Phew !!

[John]

I had an interesting observing experience this evening. Having been to an outreach event earlier tonight, my 12" dob is packed in the car. When I got back and after I'd warmed up, I decided to put my Tak 100 refractor out to have a look at some double stars as the "night was young" as they say.

Although the Tak cools very quickly I gave the scope 20 mins before popping an eyepiece in and taking a peek at Theta Aurigae, normally a strightforward split with this scope at 150x and upwards. I was rather shocked when my eye was greeted with a star image that simply refused to come to sharp focus. I dropped the magnification a bit to 150x but still could not get anything like a clear airy disk and single fine diffraction ring which is the norm for this scope. I moved the scope to Capella and was greeted again with a very untidy star image at focus and worse either side of focus. Very odd 

I bought the scope in and checked out the optics. They seemed entirely as normal and a collimation check with a cheshire eyepiece showed no collimation issues whatsoever. I swapped diagonals just in case and put the scope out again. 15 minutes later and pretty much the same results. I was starting to worry that my lovely Tak had been knocked without me knowing

I did occur to me that the seeing conditions might be to blame so I put my ED120 refractor on the mount, gave that scope another 20 minutes to cool and observed Theta Aurigae again at the same powers that I'd been using with the Tak - 180x and 225x. Now I got a much better image and close to what I'd expect from these refractors under reasonably conditions. Not perfect but a decent split of this uneven brightness pair.

Not being able to find any obvious fault with the Tak refractor, I added it to the mount alongside the ED120 and allowed a further quarter of an hour for the Tak to cool down again. Popped a 4mm eyepiece in the scope and, voila !, a near perfect high power image of Theta Aurigae !

Moving from scope to scope the views were just what I would expect from them both now - clear splits even at 300x and well defined primary and secondary stars.

I have to say that I was moe than a little relieved but I soon told myself that I should have had more faith in the scopes and less in the variability of the UK seeing conditions. I guess what happened was that a high level cloud of ice crystals passed over when I had the Tak initially out, and this distorted the image massively so the poor scope could do virtually nothing with it. By the time I'd got the ED120 outside the cloud had largely passed over and by the time the Tak was out for the 2nd time, the seeing was back to a decent level.

It was a good lesson learned as to just how much short lived atmospheric effects can impact our hobby, taking the seeing from absolutely diabolical to pretty good in less than an hour. And I can happen the other way around of course ....

 

   

 

[Tim]

The night is STILL young John  Hoping to get another few hours in yet.

You are right, there was a load of very high thin stuff passing over earlier, patchy as well. Things have settled somewhat now though, and so far no problems with dew or rapidly dropping temperatures, which don't do us astrophotographers many favours.

My warm room is very warm with a heater on, and if I open the door to the telescope department, the view goes ridiculously bad. But! I'm keen to give the new EP (31mm Nag) a run out tonight, one way or another, so at some point will need to open the portal and retrieve the 10" from the corner of the observing room.

[Tim]

Ok, now the night is old......off to bed

[Ags]

Weirdest thing I've ever seen in a telescope in bad seeing: TWO in focus but slightly distorted Saturns.

[domstar]

14 hours ago, John said:

my 12" dob is packed in the car.

 

14 hours ago, John said:

I decided to put my Tak 100 refractor out

 

14 hours ago, John said:

so I put my ED120 refractor on the mount

I like your style. I suppose it's always good to have options.

[jam1e1]

glad all ok John! Interesting to hear as I had a similar experience like that too a while back, with my APM where couldn't get to focus . I thought also it was down to scope also until tried it next night and all ok. Strangely enough couple nights later had the best few of jupiter in a long time, ultra sharp and really clear - goes to show skies play a big part! glad to say got my confidence back in the scope  

[Moonshane]

Funnily enough I was surprised how bad things looked last night in my 12" dob at about the same sort of time. I put it down to my being spolit slightly by the 120Ed  and its tight stars but perhaps I  was suffering the same issues.  Still, I found a new to me galaxy so not all bad