Cheating the rain.

[neil phillips]

Weather has been awful last few days. i guess everyone knows that. Rain cleared briefly. So i setup the little 70mm refractor. Didnt want to risk one of the bigger scopes getting rained on. which was lucky. Half way through the second capture. Cloud came over. it started raining. just got the equipment in before i was soaked. Need to be more careful in the future i think.  Seeing was the worst ive seen in ages. really quite bad. Reduced full size  to 75% to preserve sharpness. 

Think i will use this scope when good seeing occurs. So i can show you guys how good it actually is. I dont think everyone is convinced. But i have enough experiance to know this scope is likely as sharp as any 70 ED scope anyone cares to buy. Infact if anyone disagrees. we can have a comparison lunar shootout one night. if anyone is up for it. Deepsky is another matter. Because its tone is not pure enough. and focal length too long. But on lunar its likely as sharp as any 70mm ED scope out there. Sounds nuts i know. But if anyone disagrees lets test it one night on the moon under good seeing and illumination. And see which scope is sharper.  I could be wrong. And the capricorn might come second best. But i doubt it. its actually razor sharp. 

This is pants compared to what it can really do. 

SW capricorn 70mm F12.8 achromatic refractor. ZWO 178m Baarder 495 longpass filter EQ5 Deluxe mount. prime focus 

Edited November 29, 2021 by neil phillips

[paulastro]

Well done.  With my grab and go setup, when the weather is dodgy, I always take a waterproof cover out with me I can just drape over it very quickly if necessary.  It prevents panic and a wet scope.

[Franklin]

7 hours ago, neil phillips said:

And see which scope is sharper.  I could be wrong. And the capricorn might come second best. But i doubt it. its actually razor sharp. 

I doubt you will get much competition.😀

[callisto]

8 hours ago, neil phillips said:

. we can have a comparison lunar shootout one night. if anyone is up for it.

If only I lived closer!...just kidding 🤣

Anyway Neil my smallest scope is the Vixen 80M but boy, is that sharp 

 

Mark.

[neil phillips]

1 hour ago, paulastro said:

Well done.  With my grab and go setup, when the weather is dodgy, I always take a waterproof cover out with me I can just drape over it very quickly if necessary.  It prevents panic and a wet scope.

Thanks Paul. Good idea. 

[neil phillips]

1 hour ago, Franklin said:

I doubt you will get much competition.😀

Once again your a Gentleman Franklin. Although i have to be honest. I am in no way certain that the F12.8 would be sharper. The point of the post was not to be pedantic. But to try and share with people the little discovery i have found. Which obviously could benefit those on a really tight budget. Or even someone just curious that had more expensive glass. To perhaps try for themselves, and see if what i am saying is true. The only problem i would have with this, is to strongly urge though. Any potential purchase of a instrument like this primarily for lunar imaging - observation. ( planets ) would be to the buyers risk.

Being a mass produced Synta optic. At the low end of the scale. I obviously could not guarantee its optical figure would be as good as this. There will likely be more variance. Than premium instruments. Which would likely make your earlier comments to me partly valid Franklin. So with that realization in mind. I would suggest its one of those occasions. Where if one was seen say in a charity shop or whatever cheap. Some one could take little risk buying it  ( like i did from astroboot) And seeing if the scope performs. If it works out little risk high gain situation. 

Edited November 29, 2021 by neil phillips

[neil phillips]

56 minutes ago, callisto said:

If only I lived closer!...just kidding 🤣

Anyway Neil my smallest scope is the Vixen 80M but boy, is that sharp 

 

Mark.

I dont doubt it i have wanted a Vixen for many years. and it would likely wipe the floor. I am uncertain tbh. If any ED70 would perform any less than this. Perhaps it could be close to a draw. I am not certain. But you know in your gut, after many years of using different instruments, when you have a good un. And this is a little gem.

When i quickly came in after the rain started. I noticed dew on the inside of the lens. And i actually felt gutted, as i know what problems this can cause. So i took the eyepeice out and cap off. And it cleared. I actually felt relieved. Says it all really doesnt it about this classic long focus design. Albeit Chinese mass produced. 

[callisto]

4 minutes ago, neil phillips said:

I dont doubt it i have wanted a Vixen for many years. and it would likely wipe the floor. I am uncertain tbh. If any ED70 would perform any less than this. Perhaps it could be close to a draw. I am not certain. But you know in your gut, after many years of using different instruments, when you have a good un. And this is a little gem.

When i quickly came in after the rain started. I noticed dew on the inside of the lens. And i actually felt gutted, as i know what problems this can cause. So i took the eyepeice out and cap off. And it cleared. I actually felt relieved. Says it all really doesnt it about this classic long focus design. Albeit Chinese mass produced. 

Yeah, I know what you mean when you have a "gud un"...the crispness is very obvious when testing the optics

Do you not use a desiccant cap for the scope to try to combat the dew inside?

[neil phillips]

Just now, callisto said:

Yeah, I know what you mean when you have a "gud un"...the crispness is very obvious when testing the optics

Do you not use a desiccant cap for the scope to try to combat the dew inside?

Never thought about that doh. Will get some soon. Thanks for the reminder 

[callisto]

Just now, neil phillips said:

Never thought about that doh. Will get some soon. Thanks for the reminder 

Glad to remind you 

[Franklin]

45 minutes ago, neil phillips said:

I am in no way certain that the F12.8 would be sharper.

I've always had achromatic refractors over all these years and it's only recently that i've ventured into ED territory. The sharpness that a nicely figured refractor lens gives comes from two things I think. The lack of a central obstruction and a long focal length. I know this because I've seen it happen when stopping down the aperture to create a much slower focal ratio. Controls aberrations better and makes focusing easier. So I think a slow focal ratio, a long focal length, no central obstruction and the addition of the 495 longpass is the way to go for planetary imaging with an achro and your excellent results speak for themselves.

Edited November 29, 2021 by Franklin
spelling

[John]

It does look like your 70mm F/12.8 achromat has an excellent objective

I bought a low cost 90mm F/11.1 achromat last year for next to nothing hoping that I could have some cheap, portable fun. Unfortunately I got a rather mediocre performer that time and nothing I've been able to do with regards to collimation or other adjustments has improved the situation, unfortunately

I'm sure there are good 90mm ones out there because I've read about them but I didn't get one, this time around.

Your lunar images look extremely sharp - nicely done !

 

Edited November 29, 2021 by John

[neil phillips]

11 minutes ago, John said:

It does look like your 70mm F/12.8 achromat has an excellent objective

I bought a low cost 90mm F/11.1 achromat last year for next to nothing hoping that I could have some cheap, portable fun. Unfortunately I got a rather mediocre performer that time and nothing I've been able to do with regards to collimation or other adjustments has improved the situation, unfortunately

I'm sure there are good 90mm ones out there because I've read about them but I didn't get one, this time around.

Your lunar images look extremely sharp - nicely done !

 

Hi John. I know exactly what you mean. I also tried a 90mm F10 SW achro. A while back. And same result as you. I wasnt happy with it. Its a bit of a crap shoot isnt it. Something i would imagine is not the case with better glass. Certainly one reason to get better glass. If budgets allow. 

Edited November 29, 2021 by neil phillips

[Franklin]

My favourites Neil are the Venus cloud images in UV from 2007 onwards, amazing.

[neil phillips]

22 minutes ago, Franklin said:

My favourites Neil are the Venus cloud images in UV from 2007 onwards, amazing.

I have great memories of those times Franklin. My old Meade 7" Maksutov F15, and i had recently got the Orion 10" Newt. Some of those venus images. were taken on a vixen GP mount with the GP mount wooden tripod. Orion 10" on top. When i moved near the scope venus moved off screen. When i moved back. it reappeared. Fun memories.

I later put the meade steel tripod under the GP mount. That was a lot more stable. But to stop left and right movement of the mount. i used skipping rope. tightened to stop the movement. I kid you not. But it worked. The image is still on my site. Some of the processing on that old site. leaves a lot to be desired. Especially some of the Saturn shots. with awful colour here and there. But i didnt really know what i was doing. Just learning as i went along. So i have never really felt the need to create a new improved website. I probably should. But so many memories there i think i prefer to leave as is, warts and all. 

[Franklin]

I agree you should leave it, your captures of the planets are a fine record and an example to others of what can be achieved. Back in the early 80's I had a poster, a collage of images of the gas giants from the Pioneer and Voyager missions. Your images of Jupiter and Saturn remind me of that poster, particularly the Saturn image showing the light detail in the cloud bands (lightening on Saturn?).

[neil phillips]

37 minutes ago, Franklin said:

I agree you should leave it, your captures of the planets are a fine record and an example to others of what can be achieved. Back in the early 80's I had a poster, a collage of images of the gas giants from the Pioneer and Voyager missions. Your images of Jupiter and Saturn remind me of that poster, particularly the Saturn image showing the light detail in the cloud bands (lightening on Saturn?).

Yes the great storm on Saturn. Can see what you mean. It reminds me of that too. 👍

Edited November 29, 2021 by neil phillips