Rough moon with 80mm Megrez (first model)

[Leo.G (Leo)]

These images were shot with my 8" RC focuser screwed on my old Megrez since it's focuser had slop. I've since replaced the bearings now and it's fine but the GSO linear track focuser is better with my heavy Nikon D810 DSLR.
A decent night with no cloud just set up on a Manfrotto tripod.
The whole point was finding back focus distances with this focuser (and extension rings, they screw straight on the old Megrez). A bad migraine meant focus was never going to be absolute, bad sight tonight but clear skies.

The first image was taken through a 5 times Powermate with my Nikon D810. My powermate doesn't maintain a correct centre in my home design adapter but I'll machine it and put a compression band in, that's only minutes on the lathe. Pulling off centre just slightly introduces a green CA hue on the lower edge, without the PM I get no visible CA through the Megrez (semi APO). The second image straight through the camera, cropped heavily though.
Focus could have been better but the Manfrotto shook too much while I was trying to dial it in and I haven't finished my shaped alloy block to attach a remote unit to the focuser (I have but can't remember where I put it).
Far from my best shots but more experimental and not too bad considering, single images and old Megrez, minimal processing on exposure and blacks and shadows in Lightroom.

[MortonH]

Nice. This is the old Megrez SD doublet semi apo?

[leon]

Hey Leo, you cant complain about that shot mate, yea a bit shabby on the focus, but I sure would be happy with that considering the equipment you were use, well done indeed.

Leon

[Leo.G (Leo)]

Nice. This is the old Megrez SD doublet semi apo?

Possibly, it has absolutely no identification other than Megrez 80mm f6 SD in a white pearl finish with a single 1/4 holed shoe for it's travel tripod, absolutely no identification on the lens I just know it's a semi APO
This cloudy nights thread has the identical telescope:


https://www.cloudynights.com/topic/8...e-re-purchase/


(not mine unless I got it from this guy for $100, I wouldn't know), I picked it up at central station from a guy who used it as a conversation piece when he had office staff around for work parties, he had no idea what it was or how to use it. He was blown away when I sent him a simple moon image, he absolutely had no idea and it sat in a corner in his apartment.

Originally Posted by leon

Hey Leo, you cant complain about that shot mate, yea a bit shabby on the focus, but I sure would be happy with that considering the equipment you were use, well done indeed.

Leon

It was -5 out Leon and my hands were freezing, my scope was covered in ice because I set it up hours earlier expecting the moon sooner (dew strap around dew shield in approximate locale of lens, it didn't frost up) and hadn't bothered looking it up. It was only on my camera tripod and kept wobbling every time I tried to adjust the focus even slightly because I have a non locking rotating base under the gear head. It's supposed to lock but it doesn't, it moves left and right with the slightest touch (I'll remove it now while I remember it's annoying), eventually I decided where it was was how it was, I just couldn't get it better even with the fine focus on the GSO focuser.
I have a small DC moonlite remote focuser I could fit to my focuser but I'd have to figure out a bracket and mounting system, it's from a Newt or SCT and the mount design isn't easy to use with what I have. If I had my milling machine set up I'd machine a mount bracket from billet aluminium but it's still sitting new in it's crate waiting for some lazy old sod (me ) to weld up a frame and fold and weld up a swarf tray. That's a lot of money sitting around not being used with the cross slide table costing over $1,000 alone, add in vice and tooling plus the cost of the new machine and it's a lot of money not being used..




































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[Crater101 (Warren)]

Mate, not too shabby at all, although where you found the clear patch in the sky to achieve this is beyond me. No Cloud? Some people have all the luck.
How did you process the image? Photoshop? Gimp? I'm curious as to if you used any noise reduction.

[Leo.G (Leo)]

Originally Posted by Crater101

Mate, not too shabby at all, although where you found the clear patch in the sky to achieve this is beyond me. No Cloud? Some people have all the luck.
How did you process the image? Photoshop? Gimp? I'm curious as to if you used any noise reduction.

I opened the RAW in PS and changed the black and something else, maybe a little change in exposure/contrast and small amount of clarity, nothing else much, saved it and cropped the smaller straight through camera image.,More than 2 minutes ago in lightroom or PS and I don't remember what I've touched. I don't really do noise reduction, I tend to blur images too much.
I'm really not good with these programs either, my son is good but I'm a useless old twit.


We had a beautiful day of sunshine Monday (9c all day, winter high here) and a beautiful clear night if not cold.
Yesterday cold, wet and miserable all day with a 6 degree high. I assumed since it was -5 Monday night we'd get a beautiful Tuesday and quite shocked to wake up to wet miserable day. Today however is clear again.
If I didn't have a big hole where my mount is meant to sit I'd take a decent mount and scope out tonight though the moonrise will be a little late for me to want to stand out and imitate a brass monkey. I am going to find gloves, I thought my fingernails were going to explode after coming in from the cold and putting my hands in cold tap water, it was too hot for them.


I may get my Astro-trac out while the moonrise is late and play with the Milky Way if clear skies persist, depending on how much headache medication I've taken by that time, I'm about to start now with the strong stuff (MS Contin).
I hope you have a beautiful clear day today mate!


I did find the culprit of the slight focus problem, it was actually camera shake which I shouldn't get in mirror up mode using an intervalometer but also the rotating base on top of my tripod below the 25Kg capacity Cambo gear head, it can't hold it's locked position. It's centre is only very soft grade of alloy and the pointed locking pin just tears it out and the thing rotates with ease when locked, not good, it's in pieces at the moment and I may head up to the shed and turn a new rotating centre out of steel that won't have the locking pin tear through it. If I score identical spaced marks down it I can have recesses for the pin to lock and not move.
Similar to this one, not camera plate lock or this brand, same concept:


https://www.aliexpress.com/item/1005005223199551.html

[Crater101 (Warren)]

Originally Posted by Leo.G

I did find the culprit of the slight focus problem, it was actually camera shake which I shouldn't get in mirror up mode using an intervalometer but also the rotating base on top of my tripod below the 25Kg capacity Cambo gear head, it can't hold it's locked position. It's centre is only very soft grade of alloy and the pointed locking pin just tears it out and the thing rotates with ease when locked, not good, it's in pieces at the moment and I may head up to the shed and turn a new rotating centre out of steel that won't have the locking pin tear through it. If I score identical spaced marks down it I can have recesses for the pin to lock and not move.

You've pretty much already done what I was going to suggest. Are you on a good solid bit of ground? I've been caught out once or twice setting up in remote areas to find that the mount and tripod have slowly dug in / sunk in soft ground, which doesn't help.