Tuesday, 31 January 2023
  3 Replies
  458 Visits
0
Votes
Undo
  Subscribe

hi,

i was blinking thru the data set of 1894 Sh2-232 just uploaded recently. I see many frames having a huge jump away from its intended framing. I notice this in a lot of other data sets but it was quite prominent in this data set. I had to nearly throw away a 100 frames which is 500 mins of imaging time lost.

 

How do other subscribers deal with this huge jump of framing. Do they keep this as part of the dataset and let it integrate with the rest of the correct framing subs or do they also throw away the incorrectly framed subs?

 

In any case, the root cause of this needs to be investigated and fixed....

 

best

 

vikas

0
Votes
Undo

Hi Vikas, 

Just finished using Blink to look at the data and without using SubframeSelector to do a more thorough quality check, I found for me that 76 out of the 269 subs need to be rejected. Apart from the numbers I am in agreement with your assessment. 

Yes I agree that there is a huge jump between the initial sub of a mini session and subsequent subs on this target, much more than any I've seen. For this target there is no choice but to reject them, but as you said, in other instances it is not such a clear cut choice. 

The ones that I will reject on the basis of the initial misaligned first sub are :

Ha 9/48,   O3 18/131,   S2 16/90.

In addition to those there were 6 O3 subs of a slightly different region, RA 05h 37m and +35d 36m. Those were captured on 20230126 starting at 19:42:16. This happens occasionally. 

Others that I will reject because the data appears to be poor are:

O3 21/131,   S2 6/90

There could be more like those and that would require checking using the SubframeSelector. 

With regards to the earlier job 1748 for which this job is to collect additional data, I don't think I've looked at it yet. Not sure if I want to right now. :)

The variation in the amount of jump by target is strange and I suppose will have to wait for the next visit. 

Cheers, 

Ray 

 

 


Ray
Roboscopes Guinea Pig


0
Votes
Undo

Hi Vikas, 

After saying that I wouldn't I reluctantly went through the earlier job, #1748. I now agree with your numbers, and also discovered something.

From a combined total of 465 subs I will reject 129 of them. Those rejected on the basis of poor quality are 69 in total, with the remaining 60 due to misalignment.

What I did find is that the jump prior to sometime in the first week of September 2022 is just about acceptable. On that basis I will use all the decent subs from job 1748 except those captured from September 5th. That means only rejecting 11 of the subs where there is a large jump. In addition 42, mainly S2, were of poor quality.

The initial conclusion is that something happened to the mount around September 4th or 5th causing the large problem we now have with long exposures. HTH. 

Cheers,

Ray 


Ray
Roboscopes Guinea Pig


1 year ago
·
#5836
0
Votes
Undo

hi,

i was blinking thru the data set of 1894 Sh2-232 just uploaded recently. I see many frames having a huge jump away from its intended framing. I notice this in a lot of other data sets but it was quite prominent in this data set. I had to nearly throw away a 100 frames which is 500 mins of imaging time lost.

 

How do other subscribers deal with this huge jump of framing. Do they keep this as part of the dataset and let it integrate with the rest of the correct framing subs or do they also throw away the incorrectly framed subs?

 

In any case, the root cause of this needs to be investigated and fixed....

 

best

 

vikas

The SkyX was recently updated and has Possibly corrupted its model. I will check and put in a fresh one. 

Please remember that syndicate data sets are not pre-checked so sometimes these small issue are not immediately apparent.

Peter


Peter Shah - Collimation & Telescope servicing.
Visit my personal imaging website at astropix.co.uk
For Image Processing Tutorials
Contact: pete@ccdimaging.co.uk


We can supply your new high quality Newtonian or Dall Kirkham Astrograph

Peter Shah
Roboscopes Observatory Controller


  • Page :
  • 1
There are no replies made for this post yet.
Be one of the first to reply to this post!

Follow Us

Newsletter

Proud to use

  • FLI

  • 656 Imaging

  • 10 Micron

  • Planewave

  • ZWO

Company Details:

Roboscopes

802 Kingsbury Road
Birmingham
B24 9PS
United Kingdom


Roboscopes is a trading name of ENS Optical LTD ¦ Copyright© 2020 Roboscopes