Jump to content

Narrowband

Winjupos question


Adam1234

Recommended Posts

Just trying to get the best out of winjupos for derotating some stacked images of Jupiter from last weekend and I have a question on the latitude and longitude coordinates. 

If my coordinates are 50°54'N and 1°25'W, would I enter +001 25 or -001 25 for longitude?

Link to comment
Share on other sites

10 minutes ago, CraigT82 said:

West of meridian is minus, east positive.

Cool that's what I thought. Oddly, when I put my long. As +001 25, my image came out OK, but with a bright ring on the limb, but when I used -001 25 it came out blurred.

I was playing around with manual alignment of the outline rather than automatic, to try and get more accurate alignment so maybe the blurring was just an unsuccessful attempt at manual alignment. I'll try again tomorrow

Edited by Adam1234
Link to comment
Share on other sites

I've just done an experiment where I inputted my longitude as both -001 25, and +001 25, and in both cases the de-rotated images are coming out blurred, whereas my first attempt didn't.

I think I now know why - I think the automatic detection is getting north the wrong way. I'm sure I remember on my first attempt that it was putting north on the other side. I'm not sure why it would be getting this wrong now though? 

Is anyone able to confirm that the automatic detection is indeed wrong, and perhaps why?

In the meantime, I will give it another go and rotate the outline by 180 to see if it works.

 

image.thumb.png.4eba3d61cfac7fa277b2ecb6d3cb24a4.png

 

the resulting blurry derotated image

53256298_2022-09-18-2354_5-2022-Jupiter_positivelongitude.jpg.ec47cff91ed55909276497749bcac4aa.jpg

 

My first attempt, which worked ok, except for the bright limb on the right hand side

Jupiter_180922_version1.jpg.781de14fc19eb145e92445366f974740.jpg

 

 

Link to comment
Share on other sites

14 minutes ago, Adam1234 said:

I've just done an experiment where I inputted my longitude as both -001 25, and +001 25, and in both cases the de-rotated images are coming out blurred, whereas my first attempt didn't.

I think I now know why - I think the automatic detection is getting north the wrong way. I'm sure I remember on my first attempt that it was putting north on the other side. I'm not sure why it would be getting this wrong now though? 

Is anyone able to confirm that the automatic detection is indeed wrong, and perhaps why?

In the meantime, I will give it another go and rotate the outline by 180 to see if it works.

 

image.thumb.png.4eba3d61cfac7fa277b2ecb6d3cb24a4.png

 

the resulting blurry derotated image

53256298_2022-09-18-2354_5-2022-Jupiter_positivelongitude.jpg.ec47cff91ed55909276497749bcac4aa.jpg

 

My first attempt, which worked ok, except for the bright limb on the right hand side

Jupiter_180922_version1.jpg.781de14fc19eb145e92445366f974740.jpg

 

 

Hi Adam, yes, its wrong its hyper rotated. North on that image is sitting directly above the south equatorial belt. so, it should be reversed. Next time you catch Jupiter it would likely help if you captured the planet fairly straight. Makes life easier to see if nothing else. Also try dropping the LD value to 50 for that bright limb on the right. 

Edited by neil phillips
  • Thanks 1
Link to comment
Share on other sites

29 minutes ago, neil phillips said:

Hi Adam, yes, its wrong its hyper rotated. North on that image is sitting directly above the south equatorial belt. so, it should be reversed. Next time you catch Jupiter it would likely help if you captured the planet fairly straight. Makes life easier to see if nothing else. Also try dropping the LD value to 50 for that bright limb on the right. 

Great, thanks, weird how the automatic detection is getting it wrong!

Link to comment
Share on other sites

2 hours ago, neil phillips said:

It can't tell N from S unfortunately. But once the measurement circle goes beyond either the north side or south side. Automatic detection does kick in I have found.

Ah ok that makes sense. 

Link to comment
Share on other sites

The auto detection only works for the overall size of the planets disk and the rough alignment of the equator with the cloud belts… you have to check yourself if the north and preceding are set correctly.

As Neil says the bright limb is very common and can be mitigated by adjusting the LD value when you do the derotation. Can also be sorted in post process too to a certain extent. 
 

Nice image btw lots of detail 👍🏼

  • Thanks 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.