Equipment Tuning

After working since 1730 to replace the NP101 with the Meade yesterday, I began final preparations for the imaging session at 1945. There was not a cloud in the sky when I began setting up, but high thin clouds were present by the time I was finished.

In addition to putting the Meade on the G11, I also replaced the lightweight tripod that the TeleVue had been sitting on with the heavy tripod, so that evolution ended up being a from the ground up take down and set up. Other than me having somewhat of a down day with respect to my endurance, the switchover went very smoothly. I just had to pace myself and take many short breaks.

After experiencing the light panel issue a couple of sessions ago, I added a step early in my DSO work plan to check it with the idea that I could have time find and fix the fault before the end of the session if it didn’t illuminate. It would not illuminate last night. I didn’t spend too much time on it before I ran out of ideas.

I used wall power last night, so I am not calling this session a full dress rehearsal.

There were high thin clouds over most of the sky when I began powering up and was completing final preparations at 1945. The temperature and dew point were 72F and 51F, respectively. Surface air was still. Astrosphereic was calling for transparency to be average to above average and average seeing until about midnight.

The initial camera that was used for lunar closeup imaging was the ASI178MC. I was able to easily complete the lunar imaging between polar alignment from 2115 to 2126 and end of astronomical twilight at 2226. I had the ASI6200 in place for imaging M13 and was working on its initial focus by 2222.

By the time that I got started on the Moon, the clouds had dissipated, but there was a halo around the moon. By that I mean the moon appeared to be suspended within a bright orb that was maybe 2x the moon’s apparent diameter. This was not a circular moon dog.

Seeing looked pretty bad in the Firecapture display. As it would turn out the moon was right over the cottage as viewed from the telescope. That couldn’t have been helpful either. Littrow Valley (Apollo 17 site) was the only target that I bothered shooting. I am not expecting much in the way of image quality.

Changing cameras went pretty well, especially for an activity that I haven’t practiced in the dark. I took about 15 minutes.

First I focused the main camera. That didn’t go too well. Having the dew shield on the scope kept me from putting the Bahtinov mask in place, so I focused the main camera by watching FWHM numbers. Doing it that way seemed harder than it needed to be, and I could not get the FWHM below 5. Not sure if that was due to atmospheric conditions.

I seems that having the dew shield/heater on the front of the Meade and achieving critical DSO focus are incompatible. Putting the shield on after focusing and start up seems to apt to perturb polar alignment, alignment with the celestial sphere, and focus, so I need to re-think this.

Next I attempted to focus the guide camera, and again I could not get the FWHM below 5, same problem as with the main camera.

I was not able to calibrate PHD. There were only two to five stars visible in the display at any one time. This could be due to the atmosphere, or the focal length of the scope. I am well accustomed to working with 540 mm of focal length and f/5.4, but not 2430mm and f/8. When I tried calibrating, PHD would not hold a guide star due to the low SNR. I am thinking that the long focal length and slower optics is not going to be a viable guiding set up. Perhaps I should try a separate guide scope.

On top of these issues, I was tired, so I ended the session at 2253. It temperature and dew point were 65F and 52F, respectively. There was no dew on the grass or metal surfaces, which was consistent with the temperature being 13 degrees warmer than the dew point.

Between the halo around the moon and bad seeing in the Firecapture display, and difficulty focusing the 6200 and guide cameras, I do not believe that the sky conditions were as good as Astrospheric was reporting. HAL called an impromptu last night, so I’ll be on the lookout for what they have to say about conditions.

I didn’t mess around too much with wifi RDT connections. I went straight for the Ethernet cable, so I still need to test to see if the firewall adjustment made any improvement.

I think that I have achieved a change in mindset regarding sessions that do not go well in the back yard, and that is to regard them as finding opportunities to fix problems before I get to a dark site. And, practicing telescoping and imaging skills is always important. With this mindset, less than stellar 😊 sessions represent useful progress.

Leave a Reply