Re: Newt/Mak-Newt and body heat

Dan wrote:

I'd like to know what your experiences have been with body heat affecting
your newtonian or mak-newtonian telescopes. I have found that during very
cold nights heat radiating from my body to the front of a MCT can degrade
images. I repeatedly moved away from the scope and always returned to find
the image a little steadier, then turning noticeably unsteady. This happens
when observing at high powers. Was it my imagination or have others
experienced this? What have you done to resolve the problem?

It is more likely to be from the plume of warm air rising off you than any radiative effect. Wearing a hat and a thicker coat would help.

Radiative heating would be pretty uniform unless you put your hands very close to one side of the scope. And more commonly there is stronger radiative cooling of the sky facing side of the OTA.

You can see the phase errors across the aperture in the defocussed star image - putting a hand into the light path of a Newtonian will show the air currents rising.

Regards,
Martin Brown
.