MLPT newbie needs help

[nakbrooks]

I’m starting to use MLPT for the first time but am confused!

 

Sequence (ver 2.2.1) has MLPT Exposure Distance in Minutes and MLPT Iterations boxes under Settings/Sequence.

 

The Exposure Details panel under Sequence Run let’s me specify whether I want to use MLPT for a set of exposures.

 

Question 1: If i specify that I want to use MLPT for a sequence does it calculate the duration from the sequence details (ignoring the Exposure Distance specified in Sequence Settings) or do I have to set that distance manually before running each sequence?

 

There is a separate MLPT section under Sequence which asks for the Total Exposure Time, Number of Exposures and Number of Iterations; run an MLPT and upload the results to Autoslew.

 

Question 2: If I specify that I want to use MLPT for a sequence (in the Exposure Details pane) will this happen automatically immediately prior to that sequence line being executed so there is no need for me to use the MLPT button on the main Sequence screen?

 

Question 3: If I do have to use the MLPT procedure on the main Sequence screen how does it know what path to follow? Does it simply start from the current pointing location?

 

Question 4: What are the appropriate values for Number of Exposures and Number of Iterations?

 

I’ve read the Sequence and MLPT documentation but it doesn’t explain some of the fundamental points and also isn’t up to date with the latest software, so I’m hoping some kind soul can help me!

 

Many thanks

 

Nigel

[MarkS]

Hi Nigel,

 

I can only partially answer your questions, because I only use MLPT via Sequence Run.

 

In this mode,  MLPT is set up by ticking the MLPT box when you set up an exposure sequence in 'Set Exposures' on the Sequence Run screen. You ignore the MLPT button on the main Sequence screen. MLPT will start at the position of the target you are going to image which has been entered via  'Set Targets' on the Sequence Run screen, and it will calculate total exposure time and number of MLPT exposures to be taken based on the settings you entered for 'Exposure distance in Minutes' and  'MLPT iterations' in the Sequence settings screen.

 

If a meridian flip has to be made during the run, Sequence will automatically do this, and calculate the new MLPT path on the flipped-to side.

 

The default settings for 'Exposure distance in Minutes' and 'MLPT iterations' can be left at 15 and 1 respectively. This will generate a MLPT point every 3.75deg along the track. If you are using very long focal lengths you may want to try 2 iterations for higher accuracy corrections, but I've never had the need.

 

(When you 'Set Exposures' don't forget to tick the 'Dither' box.)

 

Hope this helps.

 

Mark

[MarkS]

PS: I mean't to say "....don't forget to enter 3 or so in the 'Dither' box."

 

Mark

Edited July 25, 2018 by MarkS

[nakbrooks]

Many thanks Mark. I think I’m clear now how to use MLPT on a sequence run - still not sure how or why the MLPT button on the main Sequence screen is used but seems to be superfluous to my needs!

[Astrograph]

Hi Nigel,

 

Fancy meeting you here! The MLPT in Sequence is there if you want to image completely manually. So you pick your target etc, etc in Maxim and want to capture an image but use MLPT. This is how you do it. If you control your mount from Maxim then you can also add in dither. The limitation is you have to think about the practical limit of an MLPT run. In the winter when its cold all the time this can be quite long. At the moment with such a difference between day and night, the cooling down of the system will affect the accuracy toward the end of long MLPT runs.