7 replies to this topic

[Doug_Hole]

I imaged Mercury the other morning with my 130mm telescope, I had a 3x barlow attached, and an ir - uv cut filter, with the zwo asi 678mc. I have a Red longpass filter, but I didn't use it because the seeing wasn't suffiecient enough and the rind artifact was very noticable in the camera view. Mercury was about 30° above the horizon. Comparing my image to a blurred Winjupos simulation, it seems that there is a chance I have captured some faint albedo features. I have to thank john Boudreu for all the advice he gave me on imaging this target aswell. I am curious whether it is possible to achive a better result with a 5" telescope, and if I am more likely to do so with my longpass filter when mercury is high in the sky. 

 

Mercury

 

Winjupos simulation

Edited by Doug_Hole, 16 April 2025 - 04:38 PM.

[Traveler]

It looks like you have the Kuiper crater already...

[Doug_Hole]

It looks like you have the Kuiper crater already...

Intresting! Can you point out where this is? 

Edited by Doug_Hole, 16 April 2025 - 07:29 AM.

[George N]

I imaged Mercury the other morning with my 130mm telescope, I had a 3x barlow attached, and an ir - uv cut filter, with the zwo asi 678mc. ......

 

Nice!

 

Consider going the other way -- use an IR pass filter!

 

I have a friend (posts at times here on CN, has written several articles for S&T) who did well enough on Mercury to show surface details - using a C-11 and IR-pass filter, daytime, that NASA requested copies of his work! It required lots of vid captures.

[Doug_Hole]

Nice!

 

Consider going the other way -- use an IR pass filter!

 

I have a friend (posts at times here on CN, has written several articles for S&T) who did well enough on Mercury to show surface details - using a C-11 and IR-pass filter, daytime, that NASA requested copies of his work! It required lots of vid captures.

I put on the Red longpass filter initially, but it gave me a very pronounced rind artifact, do I have to wait for better seeing?

[George N]

I put on the Red longpass filter initially, but it gave me a very pronounced rind artifact, do I have to wait for better seeing?

Are you talking about Newton's Rings? From Google Gemini AI -- "Newton's rings are a series of concentric colored or alternating bright and dark rings that appear when light is reflected between two surfaces, often a convex lens and a flat glass surface. This phenomenon is caused by the interference of light waves reflected off the two surfaces." And Wikipedia: https://en.wikipedia.../Newton's_rings

 

If that's your issue - it has nothing to do with sky conditions - the cause is right in your scope/camera.

 

There are many posts here on CN about Newton's Rings and how to get rid of them. I'm far from an expert - but I see lots of solar h-alpha imagers using a gizmo that very slightly angles the filter from being totally orthogonal to the light path. You have to get a tilt slight enough that it doesn't introduce other artifacts, but large enough to avoid the ring reflections. I think there are such for sale aimed at solar imagers. I don't have the problem because my solar scope's focuser is so poor that it is already tilted - so I don't get Newton's Rings. One of the few times I know of that a poorer telescope performs better. 

 

Of course "better seeing" helps everything in Astronomy!

Edited by George N, 18 April 2025 - 03:34 PM.

[Doug_Hole]

No, they are diffraction rings caused by the lowered resolution of the Red filter.

[azure1961p]

If I were optimistic enough - in the north east you need optimizum- I'd try daytime attempts.  Easy to state for someone else but if you can shade your scope and certainly the ground, you stand a chance.  Oddly we get great seeing here in daylight but not often at night, go figure.

 

Pete