Jump to content

1564402927_Comet2021Banner.jpg.a8d9e102cd65f969b635e8061096d211.jpg

Advice needed - considering the jump to a dedicated astronomy camera


Recommended Posts

Hi all, can I have some advice please? I'm thinking of taking the next step in my astrophotography journey and want to move from DSLR to a dedicated astronomy camera (cooled) and have been trying to decide which route to go down - mono or one shot colour.

Earlier today I was leaning more towards the OSC route (the ZWO ASI 294MC-Pro https://www.firstlightoptics.com/zwo-cameras/zwo-asi-294mc-pro-usb-30-cooled-colour-camera.html), because of the added simplicity in not needing to take separate R G & B images and then aligning them etc. 

After doing some research and understanding why it's better to go mono I am considering going down this route. FLO are doing a bundle on the ZWO ASI 1600MM-Pro that includes a filter wheel, LRGB & Ha/SII/OIII filters https://www.firstlightoptics.com/zwo-cameras/zwo-asi1600mm-pro-usb-3-mono-camera-efw8-125-lrgb-filters-125-ha-sii-oiii-filters-bundle.html. The ability to use Ha/SII/OIII filters would probably be a massive benefit to me as I image from my back garden with lots of light pollution.

So I have a few questions:

  •  There's probably not much point in asking which route to go down, as I know most people are going to say go mono, and I'll probably end up going mono eventually anyway as my skills improve, so I might as well just go for it and save money in the long run
  •  Is the 1600MM-Pro a good choice to go for? I'm using the SW Evostar ED80 on the SW EQ6-R Pro mount, using APT for image capture with mount and guide cam connected via ASCOM. 
  • Powering the camera for the cooling - I take it I need this ? https://www.firstlightoptics.com/zwo-accessories/zwo-12v-5a-ac-to-dc-power-supply-adapter-for-cooled-cameras.html. Is it safe to use an extension lead outside in the garden to plug it into? Just a bit concerned about condensation, especially during the colder months. I need to plug in my laptop anyway so if it's safe to use an extension lead outside then I will as I don't want my laptop running out of battery during imaging again like the other night 🤣 (luckily it was only 5 minutes before I planned on calling it a night anyway). On a side note of powering the camera, what do you do to power it if I were to travel to a dark sky where I won't have access to electricity?
  •  Can anyone point me in the direction of any good step-by-step tutorials on how to take LRGB images with a mono camera, either written or via youtube? One thing I know I am going to struggle with at first is going from a stack of each L R G & B to a combined final image. I was reading the LRGB imaging primer earlier and read: 'Align and combine each channel separately then align (but don't combine) the combined channel images.' How do you align but not combine? 

I'm sure I'll have many more questions, but let's leave it there for the moment :)

Thanks

Adam

EDIT: forgot to add, main targets are DSO's 

Edited by Adam1234
Link to comment
Share on other sites

The asi1600 is very popular, so difficult to go wrong there. 

You can use the quoted power supply. Just invest in a small plastic box with lid. Cut two slots, one on either side, for the cables. Then put the extension lead's contact inside the box and the lid on, when outside. 

For a guide, you can get "making every photon count" by Steve Richards, available from FLO. 

Good luck & have fun

Edited by wimvb
  • Thanks 1
Link to comment
Share on other sites

I am in the exact same position as yourself, an 80ed owner looking to upgrade.  I have decided I will be going down the mono route and have been looking at lots of cameras.  I've been unsure about the 1600, with the micro lens diffraction issue putting me off.  However, mainly down to the lack of CMOS alternates and the issue being quite rare, I think I will end up going for it.  

Link to comment
Share on other sites

8 hours ago, scitmon said:

I am in the exact same position as yourself, an 80ed owner looking to upgrade.  I have decided I will be going down the mono route and have been looking at lots of cameras.  I've been unsure about the 1600, with the micro lens diffraction issue putting me off.  However, mainly down to the lack of CMOS alternates and the issue being quite rare, I think I will end up going for it.  

What's the micro lens diffraction issue?

Link to comment
Share on other sites

In front of the sensor is an array of small lenses which cause really bright stars to appear with strange artifiacts.  A good example here: 

 

I've concluded, with the lack of alternatives (The 183MM is one but its pixels are too small) I think its rare enough, and probably easy enough to post process out to be a deal breaker.

  • Thanks 1
Link to comment
Share on other sites

Hi!

I went fro DLSR to OSC to Mono and couldn't be happier with the results. The process is a lot tougher though, don't expect results the first times around (to keep pressure off yourself :) ). There are quite a few tutorials online on how to stack, but that part is much easier than you might think. The aligning is done in Deep Sky Stacker. An example: you open all the lights from one channel (let's say G). Then you also open the light with the highest score, regardless of what channel (let's say your highest score in DSS is from an L frame). You basically tell DSS to use this L frame as a reference frame only (so not adding it to the stack). Then DSS aligns the stack to this frame. You do this also with R and B and L channels, and in photoshop you open each stack. Then it's simple combining R to Red, ....etc. L you past over the entire thing and select luminance. From now on it's playing with stretching each channel to you liking for a natural balance and changing the L opacity. I prefer processing mono over OSC because you have more control and I'm faster at it (now).

I've made a little comparison for you. Below is my Rosette in OSC (QHY8L) and Mono (1600mm pro), with similar iteration times. Rosette is not a typical LRGB target, but a narrowband target off course. The mono is with 60 min Ha, 40 min Oiii and 20 min Sii.
Please note that the OSC picture is framed 90 degree different, but it paints the picture.

Rosette-mono-vs-osc.thumb.jpg.8c42e367e4224f345682a17eb2ff2ba6.jpg

With mono it is also way easier to combat light polution AND you can get creative with the color mapping (which sounds weird at first, but I actually really like this aspect!)

One thing that made my journey into Mono imaging a LOT easier is buying a stepper motor focuser (I have the Sesto Senso). You need to do more focusing when switching filters, and by having a stepper motor ascom focuser, you can partly automate the process (either by looking at the graph plotted to get best focus or go advanced with autofocus or filter offsets).

1. Go Mono 2. prepare to get frustrated for a few months 3. get your first result and 4. never look back....

Edited by Obi Wan Ken00bi
  • Like 3
Link to comment
Share on other sites

Greetings Adam, from just the other side of the New Forest 😉

I was in exactly the same position as you about a year ago but never gave too much thought to OSC really. I simply consider my DSLR (Nikon D5300) to be my OSC camera - although it would be much nicer if it were cooled! 🙂

I took the plunge and went with the FLO package you have posted - ASI1600, 8 pos'n EFW and the LRGB and Narrowband filters - note that these filters are not mounted and will need careful loading into the EFW.

Here are my feelings on the points you raised:-

1) As you point out, you will probably end up going mono eventually anyway so I'm sure it will be more cost effective to just go this route now (that was my main rationale). Anyway, as I consider my DSLR my OSC camera I now have both options anyway!

2) The setup you have mentioned will be fine. I use my ASI1600 with an ED80 but mounted on an HEQ5 and also on a 150PDS Newt mounted on an EQ6RPro. The micro lens diffraction issue mentioned by scitmon is an issue. I noticed it most on bright stars, especially when imaging the Horsehead - Alnitak was quite badly affected. I have not let it put me off though and there are suggestions on here I think about how to get around it. I have attached a rather awful image which was an early attempt. It shows a rather exaggerated example of the diffraction issue around the star Alnitak.

3) Yes, you definitely need a recommended power supply to cool the camera. I would not take any shortcuts on this. Of course the camera really comes into its own when cooled. I also have a library of dark frames that I took at different temperatures and exposure lengths so it saves a lot of imaging time. I bought a water resistant power box off Amazon which has rubber seals and holds about 4 power adapters. This holds my power supply for my Sesto Sensor focuser, the mount, the ASI1600 and a USB power supply. It has been great and I have had no issues. I hang it from the accessory tray with a bungee cord so it does not even touch the ground! Of course I would never use it in soaking wet conditions, but then I would not be imaging.

4) As for tutorials - other than Steve Richard's book I find You Tube to be about the best resource.

All in all I have not looked back. Indeed, despite being told otherwise I have found the filters supplied to be almost par-focal. Maybe it is just my eyes but I have not seen a need yet to adjust focusing between filters. Maybe software measurement of the FWHM would tell me different but I have not got around to that yet.

You do of course need to take Flats for each filter. I find the APT Flats Aid excellent for this, especially with the EFW. You just set  a few parameters and APT takes care of all the ADU measurements for you and swaps the filters in and out as needed - brilliant!! Unfortunately I have had a few gripes connecting the EFW with APT, but I think the cables may be more to blame - still working on that issue.

Good luck and Clear Skies,

daemon Steve

 

b33_att3.jpg

  • Like 1
Link to comment
Share on other sites

8 hours ago, Obi Wan Ken00bi said:

Hi!

I went fro DLSR to OSC to Mono and couldn't be happier with the results. The process is a lot tougher though, don't expect results the first times around (to keep pressure off yourself :) ). There are quite a few tutorials online on how to stack, but that part is much easier than you might think. The aligning is done in Deep Sky Stacker. An example: you open all the lights from one channel (let's say G). Then you also open the light with the highest score, regardless of what channel (let's say your highest score in DSS is from an L frame). You basically tell DSS to use this L frame as a reference frame only (so not adding it to the stack). Then DSS aligns the stack to this frame. You do this also with R and B and L channels, and in photoshop you open each stack. Then it's simple combining R to Red, ....etc. L you past over the entire thing and select luminance. From now on it's playing with stretching each channel to you liking for a natural balance and changing the L opacity. I prefer processing mono over OSC because you have more control and I'm faster at it (now).

I've made a little comparison for you. Below is my Rosette in OSC (QHY8L) and Mono (1600mm pro), with similar iteration times. Rosette is not a typical LRGB target, but a narrowband target off course. The mono is with 60 min Ha, 40 min Oiii and 20 min Sii.
Please note that the OSC picture is framed 90 degree different, but it paints the picture.

Rosette-mono-vs-osc.thumb.jpg.8c42e367e4224f345682a17eb2ff2ba6.jpg

With mono it is also way easier to combat light polution AND you can get creative with the color mapping (which sounds weird at first, but I actually really like this aspect!)

One thing that made my journey into Mono imaging a LOT easier is buying a stepper motor focuser (I have the Sesto Senso). You need to do more focusing when switching filters, and by having a stepper motor ascom focuser, you can partly automate the process (either by looking at the graph plotted to get best focus or go advanced with autofocus or filter offsets).

1. Go Mono 2. prepare to get frustrated for a few months 3. get your first result and 4. never look back....

Thank you Obi Wan KenOObi ( that's a phrase I never thought I'd say!) I'm beginning to understand it now, can't wait for it to arrive and try it out.

I love your images of the rosette nebula by the way

  • Thanks 1
Link to comment
Share on other sites

3 hours ago, daemon said:

Greetings Adam, from just the other side of the New Forest 😉

I was in exactly the same position as you about a year ago but never gave too much thought to OSC really. I simply consider my DSLR (Nikon D5300) to be my OSC camera - although it would be much nicer if it were cooled! 🙂

I took the plunge and went with the FLO package you have posted - ASI1600, 8 pos'n EFW and the LRGB and Narrowband filters - note that these filters are not mounted and will need careful loading into the EFW.

Here are my feelings on the points you raised:-

1) As you point out, you will probably end up going mono eventually anyway so I'm sure it will be more cost effective to just go this route now (that was my main rationale). Anyway, as I consider my DSLR my OSC camera I now have both options anyway!

2) The setup you have mentioned will be fine. I use my ASI1600 with an ED80 but mounted on an HEQ5 and also on a 150PDS Newt mounted on an EQ6RPro. The micro lens diffraction issue mentioned by scitmon is an issue. I noticed it most on bright stars, especially when imaging the Horsehead - Alnitak was quite badly affected. I have not let it put me off though and there are suggestions on here I think about how to get around it. I have attached a rather awful image which was an early attempt. It shows a rather exaggerated example of the diffraction issue around the star Alnitak.

3) Yes, you definitely need a recommended power supply to cool the camera. I would not take any shortcuts on this. Of course the camera really comes into its own when cooled. I also have a library of dark frames that I took at different temperatures and exposure lengths so it saves a lot of imaging time. I bought a water resistant power box off Amazon which has rubber seals and holds about 4 power adapters. This holds my power supply for my Sesto Sensor focuser, the mount, the ASI1600 and a USB power supply. It has been great and I have had no issues. I hang it from the accessory tray with a bungee cord so it does not even touch the ground! Of course I would never use it in soaking wet conditions, but then I would not be imaging.

4) As for tutorials - other than Steve Richard's book I find You Tube to be about the best resource.

All in all I have not looked back. Indeed, despite being told otherwise I have found the filters supplied to be almost par-focal. Maybe it is just my eyes but I have not seen a need yet to adjust focusing between filters. Maybe software measurement of the FWHM would tell me different but I have not got around to that yet.

You do of course need to take Flats for each filter. I find the APT Flats Aid excellent for this, especially with the EFW. You just set  a few parameters and APT takes care of all the ADU measurements for you and swaps the filters in and out as needed - brilliant!! Unfortunately I have had a few gripes connecting the EFW with APT, but I think the cables may be more to blame - still working on that issue.

Good luck and Clear Skies,

daemon Steve

 

b33_att3.jpg

Thanks for the advice Steve. Do you do much imaging in the New Forest? My Fiance and I had a drive around the New Forest yesterday looking for potential spots

Link to comment
Share on other sites

54 minutes ago, Adam1234 said:

Thanks for the advice Steve. Do you do much imaging in the New Forest? My Fiance and I had a drive around the New Forest yesterday looking for potential spots

Hey Adam, I have not ventured into the Forest for imaging. I live just outside the forest boundary and only image from my back garden. It's officially Bortle 5 but tends towards Bortle 4 I think. Deep in the Forest should be better but I can't complain. I can't really recommend any spots but will be glad to hear of any if you find some. 

Clear skies!

Steve

  • Like 1
Link to comment
Share on other sites

I was in the same position as you 5 months ago and agree with all the guidance on here so far- I chose the same asi1600 package and it's been fab.

I use mine with reflectors and haven't experienced the microlensing issue, I don't know I've just been lucky.

Pixinsight has very good tools for colour combination, but if you're not already using it, then it may add an unnecessary extra gradient to your learning curve, but I'd recommend it for you at some point.

On the subject of your dark site I'd be inclined to try it from home first if you've got trainable enough skies. Astrophotography has enough ways to go wrong already without taking your kit for a drive and it's true that mono is better able to deal with light pollution.

  • Like 1
Link to comment
Share on other sites

2 hours ago, daemon said:

Hey Adam, I have not ventured into the Forest for imaging. I live just outside the forest boundary and only image from my back garden. It's officially Bortle 5 but tends towards Bortle 4 I think. Deep in the Forest should be better but I can't complain. I can't really recommend any spots but will be glad to hear of any if you find some. 

Clear skies!

Steve

Much better than my back garden then, I think I'm in bortle 8, complete with 4 streetlights for free

Link to comment
Share on other sites

2 hours ago, Whistlin Bob said:

I was in the same position as you 5 months ago and agree with all the guidance on here so far- I chose the same asi1600 package and it's been fab.

I use mine with reflectors and haven't experienced the microlensing issue, I don't know I've just been lucky.

Pixinsight has very good tools for colour combination, but if you're not already using it, then it may add an unnecessary extra gradient to your learning curve, but I'd recommend it for you at some point.

On the subject of your dark site I'd be inclined to try it from home first if you've got trainable enough skies. Astrophotography has enough ways to go wrong already without taking your kit for a drive and it's true that mono is better able to deal with light pollution.

It's great that I've decided to go for such a popular camera! Can't wait for it to arrive. 

Oh yes I'll definitely be trying it from home first, most of my imaging will be done from home. I'll definitely give Pixinsight a go at some point,but will stick with DSS for time being to get used to the process 

Link to comment
Share on other sites

Ok cool, I've heard some people say they don't dither with a cooled astronomy camera but I guess it's still better to dither than not dither. What value would you recommend for the dithering? I guess you could go lower compared with a DSLR?

Link to comment
Share on other sites

As a DSLR user, hopefully one day getting a "proper" astro camera, this thread is very useful.

For those with the mono cameras and filter wheels; do you tend to cycle the filter for each sub (to try to get a decent spread of each type of image across a single session), or do you tend to shoot with a single filter and just accept that it'll take several nights to get a complete image?

Link to comment
Share on other sites

1 hour ago, sploo said:

For those with the mono cameras and filter wheels; do you tend to cycle the filter for each sub (to try to get a decent spread of each type of image across a single session), or do you tend to shoot with a single filter and just accept that it'll take several nights to get a complete image?

It's unlikely that the filters will each focus at the same place, so it is better to image a batch of one colour, then refocus and take another batch of another colour and finally the third colour.  With an autofocuser, or no sleep, you could capture the set of RGB data in one night.  I have no way of autofocusing so I accepted a compromise and cylce through the filters on each sub.  This meant sub-optimal focus point on all colours - I mean it's close, but not perfect.  I use a luminance layer, captured at the same time on a different scope, so I can just about get away with just so slightly iffy RGB data as the detail is in the luminance.  However it results in larger stars, often with coloured fringes, so it's not something I wish to continue doing.   I think there comes a point when you start doing mono + filter imaging, that an autofocuser is a key ingredient to the mix.

  • Like 1
Link to comment
Share on other sites

I'll probably go the easy but longer  route and shoot each colour on a separate night until I invest in an autofocuser.  At least I'll have a lot of data to play with. Although with the frequency of good clear nights here, who knows.

Link to comment
Share on other sites

7 minutes ago, Adam1234 said:

I'll probably go the easy but longer  route and shoot each colour on a separate night until I invest in an autofocuser.  At least I'll have a lot of data to play with. Although with the frequency of good clear nights here, who knows.

Never getting a completed image wears thin very quickly.  And if you move the gear, you'll need new flats, and always need to ensure correct alignment of camera to match previous nights.  

Link to comment
Share on other sites

With a reflector, you don't need to refocus between filters, and with an expensive apo refractor, you paid for the convenience not having to. With an ed doublet you probably have to refocus. Some telescope control software have built in focus offsets for each filter, so as long as the focuser is motorised, it won't be much hassle.

I tend to shoot about 40 minutes per filter for rgb, and longer for L, then repeat that sequence as long as the weather allows. I aim for at least 100 - 150 2 minutes exposures for L, and 30 - 40 4 minutes exposures for rgb, per filter. Cmos cameras thrive on large numbers of subs.

get.jpg?insecure

 

Edited by wimvb
  • Like 1
  • Thanks 1
Link to comment
Share on other sites

11 minutes ago, wimvb said:

With a reflector, you don't need to refocus between filters, and with an expensive apo refractor, you paid for the convenience not having to.

Both my reflectors have glass correctors, will that shift the focus?  I only use them for lum so I don’t know.  But I’ve seen ones on here with esprit triplets talk about filter offsets, I don’t have any experience but assumed it meant a difference in focus position?

 

Link to comment
Share on other sites

1 hour ago, tooth_dr said:

Never getting a completed image wears thin very quickly.  And if you move the gear, you'll need new flats, and always need to ensure correct alignment of camera to match previous nights.  

When you say move the gear, I assume you just mean like removing the camera or anything else in the image train as opposed to say moving the mount?

I plan on keeping the camera attached to the scope so it's always in the same orientation. Filters I'll change using the filter wheel, so if I take flats for each filter they'll be ok for while right? Unless I change camera orientation or something in which case, take new flats. 

Link to comment
Share on other sites

3 hours ago, sploo said:

As a DSLR user, hopefully one day getting a "proper" astro camera, this thread is very useful.

For those with the mono cameras and filter wheels; do you tend to cycle the filter for each sub (to try to get a decent spread of each type of image across a single session), or do you tend to shoot with a single filter and just accept that it'll take several nights to get a complete image?

Well, focusing can be a b*tch, so I tend to calculate the total time I will be out, divide by the filters (note that you want to spend relatively more time on the L filter, I do 50% L, 50% RGB combined). I have an expensive ED triplet, and even I need to refocus. I doubt that you dont need to refocus with a reflector either. Focus is a fine art and every wavelength has its own focal point. I'm sure can choose not to refocus, but if you want very high quality images it's best to refocus between filters. With a stepper focus motor you can spend a night calibrating the filter offsets, so once you have focused 1 filter, you can automatically refocus without running the (auto) focus routine.

Edited by Obi Wan Ken00bi
typo
  • Thanks 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.