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By Ryan Adams
I recently posted a thread getting ideas for what scope and mount I should get for beginner astrophotography.
After researching on my own and getting thoughts from others on scopes and mounts here is what I have come up with.
Mount - Skywatcher EQ5 GOTO
Scope - Sky-Satcher Explorer 130P-DS
Guide Scope - Skywatcher Evoguide ED50
Guide Camera - ZWO ASI120MM Mini
DSLR - Canon 350D
I understand that the camera I am using is fairly old but it is an old DSLR that I have at home and it saves me money on buying a new camera. All in all this setup comes to just over £1000; I just wanted to people's get thoughts on this set up and if it can be improved in any way without stretching the budget by more than £100. Also I wanted to know whether any of the equipment I have chosen isn't great.
Thanks in advance,
By Anthony RS
Is anyone here using the TS Photon 6" F4 newtonian? I'm about to purchase it but I have some doubts and questions:
1- Does it hold collimation well, at least in a single session?
2- Is it impossible to balance in DEC due to its small dovetail or is it possible but harder?
3- Is the focuser rigid enough or does it introduce tilt?
4- Will collimating it be a nightmare?
5- I'm really picky when it comes to coma, should I expect some coma on edges even while using the Skywatcher Aplanatic F4 CC?
6- All in all, do you advice me to buy it or have some other option in the same price range.
I am new to astrophotography and of course started by taking a photo of the moon (as attached) using my Canon EOS500D camera - 1/250 exposure time, 800ISO. I used my celestron 127EQ telescope with a adapter for the camera of course. I used no eyepiece.
However, i find that it is slightly blurred, and upon taking pictures of nearby stars, i also found them to be blurred, even with a high exposure time. am i doing anything wrong at all or is this simply because of my setup?
By Michele Scotti
Hi everybody - I'm humbled that some of you are following the thread on the 800mm telescope. I thought it was worth starting a sub-topic specifically related to the mirror making.
So as the works on the mount got halted by the lockdown we had some time to virtually meet-up and discuss the optics for this project.
The onset was pretty straightforward with an 'if we are doing this we are making the mirror'. And that sorts out the make vs buy, I suppose.
As of now, the only two things decided so far are the diameter -at 800mm- and the f/3.3 - of course we can accommodate some variance.
Some aspects of the making are pretty unchartered territories for our club so I'd like to seek some good advice from anybody in terms of direct experience or rather point us at some resources/threads.
Back-ground: to make it short, our senior member had three 500mm f/5 done years ago. He did of course faster optics up to f/3 among many other mirrors - I actually never asked him how many, uh! He has always worked with full tool and has no experience with slumped glass. Btw we do have some experience in slumping glass but -weirdly enough- not in machining.
During our initial discussions we boiled the scenarios down to 3:
float glass, 35/40mm thickness considering 15mm of sagitta. This is a thermal challenge with its big outward mass, it's going to make the machining more of a challenge and the stabilization time longer float glass, 25mm (which seems more of a commercially available), slumped. Trading the thermal challenge with the slumping borosilicate, 25mm, slumped. Tbh this is just a better version of the previous point at a cost that is not prohibitive
What are the sources of glass in Europe for thickness over the bog standard 25mm?
Disclaimer: this is surely an ambitious endeavor and by no means we are underestimating that. Not only the bigger diameter is a step-up; the fast optics is a challenge too.
To start with we have some questions about slumped glass. It looks like an attractive, modern approach to mirrors that exceed a given diameter. I think I saw already some threads specifically about the slumping itself - that's golden.
However it's the grinding/finishing/parabolizing that is puzzling us. Are there specific techniques or is it the same as the flat back glass?
Also, how do you support the mirror? Would a support that replicates the telescope mirror cage be appropriate - a 27-point in our case? Or is it a matter to build a concave support that holds the back of the mirror? How accurate/solid should that support be?
Any experience out there??
I reckon that's enough as a start - thanks everybody in advance for your contribution.
Stay safe! Michele
So I had this problem where if I put my finder scope on my OTA, and the finder scope is around 135 degrees from the mounting part of the scope. This made my DEC axis always stay leveled but never stay in any position I put it in (if I turned my RA axis to the balancing position, then the DEC axis to balancing position and moved the DEC axis anywhere, it would go back to horizontal or balancing position).
Any help would be nice