JimH123 Loc: Morgan Hill, CA

Take a look at this site. About half way down you will find a coma + astigmatism example.

https://www.handprint.com/ASTRO/ae4.html

nikonshooter Loc: Spartanburg, South Carolina

Yes! Collimating did eliminate the Gulls on the Artificial Star visually. But the long exposures will surely bring them out if they are still present and were I a betting man....I would say they will be there.

Regarding an artificial star....you can make your own with a flashlight , aluminum foil and the smallest sewing needle you can get.........there is a 25.00 dollar one at Hubble Optics similar to the one I made. I also ordered one of these. http://www.hubbleoptics.com/artificial-stars.html#_

nikonshooter Loc: Spartanburg, South Carolina

Good read Jim! Every star is a gull in my FOV...not just the corners where coma does its worse.
Hopefully when I boot up the kit this Friday or Saturday things will be ok. If not - back to the drawing board. I will re attempt to collimate without the reducer.

I appreciate you input and article!

SonnyE Loc: Communist California, USA

I have no idea Ed.

But... this is exactly why I became a refractor nut.
Much less to go wrong.

alberio Loc: Casa Grande AZ

I've had the best results with real stars.

nikonshooter Loc: Spartanburg, South Carolina

I can see clear advantages using an artificial star.

No tracking needed (unless using Polaris)

Atmosphere turbulence eliminates the dancing star

Can do in daytime as to no waste imaging time.

Choose the star needed for focal length of scope

Fast recentering of star between adjustments

.......but like most people, I have only used a star prior to using my home made artificial star. I did order one from Hubble Optics that will offer more precise choices depending on the reflector I am using. I have three SCT's and a NEWT so I think I will get my 24.95 worth.

SonnyE Loc: Communist California, USA

I dunno... That's a $6.25 outlay per scope.

I might have to look into one so I can do more serious playing during the long days.
Trying to wrap my tiny brain around plate solving. Getting there.
But the noise is like a BB in a Boxcar.

nikonshooter Loc: Spartanburg, South Carolina

I was able to image last night - as it turned out the collimation was the issue. Unlike a Newtonian or at least my Newtonian if you get the collimation reasonably close you can image away. Besides a perfect collimation on a Newt is close to impossible because the collimator (if you use a laser and I do) also has to be collimated and that is a pain in the _ _ _! I have two laser collimators and they both render different settings and I have both collimated. Go figure. But a SCT is a different beast - I fiddled with it for an hour on an artificial star to days ago and got it dead center and tonight - walla - my round tight stars have returned. I am afraid to touch the SCT now for fear I will knock it out of collimation. Glad it is on a pier.

So my "take a way" on this adventure. If you own a NEWT and use a Laser collimator - get it perfect and then fine tune on a star or artificial star to get a perfect collimation.

If you own a SCT - expect fat stars regardless of your focus precision until you get that perfect collimation and that is a fiddling nightmare - even with Bobs Knobs.

But the fun is in the trying!

Clear skies and happy Sunday!

Europa Loc: West Hills, CA

Congrats, when I tried on the RASA, I was spending a lot of time and couldn’t get it just right.

It’s a challenging and tedious process. Let’s see some pix now.

SonnyE Loc: Communist California, USA

And now you know why I'm a refractor nut...

Honestly, my lists boiled down to the refractor I have, or an Orion Astrograph.
The tipping point for me, was collimation. I did not want to fight that in addition to all the other things I had ahead of me climbing the learning curve. (And never did I expect the damn boulders the AVX and the G3 camera threw at me.)

I might be ready for it now, but it would be due to economics. Bigger refractors cost huge $um$.
But a Orion 10" Astrograph is $700.

(One of these days my wife is going to shoot me to end her misery.)

alberio Loc: Casa Grande AZ

What kind of problems did your AVX give you?

nikonshooter Loc: Spartanburg, South Carolina

Where to start - the mount was returned twice within 1 year of purchasing - and I have bought two hand controllers (boot error issues) in addition to the ones provided with the mount. The electronics (board had to be replaced) the first time....after months of waiting on it, it arrived and also didn't work right. It was returned and i received a new/refurbished one.....the RA and DEC are so bloody stiff this mount cannot be balanced conventionally - neither of the three moved like a normal mount. You can balance in DEC by taking the OTA with all attached equipment off and using a fulcrum to mark the center point but RA is nearly impossible. I even had a celestron tech tell me all AVX mounts are like that and balancing doesn't matter...just get it close.

What I have now is working fine - you get what you pay for and this is a low end mount - but as it should work and my first two mounts did not.

I have a procedure for balancing all of my mounts that is a bit tedious and time consuming but it is the only way I know for sure - I have it right. Let me know. It will be a labor to write it out so it makes sense but I will give it a go if anyone is interested. If your guiding is working....don't mess with it.

SonnyE Loc: Communist California, USA

Oh, nothing that Celestron couldn't fix after sending the Whole thing back, twice.
(Why do they need the tripod for an electronics problem? Chinese business model.)

I have a theory based on 42 years doing electrical maintenance and troubleshooting, and failure analysis.
I've watched for and read as many problem posts as I could find about these No Response 16 and No Response 17 codes in the NexStar systems. Specifically in the AVX and lesser telescope systems.
It is not an isolated incident, it's a World Wide problem. And their approach is to change parts.
But the problems persist. So a deeper look finds us looking into Synta Corp, and problems in other lines they manufacture. It gets harder to track, because these other lines use somewhat different trouble codes.
Because of that the waters get muddied, it gets harder to see the problem.

Now, go outside of Synta Corp. Who else is manufacturing mounts, and what are the trouble reports coming in? Here is where the plot thickens.
One I am aware of is iOptron. iOptron hit the market running full speed. They built a really good reputation, but of late they too are suffering electronics problems.
We now have to zoom out and take a wider view. What is in common with these troubles? China.
The Chinese business model is fix, fix, fix, but never refund. Never! How do they fix?
They replace only. And only what must be replaced. Never any failure analysis. IF they did failure analysis, they would change the components causing the failures, and shore up their reliability.

I know for a fact the AVX suffers from voltage issues. If you go outside of 12 volts, it blows holes in their chips. If they could manufacture better components, they could make products worthy of the good names they bought and are destroying with their crappy business models.
These are not pink paper umbrellas. You don't just replace the bad paper umbrellas with the same faulty paper umbrellas.
Because eventually, the customer base will find more reliable items.

And that... is why I put my money into a Losmandy Mount as my replacement. Made in the USA, by a one man band, where the quality is controlled each step of the way. If a problem arises, it gets corrected.
Do you think a CEO and Owner of Synta Corp would actually pick up a tripod and pack it in a box for a customer? I don't.
But Scott Losmandy himself put my HD Tripod into the box while I steadied it. Tanya is a little gal, and a 35 pound tripod is a bit much for her.
Scott himself was putting together a dual mount for a customer when I arrived and was invited back into the factory. He was making sure the clamps worked to his satisfaction as he built up the mount, and that the parts were perfect.
My new mount has worked better than I could have ever dreamed it would. And it's just getting better and better as I learn the nuances about running it. And this is only week 3 now.
I wasn't doing this good with my AVX until after a year of coaxing it, and two trips back to Celestron to fix it. (My AVX died suddenly in November of 2019. And I knew I would not be repairing it.)

I found my way around the Chinese mount dilemma. At first I thought I can't afford that.
But as I tried to justify why not, I came to the conclusion that I could not afford to invest in another China mount, and rolling those dice again.

I did learn a lot from my AVX. It was a hard and cruel mistress. I coaxed a lot out of it. But it cost me $200 a year, and a whole lot of aggravations.
I can't see any of those in my future. I'm of the opinion I have my lifetime mount now.