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thanks for all of that, so what would be the ideal procedure to follow on setup. at present im polar aligning in sharpcap then over to phd2 to calibrate and run guide assistant to check polar alignment. it came back as 0.8 error, wish i'd copied that screen to post, i will tonight. fast moving to the idea of building a 250mm concrete post, fixing the mount to it and making a small waterproof housing. 

heres the last image, maybe theres some clues in the star trails that someone can see. 

L__MG_1962_ISO800_300s__27C_M13.thumb.JPG.a232c0dc17888c8944ba39c15206d1f0.JPG

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9 hours ago, Anthonyexmouth said:

Here's 70% 

I didn't mean to leave it at 100%, just as a starting point, it has moved the points more central on the target.

Could be something mechanical, try running unguided to see what the graph looks like without any corrections to see what it's trying to correct.

Also as mentioned try to balance slightly east heavy, the first few corrections may switch, east, west north south but it should then settle down to one direction, I read somewhere that PHD doesn't reverse the drive to the east,  just stops the drive until the stars catch up, don't know if this is correct but sounds logical.

Building a  pier is a good idea for a few reasons, my permanently mounted SCT usually only issues guide pulse to east and north but took a lot of fine tuning.

Poor PA  shouldn't produce oval stars just field rotation.

Dave

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Permanent pier would be something you will not regret. I just used reinforced 8" plastic pipe filled with concrete, brake discs for mount connection. I made a wooden frame and covered it in roofing material that waterproof and tie this down to the pier using bungee cords. I just open the rear (velcro) undo the bungee cords and tip it back.

Everything ready to go before the camera reaches temp.

I would check your backlash and make sure everything is balanced. Check to see if anything is moving if it is lock it down or stick it down.

Give yourself a few clear night just to make adjustments in php. Try turning off dec guiding and concentrate on your RA. Only make one adjustment at a time and let it run for a good 5 minutes before deciding on the outcome.

I found make quite large adjustments helped me get a grip on where I needed to be (lets say move RA aggression from 70% to maybe 30% see how it goes then maybe change to 50%.). Try not to take too much attention to the youtube vids as individual mounts and conditions will be different.

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Looking at the graph it looks like you are on arc mins..so as a e.g. graph 2 says you're  on .89 pixels,( 3.83 )arc mins rms..

Looking at the graph to me looks like mainly balance and abit of PA error..id suggest rebalance the scope slightly east heavy and try the drift tool after PA..really is good..

 

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5 minutes ago, spillage said:

Permanent pier would be something you will not regret. I just used reinforced 8" plastic pipe filled with concrete, brake discs for mount connection. I made a wooden frame and covered it in roofing material that waterproof and tie this down to the pier using bungee cords. I just open the rear (velcro) undo the bungee cords and tip it back.

Everything ready to go before the camera reaches temp.

I would check your backlash and make sure everything is balanced. Check to see if anything is moving if it is lock it down or stick it down.

Give yourself a few clear night just to make adjustments in php. Try turning off dec guiding and concentrate on your RA. Only make one adjustment at a time and let it run for a good 5 minutes before deciding on the outcome.

I found make quite large adjustments helped me get a grip on where I needed to be (lets say move RA aggression from 70% to maybe 30% see how it goes then maybe change to 50%.). Try not to take too much attention to the youtube vids as individual mounts and conditions will be different.

have you got a pic of your mounting? trying to work out the best design for a pier top. 

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Looking at your latest image, it looks like you may have some bounce/vibration during the exposure. Maybe whatever is causing that is also the source of all your guiding graph deflections. I see you have a 9x50 finder guider but how is it attached? Don't use the finder shoe!

The guiding assistant isn't just for pa - it gives you lots of useful info about performance. In fact, the guiding assistant only gives you an instantaneous PA which isn't of much use if you have large deflections. Drift aligning is the gold standard for PA and you can do it easily with the PHD2 drift align tool. Maybe the Sharpcap system is ok (I've no experience) but I'd still check with the drift align tool. The guiding assistant will give you a figure for RA drift and will optionally measure your DEC backlash. A pic of your setup would be useful.

Louise

edit: here is my 80mm on an eq3 pro. I mount the guide scope via the tube rings - nice and solid. Some people don't like the guide scope rings but I find they are ok for a short frac and I make sure the screws are tight!


80mm.thumb.jpg.58be35124a723a01fdc4340cf7c277fb.jpg 

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Not sure if this will make sense.

I cut a square out the top of the pipe and place a piece of wood in there when I filled it with concrete. The bottom disc had three studs bolted and secured using the existing hole where the wheel studs would have gone. This was pushed down into the concrete and roughly leveled. The top disc when then bolted to the bottom using holes I had to drill myself.

I used a metal plate at the very bottom to allow me to fix up the mount to the pier and I have enough room to get a spanner in for adjustment.

 

I had all the aggregate lying around from a shed build and the pipe was given to me for free. The brakes were old mk1 golf ones so all it cost me was a few hours of digging.

Let me know if you want the exact details of construction and I can message them over.

 

 

 

pier.jpg

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1 hour ago, newbie alert said:

..A friend had difficulty with his eq3..so much so he was getting drift in 10 sec subs..out of frustration he stripped it down,replaced all the bearings..re-lubed and re-assembled and it feels now a totally different mount

Heq5's are pretty rugged and reliable :)

Louise

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When you run the calibration how long does it take to clear backlash? Does the guiding assistant give you any message about backlash? If it's too excessive then when a star starts to drift phd issues guide signals but because the gears aren't properly meshed it doesn't move so PHD increases the guide pulse. When it suddenly moves it can over shoot so PHD does the same in reverse. This can cause the saw tooth effect on the graph. I really struggled with Dec backlash on my EQ5. RA was fine as my scope was always the heavy side. Adjusting the motors and gears really helped.

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Ok, so you're using the finder shoe - I would ditch that and do something similar to mine (I would say that!). As well as causing flex, using the finder shoe will likely affect the balance as it's to one side.

Louise

ps is that mains block attached to the leg?? Might be a bit dangerous to use outside...

 

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1 hour ago, Stub Mandrel said:

I haven't read all the thread, but if you haven't entered the focal length of your guidescope and the pixel size of your camera it can't work out the actual angle and  the arc seconds option will be grayed out.

Oh that's sorted now. Re-entered all the details and cane back, although they were in the boxes anyway, weird.

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33 minutes ago, Anthonyexmouth said:

ok, saga continues. when i polar align with sharp cap and then try to polar drift align with PHD, PHD says im way off. any ideas?

so heres a guide assist screen with backlash error. this was polar aligned with sharpcap.

image.png.8b1627207858f375c966a751af2a547d.png

image.png.3112690a3a047cd928b3f756aaa5b36b.png

Drift aligning will always give you better PA..

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