#0 - if you haven't already, drop everything and buy a copy of Chris Woodhouse' amazing book (latest edition) @Chris_W has a whole section dedicated to these beasts and his writings and experience here are most helpful
Looks good. I haven't seen that book, but the intro on Amazon looks like something I would enjoy.
#1 - invest in a set of cone tipped M5 grub screws to replace the push screws on the primary (
I have had those suggested. They do look like they would turn a lot better than the rough stainless bolts in the back of this thing.
#2 - the Tak and or a Howie was only able to get me so far, after fettling (adjusting) the Howie to the point of what looked like perfection, it was quite clearly less than perfect with extra-focal stars (ovals as you are finding) - the trick is now to use the DSI method to get you to perfection
I do have the Tak, and at the time, the only Howie pattern I could find is the grid pattern. I can't find anywhere that describes very well how to use that one. It also would require I take this 90 lb beast off the mount, adjust it, then risk bumping things out of whack when we put it back on the mount. Therefore, I've been trying to depend on the single laser point, Tak scope, a clear star and plenty of cussing.
#4 - grab a stiff drink/coffee/sedative (you can also try mixing all three - the precise cocktail is still something I have yet to figure out)
The adult beverages after I quit for the night (maybe I should try before?) have been the only thing that has gone right. Dulls the suffering!
#5 - wait for the clouds to clear. Avoid sucker holes at all costs :-)
Yes, I've worked on this 3 nights this week, I gave up last night, and we have probably 2 more good nights. I may use my own observatory tonight to regain my love for the hobby, my refractor, dome, EQ6R mount are all working 95% perfectly!
#6 - preferably using your Red filter to cut the degree of atmospheric disturbance, grab your dog eared copy of the DSI manual and SLOWLY start tuning. One thing worth trying here is to make all adjustments with teh scope pointing as close to the zenith as possible to ensure that large lump of silicate isn't shimming itself around under gravity
Red filter? That is the first time I heard that tip. I use an ASI071MC Pro one-shot color on the scope (yeah, the pixel size does have oversampling, but it's also good $$), does the red clear up some of the glare or something? I feel that most things have gone well and look good - then I get to the primary mirror and the DSI method. I arrange the camera/display on screen/merdian side so I match the 'hand quadrant" test and start twisting bolts. For some reason, I never seem to make much difference when trying to tighten the bright part of the star or loosen the opposite side to get a nice ring. I need more convincing that the DSi actually does anything at this point - since I usually fail to see it. I then look through the Tak and see all I've done is ruin all the symmetry and mis-line all the reflections of the spider vanes. I know the mechanics of the baffles and such could be off from the factory, but I just mess it up.
#7 - long exposures are super helpful, I made the mistake of using shorter ones thinking I could adjust in real time - most of the time I wound up chasing the seeing
How long? I usually pick a medium star and use about 2-3 seconds exposure. I try lower gain too, but seems if I go too long it just gets overexposed to see the details very well. I've been pointing at clusters so I have plenty of similar distorted stars to pick from - and move one of them to the center, then recenter after twisting.
#8 - CCD inspector isn't the BEST tool in the world, but with the right star field it can help you eek out the last few % of aspect ratio that the eye fails to see
I see there is a 30 day trial on that. Usually when I try a trial I end up with 32 days of clouds once I install it! Then the price of the software. I already squeezed nearly $2,000 more out of club funds in my efforts and have nothing good to show.
#9 - consider but do not rely on a tool like the Gold Astro collimation mask - I tried using it myself, but frankly it was quicker for me to do it by eye
I have been reading about these masks a bit now too. I'm tempted to cut my own or buy one. Cutting my own would be a nice mind numbing activity during pandemic - anything to numb my mind over the daily current events is a good thing - and a drink - but need to cut straight!
#10 - Stare longingly at the Planewave website at least once a day, Google the value of a human kidney and ask yourself seriously whether Robert Redford *might* pay $1M to spend the night with you, perhaps a little makeup? ;-)
For that price, does it come with a telescope expert to help get round stars? GSO has really made me upset. Nice looking gear, but.....ugh! I do still have a kidney I could donate to the cause, that would add "hero" to my list of achievements for the club!
In all seriousness I have found that I can now take the thing completely OUT of collimation (including accidentally pinching the mirror by over tightening one of the Allen key heads near the rear cell fans that had come loose!) and get it back to a very acceptable state in under an hour or two at most - each time I find my muscle memory helps me converge on a better and better collimation.
I guess I'm a very slow leaner, or it takes me more time since I have to run up and down a ladder to get between the secondary and the focuser with my Allen key in hand. I've probably got 100 hours of "learning" now, but only make very small progress.
It's not ideal, but then neither is trying to find a 16" scope with these sort of optics at a 1/4 the price of a Planewave. If you're ready to give up, I'll DM you my shipping address here in Aus ;-)
I'll keep you in mind as I pass this by the board of directors. Ha! I have a home Ebay business that sells heavy gear, so I'm very experienced shipping freight - something I have learned better than collimating an RC.