M20 and 21, with a question.

[alan potts]

I have got about 90minutes or so on this target which is very low at between 18 and 22 degrees whilst I can see it, when it goes from sight it is not getting any better, trees for you.

On the first nights subs one of the stars has a set of spikes, where as, the second night it was not there. Now both sets were not matched up exact there was a little difference in the frames and I do mean little. I have never seen this before, what caused it?

24x 180seconds at 1600iso and 5x 240seconds.

Only bashed through PS quick to ask the question, it is struggle getting the orange colour out of the subs, I guess this is because the low position in the sky.

 

Alan

[AbsolutelyN]

Is it a permanent setup? Perhaps something in the light path internally if camera was removed and put back? Lovely image even if it is only quickly bashed through PS.

[alan potts]

Just now, AbsolutelyN said:

Is it a permanent setup? Perhaps something in the light path internally if camera was removed and put back? Lovely image even if it is only quickly bashed through PS.

Yes it is a permanent set up but I took the camera off after the first night to download, it's only a DSLR, Sometimes I take the laptop to download which I did this morning, I want to add another 45 minutes or so tonight.

Alan

[HunterHarling]

It looks like there was a tree or something in the way. Maybe the observatory roof/dome was partially in the light path?

[alan potts]

10 hours ago, HunterHarling said:

It looks like there was a tree or something in the way. Maybe the observatory roof/dome was partially in the light path?

The first nights images were definitely not near a tree and the roof slides way backwards away from it, oddly and correct as you are the second night I did start shooting with part of a tree in shot, I just waited five minutes for it to clear the tree.

Alan

[HunterHarling]

12 hours ago, alan potts said:

oddly and correct as you are the second night I did start shooting with part of a tree in shot

Did you include this data? If so, I think this caused the spikes.

[alan potts]

2 hours ago, HunterHarling said:

Did you include this data? If so, I think this caused the spikes.

No I didn'nt, I saw the issue which was the second night and didn't take the sub, the spike is on the first nights images, all of them 3 and 4 mins when it was in the clear of trees.. Interestingly I added a 3rd nights data a mere 48mins of subs and after stacking the spike has gone, though the data with it on is still in the stack, bit of an odd one, never seen it before as there should be no spikes and within a tad the scope and everything else was int he same place all three nights.

Alan.

[Rodd]

I have found that microlensing (if that is what is happening--still unsure) is intensified with high humidity, haze.   The other night I slewed to my first focus star and wham--it was like looking through a kaleidoscope.   Maybe co nditions were different from night to night?

Rodd

[alan potts]

On 05/07/2019 at 15:16, Rodd said:

I have found that microlensing (if that is what is happening--still unsure) is intensified with high humidity, haze.   The other night I slewed to my first focus star and wham--it was like looking through a kaleidoscope.   Maybe co nditions were different from night to night?

Rodd

`Thanks, Rodd, could have a point as haze was in the mix for sure the first night. It was a getting better night and the target was picked up about the same time each of 3 nights, and within a small margin framed the same, so you could have a point there. What I found even more interesting was after the 3rd nights added data, which I have not posted yet due to being away, the spike vanished. This was maybe one set of data outweighing the other.

Alan