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I'm aiming for the best possible field illumination for my Explore Scientific PN208 f/3.9 imaging newtonian. The scope is 5 years old now and while doing maintenance I wanted to do something about the design flaws as well.
With the current secondary holder design it's impossible to center the mirror beneath the focuser. My question is: is this really an issue when the entire primary is visible? I read about optimal field illumination when the secondary is centered, but this isn't achievable with this telescope.
I attached an image showing the (very bad aligned and already degrading) secondary at the moment. This is as far down as I can go, I would need to replace the holder screws with longer threads to go further but I don't know if it would make any difference for field illumination?
Thanks in advance,
Hi, I have just recieved the last item which was on back order for a couple of months from USA. I already had the Infinity Eyepiece but was waiting for the BlackCat.
Everything was ordered from FLO and i was very happy with their service.
Instead of writing an essay, i made a video of how I use the tools and how they look, but in short - Theese tools are FAR superior to the Howie glatter, even with the Tublug.
Hi there, I've recently jumped fully into the DSO side of astrophotography and have been having trouble with stars that aren't quite round. My last two imaging sessions have produced stars seemingly pointing in different directions across the field of the image. After the first image we collimated the scope and the problem has continued but we think our collimation may still be off.
I use a SkyWatcher 130PDS with a Canon 6D Mark II and the Baader MPCC Coma Corrector. The problem persists regardless of whether or not the coma corrector is in the imaging train. It also persisted regardless of the exposure time. I have uploaded processed images which show the problem, but if unprocessed files would be more helpful I can upload them also. The processed images have been cropped slightly.
If anyone has suggestions as to what the problem could be I'd really appreciate it.
150mm F/5 Newt, as received new, view down eyecap collimator (no adjustments attempted by me):
I've read a couple of intro guides, so I'm led to believe that the off centre image of the secondary in the primary is normal for a fast reflector.
The whole image of the primary in the secondary seems to be reasonably central too.
My concern is obviously that the black dot from the collimation cap is not within the "doughnut" centre marking from the primary.
I've tried here to superimpose a circle with centre lines, but I'm not sure if I've got the circle itself correctly positioned (I'm not sure what I should be lining it up against):
Now, the interesting thing is that it's one of those jobbies with a sealed, non-collimatable primary. But I believe the secondary has all the usual degrees of movement.
Does it look likely to be far out?
I can try a star test tonight (first time for that too).
So, I have been testing three different kind of lasers, each one is supposed to be the "best" in each category or what you want to call it, the hotech and HG is almost the same, but whit the difference in how you lock it down.
The Catseye is very different in how it works.
I made a Youtube video of my thoughts
What do you think? which one do you use?