MLPT Question

[john32712]

Hey Guys,

 

I am hoping that someone will know the answers to my questions. I have read through the manuals and cannot find any answers. So here goes...

 

I now use MLPT on each and every run that I perform. I consistently get 15 -20 min subs with perfect stars each and every time. But there is a couple of things that I am not sure of.

 

1. When my MLPT run has completed, it is automatically sent to Autoslew. I notice by increasing the "CalcFourier" value I can get better numbers (sometimes, not always). Do I just hit the "Send to Autoslew" button? Can someone describe this process?

2. Does everyone use MLPT or are some of you using Superfit and not using MLPT?

3. I would be curious to know some of your routines...

 

Thank you,

 

John Nemcik

[MarkS]

Hi John,

 

I can't answer your first question - I always leave the Resolution at the default setting of 3. (I have a vague memory from some time back to the effect that going for a higher resolution was generally not of much value - but I hope someone can answer this, as I, like you, would like to know)

 

Regarding MLPT, I always use it. As my set-up is mobile, I'm careful to get an accurate PA (

 

Usually, I then go straight to MLPT using the last 3 star config. My standard subs are 5 min for LRGB and 10 - 20min for NB. Non-round stars are not an issue for me - unless something has gone wrong in the above routine! My understanding is (someone will no doubt correct me if I'm wrong!) that MLPT has advantages over a large pointing file, including better performance if there's hysteresis in the system.

 

If I particularly require accurate pointing across the meridian flip, I make and use a 10 or 15 star pointing file before MLPT.

 

I never image more than one target in any one session, so my comments are in that context.

However, if you are going to many positions in the sky for short exposures during a session, I imagine MLPT would not be very practical.

 

Mark

[john32712]

Thanks Mark!

 

Without any updated documentation, I hate to just assume. So I really appreciate your response. Great stuff!

 

My setup with the DDM85 is fixed, so I would be curious to see what others will say. Most importantly, what should my goals be for PA, MLPT, and/or superfit.

 

Best,

 

John Nemcik

[si6pack]

Hi John,

 

Sorry I can not comment on Q1, since my I left the "CalcFourier" as it was when I installed SEQ and I use MLPT only during my SEQ-runs.

 

As Mark, I use a mobile setup of my DDM85 on a wheelybar - I can confirm what Mark is posting: First I do a 3-star polar alignment using SEQ. This normally brings the PA error down approx. 3"; depending on schedule, I do a second PA to limit the PA error to

 

With these preparations in place I do a SEQ-run (one or two objects per night) using MLPT - my last sessions were perfect (if you look in this forum, I had lots of trouble of solving MLPT frames using SEQ while external solves worked out perfectly - this issue went away, I do not know why, but I am happy for that ;-) ).

 

Meridian Flips are no issue, SEQ automatically starts with an additional MLPT run and sends the data to AS. 

 

Christian