Hesiodus crater ray phenomenon

[Nyctimene]

Once again, this lunar light-shadow phenomenon will be observable Thursday evening. A cleft in the wall of the neighbouring crater Pitatus projects a triangular light ray (like a searchlight) across the floor of crater Hesiodus for several hours. Beginning: March 30th, 20.20 (UT).

Next occasion will be May 28th, 22h00min UT, according to this:

http://www.lunar-occultations.com/rlo/rays/hesiodusp.htm

A magnification of 100x and more is recommended; and you may have a look, if you can spy the concentricity of the small crater Hesiodus A close by.

Good luck with the hunt!

Stephan

Edited March 31, 2023 by Nyctimene

[Grump Martian]

Thanks for your post Stephan. I call myself a visual observer. Having looked at your picture of Hesiodus crater and trying to find it in my Hamlyn Atlas of The Moon, failed to correctly locate it. Clouds swept in and that was it. I will do some more learning before the next event.

[Nyctimene]

Was lucky enough to spot the Hesiodus ray just now in a short cloud gap between two rain showers. The Heritage 130 P Flextube, equipped with the 2.25x Baader Turret barlow and the Seben 8-24 mm zoom, showed again it's qualities as a perfect grab-and-go scope. At 22h 30min CEST, I found the light ray already fully evolved, as a tiny searchlight, projecting an obvious light spot at the W crater rim. Hesiodus' floor was still completely dark, as was the interior of Hesiodus A, so no concentricity visible here. Seeing was moderate, allowing magnifications of around 150-170x. The third time for me to spot this event. Next time, I'll try to observe the opposite phenomenon, the Pitatus ray, but for that I will have to rise in the morning hours (waning moon). Have a look:

http://www.lunar-occultations.com/rlo/rays/pitatus.htm

Stephan

Edited March 30, 2023 by Nyctimene

[maw lod qan]

I wanted to get a look, but oh my is Sol still bright in our sky!

I also had to work with an occasional cloud.

Searched through Lunar maps and was able to locate the crater in Mare Nubrium.

I am always amazed when reading information about the Lunar surface. 4000' height on the crater walls.

 

[Littleguy80]

Thanks Stephan! Managed to catch this tonight. A first for me with my 80mm frac and Nagler zoom. Really neat to see this. Enjoyed the straight wall feature too. Has always been a favourite.

[Knighty2112]

Just been out with my 80mm ED ‘frac and spotted this with 5mm EP with 2x Barlow fitted. Moon was hazy to see but beam on crater floor was easy to spot still. Thanks for heads up.  

Edited March 30, 2023 by Knighty2112

[josefk]

That is absolutely lovely - the sketch that is. I am putting a reminder in my phone for the 26th July so thanks for the tip off!

Edit - i've just taken a look at the table on your link - what value is it in that table that gives the hint that the 26th July is good but not 29th April, 28th May etc. i am completely new to this level of "detail" in more ways than one.

Cheers

Edited March 31, 2023 by josefk

[Nyctimene]

6 hours ago, josefk said:

That is absolutely lovely - the sketch that is. I am putting a reminder in my phone for the 26th July so thanks for the tip off!

Edit - i've just taken a look at the table on your link - what value is it in that table that gives the hint that the 26th July is good but not 29th April, 28th May etc. i am completely new to this level of "detail" in more ways than one.

Cheers

The drawing is taken from the net - my own drawing skills are very rudimentary. It's showing the details more clearly than most of the photos I've found.

To answer your question: you pointed me to a mistake I've made accidentally! Of course, the ray's visibility will depend  on the moon's night visibility. So, the second column, giving the UT time, is important. April 29th, the ray will appear at 9h36min UT; and I assume, that it can't be made out in the daylight, due to low contrast. But I omitted the next occasion May 28th, 22h00min UT - a good opportunity (albeit starting at midnight); I cannot recall, why I made this mistake. I shall correct this in my first post. Thank you for the hint!

Stephan

[josefk]

Thanks. I shall put several dates in my phone then 👍🏼

[Nik271]

I managed to see the ray this evening (18 Feb 2024) at about 18:00 with my 102mm ED F7 refractor, using magnification of x120. There was some passing cloud and in the gaps between the clouds the bright ray on Hesiodus floor  was evident framed by dark shadows on both sides. It looked  to me like a bright door opening on the crater rim and letting the light in.

Edited February 18 by Nik271

[Nyctimene]

Another favourable occasion to observe the Hesiodus ray will be in about two weeks, Wednesday 17th April, during the evening hours. The given time 18:54 (UT) may vary a bit, so have a look an hour before or after this time. The phenomenon itself will last for several hours, and will start as a bright patch on the W wall of Hesiodus, slowly expanding to the crater floor, and finally showing the triangular form, as shown in the drawing above.

If you miss this occasion, the next one will be June 15th, 19:12 (UT).

On 18/02/2024 at 21:05, Nik271 said:

It looked  to me like a bright door opening on the crater rim and letting the light in.

Exactly my impression; so let's hope for clear weather to "open the door" for many of us!

Stephan

[dweller25]

Thanks for the heads up 🙂

[dweller25]

Just bumping this as a reminder for Wednesday evening….

[Nyctimene]

Hesiodus crater ray this evening (18.54 UT). Weather forecast not promising here in SW Germany; best wishes for clear skies to all of you in other parts of Europe!

Stephan

[Stu]

Trying here, but waiting for some cloud to pass. Hope I haven’t missed it all.

[Stu]

Remarkably I managed to see this through the little 76mm. Not the clearest view as I was cloud dodging, but clear enough for me to be certain. Just had to drag a wet scope in from an unexpected shower, fortunately scope and eyepiece was capped although the finder is a little damp!

[dweller25]

It’s totally clear here and stopped raining just in time 🤣😄🌝🤪🥳

I have been viewing/ drawing since 18:45, watching a fan shaped beam of light gradually getting longer, will post some drawings tomorrow…..

Edited April 18 by dweller25

[Stu]

5 minutes ago, dweller25 said:

It’s clear here and stopped raining just in time 🤣😄🌝🤪🥳

I have been viewing/ drawing since 18:45, watching a fan shaped beam of light gradually getting longer, will post some drawings tomorrow…..

Excellent, better views than me by the sounds, nice one.

[Captain Scarlet]

Things were looking optimistic early evening. There’s clear sky north but moon area has remained stubbornly covered. 🤞 

[Mr Spock]

Just been looking at it. The shadow is receding slightly now, but it's still a good view.

[IB20]

Managed to grab a few iPhone snaps with the SM125. 

[Stu]

4 minutes ago, IB20 said:

Managed to grab a few iPhone snaps with the SM125. 

Excellent! Wish I had a bigger scope with me but glad I shoved the FC-76DCU in so I could have a chance of seeing it 

[Captain Scarlet]

Yippee I got it! fast-moving cloud with a good few gaps. I used my 88mm Kowa spotting scope with Delos 4.5 inserted giving 113x. Awkward angle of course but once seen it leapt out. Very pleased.

Magnus

 

[Stu]

13 minutes ago, Captain Scarlet said:

Yippee I got it! fast-moving cloud with a good few gaps. I used my 88mm Kowa spotting scope with Delos 4.5 inserted giving 113x. Awkward angle of course but once seen it leapt out. Very pleased.

Magnus

 

Astronomia postulat adlatum as per the WAG motto 👍👍

[John]

I've just managed to catch some of this event with a hurried deployment of my Tak FC100-DL after completely forgetting about it.

Nice to see at least some of the effect.

Thanks to @dweller25 for "bumping" the original thread as a memory jogger - my memory seemed to need more "jogging" than usual this evening though 🙄

Hats off to the Tak as well for being able to give sharp views at 250x straight out of the house !