Recommendations for Astrophotography Lenses/Equipment (DSO specifically)

Hi, 

maybe you're pushing a bit too far with up to 400mm on a star tracker but maybe you get it to work. In case you live on the northern hemisphere we now have "galaxy season" and there are not so many large nebulae available for a lens and a DSLR. Pinwheel is already quite a challenge for a DSLR + lens combo. 

The Samyang 135mm is a fine lens. There is always some sample variation but it seems to be reasonably controlled for the Samyang 135mm. For examples that can be achieved with this lens you may look here: Samyang 135 f/2 - AstroBin

You're not the first one to miss a target by star hopping: April fools day - time to reveal our major fails - AstroBin

It takes some preparation and this is how I do it:
1) You need a wider zoom, it can be a cheap kit lens
2) Install Stellarium on your computer and add your camera and lens combination to Stellarium. Add several wider focal lenghts covering the whole range of your equipment.
3) Search for your target in Stellarium and frame it the way you want to take images
Example: Heart and Soul Nebula, a target frame with 135mm on my Olympus (270mm effective focal length) may look like this

4) Look for specific patterns of the stars in your target frame which may help you identify whether your framing is correct or not. You need this because you won't see the faint nebula in your images if you work with short unguided subs. So you're photographing "into the void". 

As you can see there are star chains, "double stars" (circled), polygons etc. Tipp: Triangles won't help you because you will see plenty of them in any part of the sky ...
5) Now while keeping image orientation and centering switch to wider focal lengths until you see familiar and easy to find bright stars in the sky. It helps to know the major constellations so you may start by learning them. A very good, cheap and nice book is "The Stars" by H.A. Rey.
In my case I end up with:

Mirfak in Perseus and Ruchbah in Cassiopeia are easy to find in the sky and I now have a framing with 35mm
6) Highly reccommended: Take some additional frames in Stellarium with focal lengths between your widest framing and your final framing.
In my case I add 45mm and 75mm:

It helps to watch out for patterns i.e. "Mirfak just on the upper left edge in the image"


Watch out for "patterns" like the fact that gammy Perseus (upper left) and Segin (lower right) are just a little bit out of the frame. 
 
7) Optional step: look for an easy to find star with the same declination as your image centre. This may not always be achievable but in case you manage to do so, you can put this star into the centre of your image and then you only have to move the RA axis to centre your final target,
In my case Navi fits the bill:


In the field you now execute the following steps: 
1) in case you found a star in optional step 7 put it right in the centre of your image. Digital cameras have the capabilities to display a grid - ideally a crosshair - which will help you to do so. You may use your longes focal length to do so.
2) Switch lenses to your wide angle zoom - without shaking the tripod and messing up your polar alignment
3) Move your RA axis until the image in your display looks like the one from step 5 at the same focal length (in my case 35mm). Check whether your camera has a "boost mode" for live view to see the stars. Actually for a beginner it's better not to see too many stars in the display ...
In case the display is too dark and you don't see the stars well, you have to take images and look at them. Quite cumbersome I have to admit.
4) Now continue zooming in and double check for the images from step 6. If you did everything right, you will see gamma-Perseus and Segin leave the image at about the same time if your centering is correct. Watch out for similar patterns for other targets.
5) At some point you have to switch lenses to your longer zoom. It helps a lot if your zoom lenses have an overlap in focal length. Take some time to check that you didn't mess up your centering while switching lenses. If you did and lost your target take some time out to get your blood pressure back to normal and start from zero, including polar alignment ...
6) Once you reached your target focal length take an image and compare the patterns you see with what you expect. The target image will show many more stars than Stellarium so it may be a little bit confusing. It takes some practice to find your patterns and the more you identified the easier it gets

Comparing to Stellarium I didn't nail it (a little bit too high and too much to the right). The soul nebula is cut off so I have to move on a tiny bit more along the RA axis. It helps a lot if your mount/tracker allows slow slewing because at that stage you need tiny changes. Doing this manually is a nightmare. Of course framing not too tightly helps a lot in the process.


I hoped this helped. Of course an ASIAIR or a NINA will replace this "manual platesolving" by a fully automated process. I'm still a firm believer that knowing the sky and being able to find the target on your own increases the satisfaction of our hobby.

I hope this helped and I'm eager to learn if someone found a better, easier or more straightforward method.

Good luck, have fun and clear skies
Wolfgang

Plate solving with a tracker ????

Yogesh S:

andrea tasselli:
Plate solving with a tracker ????

Why not, you just have to disable auto slewing and move RA/DEC manually. Repeat it until you are within range. When you have technology why not use it!

Auto-slewing with a tracker?? Repeat what, pray? It hasn't got a Dec axis, at all! And what tells you the OP has got a PC with him when doing AP?  If I were him I wouldn't. Why don't assume the lowest common denominator when advising things to a newcomer to the hobby?

There are a lot of assumptions in plate-solving your way to a target, manually moving a camera + lens sitting on a  ball-head. You can rest assured of that. My advice is at least test-and-tried because I use it myself.

andrea tasselli:

Yogesh S:

andrea tasselli:
Plate solving with a tracker ????

Why not, you just have to disable auto slewing and move RA/DEC manually. Repeat it until you are within range. When you have technology why not use it!

Auto-slewing with a tracker?? Repeat what, pray? It hasn't got a Dec axis, at all! And what tells you the OP has got a PC with him when doing AP?  If I were him I wouldn't. Why don't assume the lowest common denominator when advising things to a newcomer to the hobby?

Sorry if I wasn’t being clear, I mentioned turn off auto slewing on the software, if it is on Ekos it keeps on taking pictures and keep plate solving it until I stop it.

Hi, 

maybe you're pushing a bit too far with up to 400mm on a star tracker but maybe you get it to work. In case you live on the northern hemisphere we now have "galaxy season" and there are not so many large nebulae available for a lens and a DSLR. Pinwheel is already quite a challenge for a DSLR + lens combo. 

The Samyang 135mm is a fine lens. There is always some sample variation but it seems to be reasonably controlled for the Samyang 135mm. For examples that can be achieved with this lens you may look here: Samyang 135 f/2 - AstroBin

You're not the first one to miss a target by star hopping: April fools day - time to reveal our major fails - AstroBin

It takes some preparation and this is how I do it:
1) You need a wider zoom, it can be a cheap kit lens
2) Install Stellarium on your computer and add your camera and lens combination to Stellarium. Add several wider focal lenghts covering the whole range of your equipment.
3) Search for your target in Stellarium and frame it the way you want to take images
Example: Heart and Soul Nebula, a target frame with 135mm on my Olympus (270mm effective focal length) may look like this

4) Look for specific patterns of the stars in your target frame which may help you identify whether your framing is correct or not. You need this because you won't see the faint nebula in your images if you work with short unguided subs. So you're photographing "into the void". 

As you can see there are star chains, "double stars" (circled), polygons etc. Tipp: Triangles won't help you because you will see plenty of them in any part of the sky ...
5) Now while keeping image orientation and centering switch to wider focal lengths until you see familiar and easy to find bright stars in the sky. It helps to know the major constellations so you may start by learning them. A very good, cheap and nice book is "The Stars" by H.A. Rey.
In my case I end up with:

Mirfak in Perseus and Ruchbah in Cassiopeia are easy to find in the sky and I now have a framing with 35mm
6) Highly reccommended: Take some additional frames in Stellarium with focal lengths between your widest framing and your final framing.
In my case I add 45mm and 75mm:

It helps to watch out for patterns i.e. "Mirfak just on the upper left edge in the image"


Watch out for "patterns" like the fact that gammy Perseus (upper left) and Segin (lower right) are just a little bit out of the frame. 
 
7) Optional step: look for an easy to find star with the same declination as your image centre. This may not always be achievable but in case you manage to do so, you can put this star into the centre of your image and then you only have to move the RA axis to centre your final target,
In my case Navi fits the bill:


In the field you now execute the following steps: 
1) in case you found a star in optional step 7 put it right in the centre of your image. Digital cameras have the capabilities to display a grid - ideally a crosshair - which will help you to do so. You may use your longes focal length to do so.
2) Switch lenses to your wide angle zoom - without shaking the tripod and messing up your polar alignment
3) Move your RA axis until the image in your display looks like the one from step 5 at the same focal length (in my case 35mm). Check whether your camera has a "boost mode" for live view to see the stars. Actually for a beginner it's better not to see too many stars in the display ...
In case the display is too dark and you don't see the stars well, you have to take images and look at them. Quite cumbersome I have to admit.
4) Now continue zooming in and double check for the images from step 6. If you did everything right, you will see gamma-Perseus and Segin leave the image at about the same time if your centering is correct. Watch out for similar patterns for other targets.
5) At some point you have to switch lenses to your longer zoom. It helps a lot if your zoom lenses have an overlap in focal length. Take some time to check that you didn't mess up your centering while switching lenses. If you did and lost your target take some time out to get your blood pressure back to normal and start from zero, including polar alignment ...
6) Once you reached your target focal length take an image and compare the patterns you see with what you expect. The target image will show many more stars than Stellarium so it may be a little bit confusing. It takes some practice to find your patterns and the more you identified the easier it gets

Comparing to Stellarium I didn't nail it (a little bit too high and too much to the right). The soul nebula is cut off so I have to move on a tiny bit more along the RA axis. It helps a lot if your mount/tracker allows slow slewing because at that stage you need tiny changes. Doing this manually is a nightmare. Of course framing not too tightly helps a lot in the process.


I hoped this helped. Of course an ASIAIR or a NINA will replace this "manual platesolving" by a fully automated process. I'm still a firm believer that knowing the sky and being able to find the target on your own increases the satisfaction of our hobby.

I hope this helped and I'm eager to learn if someone found a better, easier or more straightforward method.

Good luck, have fun and clear skies
Wolfgang

Thanks for sharing such a detailed step-by-step process! I did try quite a few things you had mentioned in your reply however only had the chance to try it couple of times. Probably with time and practice I will get better. This was my first stint with DSO Photography and using the Star Tracker . Thank you again and Clear skies!

Yogesh S:
Hi,

For Framing you could do plate solving.
If you have a spare Raspberry Pi, you could load astroberry or stellarmate os on to it and use Ekos to plate solve and adjust the targeting accordingly. This is what I do.
Side note, you need to disable auto slewing to make sure the pi doesn’t get overloaded because the RAW image is pretty large.

It also works if you have a spare laptop/mini pc and use software like NINA to do plate solving.

There is another alternative, by using your phone. You can send the jpg to your phone or capture the live view screen and send that image here, it will do plate solving and tell you where exactly you are pointed at.

The Samyang 135mm is a very good lens for wide field astrophography. I did read somewhere that the quality depends on piece to piece. I have however used it only few times, I did get good quality stuff from the lens when I used it.

For devices, I would recommend you get StellarMateOS or Astroberry on a Raspberry Pi as a start off, later you can upgrade to mini pc.

Clear Skies,
Yogesh S

Hi Yogesh, thanks for the quick and precise advice! I do have some further doubts:

-From what I have read ASIAIR Pro platform or any other ASIAIR model doesn't support Sony A7III? I am confused as to why it has to be compatible with the Camera when I am using a separate camera (Guiding Camera) which will be connected to the SA and to my phone using the ASIAIR App or did I misunderstand something here?
-What if I use Auto Guiding setup like below? Would it still need to be compatible with my Sony A7III?

ZWO Mini Guide Scope
ASI120MC-S (color)
ASIAIR Plus
Star Adventurer
Sony A7III

-I don't want to use the laptop in any case for the guiding as it will not be feasible for me to have a power supply wherever I go and it's going to be a task setting all these things up and providing power to them. I like the idea of using the ASIAIR app which is available for ASIAIR Plus and PRO, if only that is something I have as an option. Thoughts?

For now, I think those are the only ones that are coming to my mind but based on your response I might have more questions for you.

Pardon my ignorance here. I am trying to go through as much info as I can to educate myself in this field but it's a vast one, I tell you that

TIA!

Do you have one of the ASIAIR already?
If so you are probably limited in terms of camera compatibility, as they are aiming for a ecosystem that supports only ZWO products. There are few cameras they support out of their camera lineup, if yours isn’t in the list then probably you are out of luck.

ASIAIR products help you in the image acquisition process. It is a whole package where you can automate a lot of things including image framing (for goto mounts), focusing using a focuser, filter wheel, image acquisition itself, etc.

You can do all these manually if the camera isn’t supported. However with your setup you can do auto guiding with the ASI120MC-S and the mini guide scope using the ASIAIR, and leave the imaging to your intervalometer if you have one for your sony camera. It perfectly works.

With ASIAIR you are probably limiting yourself in terms of camera and other accessories upgrade. I hear they support mounts that are not from ZWO (not sure about future mounts that gets released). I don’t own an ASIAIR device. If you are looking for a portable setup and haven’t bought one of the ASIAIR, you can take a look at astroberry or stellarmate os on a Raspberry Pi 4, you can use a powerbank to power the raspberry pi.

Hope I was able to help you.

Yogesh S
Clear Skies!

kuechlew

"Astrophotography on the go - using short exposures with light mounts" by Patrick Moore

Just a short correction: the book is from Joseph Ashley, the book's collection is " by Patrick Moore" although I gather none of them were edited or read by him, main issue being he is long dead.

Yogesh S:

Yogesh S:
Hi,

For Framing you could do plate solving.
If you have a spare Raspberry Pi, you could load astroberry or stellarmate os on to it and use Ekos to plate solve and adjust the targeting accordingly. This is what I do.
Side note, you need to disable auto slewing to make sure the pi doesn’t get overloaded because the RAW image is pretty large.

It also works if you have a spare laptop/mini pc and use software like NINA to do plate solving.

There is another alternative, by using your phone. You can send the jpg to your phone or capture the live view screen and send that image here, it will do plate solving and tell you where exactly you are pointed at.

The Samyang 135mm is a very good lens for wide field astrophography. I did read somewhere that the quality depends on piece to piece. I have however used it only few times, I did get good quality stuff from the lens when I used it.

For devices, I would recommend you get StellarMateOS or Astroberry on a Raspberry Pi as a start off, later you can upgrade to mini pc.

Clear Skies,
Yogesh S

Hi Yogesh, thanks for the quick and precise advice! I do have some further doubts:

-From what I have read ASIAIR Pro platform or any other ASIAIR model doesn't support Sony A7III? I am confused as to why it has to be compatible with the Camera when I am using a separate camera (Guiding Camera) which will be connected to the SA and to my phone using the ASIAIR App or did I misunderstand something here?
-What if I use Auto Guiding setup like below? Would it still need to be compatible with my Sony A7III?

ZWO Mini Guide Scope
ASI120MC-S (color)
ASIAIR Plus
Star Adventurer
Sony A7III

-I don't want to use the laptop in any case for the guiding as it will not be feasible for me to have a power supply wherever I go and it's going to be a task setting all these things up and providing power to them. I like the idea of using the ASIAIR app which is available for ASIAIR Plus and PRO, if only that is something I have as an option. Thoughts?

For now, I think those are the only ones that are coming to my mind but based on your response I might have more questions for you.

Pardon my ignorance here. I am trying to go through as much info as I can to educate myself in this field but it's a vast one, I tell you that

TIA!

Do you have one of the ASIAIR already?
If so you are probably limited in terms of camera compatibility, as they are aiming for a ecosystem that supports only ZWO products. There are few cameras they support out of their camera lineup, if yours isn’t in the list then probably you are out of luck.

ASIAIR products help you in the image acquisition process. It is a whole package where you can automate a lot of things including image framing (for goto mounts), focusing using a focuser, filter wheel, image acquisition itself, etc.

You can do all these manually if the camera isn’t supported. However with your setup you can do auto guiding with the ASI120MC-S and the mini guide scope using the ASIAIR, and leave the imaging to your intervalometer if you have one for your sony camera. It perfectly works.

With ASIAIR you are probably limiting yourself in terms of camera and other accessories upgrade. I hear they support mounts that are not from ZWO (not sure about future mounts that gets released). I don’t own an ASIAIR device. If you are looking for a portable setup and haven’t bought one of the ASIAIR, you can take a look at astroberry or stellarmate os on a Raspberry Pi 4, you can use a powerbank to power the raspberry pi.

Hope I was able to help you.

Yogesh S
Clear Skies!

Hi Yogesh,

Thanks again for the information!

I don't own the ASIAIR as of now and might not go for it. Instead I will take the Stellarmate/Astroberry route for the reasons you mentioned above.

I did some research on the ASIAIR compatibility with my existing camera and looks like a better option is Stellarmate/Astroberry in terms of wide compatibility range with different products. I might just buy the Guide Scope and Guide Camera as mentioned above and not the ASIAIR and instead use Stellarmate/Astroberry on Raspberry Pi4. However, another thing that came up during my research on this is that EKOS may or may not be compatible with Sony A7III. I haven't heard back from Stellarmate support yet so still waiting on that confirmation.

With the Stellarmate/Astroberry (which one would you recommend out of the two for my setup and need) integration with my SA, Guide Scope, Guide camera, and Sony Camera (A7III) do you think I would be able to achieve Auto-Guiding and Dithering at the same time using EKOS/Kstars? Would I need to consider something else as well here?

Do you have any links/tutorials that I can take a look at to learn more about this setup?

TIA!

Regards,
Nick

Just my 2 cents: Before you start with autoguiding in your shoes I would make my first steps with short exposure times. You will need plenty of them and it looks irritating when there is no target object in the image but its perfectly feasible. Once you enjoy the overall process of astro photography you may take the decission how to move up in your equipment. With the recommended Samyang you won't need guiding anyway because you will get sky limited quite fast.
You may have a look at the book "Astrophotography on the go - using short exposures with light mounts" by Patrick Moore. The author shows some of his own achievements with exposures in the range 15 to 90 seconds, all of them unguided. Admittedly with some mounts 90s unguided may not be achievable but you can always split into 2x45 or 3x30s without getting too much issues.

As already pointed out I prefer a "take it easy and step by step" approach over expanding your equipment too fast and then stumbling over the own feet.

Have fun and clear skies.
Wolfgang

@kuechlew I will definitely look into finding that book and read through it. Thank you for sharing!

Astrophotography on the Go | SpringerLink

I got the kindle edition: Astrophotography on the Go: Using Short Exposures with Light Mounts (The Patrick Moore Practical Astronomy Series) : Ashley, Joseph: Amazon.de: Bücher

The hardware mentioned in this book is no longer up-to-date but its strength is in describing the approach. I like that it is an honest book, it clearly states the limitations of light mounts and short exposures too. I believe it's a good way to get started and create first encouraging results.

Have fun and clear skies
Wolfgang

Yogesh S:

Yogesh S:
Hi,

For Framing you could do plate solving.
If you have a spare Raspberry Pi, you could load astroberry or stellarmate os on to it and use Ekos to plate solve and adjust the targeting accordingly. This is what I do.
Side note, you need to disable auto slewing to make sure the pi doesn’t get overloaded because the RAW image is pretty large.

It also works if you have a spare laptop/mini pc and use software like NINA to do plate solving.

There is another alternative, by using your phone. You can send the jpg to your phone or capture the live view screen and send that image here, it will do plate solving and tell you where exactly you are pointed at.

The Samyang 135mm is a very good lens for wide field astrophography. I did read somewhere that the quality depends on piece to piece. I have however used it only few times, I did get good quality stuff from the lens when I used it.

For devices, I would recommend you get StellarMateOS or Astroberry on a Raspberry Pi as a start off, later you can upgrade to mini pc.

Clear Skies,
Yogesh S

Hi Yogesh, thanks for the quick and precise advice! I do have some further doubts:

-From what I have read ASIAIR Pro platform or any other ASIAIR model doesn't support Sony A7III? I am confused as to why it has to be compatible with the Camera when I am using a separate camera (Guiding Camera) which will be connected to the SA and to my phone using the ASIAIR App or did I misunderstand something here?
-What if I use Auto Guiding setup like below? Would it still need to be compatible with my Sony A7III?

ZWO Mini Guide Scope
ASI120MC-S (color)
ASIAIR Plus
Star Adventurer
Sony A7III

-I don't want to use the laptop in any case for the guiding as it will not be feasible for me to have a power supply wherever I go and it's going to be a task setting all these things up and providing power to them. I like the idea of using the ASIAIR app which is available for ASIAIR Plus and PRO, if only that is something I have as an option. Thoughts?

For now, I think those are the only ones that are coming to my mind but based on your response I might have more questions for you.

Pardon my ignorance here. I am trying to go through as much info as I can to educate myself in this field but it's a vast one, I tell you that

TIA!

Do you have one of the ASIAIR already?
If so you are probably limited in terms of camera compatibility, as they are aiming for a ecosystem that supports only ZWO products. There are few cameras they support out of their camera lineup, if yours isn’t in the list then probably you are out of luck.

ASIAIR products help you in the image acquisition process. It is a whole package where you can automate a lot of things including image framing (for goto mounts), focusing using a focuser, filter wheel, image acquisition itself, etc.

You can do all these manually if the camera isn’t supported. However with your setup you can do auto guiding with the ASI120MC-S and the mini guide scope using the ASIAIR, and leave the imaging to your intervalometer if you have one for your sony camera. It perfectly works.

With ASIAIR you are probably limiting yourself in terms of camera and other accessories upgrade. I hear they support mounts that are not from ZWO (not sure about future mounts that gets released). I don’t own an ASIAIR device. If you are looking for a portable setup and haven’t bought one of the ASIAIR, you can take a look at astroberry or stellarmate os on a Raspberry Pi 4, you can use a powerbank to power the raspberry pi.

Hope I was able to help you.

Yogesh S
Clear Skies!

Hi Yogesh,

Thanks again for the information!

I don't own the ASIAIR as of now and might not go for it. Instead I will take the Stellarmate/Astroberry route for the reasons you mentioned above.

I did some research on the ASIAIR compatibility with my existing camera and looks like a better option is Stellarmate/Astroberry in terms of wide compatibility range with different products. I might just buy the Guide Scope and Guide Camera as mentioned above and not the ASIAIR and instead use Stellarmate/Astroberry on Raspberry Pi4. However, another thing that came up during my research on this is that EKOS may or may not be compatible with Sony A7III. I haven't heard back from Stellarmate support yet so still waiting on that confirmation.

With the Stellarmate/Astroberry (which one would you recommend out of the two for my setup and need) integration with my SA, Guide Scope, Guide camera, and Sony Camera (A7III) do you think I would be able to achieve Auto-Guiding and Dithering at the same time using EKOS/Kstars? Would I need to consider something else as well here?

Do you have any links/tutorials that I can take a look at to learn more about this setup?

TIA!

Regards,
Nick

With Star Adventurer, you can only guide and dither in RA, since DEC is manual.

Wolfgang in the comment above have provided good tutorial links. I would like to add Stellarmate Channel in to the mix as well. They provide good step by step process as well.

Clear Skies
Yogesh S