What Could Cause This?! All Of A Sudden - Super-Blown Stars?

[bobford55]

 

Half way through an imaging session I started getting big trouble around my brighter stars? Dew heaters working okay. Cant imagine what could suddenly happen to do this?

 

Any thoughts appreciated!

 

I am using a Skywatcher ED(), 0.85 reducer and Canon 1100D.

 

Many thanks

 

Bob

[admin]

Looks like dew is building up on your OTA.  You may need a dew heater... or just use a hair dryer and blow worm air on your lens.

 

Regards,

[PoppaChris]

I often need to use both a dew shield and a dew heater. It gets awfully humid down here in Louisiana.

[Dirty Harris]

Bob, something very much like this happened to me back in Dec. 2014. I was imaging on "Orion" and getting very good seeing and transparency, stars were crisp and bright, when suddenly they began to go fuzzy, and had a similar halo around them as yours did. Checked my Astro-zap dew shield and it's heater , everything was A-OK. Then just as suddenly everything cleared up. Come to find out it was the neighbors fireplace smoke that would waft my way that evening with just a slight breeze, right over my field of view for a few moments then dissipate. There was no moon that night to see it with the naked eye but it was evident through the scope. The give away was I smelled it and judged the breeze direction and sure enough that was it. May not have been your problem, but that was my experience. No equipment problems just winter in Colorado and smoky fireplaces.  Dirty Harris. Colo.