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Meridian Flip with HEQ5 Pro?

Acquisition Meridian Flip Deep Sky
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schmaks avatar
schmaks avatar
Hi there,

Is there a way to know/calculate when I will need to perform the meridian flip without having to check how close my camera is getting to the mount frequently?

Or is there a way to not have to meridian flip at all midway through acquisition? Perhaps an extension to the mount?

Thanks!
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William Fewster avatar
William Fewster avatar
You could use a planetarium software or website to check what time your target will cross the meridian.
Well Written Concise
schmaks avatar
schmaks avatar
William Fewster:
You could use a planetarium software or website to check what time your target will cross the meridian.


Thanks!

Does anyone know if the ZWO ASIAIR PRO can be programmed to perform and auto-meridian flip?

Im looking to automate so I can sleep a bit more  ;)
schmaks avatar
schmaks avatar
Also… for photos after the flip… do you have to rotate them 180 degrees before stacking or do most softwares automatically do such?
mackiedlm avatar
mackiedlm avatar
Take a look at astrophotohraphy tool ( APT), https://astrophotography.app You can use it free though full is about €18. It will completely manage the meridian flip for you.

I use Astro Pixel Processor for stacking a d it deals automatically with pre a d post flip images. I think DSS does too but have not tried it.
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Sigga avatar
Sigga avatar
There 5 items on front page forum area, 4 yours on things easily looked up on Google. Are aware of Google or search engines?

Sigga
Die Launische Diva avatar
Die Launische Diva avatar
smile smile smile Thanks Sigga!
mackiedlm avatar
mackiedlm avatar
Sigga:
There 5 items on front page forum area, 4 yours on things easily looked up on Google. Are aware of Google or search engines?Sigga


That's a bit harsh. Surely one of the purposes of a forum like this is for people to ask for help. Some people learn better in a interactive type situation rather than single handedly wading through google search results.

Or am I missing something in relation to this. Is there a limit to number of questions a beginner can post? Are the forums not for people to look for help? Is it limited to only those sorts of questions that cant be answered by a google search? If the last is the case then I think the forum would be rather quiet.
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David Redwine avatar
David Redwine avatar
Schmaks,

   Stacking programs can only stack mixed data from before and after the flip if you use a triangulation or triangle similarity stacking algorithm, for high signal-to-noise subs triangles work just fine.  Higher polygonal matching algorithms are more robust and accurate, but they lack an element of mirror symmetry which is necessary to stack flipped data.

  For low S/N data you may have excessive rejection from a triangle stacking algorithm.   On a couple of occasions I have rotated the raw fits data 180 degrees before stacking  and used pentagonal or even octagonal (M97) stacking algorithms.  Compare the two versions of M97 on my page.  Stacking this data properly required  manually flipped subs (using Pixinsight)  with octagons matching in RANSAC.  For this dataset triangle and triangle similarity gave 100% sub rejection in both DSS and PIX  so I did my first stack in Photoshop.  In this case "flip-then-stack" saved the entire dataset.

Flipping the data (180 degree rotation) is NOT a lossless operation, so only do "flip-then-stack" if you have to!

My workflow WRT flipping data:
1. Process with triangle similarity alignment
2. Integrate using Windsor clipping
3. If there was significant high clipping "Blink" the registered files.
4.  If "Blink" shows star movement I flip the data and re-stack it using at least pentagons.
5. If "Blink" shows missed bad guidance frames I reject them and re-integrate.

BTW Sigga, this information would not be easy to find on Google!

David

Correction: Only triangle similarity algorithms can be used to stack mixed, flipped data.
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Eddie Pons avatar
Eddie Pons avatar
Hi there,Is there a way to know/calculate when I will need to perform the meridian flip without having to check how close my camera is getting to the mount frequently?Or is there a way to not have to meridian flip at all midway through acquisition? Perhaps an extension to the mount?

Thanks!


As someone suggested you can download APT or you can use the software I wrote (FAST) which I'm going to release for FREE in few days, maybe some weeks, and that manages the flip during the session.

Cheers.

Roberto


. Roberto! Where will your software be posted? Is it Linux only? Looks cool.
Roy Hagen avatar
Roy Hagen avatar
Does anyone know if the ZWO ASIAIR PRO can be programmed to perform and auto-meridian flip?Im looking to automate so I can sleep a bit more


Hi schmaks

No problem, you can program the Asiair to do a meridian flip
Select the option for "meridian flip" in the shooting schedule
schmaks avatar
schmaks avatar
Roy Hagen:
Does anyone know if the ZWO ASIAIR PRO can be programmed to perform and auto-meridian flip?Im looking to automate so I can sleep a bit more
Hi schmaks

No problem, you can program the Asiair to do a meridian flip
Select the option for "meridian flip" in the shooting schedule


Good to know! Thanks!