Saturn 20/21 Sept 2024 - excellent seeing, but a host of dew related issues.....

[geoflewis]

Having missed the excellent seeing on 17 Sept due to cloud at my location, I thought that last night would be my turn. The seeing was indeed very good, but my scope didn't want to play ball, or at least the dew heater strap didn't. The poor image quality seen on screen had me thinking that maybe I was imaging through fog with a bright Moon nearby Saturn, but once I checked the corrector plate on my C14 it was clear that it was anything but clear, instead it was dripping with dew. I had to get a hair dryer to it, then once that was clear I could see that the main mirror itself was completely fogged over. I experienced this a couple of times last year and believe that running the fans had pulled moist air inside the OTA, which then condensed on the mirror. Being a closed tube, there was nothing I could do but turn the fans off and wait whilst the mirror cleared, which took about 30 minutes. However, with the dew heater strap not working, I had to repeat the hairdryer method a few times and was unable to run my usual continuous sequence of SERs, instead it was case of grab some data, apply hairdryer, rinse and repeat. I also lost the best of the conditions just hanging around. When I checked the data today the resulting SERs were a mixed bag, so I've had to pick and chose what to include. The net is that the colour image is from 6x2 min SERs captured over nearly 1 hour elapsed time, so lots of gaps in the data. The IR was from a continuous sequence of 9x2 min SERs, but later in the night when Saturn was well past the meridian and losing elevation. Anyway, I'm pleased to have salvaged something from what should have been a far better session.

The colour image has some nice colour banding, but the regions close to the limb suffer from what I suspect are gaps in data after de-rotation in WinJupos. Both images show the Cassini division quite well. The brightening from the Seelinger effect at opposition is no longer seen.

Thanks for looking.

[Kon]

Excellent images Geof. I really like the banding you have got, especially in the southern hemisphere. It's a shame excellent seeing was ruined by hardware issues. 

[geoflewis]

Thanks Kostas, it was certainly a frustrating session, but I'm glad that I hung in there and tried to make the best of it. I think the colour image is the best one I've got this year, just might have been so much better, but no point crying over spilt milk...🙄

[CraigT82]

Excellent images Geof despite the tribulations!

[geoflewis]

1 minute ago, CraigT82 said:

Excellent images Geof despite the tribulations!

Thanks Craig

[bosun21]

It's amazing to me how the nights when we are faced with difficulties and tribulations almost always fall on nights of excellent seeing. Despite this you have produced some lovely images of Saturn. Perseverance paid off. Well done Geof.

[siatnite]

Lovely shots there Geof despite the dew problems.

[Space Cowboy]

Very good images despite the dew issues! There is always something trying to frustrate us especially when seeing is good.

[geoflewis]

21 hours ago, bosun21 said:

It's amazing to me how the nights when we are faced with difficulties and tribulations almost always fall on nights of excellent seeing. Despite this you have produced some lovely images of Saturn. Perseverance paid off. Well done Geof.

21 hours ago, siatnite said:

Lovely shots there Geof despite the dew problems.

17 hours ago, Space Cowboy said:

Very good images despite the dew issues! There is always something trying to frustrate us especially when seeing is good.

Thanks all, it's not the 1st time (probably not the last) when I've experienced very heavy dew during good seeing, especially this time of the year. Still, as they say, what doesn't kill you, makes you stronger.....🙄

 

 

[morimarty]

Thats a lovely clean detailed Saturn image Geof. You have captured some excellent banding detail despite the dew on the corrector problem.

[geoflewis]

1 hour ago, morimarty said:

Thats a lovely clean detailed Saturn image Geof. You have captured some excellent banding detail despite the dew on the corrector problem.

Thanks Martyn

[Chrb1985]

On 21/09/2024 at 17:55, geoflewis said:

Having missed the excellent seeing on 17 Sept due to cloud at my location, I thought that last night would be my turn. The seeing was indeed very good, but my scope didn't want to play ball, or at least the dew heater strap didn't. The poor image quality seen on screen had me thinking that maybe I was imaging through fog with a bright Moon nearby Saturn, but once I checked the corrector plate on my C14 it was clear that it was anything but clear, instead it was dripping with dew. I had to get a hair dryer to it, then once that was clear I could see that the main mirror itself was completely fogged over. I experienced this a couple of times last year and believe that running the fans had pulled moist air inside the OTA, which then condensed on the mirror. Being a closed tube, there was nothing I could do but turn the fans off and wait whilst the mirror cleared, which took about 30 minutes. However, with the dew heater strap not working, I had to repeat the hairdryer method a few times and was unable to run my usual continuous sequence of SERs, instead it was case of grab some data, apply hairdryer, rinse and repeat. I also lost the best of the conditions just hanging around. When I checked the data today the resulting SERs were a mixed bag, so I've had to pick and chose what to include. The net is that the colour image is from 6x2 min SERs captured over nearly 1 hour elapsed time, so lots of gaps in the data. The IR was from a continuous sequence of 9x2 min SERs, but later in the night when Saturn was well past the meridian and losing elevation. Anyway, I'm pleased to have salvaged something from what should have been a far better session.

The colour image has some nice colour banding, but the regions close to the limb suffer from what I suspect are gaps in data after de-rotation in WinJupos. Both images show the Cassini division quite well. The brightening from the Seelinger effect at opposition is no longer seen.

Thanks for looking.

Really nice work as always! I can't but admire!

[geoflewis]

15 minutes ago, Chrb1985 said:

Really nice work as always! I can't but admire!

Thanks Christian