View Full Version here: : Newtonian drawbacks?
BeardFace
01-10-2020, 10:40 AM
So this may be incorrect, but it feels like most of the best deep sky images I've seen come from newts. Is this just because they are more prevalent and cheaper? Or am I just plain wrong?
I'm also wondering what the drawbacks are, as far as I can tell the mains issues seem to be:
-Size makes wind your greatest enemy, and tracking difficult
-Coma, but can be fixed with a coma corrector
The reason I'm asking about all this is that I'm looking to sell my 12 inch dob and replace it with a 12 inch newt that fits on my Alt-Az mount. I'll save a bunch of money, and now I'm also wondering how well it'll double for astrophotography.
Cheers!
glend
01-10-2020, 10:54 AM
Your mount will need to have EQ capability, not just Alt Az. Things that favour newts for imaging:
True colour rendition from mirror systems,
Cost effective aperture,
Easily coma corrected.
Fast photographically, nominally f4 or f5.
As far as tracking concerned, you will need to learn to guide the scope if you wish to take longer sub exposures, which means a guide scope attached, PHD2 etc.
You can image with other mirror system scopes like RCs, but most people start with Newts because of simplicity and budget.
sunslayr
01-10-2020, 11:04 AM
Sounds like you might be biased to medium focal length images :rofl: Or maybe it's because of all the Hubble Photos :question: What sort of mount do you have? Must be pretty beefy to handle a 12" newt. The only drawbacks I've experienced are fairly minor. Colimation every time you move it, the length compared to collapsed reflector style telescopes, diffraction spikes and the awkward focuser position. I also have experienced my secondary getting dewed up but that seems to be pretty rare, seems like if I were to add heating it might disrupt the view with all the thermal air currents but I'll have to do more research.
TareqPhoto
01-10-2020, 11:04 AM
There is collimation issue, some said they manage it fine, and some don't, mainly with faster scopes such as F/4 or faster.
BeardFace
01-10-2020, 11:05 AM
Oh sorry, I meant I have an AZ-EQ6 GT mount, and I'm currently working on getting my RC8 up to scratch, but to save money I want to sell the dob and buy a newt tube. Primarily for observation but if it performs better for photography than my RC8 then I might stick with it.
Do OAGs work well with newts?
mental4astro
01-10-2020, 11:09 AM
If your 12" dob is a solid tube OTA, you can actually use it on the mount you have. No need to buy and sell scopes, but a pair of tube rings to go around the OTA and a dovetail plate.
You then also keep the flexibility of having the 12" as an imaging rig and the convenience of a dob for visual.
BeardFace
01-10-2020, 11:11 AM
Unfortunately it's collapsible :(
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