The Owl Nebula & Messing with Filters

[PeterStudz]

Nice little session on Sunday 3rd March that included testing/trying out a secondhand Astronomik OIII filter which had just arrived in the post, well, on the very day, from @bosun21. It arrived with some clouds, but not enough to completely stop play! This to add to my Astronomik UHC, also purchased secondhand from SGL. And to make things more interesting I chose a target I hadn’t successfully seen.

I’d not yet been able to see M97 - the Owl Nebula - from my light polluted Bortle 7 back garden, which is the only place I’ve tried. Conditions on the night weren’t great with poor seeing and below average transparency. But at least the moon was out of the way and M97 at a good altitude. I used the PushTo feature in the smartphone app PS Align Pro which always gets me on target. But looking through a low power eyepiece M97 simply wasn’t there. I tried averted vision and at one point, but only for a brief split second, thought I could see something. Mind, I couldn’t be sure it wasn’t my imagination. But, when I tried the OIII filter there it was -  M97 - right in the centre of the FOV. Sure, it was just a faint fuzzy circle without detail, but no averted vision necessary. Really surprised that it would make the difference of not seeing anything to seeing something. Looking forward to trying it out again & experimenting (plus the UHC). Hopefully at a dark(er) site too.

I was going to play around with different eyepieces, but clouds were coming in and I decided to try and take a smartphone image. First without the filter and then hopefully with. I did this via the AstroShader app which I’d last used properly and described here way back in May. Using the apps live view quickly showed the outline of M97 on the phone screen. It’s like a simple EEVA and in this case showing something that I couldn’t see without a filter. I took a shoot using a few subs, but that clearly wasn’t enough, so took a few more and by luck got a decent image. I’m still not sure on all the app settings. And I could see the “eyes” of M97 in the image! A bit of editing in the app and on the phone gave the resulting image. Honestly I’m pleased with that. I don’t think It’s an easy smartphone target! 

Unfortunately thicker clouds soon rolled in and I called it a night. I had work in the morning, so probably just as well. Would the image be any better using a visual OIII filter? I’m not sure. 

03/03/24, Southampton urban back garden, Bortle 7. SkyWatcher 200p Dob on DIY EQ platform. BST StarGuider 25mm. iPhone 14 Pro on no-brand smartphone adapter. Image taken via the AstroShader app. Cropped plus basic editing only on the phone using AstroShader, WaveletCam & Lightroom. 

Edited March 5 by PeterStudz

[Roy Challen]

That's great! I was expecting something barely visible and without colour.

[Saganite]

11 hours ago, PeterStudz said:

Nice little session on Sunday 3rd March that included testing/trying out a secondhand Astronomik OIII filter which had just arrived in the post, well, on the very day, from @bosun21. It arrived with some clouds, but not enough to completely stop play! This to add to my Astronomik UHC, also purchased secondhand from SGL. And to make things more interesting I chose a target I hadn’t successfully seen.

I’d not yet been able to see M97 - the Owl Nebula - from my light polluted Bortle 7 back garden, which is the only place I’ve tried. Conditions on the night weren’t great with poor seeing and below average transparency. But at least the moon was out of the way and M97 at a good altitude. I used the PushTo feature in the smartphone app PS Align Pro which always gets me on target. But looking through a low power eyepiece M97 simply wasn’t there. I tried averted vision and at one point, but only for a brief split second, thought I could see something. Mind, I couldn’t be sure it wasn’t my imagination. But, when I tried the OIII filter there it was -  M97 - right in the centre of the FOV. Sure, it was just a faint fuzzy circle without detail, but no averted vision necessary. Really surprised that it would make the difference of not seeing anything to seeing something. Looking forward to trying it out again & experimenting (plus the UHC). Hopefully at a dark(er) site too.

I was going to play around with different eyepieces, but clouds were coming in and I decided to try and take a smartphone image. First without the filter and then hopefully with. I did this via the AstroShader app which I’d last used properly and described here way back in May. Using the apps live view quickly showed the outline of M97 on the phone screen. It’s like a simple EEVA and in this case showing something that I couldn’t see without a filter. I took a shoot using a few subs, but that clearly wasn’t enough, so took a few more and by luck got a decent image. I’m still not sure on all the app settings. And I could see the “eyes” of M97 in the image! A bit of editing in the app and on the phone gave the resulting image. Honestly I’m pleased with that. I don’t think It’s an easy smartphone target! 

Unfortunately thicker clouds soon rolled in and I called it a night. I had work in the morning, so probably just as well. Would the image be any better using a visual OIII filter? I’m not sure. 

03/03/24, Southampton urban back garden, Bortle 7. SkyWatcher 200p Dob on DIY EQ platform. BST StarGuider 25mm. iPhone 14 Pro on no-brand smartphone adapter. Image taken via the AstroShader app. Cropped plus basic editing only on the phone using AstroShader, WaveletCam & Lightroom. 

That's a lovely image Peter, and amazing that you got it with a smart phone !

  I tried to see this on Monday but failed , transparency simply not good enough.

[PeterStudz]

On 06/03/2024 at 07:18, Saganite said:

That's a lovely image Peter, and amazing that you got it with a smart phone !

  I tried to see this on Monday but failed , transparency simply not good enough.

Thanks! I prefer visual, but do find the smartphone only images fun and interesting. And to see what I can do with something that I already have. It doesn’t cost anything and if I need to use a computer or laptop then for me it loses that straightforward simplicity. Not that I have a computer or laptop! They are also handy to help record my sessions - especially if I tag an observation report to the image. 

Transparency is one of those things that you learn to appreciated with experience. On that night I’d already taken a look at M81 and M82. Something that I’m familiar with. And this confirmed that transparency could have been better. I’d certainly seen these two better in the past from my back garden.

The app that I used - AstroShader - does a good job of keeping the background sky dark when under an urban sky. When taking a smartphone image through a telescope, using the stock camera app, it also magnifies the surrounding light pollution. And you then need to go through a load of hoops trying to minimise it. Which is why you are always at an advantage (aren’t you always!) when taking a smartphone image at a dark/darker site.

Edited March 8 by PeterStudz