Pbrico wrote:
So what telescope are you using? The pictures are absolutely beautiful.
If you are asking me, Thank You.
I decided when I was researching how to do what I was interested in, Nebula, that the telescope was going to be the lens a camera was going to look through.
So I decided the quality of the lens needed to be as good as I could justify into the amount I wanted to invest. Because this stuff is expensive to me.
I was looking at Refractor telescopes because I felt there would be less to "get out of whack" with something as simple as a tube and lens.
Reflector types gain a lot of magnification, but they need special attentions I did not think I personally want to put up with, Collumating being the biggest concern.
https://simple.wikipedia.org/wiki/Collimated_lightSo I decided to get an ED80 T Orion Telescope. I knew the name of the brand, and felt I could trust it.
I since learned there is a corporate parent that owns about 5 of the brands that use to be considered fairly reputable.
But the ED80T had a carbon fiber tube assembly. That can be important to focusing. Carbon fiber does not change length with temperature changes like metal tubes can. So it stays closer to your focusing over a nights use.
Example: (I use this only as an example.)
If you take something like Celestron's 6" refractor telescope, at 47" in length, well, expansion and contraction with temperature changes, changes the focal length of the camera to lens distance. So you'd need to correct your focus. That could mean your pictures you want to stack are not all in sharp focus. And that would mean your results could be not as sharp as you would hope for.
So the tube of whatever Telescope you want to consider can have a direct result in your outcome. Carbon fiber, while more expensive initially, can certainly be of advantage in your results and satisfaction.
(I'm a Nikon head, too. So I like black things, and things that look cool. I think Carbon Fiber looks cool.
)
I've forgotten the terminology, but it has to do with Duplex vs: Triplex lens construction, hence you will encounter T, for Triplex lens construction. More easily explained HERE:
https://starizona.com/tutorials/And by far, this is the best Graphic example I know of:
https://starizona.com/tutorial/achromatic-and-apochromatic-refractor-designs/This is why Achromatic telescopes are OK for viewing, but do not make good Astrophotography Telescopes, usually. Your eye and brain can trick you into seeing with a Achromatic. But you cannot trick a camera sensor. It will tell on you. And you won't enjoy the results.
So these are the elements to getting good images. Really good telescopes, not just "any old" telescopes.
It was tough to swallow spending $1,000 on a telescope that is really so basic as to be a triplet lens in a Carbon fiber tube. But we can see the results. (when the atmosphere wants to play nice...)
My next up option at the time was about $1700 more for very little aperture gain.
And I discovered the 80mm was recommended for my intended targets anyway. Case closed, for me.
I began looking at huge, but found myself at small and precise in the end. There is another advantage to me. I can carry my entire telescope assembly with one hand back and forth to my house. It's about 13 pounds, total.
That brings us to mounts. Mounts have a payload rating. Say it's 30 pounds. For Astrophotography work, the Rule of Thumb is, 1/2 of the rated payload of the mount.
My telescope, with guide scope, Red Dot aim-point, Filter wheel assembly, and camera comes in as I said at ~13 pounds total. Less than half the 30 pound rating of my Celestron Advanced VX mount. (AVX for short) (Oh, I also have a Laser mounted, but never use it. It is for demonstration to the kids as to where the telescope is aimed.)
A mount for Astrophotography needs to be as good as is affordable. Or you pay with learning how to make a "silk purse out of a sows ear." I did that with my AVX, but now that all the bugs are out of it, it works like a charm. I only run it with a 50+ pound AGM type battery, so it only gets pure clean DC battery power. That insures the questionable Chinese electronics components get clean power. So far, so good.
Part of the mounts capabilities depends on guiding. Or to my simplistic ways, giving the mount an eye on the sky. I gave mine and Orion Guide Scope and camera. It has been the most reliable thing I have on the entire endeavor. Coupled with PHD2, it holds true. That's important why?
Well, if your mount "wanders" you get blobs instead of stars, or "eggs", or streaks. And you get all of those in the beginning. But as you learn not to walk around your mount as it is imaging because you'll cause vibrations, or that where it is set up can make of break your images due to even things like traffic on nearby streets, things improve.
I think I learn something new every time I go outside to play. My newest thing is to check the mount is zeroed on Polaris as a starting point. That is an Elevation, and Alt/Azimuth adjustment. Mechanical adjustments, And I use my main camera to zero in the cross hairs.
My intended targets after careful alignment seem to come in centered, or closer to centered all the time. That is making my resurgence in Astrophotography more fun.
And we haven't even begun on the little nuances of this stuff. But I've probably bored you enough for now.