even a couple of 30s exposures when the movement is the least uniform in one complete rotation of the gears. That's 8min for the heq5 if I remember well.

And yes, increasing the gain is about the same thing, just that you can increase it in smaller increments.

On another note: what's more expensive than a camera? 2 cameras. You still have enough time to think until June. Btw, do you have astronomical darkness in June?

Thanks for the info, I think guiding is the way i'd like to go then really. Where I live, in June we probably get around 3hrs of astronomical darkness so not a good time for AP, although it will give me time to get used to the gear & also a bit of practise with the moon.

Regards

Steve

[nephilim]

1 hour ago, wimvb said:

Almost any mount can handle exposures up to about 30 - 60 seconds without any visible degradation in tracking. If you have the ability to correct the periodic error of the gear (worm wheel), you can probably get even longer exposures. If you don't overload the mount, balance your scope, and have a good polar alignment, this will all improve the tracking. Due to the very low read noise of cooled cmos cameras, you can get good images with short (less than 60 seconds) exposures. And since the total integration time should be kept the same as with long exposure AP, you will collect a lot more frames, and can afford to lose a few.

Here's a recent image I took with only 30 and 45 second exposures, unguided:

 

You should be able to get exposures up to about 60 seconds without too much trouble. Yes, increasing gain is equivalent to increasing ISO in dslr cameras, but the read noise (which is the ultimate limiting noise contribution from the camera) is so low, that this isn't really a problem. Unless of course you want to chase VERY faint signal, in which case there's no shortcut but to use long exposures.

The ability to "go deep", and image faint nebulae depends more on the darkness of the sky, than the length of your exposures. But there is no shortcut: the total time on target (total integration time) determines the qualitiy of the stacked image. So, fewer long exposures, or lots more shorter exposures.

Btw, your imaging site seems almost ideal. Dark skies and sheltered. If you can also park the car where you want near that hut, you can use that as a wind screen.

That's a lovely image of the Iris & i'm happily surprised that's been taken with such short exposures.I was hoping for longer exposures than 30 seconds but as the image above shows, a lot of short subs can produce a great image.

To start with I wouldn't be guiding anyway as it just adds an extra list of possible things that could mess up as i'll just be starting out. If I later decide that Id like longer exposures (120,s 300,s 600,s) then guiding it'll have to be. My dark sky site is pretty much ideal & the car does go all the way to the hut. Also my parents have a farm in Yorkshire with fairly dark skies & although its a 2 hr drive they would have no objections for me putting up a permanent set up (a small obs) with a concrete base/pier etc plus i'd be able to run electrics from one of the many out buildings.

I'm lucky that I have a lot of options available & the time (aside from work ) to research  all the ideas I have, also this forum is a goldmine of good helpful info which is half the battle

ATB

Steve