Venusian clouds in IR (19/2/23)

[Kon]

I had a go at trying to capture some of Venus clouds with my IR and UV filter. I shot the images at daylight when the sun was up (1545 UTC) which I think compromised my UV results (not worth sharing. The IR pass is showing some nice darker structures (even in my unsharpened image) which are likely Venusian clouds. 8" Dob, manual, asi462mc, 2.5x TV powermate and IR pass filter. Resized 150%. (edited to add the more stretched image as well from further down)

 

 

Edited February 22, 2023 by Kon

[PeterStudz]

That’s a very good image of Venus! I did wonder if you were going to give Venus a go during daylight. And I have heard from somewhere that in the daytime UV filters don’t give worthwhile results. 

[Kon]

1 hour ago, PeterStudz said:

That’s a very good image of Venus! I did wonder if you were going to give Venus a go during daylight. And I have heard from somewhere that in the daytime UV filters don’t give worthwhile results. 

Thanks Peter. Yes I was itching for an imaging session after the awful weather the past few weeks and the clear spell yesterday afternoon was worth it; I was also kin to try early afternoon imaging, as your mobile capture was superb during daytime. The UV signal did suffer imaging with the bright sun next to it; i can see something in the UV data but I think it is more noise than signal. By the time it was darker the clouds had covered my skies. Next time 😉.

[Space Cowboy]

Terrific effort Kostas! Certainly cloud detail on that image.

[Kon]

1 hour ago, Space Cowboy said:

Terrific effort Kostas! Certainly cloud detail on that image.

Thanks Stuart. I am glad to have further verification.  I hope to try with UV filter when the weather permits and try make a composite colour image.

[Sunshine]

Impressive, that's a great image, it's so clean.

[Kon]

1 hour ago, Sunshine said:

Impressive, that's a great image, it's so clean.

Thanks. I was pleasantly surprised when I saw the stacked image.

[Space Cowboy]

Hmm....just looked on my big monitor, not sure that is cloud detail now 🤔

[CraigT82]

Very nice image… gotta be honest I’ve no idea if you have captured IR details there as it’s quite rare to see and I’m not sure what they should like through an 8” scope - they’re usually seen captured with larger instruments under v. good conditions. For reference the most recent one I know of (included below) is by Antonio Cidadao in Portugal using a 14” SCT and Baader Sloan 820nm to 920nm bandpass and the 850nm long pass captured in early Jan. You’re image certainly has the brighter area in the centre of the disk just like Antonio’s! I think it’s definitely  worth submitting to Dr Paul Abel at the BAA and getting his opinion, would certainly be a great achievement if you have managed it.

Regarding the UV captures I always had my best results in bright blue sky, I have great memories of sitting out by my scope in the sunshine whilst on furlough back in May 2020, gin and tonic in hand and Venus on the laptop screen 😃 (I was unsung Baader UV filter btw not sure what you’re using or if it makes a difference?)

[Kon]

Stuart @Space Cowboyand Craig @CraigT82 thanks for the further feedback and comments; Happy to be proven wrong if I indeed over interpreted the capture. I though the darker areas may have been the clouds in the original image. Based on Craig's images, I went back to my capture and pushed the wavelets a bit harder and I came with this more 'convincing' image? Thoughts on this one? I will also get in touch with Paul and see what he has to say and report back.

 

1 hour ago, CraigT82 said:

Regarding the UV captures I always had my best results in bright blue sky, I have great memories of sitting out by my scope in the sunshine whilst on furlough back in May 2020, gin and tonic in hand and Venus on the laptop screen 😃 (I was unsung Baader UV filter btw not sure what you’re using or if it makes a difference?)

Interesting as other reports I have read say that daylight is a killer for UV. I have a cheap Astromania UV filter but I found that I need to do 33ms exposures to get any signal though (I know the asi462 is not the most sensitive in that wavelength) and I only had 6000 frames to stack. I might look at the W#47 with IR cut as well.

[CraigT82]

9 hours ago, Kon said:

Thoughts on this

That certainly looks good to me but I’ll leave it to the ‘pros’ to critique… I’ve never managed to capture loud details in IR so I’m not qualified to! 

Yes with the UV you may struggle with a colour camera. Not sure what the QE curve below 400nm looks like for the 462mc as the chart stops at 400nm, but it looks like only the blue channel is letting anything through, as opposed to all channels at the longer end. The Astromania UV filter advert states it’s bandpass is 300nm to 400nm so quite broad and that’s probably not great for daylight imaging either. 

If you’d like I can send you my Altair GPCAM3 290mono to try it out with your UV filter? I don’t use it much anymore, just for guiding occasionally. I removed the AR coated glass sensor cover to maximise the UV signal and it performs pretty well on Venus.  
 

Edit: for info this collage was produced in 2020 with the 290m, Baader filter and my old 8.5” f/7.5 Fullerscope. All captured in bright sunny blue skies.

 

Edit 2: Just a thought, what capture parameters are you using with the UV filter and the 462mc? Checking my old posts the above images were captured with 9ms exposures at 75% gain and 90,000 frames captured, best 10% stacked.

Edited February 21, 2023 by CraigT82

[Kon]

6 hours ago, CraigT82 said:

That certainly looks good to me but I’ll leave it to the ‘pros’ to critique… I’ve never managed to capture loud details in IR so I’m not qualified to! 

Yes with the UV you may struggle with a colour camera. Not sure what the QE curve below 400nm looks like for the 462mc as the chart stops at 400nm, but it looks like only the blue channel is letting anything through, as opposed to all channels at the longer end. The Astromania UV filter advert states it’s bandpass is 300nm to 400nm so quite broad and that’s probably not great for daylight imaging either. 

If you’d like I can send you my Altair GPCAM3 290mono to try it out with your UV filter? I don’t use it much anymore, just for guiding occasionally. I removed the AR coated glass sensor cover to maximise the UV signal and it performs pretty well on Venus.  
 

Edit: for info this collage was produced in 2020 with the 290m, Baader filter and my old 8.5” f/7.5 Fullerscope. All captured in bright sunny blue skies.

 

Edit 2: Just a thought, what capture parameters are you using with the UV filter and the 462mc? Checking my old posts the above images were captured with 9ms exposures at 75% gain and 90,000 frames captured, best 10% stacked.

Thanks for the generous and kind offer on borrowing the camera (I will follow via message).  Your UV images are outstanding! So much details.

I remember Neil telling me that colour cameras are not very sensitive for UV imaging. Looking at the ASI site, the QE drops at around 40% at 400nm. I am not sure if you have seen the post from @JokubasJar who is having some nice IR and UV clouds (https://stargazerslounge.com/topic/406428-venus-irguv-feb-10th/) with a similar setup to mine. I will look into the filters he used for his UV imaging. The Astromania is giving a bad ghosting as expected for cheap filters; regarding gain i had 300 (50%) and exposure of 33ms so if up my gain it should give me a slightly faster fps.

 

 

 

 

I also got a reply from Paul who stated (this is an extract from our email exchange):

Your images of Venus do look very good!  Usually the cloud markings on Venus are best seen in UV wavelengths, however a few amateurs have recording cloud markings in IR wavelengths this past few weeks, so it does seem likely that this is what you have recorded.  I am a visual observer and I observed Venus yesterday evening with a W21 orange filter and I did notice cloud markings not to dissimilar from what you and others have recorded.

 

 

 

[Space Cowboy]

That's a great result Kostas! Please ignore my previous comment. I've never imaged Venus in ir and was doubting my initial reaction 🙂

Fantastic offer from Craig and super UV images there! 

[CraigT82]

5 hours ago, Kon said:

Thanks for the generous and kind offer on borrowing the camera (I will follow via message).  Your UV images are outstanding! So much details.

I remember Neil telling me that colour cameras are not very sensitive for UV imaging. Looking at the ASI site, the QE drops at around 40% at 400nm. I am not sure if you have seen the post from @JokubasJar who is having some nice IR and UV clouds (https://stargazerslounge.com/topic/406428-venus-irguv-feb-10th/) with a similar setup to mine. I will look into the filters he used for his UV imaging. The Astromania is giving a bad ghosting as expected for cheap filters; regarding gain i had 300 (50%) and exposure of 33ms so if up my gain it should give me a slightly faster fps.

 

 

 

 

I also got a reply from Paul who stated (this is an extract from our email exchange):

Your images of Venus do look very good!  Usually the cloud markings on Venus are best seen in UV wavelengths, however a few amateurs have recording cloud markings in IR wavelengths this past few weeks, so it does seem likely that this is what you have recorded.  I am a visual observer and I observed Venus yesterday evening with a W21 orange filter and I did notice cloud markings not to dissimilar from what you and others have recorded.

 

 

 

Well that settles it then! Very nice work Kostas 👍🏼👍🏼👍🏼 Yes I did see JokubasJar’s post but I didn’t really realise he was using an 8” scope too until looking at it again now. Fantastic stuff, conditions on Venus must be just right for it right now. 

[Kon]

5 hours ago, Space Cowboy said:

That's a great result Kostas! Please ignore my previous comment. I've never imaged Venus in ir and was doubting my initial reaction 🙂

Fantastic offer from Craig and super UV images there! 

Stuart, any feedback and discussion is always welcomed and not taking things face value is part of the fun. After all, most of us here are amateur astronomers and having healthy discussions and questions, can make us better in what we do and how we interpret our images.  I am running a research lab so I am used to the questioning/criticism, and I hope I do not sound patronising. SGL is a great environment for this.

[Kon]

2 hours ago, CraigT82 said:

Well that settles it then! Very nice work Kostas 👍🏼👍🏼👍🏼 Yes I did see JokubasJar’s post but I didn’t really realise he was using an 8” scope too until looking at it again now. Fantastic stuff, conditions on Venus must be just right for it right now. 

🙃 Thanks for telling me to get in touch with Paul, he is a great guy. I agree that @JokubasJarimages are excellent, I think some of the best I have seen with manual Dob on Venus. Since the discussion here, I found an old thread that you and Neil were discussing similar filters to what JokubasJar used on his imaging. We need more clear skies though!😆

[JokubasJar]

10 hours ago, Kon said:

🙃 Thanks for telling me to get in touch with Paul, he is a great guy. I agree that @JokubasJarimages are excellent, I think some of the best I have seen with manual Dob on Venus. Since the discussion here, I found an old thread that you and Neil were discussing similar filters to what JokubasJar used on his imaging. We need more clear skies though!😆

Thanks for the compliments! I did another capture a few days go that I will post later today. Got some very nice IR detail this time, a very prominent dark band in the northern hemisphere. My dob isn’t exactly manual btw, I have it on an EQ platform, makes things a lot easier.

[BGazing]

On 19/02/2023 at 22:35, Kon said:

I had a go at trying to capture some of Venus clouds with my IR and UV filter. I shot the images at daylight when the sun was up (1545 UTC) which I think compromised my UV results (not worth sharing. The IR pass is showing some nice darker structures (even in my unsharpened image) which are likely Venusian clouds. 8" Dob, manual, asi462mc, 2.5x TV powermate and IR pass filter. Resized 150%.

 

Very nice, which IR pass did you use?

[Kon]

1 hour ago, BGazing said:

Very nice, which IR pass did you use?

I use either the Svbony or Astromania (it came with a methane, UV and IR pass) IR pass filter; I have not personally seen any difference in quality between the two.

[BGazing]

1 hour ago, Kon said:

I use either the Svbony or Astromania (it came with a methane, UV and IR pass) IR pass filter; I have not personally seen any difference in quality between the two.

No, I meant which bandpass in nm.

[Kon]

29 minutes ago, BGazing said:

No, I meant which bandpass in nm.

685nm and 650nm respectively

[geoflewis]

Very nice result Kostas. I've done very little Venus imaging, never had the gear for it, plus it's difficult to access from my observatory early evening due to neighbour's trees, though one of then fell down a couple of years ago so things might be btter this apparion. I don't have any UV filter, so that is on my want list, but whether I get it is another matter.....

Edited February 23, 2023 by geoflewis

[Kon]

3 hours ago, geoflewis said:

Very nice result Kostas. I've done very little Venus imaging, neverb had the gear for it, plus it's difficult access from my observatory early evening due to neighbour's trees, though one of then fell down a couple of years ago so things might be btter this apparion. I don't have any UV filter, so that is on my want list, but whether I get it is another matter.....

Thanks Geof. I am using a cheap set of Astromania filters and so far so good. I have got some great suggestions to try and see if I can get something decent. I didn't fancy the price tag of the high end ones just for one planet. Looking forward to the planetary season.

[Space Cowboy]

On 21/02/2023 at 21:29, Kon said:

Stuart, any feedback and discussion is always welcomed and not taking things face value is part of the fun. After all, most of us here are amateur astronomers and having healthy discussions and questions, can make us better in what we do and how we interpret our images.  I am running a research lab so I am used to the questioning/criticism, and I hope I do not sound patronising. SGL is a great environment for this.

Thanks Kostas. I guess sometimes enthusiasm gets ahead of experience and I'm certainly no Venus expert so should have made that clear. 🙂 

Look forward to seeing your next Venus results 👍