Topics

First Image with the new mount! #iexos-100

@Huangdi
 

Sooooo, it's been two months since I bought the iExos100, the weather didn't like me. And neither did the mount at first. 

But after getting past those issues, I managed to gather ~5 hours of integration time on M31. It's a flawed image, due to my bad optics, but I'm more than happy with the performance of the mount. It had no issue whatsoever to produce very good stars at 7 minute sub length (300mm+APS-C) and I'm pretty sure I could, if i wanted to, push it to 10min. 
Gear:
Nikon D3300
Sigma 100-300 F4
iExos 100
ASI 120mm guide camera
Processing done in DSS&PS

Let me know what you think!

Wes Mcdonald
 

Julian:

Nice!

--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

brian skinner
 

Brilliant, can I ask what stacker software you use? please.
Kind regards, Brian 

On Sun, 25 Aug 2019 12:35 julian.shroff1 via Groups.Io, <julian.shroff1=googlemail.com@groups.io> wrote:
Sooooo, it's been two months since I bought the iExos100, the weather didn't like me. And neither did the mount at first. 

But after getting past those issues, I managed to gather ~5 hours of integration time on M31. It's a flawed image, due to my bad optics, but I'm more than happy with the performance of the mount. It had no issue whatsoever to produce very good stars at 7 minute sub length (300mm+APS-C) and I'm pretty sure I could, if i wanted to, push it to 10min. 
Gear:
Nikon D3300
Sigma 100-300 F4
iExos 100
ASI 120mm guide camera
Processing done in DSS&PS

Let me know what you think!

jrichard333 <jrichard333@hotmail.com>
 

Howdy,

 

Very new to galaxy captures.  I mostly do planetary imaging.  For me it is way easier.  But a C90 can only do so much J

 

Not understanding the bad optics.  I think the image looks good.  The color is beautiful.

 

If you pixel-peep, you can see some of the stars have an oval shape and at the edges, you can see some small star trails.

 

I have a couple of questions.  I plan on doing some accelerated learning after I am done with capturing Mars sometime in late September to Early October:

1.       How many individual frames were captured at 7-minutes? 

2.       How many did you discard if any?

3.       Did you do dark, light, and bias frames as well?

4.       Did you use a Bahintov mask in order to adjust your focus?

 

JR 

 

From: MAIN@ESPMC-Eight.groups.io [mailto:MAIN@ESPMC-Eight.groups.io] On Behalf Of julian.shroff1 via Groups.Io
Sent: Sunday, August 25, 2019 6:35 AM
To: MAIN@ESPMC-Eight.groups.io
Subject: [ESPMC-Eight] First Image with the new mount! #iexos-100

 

Sooooo, it's been two months since I bought the iExos100, the weather didn't like me. And neither did the mount at first. 

But after getting past those issues, I managed to gather ~5 hours of integration time on M31. It's a flawed image, due to my bad optics, but I'm more than happy with the performance of the mount. It had no issue whatsoever to produce very good stars at 7 minute sub length (300mm+APS-C) and I'm pretty sure I could, if i wanted to, push it to 10min. 
Gear:
Nikon D3300
Sigma 100-300 F4
iExos 100
ASI 120mm guide camera
Processing done in DSS&PS

Let me know what you think!

@Huangdi
 

Thanks Brian! I use DeepSkyStacker 

@Huangdi
 

On Sun, Aug 25, 2019 at 07:57 AM, jrichard333 <jrichard333@...> wrote:

Howdy,

 

Very new to galaxy captures.  I mostly do planetary imaging.  For me it is way easier.  But a C90 can only do so much J

 

Not understanding the bad optics.  I think the image looks good.  The color is beautiful.

 

If you pixel-peep, you can see some of the stars have an oval shape and at the edges, you can see some small star trails.

 

I have a couple of questions.  I plan on doing some accelerated learning after I am done with capturing Mars sometime in late September to Early October:

<![if !supportLists]>1.       <![endif]>How many individual frames were captured at 7-minutes? 

<![if !supportLists]>2.       <![endif]>How many did you discard if any?

<![if !supportLists]>3.       <![endif]>Did you do dark, light, and bias frames as well?

<![if !supportLists]>4.       <![endif]>Did you use a Bahintov mask in order to adjust your focus?

 

JR

Thanks a lot! Regarding the "bad optics", I absolutely love the lens. But it shows severe coma (which causes the stars in the corners to trail off towards the respective corner). The oval shapes are probably a mixture of chromatic aberration and my sensor not being perfectly aligned, I modified it myself and I didn't do enough research (duh, stupid me.) but I'm working towards fixing that.
As for your questions,
1. I took 23 Frames at 7 min, but that was only last night, in the two nights before I used 2 min and 3 min frames (simply because I didn't think the mount could handle it, boy was I wrong.). 
2. I discarded 5 frames due to satellite trails/heavy tracking errors (a tractor passed by lol)
3. I don't take dark, bias or flat frames. My sensor is pretty decent for nightphotography and it's fairly easy to get rid of most of the noise through dithering, so darks and bias are not really needed. Due to the fact that I use a camera lens I don't need flats either, Lightroom has pre-installed lens profiles, which almost completely negate the vignetting.
4. I am using a Bahtinov mask, however with camera lenses it's always tough to hit perfect focus because of the imprecise movement.

I hope that helps :p

jrichard333 <jrichard333@hotmail.com>
 

Thank you Sir,

 

The information you provided will assist me greatly.   I have a Sigma 150-600mm lens which I will be using for galaxies and other DSOs.  I am pretty sure I will encounter chromatic aberration as well since there isn’t a lens profile for the Sigma on my Canon 70D.  98% of my imaging software is freeware.  I am not a fan of yearly software licensing software.

 

I was considering picking up a light pollution clip-in filter until I started thinking about dust entering the chamber.  

 

Twenty-three frames is excellent.  I have an external intervalometer, so it should be pretty easy to set things up.  The other concern I had was shutter counts; but the Canon 90D looks pretty good J.  I just have to make sure it has digital zoom.

 

Thank you again for the tips, I will start looking into plate solving and dithering.  My main issue is seeing Polaris and other stars through trees and street lights.   

 

Thank you again.

 

JR                                                                                                             

From: MAIN@ESPMC-Eight.groups.io [mailto:MAIN@ESPMC-Eight.groups.io] On Behalf Of julian.shroff1 via Groups.Io
Sent: Sunday, August 25, 2019 10:13 AM
To: MAIN@ESPMC-Eight.groups.io
Subject: Re: [ESPMC-Eight] First Image with the new mount! #iexos-100

 

On Sun, Aug 25, 2019 at 07:57 AM, jrichard333 <jrichard333@...> wrote:

Howdy,

 

Very new to galaxy captures.  I mostly do planetary imaging.  For me it is way easier.  But a C90 can only do so much J

 

Not understanding the bad optics.  I think the image looks good.  The color is beautiful.

 

If you pixel-peep, you can see some of the stars have an oval shape and at the edges, you can see some small star trails.

 

I have a couple of questions.  I plan on doing some accelerated learning after I am done with capturing Mars sometime in late September to Early October:

<![if !supportLists]>1.       <![endif]>How many individual frames were captured at 7-minutes? 

<![if !supportLists]>2.       <![endif]>How many did you discard if any?

<![if !supportLists]>3.       <![endif]>Did you do dark, light, and bias frames as well?

<![if !supportLists]>4.       <![endif]>Did you use a Bahintov mask in order to adjust your focus?

 

JR

Thanks a lot! Regarding the "bad optics", I absolutely love the lens. But it shows severe coma (which causes the stars in the corners to trail off towards the respective corner). The oval shapes are probably a mixture of chromatic aberration and my sensor not being perfectly aligned, I modified it myself and I didn't do enough research (duh, stupid me.) but I'm working towards fixing that.
As for your questions,
1. I took 23 Frames at 7 min, but that was only last night, in the two nights before I used 2 min and 3 min frames (simply because I didn't think the mount could handle it, boy was I wrong.). 
2. I discarded 5 frames due to satellite trails/heavy tracking errors (a tractor passed by lol)
3. I don't take dark, bias or flat frames. My sensor is pretty decent for nightphotography and it's fairly easy to get rid of most of the noise through dithering, so darks and bias are not really needed. Due to the fact that I use a camera lens I don't need flats either, Lightroom has pre-installed lens profiles, which almost completely negate the vignetting.
4. I am using a Bahtinov mask, however with camera lenses it's always tough to hit perfect focus because of the imprecise movement.

I hope that helps :p

brian skinner
 

Hi Julian, many thanks. I'll look into Deepskycapture certainly. I'm new to astro photography so I need to go one step at a time here. I presume (and hope!) that DSC is reasonably intuitive?
Kind regards, Brian 

On Sun, 25 Aug 2019 16:03 julian.shroff1 via Groups.Io, <julian.shroff1=googlemail.com@groups.io> wrote:
Thanks Brian! I use DeepSkyStacker 

brian skinner
 

Sorry Julian, should have said Deepskystacker. Kind regards, Brian 


On Sun, 25 Aug 2019 16:03 julian.shroff1 via Groups.Io, <julian.shroff1=googlemail.com@groups.io> wrote:
Thanks Brian! I use DeepSkyStacker 

@Huangdi
 

Hey Brian,

for astrophotography standards, I'd say DSS is very intuitive. There are a good bunch of tutorials on the web on how to use it, but basically all you have to do is put in the light (and dark/flat/bias if you wish so) frames and let it do the work.

Here's a short excerpt of a small astrophotography guide I'm writing, it's not even close to being complete but it might help you :)


Import the .TIF Files as Lights into DSS

WHEN USING MODERN DSLR + LENS: NO DARK/BIAS/FLAT FRAMES  NEEDED !! (assuming you pre-processed the raw frames and converted them to .TIF files)

Register checked pictures -> Select Best 85% ; Advanced -> Compute number of detected stars, should be ~100-200

Set stacking parameters → Kappa-Sigma Clipping

Save as 16-Bit TIF (Save picture to file…) Make sure not to use the Autosave file (It’s 32bit)

brian skinner
 

Hi Julian many thanks for this, much appreciated. I had problems loading DSS unfortunately I think because I have an older 32 bit PC. I presume DSS requires a 32 bit platform.
I have now successfully loaded the last Sequator 32 bit version so will try this for my stacker. One question I do have if I may; how do you convert the camera RAW files to TIFF files? Both DSS and Sequator require or recommend this for successful processing.....
Any help on this would be appreciated Thank you, Brian, 

On Mon, 26 Aug 2019 11:00 julian.shroff1 via Groups.Io, <julian.shroff1=googlemail.com@groups.io> wrote:
Hey Brian,

for astrophotography standards, I'd say DSS is very intuitive. There are a good bunch of tutorials on the web on how to use it, but basically all you have to do is put in the light (and dark/flat/bias if you wish so) frames and let it do the work.

Here's a short excerpt of a small astrophotography guide I'm writing, it's not even close to being complete but it might help you :)


Import the .TIF Files as Lights into DSS

WHEN USING MODERN DSLR + LENS: NO DARK/BIAS/FLAT FRAMES  NEEDED !! (assuming you pre-processed the raw frames and converted them to .TIF files)

Register checked pictures -> Select Best 85% ; Advanced -> Compute number of detected stars, should be ~100-200

Set stacking parameters → Kappa-Sigma Clipping

Save as 16-Bit TIF (Save picture to file…) Make sure not to use the Autosave file (It’s 32bit)

@Huangdi
 
Edited

Hey Brian, 

I use Lightroom to pre-process my lights, I use the lens profile of my lens to remove the vignetting and apply some small steps like reducing the highlights and the blacks to get rid of bloated stars/background noise.

There are many people who swear on leaving your lights untouched, in my opinion that doesn't matter when using DSLR's but hey, it's a never ending discussion. Alternatively you can use something like Adobe dng converter, it's free as far as I know. 

brian skinner
 

Many thanks again Julien. I'm waiting for clear skies now but will see how I go with just my DSLR and Sequator (which appears to be loaded successfully),
Kind regards, Brian 


On Tue, 27 Aug 2019 16:51 julian.shroff1 via Groups.Io, <julian.shroff1=googlemail.com@groups.io> wrote:

[Edited Message Follows]

Hey Brian, 

I use Lightroom to pre-process my lights, I use the lens profile of my lens to remove the vignetting and apply some small steps like reducing the highlights and the blacks to get rid of bloated stars/background noise.

There are many people who swear on leaving your lights untouched, in my opinion that doesn't matter when using DSLR's but hey, it's a never ending discussion. Alternatively you can use something like Adobe dng converter, it's free as far as I know. 

Jim McKee
 

Beautiful detail. Also in the context of DSLR and telephoto lens with EXOS-100 you produced a beautiful result. I am working the same target, and I guess I need more subs and better focus to achieve what you have done.  The color variations and dust lanes are great.   Congratulations.
Jim 
--
Scope:        Orion EON 115mm APO
Mounts
:      ES EXOS2-GT w/ PMC-8
Cameras:   Canon 6D Astro Mod, Canon 7D2, 1D Mk 2, EOS 60D Asto Modified
Lens:
          Canon EF 100-400mm f/4.5-5.6L IS II
Misc:          TELRAD, ZWO ASI120MM Guide Camera, Astromania 60mm Guidescope, Senso Sesto Focus Motor
Software:   EXPLORESTARS IOS & WIN, Stellarium. Backyard EOS, StarTools, APT, DSS
Computer:  Dell Latitude E5450, Windows 10

Joe Izen
 

Julian,
I’m new to the DSO world. I’ve mostly done planetary imaging. I understand that the length of time one chooses is based on the stability of the mount and the reliability of tracking. What ISO were you you using, and more importantly, hoe you decided what to use. Did you make use of histograms? If so, is the goal to prevent stars from saturating, or does one boost the iso and saturate stars in order to get the DSO recording at some set fraction of scale? I suspect every object is a bit different, but what are the rules of thumb?
Thanks,
Joe

@Huangdi
 
Edited

Hey Jim, thanks for your kind words. I actually reprocessed the entire image, it lacked sharpness and was oversaturated. I think the new version is much better and looks more natural.

Good luck with getting more subs/focus, I can't wait to see the result ! :)

https://drive.google.com/open?id=1bsfFfDXzoaq51yu_wvni6ZD3ifYImbin

@Huangdi
 

Hey Joe,

the length of your subs depends on a lot of factors. 

1. The noise level of your camera = the higher the temperature of your sensor rises, the more noise it will introduce. For DSLR's, I would limit the exposure to 10minutes (Narrowband only)

2. The brightness of your target= Objects like the Andromeda galaxy or the Orion Nebula are extremely bright. Shooting for longer periods of time will cause the highlights to clip (pure white) and be rendered useless. In those cases you have to either shoot with shorter sub exposure length, or take shorter ones for the bright areas and create an HDR image.

3. The quality of your skies = My skies aren't amazing, but they're more than many APers have (Bortle 3-4). That allows me to do long exposures, up to 7 minutes, without having a white image. When imaging from a city, you'll want to keep it short in order to preserve your highlights.

4. Your ISO in correlation with your histogram. Ideally you want your subs to be at 1/3 of the histogram from the left. Using the vast knowledge of the internet, you can quite easily figure out the ISO setting that gives you the highest dynamic range (in my case, ISO 200). At that point it's simply a matter of testing. If 5 minutes are needed to get a decent histogram at ISO 200, and your skies/mount/camera allow it, then that is what you should be doing. Otherwise you can always shoot at a higher ISO, or expose shorter.

If your guiding isn't on par or your skies won't allow it, 2min subs at ISO 800 will still give you great results!

I hope this helps&sorry if it's too much information. AP is quite complicated and imo there are no shortcuts to knowing what to do :D