Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_30_second_exp_2_winners.thumb.jpg.b5430b40547c40d344fd4493776ab99f.jpg

Sign in to follow this  
ecuador

UV/L/IR Moon

Recommended Posts

I thought I'd post my image from last month, since we don't see these posted often.

So, I shot through a Venus U filter, an Orion Imaging and a 640nm IR-pass, assigning them to B,G,R respectively (and boosting saturation to great levels as the moon is very reflective on all those frequencies). Each of those images was actually a mosaic of 3 subframes made by processing videos shot with an ASI290MM. I used my least sharp OTA, the 130PDS, since I wanted to avoid lenses/correctors for the UV filter.

Moon-130PDS_UV_L_IR_20170504.thumb.jpg.db44756bdc8f50f15b08b1e15578cd7b.jpg

Before I got the mono camera, I had tried one with my color Altair IMX224, but as it is much less sensitive to UV, the UV image was closer to the visible (and noisier), so there was some "extra" curve manipulation (the above is pretty much extreme contrast boost instead) which I would call "cheating", but you can also call "artistic":

Moon-130PDS_UV_L_IR_20170407.thumb.jpg.e01c488aa1ca6381dc41710c912aea57.jpg

 Same technique otherwise, although the smaller sensor required 4 frames to capture the whole moon. I documented my processing in a blog post if you are curious.

  • Like 9

Share this post


Link to post
Share on other sites
8 minutes ago, michael.h.f.wilkinson said:

Very nice idea! I must get one of those Venus UV filters and try this with the C8

Supposedly the corrector plate cuts a lot of UV, but it might still be usable. I haven't yet tried my C9.25 to tell you for sure. The ED refractor blocks everything though :)

Share this post


Link to post
Share on other sites
Just now, ecuador said:

Supposedly the corrector plate cuts a lot of UV, but it might still be usable. I haven't yet tried my C9.25 to tell you for sure. The ED refractor blocks everything though :)

I have seen shots of Venus with the UV-Venus filter taken with an SCT, so I assume it could work.

Share this post


Link to post
Share on other sites
8 hours ago, michael.h.f.wilkinson said:

I have seen shots of Venus with the UV-Venus filter taken with an SCT, so I assume it could work.

It depends a bit on which Venus U filter you have. I have the Optolong version (you can find it at Agena), which has a sharper cutoff over 350nm, so it is less suited for SCTs than the Baader. Both are bad with refractors of course, especially APOs...

Share this post


Link to post
Share on other sites
3 hours ago, ecuador said:

It depends a bit on which Venus U filter you have. I have the Optolong version (you can find it at Agena), which has a sharper cutoff over 350nm, so it is less suited for SCTs than the Baader. Both are bad with refractors of course, especially APOs...

I will go for the Baader, in that case. I know SCTs pass a good deal of Ca-K (393nm), but I am not sure of transmission beyond that. Correction of spherical aberration will be somewhat off, and seeing problems abound at the shorter wavelengths, but with the filter being useful for two targets instead of a single one, it makes the (quite considerable) outlay more worthwhile.

Share this post


Link to post
Share on other sites

Very interesting approach. I guess the 9.25 corrector plate could cut UV as would the cover plate on the cam. No idea of the wavelengths affected though. Thanks for posting.

Share this post


Link to post
Share on other sites
1 hour ago, Owmuchonomy said:

Very interesting approach. I guess the 9.25 corrector plate could cut UV as would the cover plate on the cam. No idea of the wavelengths affected though. Thanks for posting.

Well, the second image I posted was through a color camera that is not UV sensitive, so I guess you could try out even something like a Blue filter, the image will be too close to the "full visual" spectrum image so you might need some creative processing to bring out any difference like I did. But it did come out pretty :)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.