PIER-14 12 panel mosaic of the Southern part of the constellation Orion

Hi Mike,

Very interesting and I hope between us we can come up with a plan on how best to go about something like this, and any other future large mosaics. I'd like to do the area around Polaris during the galaxy season next year when there is little else suited to this setup. 


On the top of my head my immediate thoughts are:

Start off with a couple of panels and see if the integration times result in satisfactory images. Agree on a sequence for the rest of the panels and submit them 'gradually'. I don't know right now how long the imaging window will be, but if it is long enough then adding them a frame or two at a time would impact on other jobs less. 

Hopefully everyone in the Syndicate will make their thoughts known. 

The only way I know of showing the Telescopius image is taking a screenshot of it and adding it, as the example below. 

Regards, 

Ray 

i think if we are to do mosaics then the stars on the edges and corner issue needs to be resolved, right now they are really terrible and makes for a less than pleasing experience or result when processing said mosaics -  with single images atleast the corners and edges can be cropped out ....i love mosaics but for that we need to go back to native FL and remove that horrible reducer

Hi Vikas,

A very good point and something we can discuss on how we might mitigate those effects.

A decent overlap would help and using the method described by Richard in the Imaging Tips section of the forum, should make it possible to produce a very acceptable and enormous image. You can always crop out from this any individual area you would like to view closeup. Surely you're not going to pixel peep the whole mosaic?  

Personally I don't think I'd tackle the full 12 frames. When a clearer idea of the area being captured I'll likely pick a couple of 'smaller' mosaics, so I'd certainly make good use of it. 

Cheers,

Ray 

Hi Ray and others ....
while we are on the topic of the stars of Pier 1, have a look at the attached crop of the Andromeda  data set. Huge purple halos on the stars and this was not even from the corners. Even though i can fix this in processing i am very surprised that this is happening on the Tak FSQ 106 !! Cud it be a case of bad seeing or focus when the blue filter was being imaged or is it because of that reducer ? I wonder if it can get fixed....

... and the finished image ...

Very nice Vikas  

I have a proposal to do a 4 x 3 panel mosaic of the Southern part of the constellation Orion.
Every panel will be made in RGB and I propose to do per channel 30 x 2 minutes.
What do you think of this project ?
how can I copy the telescopius image to the forum ?
I tried but didn't succeed.

Mike

Mike - to get an image from Telescopius into the forum, I clip the image to the clipboard (Shift-Win-S) and then paste into a graphics program and save as a .png. Then I can upload to the forum. I don't know a more direct process.

On large mosaics, I agree with Vikas. We have to do something about the coma at the edges and also the curvature. I am struggling with the 2x2 Sadr region mosaic, because these defects are now in the centre of the final image and you have distortions flowing in different directions in the overlap regions.

I think our only option is to increase the overlap and then crop out the nasty bits before creating the mosaic. If you post your planned mosaic from Telescopius with the frame coordinates, we could crudely model how much overlap we would need and whether or not we get the target you want with a 4x3.

As a solution, may I bring up the subject again of perhaps going back to native F5 ?

The Tak 0.73 reducer was designed 10 years ago with spot sizes and correction to suit CCD cameras, very much prior to these new multi mega pixel CMOS cameras and in retrospect was a poor idea in the first place to fit to the the telescope as I believe it is has pushed the reducer to its limit and beyond trying to correct a 60million pixel camera

1. The camera and speed of scope will still only need a maximum of 300s subs[/*]
Personally (putting correction to one side) the slight decrease in FOV will make single shot framing of normal DSO's far easier without so much wasted space round the sides[/*]
It will be a better all round FOV when galaxy season arrives, which would you believe the very start of is only just over 3 months away
[/*]
Yes mosaics may need an extra panel but its still a huge FOV even at its native F5[/*]
less vignetting due to the increase in native image circle[/*]

I do understand that it was my idea when installing the pier in the first place to fit the reducer but feel it was an error on my part


We hope this Autumn if Covid does not get the better of the travel situation again, to travel over for one last trip this year so the option fingers crossed is still open for you to go native on this scope

I have fingers and toes crossed TBH as I fervently believe it will be a massive benefit to P14

Steve

Just a suggestion. If Mike could get the frame coordinates and we could agree to starting with 12 sets of luminance only data, 15 to 30 minutes only, then we'd be able to make a more informed decision. The luminance is all we need right now as it is mainly the stars we're concerned about. 

It might depend on whether or not you're trying for an APOD or wanting to print it A3 or larger as to what you're prepared to accept. A starless image with a minimal number of stars added back, maybe?

Just read Steve's take on this just before I posted. That would be for the future so maybe we ought to give it a try. 

Cheers, 

Ray 

As a solution, may I bring up the subject again of perhaps going back to native F5 ?

The Tak 0.73 reducer was designed 10 years ago with spot sizes and correction to suit CCD cameras, very much prior to these new multi mega pixel CMOS cameras and in retrospect was a poor idea in the first place to fit to the the telescope as I believe it is has pushed the reducer to its limit and beyond trying to correct a 60million pixel camera

1. The camera and speed of scope will still only need a maximum of 300s subs[/*]
Personally (putting correction to one side) the slight decrease in FOV will make single shot framing of normal DSO's far easier without so much wasted space round the sides[/*]
It will be a better all round FOV when galaxy season arrives, which would you believe the very start of is only just over 3 months away
[/*]
Yes mosaics may need an extra panel but its still a huge FOV even at its native F5[/*]
less vignetting due to the increase in native image circle[/*]

I do understand that it was my idea when in stalling the pier to fit the reducer but feel it was an error on my part in the first place


We hope this Autumn if Covid does not get the better of the travel situation again, to travel over for one last trip this year so the option fingers crossed is still open for you to go native on this scope

I have fingers and toes crossed TBH as I fervently believe it will be a massive benefit to P14

Steve

Steve,

I think this is now a good idea. When you suggested it last time we were in the middle of some large mosaic projects (which had to be restarted in the end for other reasons), and anxious to see how they came out. So there was a sense of "let's stay at the reduced FL for the moment and see what we can do".

Now we have a bit more experience and can see the problems created by the mismatch between the camera and the reducer. It is not just the star shapes it is the lack of field flatness that makes it very difficult. 

I would now vote for a change. it is swings and roundabouts for single frames, but it will make Mosaics a lot less frustrating.

old_eyes

Vikas,

Love the M31 image!

Just started processing this data and I hope I can produce an image as good as this one.

As a solution, may I bring up the subject again of perhaps going back to native F5 ?

The Tak 0.73 reducer was designed 10 years ago with spot sizes......... 

We hope this Autumn if Covid does not get the better of the travel situation again, to travel over for one last trip this year so the option fingers crossed is still open for you to go native on this scope

I have fingers and toes crossed TBH as I fervently believe it will be a massive benefit to P14

Steve

Steve,

Just to jog your memory of a telephone call on the set up about a year ago. We both had a preference for going with the native set up. At the time however you were convinced that users would prefer having the reducer fitted to make it faster at capturing data. The question of mosaics was never mentioned. At the time that was a valid commercial decision. 

Despite the downsides that have become more and more apparent, it has given us really good opportunities to capture in one set of data amazingly wide shots. Just please, please ensure that the job Simeis 147 gets completed. It is only just accommodated with the reducer fitted. I must declare a personal interest in that one.  

On the question of when, and you will not be held to it , can you give us a rough idea of the earliest you'd make a visit. That might assist us in deciding what we submit right now, trying to avoid putting in anything that might not get finished. I don't know though how we might go about that. We don't really want to end up with too many incomplete jobs that require starting from scratch., or, ending up compromising any preferred travel dates you may have in mind. 

Cheers,

Ray 

As a solution, may I bring up the subject again of perhaps going back to native F5 ?

The Tak 0.73 reducer was designed 10 years ago with spot sizes......... 

We hope this Autumn if Covid does not get the better of the travel situation again, to travel over for one last trip this year so the option fingers crossed is still open for you to go native on this scope

I have fingers and toes crossed TBH as I fervently believe it will be a massive benefit to P14

Steve

Steve,

Just to jog your memory of a telephone call on the set up about a year ago. We both had a preference for going with the native set up. At the time however you were convinced that users would prefer having the reducer fitted to make it faster at capturing data. The question of mosaics was never mentioned. At the time that was a valid commercial decision. 

Despite the downsides that have become more and more apparent, it has given us really good opportunities to capture in one set of data amazingly wide shots. Just please, please ensure that the job Simeis 147 gets completed. It is only just accommodated with the reducer fitted. I must declare a personal interest in that one.  

On the question of when, and you will not be held to it , can you give us a rough idea of the earliest you'd make a visit. That might assist us in deciding what we submit right now, trying to avoid putting in anything that might not get finished. I don't know though how we might go about that. We don't really want to end up with too many incomplete jobs that require starting from scratch., or, ending up compromising any preferred travel dates you may have in mind. 

Cheers,

Ray 

My memory is pretty good most of the time Ray, hence why i stated the error was mine, however in hindsight and knowing what we know now i wish I had not done it

I must admit with the FOV as it is,  I never envisioned member doing multi pane Mosaics as well, my bad

Hey ho you live and learn


November we hope but if that changes I will let you know!

Yes Sime 147 will be done as I will alter the software priority settings LOL. As for the other jobs., I will also manually sort things to get them finished and override the algorithms where needed (as best as I can)

Ps P3  NGC6888 will be up later, to go off topic if i may....