Collimation Frustrations

I really hate having to collimate any telescope which is just one reason why I prefer refractor telescopes.  I have a few refractor telescopes at different focal lengths, however, I do have one Maksutov-Cassegrain telescope that does require occasional collimation.  It doesn't require collimation nearly as often as a typical Newtonian reflector telescope but it does require it occasionally.  

I have the tools and the skills to collimate any telescope but having to align mirrors just to view the sky simply grates on my nerves.  I feel like it is a waste of precious time.  I have other telescopes that are ready to go at a moment's notice but I have one telescope that requires time and effort to simply view the sky...  so, I find that having to spend time and effort collimating this scope is frustrating.  It is much easier and satisfying to just grab one of my refractor telescopes to view the sky without any other pre-requisites. 

Collimation is the act of aligning mirrors in any type of reflector telescope.  Well, technically, on exceedingly rare occasions, you might need to re-align the lens elements of a refractor telescope but reflector telescopes do require collimation on a regular basis, sometimes before every use.  This is because reflector telescopes use mirrors to magnify and direct the light to your eye.  If the mirrors aren't perfectly aligned with each other, the quality of your view is diminished.  The greater the mirrors are out-of-alignment, the worse the views.  

This one telescope of mine that requires occasional collimation is a small Maksutov-Cassegrain telescope with a 102mm aperture.  Amateur astronomers are always clamoring about how this particular type of telescope is "tack-sharp".  Either they are grossly exaggerating or they have never peered through a halfway decent refractor telescope because I find the views through all of my refractor telescopes to be far superior to the views through any reflector telescope I have ever used especially this little piece of junk Mak-Cass telescope.  

I have a few problems with this Mak-Cass... 

First, the dovetail bar for mounting on a telescope mount is too short.  I have to mount a longer dovetail bar to the short one whenever I want to image with a camera.  

Next, I find the views through any type of reflector telescope to be lacking contrast.  This is due to the secondary mirror obstructing the center of the view.  Even my achromat refractor telescopes show noticeably more contrast that any reflector telescope I've used.  This little Mak-Cass telescope that I have is quite low-contrast.  I find that frustrating.

Next, this little telescope requires time to acclimate to the ambient temperature.  If it is freezing cold outside, the telescope will require about an hour or more to acclimate.  If you view before the telescope has acclimated, you will get wavy, blurry views due heat currents in the tube.  This is true of any reflector telescopes.  The big mirrors hold heat and require time acclimate. When I want to view the sky, I really want to view it now, not an hour from now. 

And, perhaps most importantly, I find the views through this little Mak-Cass to be quite soft when compared to any of my refractor telescopes.  It is about as far from "tack-sharp" as one could be.  In my opinion, no description of sharpness should be used when talking about these types of telescopes because, to me, there is no sharpness.  We should be rating these telescopes in blur units.  

So, once again as I do occasionally, in an effort to somehow improve the views that I get through this little telescope, I decided to sit on my butt and spend some time collimating this little Mak-Cass telescope.  As my health recovers from my last hospital visit, there isn't a whole lot I can do but I am feeling well enough to sit around aligning mirrors perfectly.  

I started this task last night.  I got it aligned perfectly but then noticed that the rubber gasket around the back end of the telescope had fallen into the telescope.  In order to remove the gasket to put it in its proper place, I had to loosen the screws that align the primary mirror so that the gap at the back plate would widen.  So, after collimating the scope and noticing this gasket was missing around half of the telescope tube, I loosened those screws last night.  Naturally, this ruined the collimation so I needed to start over this morning.  

Aligning the mirrors this morning was trouble-free.  I had concentric circles around my artificial star (a special flashlight made for collimating optics) on both inside focus and outside focus.  Then I tested it on some terrestrial objects...  uggg...  these mirrors must be horrendous because the views were still rather hazy (lacking contrast) and soft when compared to my refractor telescopes.  

The ironic thing is that beginners always tend to gravitate toward reflector telescopes.  I don't know why.  Maybe they look impressive because they are fat and look larger than refractor telescopes?  Maybe it is due to marketing product literature?  I don't know.  What I can say is that my $89 refractor telescope puts up far better views than this little Mak-Cass telescope.  My ED and APO refractor telescopes are significantly better than this little Mak-Cass telescope or even better than any reflector telescope I've used.  It makes no sense to me why most beginners would gravitate toward the more difficult, temperamental telescope that lacks contrast and requires regular collimation but they do. 

This little Mak-Cass is now collimated.  I'll still test it on a star when I finally get to see the night sky again but it is collimated perfectly on an artificial star at a distance of just over 11 meters at 104x magnification.  The chart for collimation shows the 102mm Mak-Cass needs only 9 meters at 100x magnification so I should be "okay".  Longer is better so I'll refine this collimation outdoors when the weather improves and is more tolerable.  

Every time I peer through this telescope, though, I just shake my head in disgust because it puts up such lousy views compared to my refractor telescopes. 

On the positive side, I have accomplished something while my health is still rather lousy.  

This photo, below, was shot after collimation.  I had to be very heavy-handed in boosting contrast and sharpening.  Oh...  and I shot this through our double pane living room window.  Opening the window created a worse situation than shooting through the closed window due to heat plumes escaping through the open window.  

Just for reference, I should point out that this is the full frame equivalent to around 2000mm focal length.  This Mak-Cass telescope is 1300mm and I used an APS-C sized sensor which is a 1.5x crop...  so, just under 2000mm, which is significant so that is saying something.  Also worth mentioning is that this had to be shot at ISO 3200 so that adds noise which does affect sharpness.  I had to shoot with such a high ISO because the scope is a very slow f12.7 which does not let in much light.  Less light means the need for higher ISO values which means more noise.  

That being said, I know that I would not have needed to be so heavy-handed with the sharpening and contrast if I shot this using one of my refractor telescopes because I have done it many times in the past.  My refractors always look sharp even through this same window.

This photo really is mush.  It is difficult to see just how mushy this image is because I shrunk it down from 6000x4000 pixels to 1280x860 pixels.  Plus, I added sharpening and contrast...  significantly.  

The shot below is a 100% crop of the spot where I focused.  In this crop, it is easy to see what I am talking about when I say "mushy" and "lacking sharpness" and "lacking contrast"...

This 100% crop shows how bad this little Mak-Cass really is.  What a hunk of junk.  It is difficult to believe just how much I was able to improve the image (the previous image) with two different sharpening tools and the levels slider.  

Maybe...  maybe I will be able to refine the image a bit more when I do the collimation again at infinity on a star in the sky.  And, to be honest and fair, it might improve slightly if I am not shooting through my living room window.  I have shot through this same window many times using my refractor telescopes and never captured mush though!  We'll see what happens after refining the collimation on a star in the sky but I really don't think it will improve much.  

I really hate everything about reflector telescopes.

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EDIT - January 31st, 2023:  I had my Orion Apex 102mm Mak-Cass and my Celestron 70mm achromatic refractor side-by-side in our living room today to compare both scopes at around 100x magnification.  What I was seeing didn't make a lot of sense to me (these two scopes were pretty much equal in image quality) so I pulled out my Skywatcher ED 72mm refractor to add to this comparison.  

I used a Baader Morpheus 12.5mm eyepiece in the Mak-Cass for a magnification of 104x.  I used a Baader Morpeus 6.5mm eyepiece in the achromatic refractor for a magnification of 108x.  I used a Baader Morpheus 4.5mm eyepiece in the Skywatcher ED refractor for a magnification of 93x.  So all magnification levels were very close to 100x.

    First, I compared the Mak-Cass to the achromatic refractor:  

I needed to go back and forth a few times between the scopes to discern the very slight differences but the Mak-Cass had the very slight better view mainly due to a lack of chromatic aberration.  There was a very tiny hint of chromatic aberration in the refractor, as expected.  Contrast was slightly better in the achromatic refractor but sharpness was slightly better in the Mak-Cass.  And, again, I should not use the term "sharpness" for this particular comparison because I don't consider either scope to be "sharp" at 100x.  So, what I should say is the Mak-Cass was slightly less blurry.    

    Next, I compared the Mak-Cass to the Skywatcher ED 72mm refractor:

Although the Skywatcher ED refractor at f5.8 is better utilized as a wide-field telescope, it was easily sharper than the Mak-Cass even at 93x magnification.  The 10:1 focuser on the refractor makes fine focusing easier too.  The Skywatcher ED refractor is also free of chromatic aberration.  The Mak-Cass was simply "soft" by comparison.  

Refining the collimation at a much longer distance might help sharpen things up a bit.  Unfortunately, it is too cold out there for me today so I have no desire to do another collimation at a much longer distance.  I can do a 33 meter distance in our yard which would be better than the indoor 11 meter distance.  Using the North Star, Polaris, would be better.  This will have to wait until the weather is warmer though.  I do not do well in temperatures below around 45 degrees anymore.