Re: What's the effect of imaging through jet stream?
What do the stars look like when you take the system out of focus like for a focus run? Are they nice concentric circles or do they go from round to oval to any one of a number of shapes? This can be a rough look at seeing. The type of seeing can do different things (high seeing like from the jet stream to local seeing from heat rising off of a building). If you are imaging through a river of moving air, you are likely to see this in your images. If your system has returned round stars consistently, and all of a sudden it doesn't then something has changed. If you haven't moved, adjusted, screwed with the imaging train or instrument, changed software settings, anything like that then seeing can be a potential culprit. If the system has struggled to return round stars and the issues you described are not new, then there is another issue and differential flexure is a likely suspect. If the jet stream is overhead with that river of fast moving air, seeing will likely be poor.
Mike J. Shade
Mike J. Shade Photography:
In War: Resolution
In Defeat: Defiance
In Victory: Magnanimity
In Peace: Goodwill
Sir Winston Churchill
Already, in the gathering dusk, a few of the stars are turning on their lights.
Vega, the brightest one, is now dropping towards the west. Can it be half
a year since I watched her April rising in the east? Low in the southwest
Antares blinks a sad farwell to fall...
Leslie Peltier, Starlight Nights
International Dark Sky Association: www.darksky.org
firstname.lastname@example.org [mailto:email@example.com] On Behalf Of Cheng-Yang
Tan via groups.io
I used a guide scope that is 4.59 arcsec/pixel (focal length 168 mm). Scope is a FSQ106. I plan to image again tonight. Again, the jet stream seems to be quite bad: 45 m/s. So if there's anything else to check, I'm open to suggestions.
P.S. I will be upgrading to OAG next week after my SBIG Starchaser SC-2 arrives. This is in preparation for an Adaptive Optics AO-8A in the future.
On Saturday, May 30, 2020, 02:32:25 PM CDT, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:
Are you using an off-axis guider or separate guide scope? What is the main scope you are imaging with?