Shooting darks in the morning?

[Larry 1969]

My imaging session ran long a few days ago and, by the time I woke up it was well into the morning.
I placed the end cap over my scope (the original cover provided by Orion for my 8" astrograph) and shot my darky.
Much to my lament, my darks looked like flats! Since the scope was covered, I can only assume I have a large light leak!

Was it just a beginners mistake shooting darks in the daylight or do I have an issue worth pursuing?

Thanks!

Larry

[Juno16]

Hi Larry,

I have also had the same issue with my refractor.

After I thought about it, no wonder that any tiny amount of light infiltrating the scope would really get enhanced at say iso 800 for 3-5 minutes would contaminate the heck out of the sensor.

I only shoot darks after the lights and with black trash bags over everything because I turn on the porch light to break down.

I guess that you could use the ice chest method to shoot the darks. Thanks

[JayTee]

Is there a reason why you didn't disconnect your camera to take your darks? If you have a permanent set up then I understand why but if you don't, I never take darks on my equipment during daylight. The camera always goes into a dark closet with the lens off and the camera cover on and I use an intervalometer to take my darks. if I need my darks to be temperature controlled then it actually goes into the refrigerator in a ziplock bag, intervalometer and all.

Cheers,
JT

[Larry 1969]

Thanks for the replies!
That makes sense... I just shot them during the morning hours because the temperature was close enough.
I could use the refrigerator method I suppose... Just trying to maximize my time on target.

Larry

[JayTee]

To me, the most important frames are the lights and the flats. The darks and the bias can all be gotten and simulated later. So I don't waste night time on either of those unless I'm done for the evening and putting things away. But usually I'm too tired so I always put them off to the next day.

JT

[KathyNS]

There is a lot of potential for light leaks in daylight. The dust cover is not intended to be light-proof. And there is a substantial gap around the mirror for ventilation, through which light can enter. Better to disconnect the camera, install its body cap and shoot darks that way.

[DEnc]

There is a lot of potential for light leaks in daylight. The dust cover is not intended to be light-proof. And there is a substantial gap around the mirror for ventilation, through which light can enter. Better to disconnect the camera, install its body cap and shoot darks that way.

+1 on that! I seal off an interior room with opaque plastic, have the exterior lights off, and cover the camera with black-out cloth. The dark libraries I shoot go up to 30 minute exposures so I pull out the stops.

This, in spite of having previously shot some darks with black-out cloth over various parts of the camera, leaving some parts exposed to daylight, to determine if there were light leaks--none seen in ~5 min exposures.

[DMouse]

Personally I shoot a set of darks and bias for a library about every 6 months. That way I can control, temp and darkness so I have a good library control set to use for processing. I have an astro shed, so shoot mine during cloudy or windy nights when I am not imaging. The only calibration frames I shoot on the night of imaging are flats.I even used to do this with my DSLR, by putting an ice block in a cooler bag and putting the camera in there. Using BYEOS to control and capture the images and sort out for average temp groups later on.

Clear Skies and good luck!

[yobbo89]

yes light can leak pretty good, filter wheels t adapters, you name it, it will find any nook and cranny, taking darks on the scope at night with a lense cap should be fine, make sure you do it on a cloudy night, i wouldn't recommend it at day time.