PEC - Any tips / guidance?

[swag72]

In order to improve my guiding I have decided that the first thing I will do is PEC. So, looking in the handbook with the scope, it seems I need an illuminated eye piece - So, is there a way to carry this process out in a different way to the manual?

If there is, can I use the QHY5 through the guide scope or would I need to connect it directly to the main scope itself?

[bamus]

i would say main scope is better than guide scope. Use as much magnification as possible.

[swag72]

Thanks Bamus - Any way around the illumintated eye piece or do I have to buy one of those?

[bamus]

you would need illumintated eye piece only in case you would do it manulay. Using PHD you can let your camera do the job.

[themos]

Hello, I guess you are reading the PEC instructions in this SynScan manual (page 11):

http://www.skywatchertelescope.net/swtsupport/Instruction_Manuals/SynScan%20240406V2.pdf

The way I see it you don't need an illuminated crosshair eyepiece. Just stick your QHY5 (pixel pitch 5.2 microns) in your 120ED (900mm focal length). That should give you 1.2 arc-seconds per pixel which should be enough resolution.

Then fire up PHD and connect the QHY5 to it but not the mount. I think PHD will give you a crosshair reticle superimposed on the preview image. So you don't NEED a reticle eyepiece. Just watch the PHD preview and run the PEC training on the SynScan handset.

NB: I've never done this. I have done PEC recording using EQMOD though.

[swag72]

OK that makes sense Thermos - Sorry for all the silly questions, but I am really struggling to understand what is going on and how to achieve it.

Here is the guide on how to dift align with PHD - I am stuck at the VERY beginning of where to locate the stars for the 0 degree meridian. I live in a bit of a bowl, surrounded by hills and woodland and do not know how to achieve seeing this star. Also, in which direction do I point for the meridian? North?

To check the RA alignment chose a star at 0° elevation close to the meridian. To set the DEC alignment choose a star as close to the E or W horizon as possible.

1. Turn on the guiding program (PHD) , select the mount and camera and run thru your calibration a usually. This bit is OK - I can manage this!!
   
2. To Check the RA select a star near the Meridian at 0° elevation. As above, don't know how to locate a star - In what direction do I point, North?
   
3. Start Guiding on the selected star.
   
4. Turn on the GRAPH and select DX/DY instead of RA/DEC.
   
5. Turn off the DEC guiding
   
6. If your mount is perfectly aligned the DY ( red line) should track across the graph near the center line. If it drift up or down you need to make a very small adjustment to your AZIMUTH screws to compensate for that. You will see the change immediately. No need to wait 5 or 10 minutes for the visual drift.
   
7. Now set up the elevation. Set up what elevation? Confused.
   
8. Stop the guiding and look for a star near the western or eastern horizon at whatever elevation allows you to clear any obstruction. The lower the better.
   
9. Recalibrate the guiding on the new star.
   
10. As in step 3,4 & 5 above start guiding and make sure that the DEC guiding is off.
    
11. Once again if your alignment is on then the DY trace should not drift from the horizontal graph line. If it does, carefully mar small adjusts to the ELEVATION screws to compensate. Again you should see an immediate change in the graph.
    

I am so sorry for being so stupid and asking such simple questions over and over. Is there a guide for this with pictures and examples somewhere? Thanks for being so patient everyone - You really must be banging your heads on a brick wall by now.

** Edit ** Just realised I'm talking again about drift alignment - Not PEC - Oh man, I am SOOOOOOO confused. How do I PEC with PHD?

[Psychobilly]

I would get your PA nailed before worrying about PEC... I have never used it...

Billy...

[swag72]

Oh Billy, I am just falling at every hurdle. Everything may as well be written in chinese for all the sense this is making to me. Can you help on the above post, the bits I've written in blue?

[themos]

Did you watch my Youtube video on the principle of what we are trying to do?

For drift alignment, you first pick a star in the South about half-way up in the sky. If you're in England, tonight, Aldebaran (orange star in Taurus) would be perfect for this at around 8pm. Or Rigel (bottom left blue star in Orion).

[swag72]

Yes I did watch it, but the speech was really hard to hear so missed a lot unfortunately.

I'm in Spain, so will these stars still be OK?

[themos]

Oh forget the speech, it's awful, just read the captions.

Yes, the two stars should be ok in Spain, one is a bit above the equator and one is a bit below but close enough. In Spain, they'll be higher in the sky than in England.

[swag72]

For drift alignment, you first pick a star in the South about half-way up in the sky. If you're in England, tonight, Aldebaran (orange star in Taurus) would be perfect for this at around 8pm. Or Rigel (bottom left blue star in Orion).

Are these for the RA meridian? (Sorry sure I'm using all the wrong terminology) What stars would be good for the DEC setting?

[SteveP]

To check the RA alignment chose a star at 0° elevation close to the meridian. To set the DEC alignment choose a star as close to the E or W horizon as possible.

1. Turn on the guiding program (PHD) , select the mount and camera and run thru your calibration a usually. This bit is OK - I can manage this!!
   
2. To Check the RA select a star near the Meridian at 0° elevation. As above, don't know how to locate a star - In what direction do I point, North? The Meridian is due South. Have alook at Stellarium to see roughly where the 0 degree elevation is. But don't worry too much cos it isn't that critical
   
   
3. Start Guiding on the selected star.
   
4. Turn on the GRAPH and select DX/DY instead of RA/DEC.
   
5. Turn off the DEC guiding
   
6. If your mount is perfectly aligned the DY ( red line) should track across the graph near the center line. If it drift up or down you need to make a very small adjustment to your AZIMUTH screws to compensate for that. You will see the change immediately. No need to wait 5 or 10 minutes for the visual drift.
   
7. Now set up the elevation. Set up what elevation? Confused. This is really referring to what Steps 8 & 9 are about to do
   
   
8. Stop the guiding and look for a star near the western or eastern horizon at whatever elevation allows you to clear any obstruction. The lower the better.
   
9. Recalibrate the guiding on the new star.
   
10. As in step 3,4 & 5 above start guiding and make sure that the DEC guiding is off.
    
11. Once again if your alignment is on then the DY trace should not drift from the horizontal graph line. If it does, carefully mar small adjusts to the ELEVATION screws to compensate. Again you should see an immediate change in the graph.
    

I hope my comments help you! Sorry but i don't use PHD so can't advise on what the other references are. I could guess but that wouldn't be helpful to you!

My general advice would be to try and resolve one issue at a time. Polar Alignment is difficult enough without worrying about PEC as well. As Psycho, oops I mean Billy says, PA is more important than PEC at this stage. When you've mastered PA, and done ot several times, then turn your attention to PEC

HTH

Steve

[swag72]

Very helpful thanks Steve - Watched the video Thermos and it makes the reason for the alignment very obvious - Thank you.

[themos]

Are these for the RA meridian? (Sorry sure I'm using all the wrong terminology) What stars would be good for the DEC setting?

The stars in the south (the "meridian") are used for the AZIMUTH adjustment of the mount's polar axis, that is, the left-right adjustment. I'm not sure where you found the term "RA meridian", it's confusing.

For the up-down adjustment ("altitude" or "elevation") of the polar axis, you need a star in the East (or West), fairly low down but above 15-20 degrees (to avoid distortions by the atmosphere). The reason is that stars in that part of the sky appear to rise up the fastest and so will show up up-down alignment errors the quickest.

[themos]

Remember that in both adjustments, we are looking for deviations of the star not along the tracking direction (the RA coordinate) but the direction perpendicular to it, the Declination direction. If you look to the South, declination goes up/down. If you look to the East, declination goes up+left/down+right.

[davew]

Hi Sara,

I've read your posts with interest. I can tell you want to do this imaging thing properly. So, I'll now say, " My advice is free and worth every Euro "

As you've said elsewhere, you've only just got your gear. That tells me one of the most important parts of imaging will be missing. That's a solid routine. What I mean is that when you set up you need to do things one at a time in the correct order. Each of these things needs to be done right. I'm assuming you're setting up the mount level and solid and you're balancing for the area of interest. What you must have is a good Polar alignment routine. PEC, DSS, photoshop and all other fancy things will come undone if the mount is not aligned properly. Even guiding will fall apart because you will get rotation showing in your subs even if the guiding is the best it can be and there is no PE.

I've looked up your location in Google Earth and assume you have more clear nights than we do. Go back to basics and nail each step until the mount almost looks after itself.

Boring old devil aren't I ?

I can't give you advice re your gear because I use a totaly different Mount.

Dave.

[themos]

If Sara shot the images in swag72's album, she's doing splendidly so far!

[davew]

Does it sound like I'm knocking her efforts ? If it does I apologise. No slur intended in the least. I think Sara is producing more good photos than me. ( Not hard )

I'm more referring to the post that's showing bad rotation. PEC doeasn't cure that.

Perhaps I should think more about my posts and word them another way. This isn't the first time people have taken offence.

Dave.

[themos]

Goodness, no, Dave, I didn't take it like that at all!

[davew]

So sorry. Now I'm getting the wrong end of the stick.

Themos. You were quite right pointing it out.

Sara. Ignore me. If I lived under some of the best skies in Europe I'd want it right. I have fancied a trip to Cala Alto for a while. Bit south of you.

Dave.

[swag72]

Hey guys, absolutely no offence taken in any of your posts - I really appreciate the help you are all giving me. This is a challenging and extremely frustrating time as I thought I was doing things right with the PA and I guess that maybe I'm not. I am methodical in my approach, with a little neumonic to make sure I don't forget anything!

I guess that I just want everything to work well from the off. I easily become uptight and frustrated when things don't go well and generally then I just give up. I'm trying hard not to go into that frame of mind at the moment.

I appreciate your comments about my pics so far in my album, perhaps that's the problem, these are OK and I thought I'd be able to take them to another level with the minimum amount of hassle. Clearly not!

So I am waiting for the next cloudless night. I'll not be doing any imaging, just running through the PA steps with PHD - I already suspect that the graph will be laughable and hope that I can get it to some thing more useful. I know that I will ask loads of stupid questions along the way, and just thank you all for being so patient with me as I lurch from one crisis to another in my head!!

[Whippy]

FWIW Sara, a lot of people don't bother with PEC. Unless your mount has real mechanical issues, your guiding system should iron out any little errors your mount might have during it's use. See how you go with getting your mount polar aligned and take it from there.

I'd also echo Dave's point about getting into a routine, it might sound a bit OCD but getting organised and setting up the same way does make life a darn sight easier. It does take time, but you're making big strides so don't worry, you'll get there soon enough .

Tony..

[Psychobilly]

Stick at it Sara...

Sorry couldnt reply earlier ... work soemtimes gets in the way... a neccesary evil... I have never used PEC either...I Just let the guiding take care of it...

Billy...