Europa transit - 6 June 2018

[geoflewis]

Here are 3 images captured during the Europa transit of Jupiter on 6 June 2018. The seeing and transparancy were both fair early on, but by the time Europa's transit ended the haze around the horizon was thickening into cloud, also not helped by me discovering after I packed up that my dew band was not working, so the later images were being taken through increasing dew on the corrector lens.

I mixed taking images with some lovely views at the eyepiece, especialy during the period as Europa's shadow started to transit.

I hung out for a final image to try to get the GRS in view just after Europa exited transit, which I observed rather than imaged, but I lost the sky completely soon after that. However, the GRS is just peeking round the corner in the latest of the above three images.

Regards, Geof

[U Cyg]

Nice set of images. ?

Angie

[geoflewis]

1 minute ago, U Cyg said:

Nice set of images. ?

Angie

Thanks Angie

Geof

[Tommohawk]

Nice images Geof especially given the low elevation. Shame about the dew band issue -  the last one would have been great!

[geoflewis]

3 minutes ago, Tommohawk said:

Nice images Geof especially given the low elevation. Shame about the dew band issue -  the last one would have been great!

Thanks and yes a pity, but these things are sent to try us. it was a follow on from the previous night when I had issues with a home made dew heater on my Telrad which I had to repair. I hadn't realised that in messing with that I'd losened the connection to the dew band on the C14, so one thing just led to the other ?. The sky was already pretty poor by then anyway and Jupiter was heading down into the murk, so it was a combination of things that resulted in the poor quality, so I only included to show more of the transit. Cheers, Geof

[Sunshine]

Very beautiful! i can see the GRS just peeking around the limb on the third image, reminds me of the monolith scene from 2010.

[geoflewis]

Thanks Sunshine. I was hoping to capture a bit more of the GRS, but I lost the sky before I could get all the RGB frames. However, I just decided to proces what I got ,so here it is and it's not too shabby considerring I lost the sky completely about a third the way through the blue filter capture. Fortunately (or maybe not ?) there was just enough passable blue data to get something, despite the poor seeing and dew on corrector lens.

I don't know the monolith scene from 2010 (I guess it's a film, but I rarely watch any films...)

Cheers, Geof

[morimarty]

They are extremely good images Geof considering your corrector plate was misting up a problem all cat owners know only to well unfortunately?

[si@nite]

Great images Geof despite the conditions, early was definitely better seeing wise, unfortunately i car'nt get on it till later due to some very tall leylandi trees!

[geoflewis]

6 hours ago, morimarty said:

They are extremely good images Geof considering your corrector plate was misting up a problem all cat owners know only to well unfortunately?

Thanks morimarty,

Yes the dew problem can always creep and bite you. I don’t usually have a problem as I have both a 14” flexi dew shield strapped to the OTA with a dew heater band between the dew shield and OTA in line with the corrector plate. With Jupiter so low I did not expect any dew to get past those two.... As back up I have both 12v and mains hair dryers to gently encourage the dew to lift off the lens, but I hadn’t had to use either of those for a while. Lesson learnt, I still need to periodically check the lens during a long session, just in case.

Cheers, Geof

[geoflewis]

1 hour ago, si@nite said:

Great images Geof despite the conditions, early was definitely better seeing wise, unfortunately i car'nt get on it till later due to some very tall leylandi trees!

Thanks, yes the seeing was best early on. Past experience has taught me that the best seeing is often when the planets are in a blue sky. I have wondered if seeing deteriorates once the sun goes down as that is when there is the most rapid change in air temperature leading to localised air turbulance at the surface layer in the atmosphere, which stabilises again after a couple of hours.

I’m all too familiar with the tall tree problem as I had 20’ tall pesky leylandi trees along the east boundary at my last home. I took them out, but my neighbor had the same back to back with mine so it didn’t really solve the problem. When we moved to Norfolk 2 years ago, I carefully checked the boundary for trees and ended up with a far better horizon. There are trees to the north and west, but I’ve been able to site the Obs where I can still see polarise for polar alignment and all the stuff in the north gets overhead sometime during the year, so I’m ok with that. Most of my southern horizon is clear down to about 5 degrees which is great. What I have come to realise this year though is that the trees towards the west are blocking Venus in the evening, so I haven’t been able to get on that yet. Also my house is towards the east horizon so I can’t see anything there below about 25 degrees, so I think that Venus and Mercury are always going to be a challenge for me. What we really need is an observatory in an open field..., oh right, that would be what star parties are for....!!!

Cheers, Geof

[si@nite]

13 minutes ago, geoflewis said:

 What we really need is an observatory in an open field..., oh right, that would be what star parties are for....!!!

Roll on higher elevation of the planets, solve a lot of our problems Geof!

[morimarty]

1 hour ago, geoflewis said:

Thanks, yes the seeing was best early on. Past experience has taught me that the best seeing is often when the planets are in a blue sky. I have wondered if seeing deteriorates once the sun goes down as that is when there is the most rapid change in air temperature leading to localised air turbulance at the surface layer in the atmosphere, which stabilises again after a couple of hours.

Hi Geof

I think there is a lot of substance in what you say above as I've recently noticed this effect too.