Ritchey–Chrétien enjoyers thread

[slate falcon]

[harsh matrix]

the last one is a tilt test since i noticed monitor stars look a lot like actual stars

there's not a horrendous amount there, assuming that's not from the DSLR

also the back focus of the roki w/ my canon is 11 mm off

[slate falcon]

[oblique sun]

wow, so sharp you resolved the pixels in the firmament!

[harsh matrix]

so that's obviously a huge issue with this test

luckily it looks like while my weather is crap, i can possibly fine tune the back focus by using a computer screen @ "infinity"

i need to source some adjustable length extensions and then i can get to work

[slate falcon]

[harsh matrix]

lmfaoooo

you can see chromatic aberration in the fake stars LOL

oml i love this already

[slate falcon]

[slate falcon]

my phone cam has barrel distortion up close so stars on monitors look messed up

[harsh matrix]

@slate falcon look at my monitor in these photos

that's what my phone lens looks like

it is far more distorted than the roki with bad back focus

at f/2

[slate falcon]

thats cursed

[harsh matrix]

birds

comets at best

btw the fact that JWST has no noise out of the gate is absurd

this is just

like

how

Nasa wizardry I guess

[harsh matrix]

getting somewhere

this is a bit eerie

reminds me of the fighting dragons of ara

i love this data

this stuff is great

[tight lodge]

@frosty shard remember when I asked you if this is a good shape? Yeah... this is 2nd worst option that I could have picked.
1st. Spherical
2nd. Eliptical
3rd. Hyperbolic
The best is parabolic
I have to redesign everything 😭

[slate falcon]

what are you trying to make?!?

[tight lodge]

Antenna dish

[slate falcon]

ooo

[tight lodge]

Basically something like this😅

[slate falcon]

iseeee

[slate falcon]

@sinful sapphire

[sinful sapphire]

is that F/30

[slate falcon]

yea 😭

[slate falcon]

the traced ray looks insane tho

[sinful sapphire]

atp a newtonian has less coma at F/30

[sinful sapphire]

show

[sinful sapphire]

https://cdn.discordapp.com/attachments/1454583948943298692/1490457666651422720/togif.gif

[slate falcon]

theres 4 focal points

[slate falcon]

its the greggreggregorian

i didnt think it would be possible

but it is

[slate falcon]

it has no choice but to be a point

@fickle flower would you buy the greggreggregorian

perfectly corrected to a sensor with a 20mm diagonal

[tight lodge]

If I was you I would call it Colossally Handsome Astronomical Device or CHAD

[slate falcon]

[tight lodge]

Ooor Catastrophically Hard Astrograph Design

I just want to use CHAD for it

[slate falcon]

also i just noticed the max brightness of this design falls off slow

[slate falcon]

10mm off axis and its only down to 0.758 max

[fickle flower]

If it was literally called the greggreggregorian, I would just for the goofy name

[slate falcon]

i made the design so i think im allowed to name it

[sinful sapphire]

ay thats not true

it follows the basics of the three mirror gregorian

[slate falcon]

nono, this is different to the folded greg

[slate falcon]

not really

[slate falcon]

heres the rays

i could call it a greggreggregorian

[slate falcon]

if you put a cam at any of those points you would get an image

its so silly

[frosty shard]

That is reserved for the glorious Ritchey–Chrétien, thank you very much

[slate falcon]

just wait until i make the ritchey ritchey-chretien

[sinful sapphire]

you dare to suggest the Ritchey-Chrétien is an insufficient name?

[frosty shard]

...good point.

[slate falcon]

amma join vc in 10-200 mins

[slate falcon]

its like completely different!

[slate falcon]

look how only 1 inversion of the focal point happens on the tmg

[slate falcon]

tmg gives you a correct view

without a prism

wait so does mine

omg yesss

@sinful sapphire three mirror gregorian is 3 mirrors, 2 concave and 1 flat/spherical concave secondary, my secondary is ellipsoidal!!

splitting hairs

and yea it obv doesnt follow the same path at all

i think i will try make a coma corrector out of mirrors

[slate falcon]

@frosty shard ritchey ritchey chretin, 2 convex mirrors and 1 concave, all are verry hyperbolic

[frosty shard]

Ahem...have you heard of the glorious Ritchey-Chrétien?

[frosty shard]

What is this monster

(I'm going full purist today)

Unrelated: we are so back (for one night only)

[slate falcon]

ritchey ritchey chretin

[candid flame]

reflecting twice on the same mirror is low key kinda cool

[frosty shard]

I think the Eisenberg-Pearson design does that? (Which is what Vera Rubin uses)

[slate falcon]

guess the f ratio lmaoooo

[frosty shard]

f/67

[slate falcon]

f50

[frosty shard]

Not actually as far off as I was expecting.

[slate falcon]

for reflecting 3 times on convex mirrors its not bad

(pretend my brain works)

[haughty steppe]

seti astro released an AI in his software that removes and denoises walking noise. Worked pretty well on my old data. Note, this is at I think .75 denoise, looks cleaner at 100 but also depends on image.

he also ran it on comet aligned images and it cleans up that streak noise as well

[slate falcon]

hmmm

[harsh matrix]

@frosty shard

holy sheet

[slate falcon]

im gunna replace your rc with an rrc btw

jus you wait

[plush raptor]

im gonna replace your cc with a nexus

[tall summit]

Tnx for the tip, I'll try it out!

[frosty shard]

I SAW THE CRESCENT TONIGHT

[versed roost]

I KNEW IT

IVE BEEN CALLING THIS FOREVER

I SAID SETIS GONNA RELEASE SOME WALKINGNOISEXTERMINATOR OR SMTH

always making random stuff

[slate falcon]

nexus doesnt work on f3.3 mirrors

[frosty shard]

In the words of Will Smith: AW THAT'S HOT

[plush raptor]

yea it does lol

f3-f/5

[slate falcon]

@sinful sapphire

im sure you can explain

[plush raptor]

https://tenor.com/view/ishowspeed-my-mom-is-kinda-homeless-please-speed-i-need-this-tired-blow-gif-15401023925154467112

[slate falcon]

paint yk resellers do just say stuff

like that thing can barely do an f4 scope

and its almost unusable at f3.3

[plush raptor]

tf you on

[slate falcon]

nothing?

[plush raptor]

its starizona who saidd that

[slate falcon]

it can still correct an f4 scope but barely

[plush raptor]

https://tenor.com/view/cat-drugs-drug-snow-animal-gif-10335506710319479131

[slate falcon]

starizona is the reseller yea

they want you to buy their stuff therefore they stretch how far it can be used

[plush raptor]

they make it lol

[slate falcon]

they make it but they are still a reseller

anyways

beside the point

[slate falcon]

its only really meant to be used from f6-f4

[plush raptor]

its made for f/4

[slate falcon]

yea, f4 is also the limit

with such a reducing optic it has a very small usable range

if you use it with an f3.3 mirror expect your stars to look horrendous

[plush raptor]

it works very well with f/4

[slate falcon]

yes, its the limit

[plush raptor]

ah, the limit for it to work well?

[slate falcon]

yes!

[plush raptor]

ohhhhhhhh

[slate falcon]

as long as it still works and you can tell a star is a star they can say its usable at f3 (mirror(not reduced f/num))

[slate falcon]

it becomes f2.5

[sinful sapphire]

It is rated for F3 to F/5, however it is optimised for F/4.

The issue with using it with F/3 is spherical and chromatic abberation

images become soft.

It corrects, yes, but your image quality degrades.

CA isnt very noticable but its there.

the spherical abberation however is

[slate falcon]

[slate falcon]

@sinful sapphire should i do a comparrison of 60 60s subs and 1 3600s sub

[sinful sapphire]

just because you have to get that 3600s sub

no

[slate falcon]

i get 0.77 arcsec guiding on average!!!!

my pixel scale is 0.89!!!

my guidescope is aligned with my main scope!!!

[crisp flower]

i want to get proper int on rgb for this soooooooo badly, but i cant with this weather rn

[waxen mountain]

Wow

So much dust

@crisp flower How does it look without denoising ?

[crisp flower]

I can send that later, im Not Home atm

[plush raptor]

one gust of wind or some sizemic activity and ur dead

[slate falcon]

oh yea

uk moment

[crisp flower]

@waxen mountain this is with just an stf-stretch

and this with a bit overboard mas

[waxen mountain]

nice looks clean

[waxen mountain]

hope you get better weather soon

[crisp flower]

thank u

[crisp flower]

i hope so too..forecast doesnt look too good but one can still hope

[waxen mountain]

https://tenor.com/view/hopium-half-life-critical-hopium-hopium-levels-critical-gordon-freeman-gif-9669139738936544681

[slate falcon]

i like

[crisp flower]

me too

[safe bison]

how much int? looks really good

[crisp flower]

about 8.5 hours

[slate falcon]

[crisp flower]

im still at only 30 mins green and blue

[slate falcon]

when i switch to mono the 3 things i will be able to use is lum, ir and oiii

[plush raptor]

and ha

[slate falcon]

nah, no ha filter

[slate falcon]

i will have access to sii too

i can make a makeshift sii filter

[crisp flower]

for me having an oiii filter, i think ive only used it 2 times xd

[slate falcon]

[crisp flower]

im just hating on its halos because is shows me how off my mirror spacing is

[slate falcon]

[frosty shard]

One of my attempts to make a refr*ctor more aesthetically pleasing.

[waxen mountain]

Nice

[slate falcon]

im sorry but the only pleasing to look at refractors are the 90mm f15 ones

specifically with a diagonal on it

[frosty shard]

What if it's a 6" f/15

[slate falcon]

🤤

-# 6" f/20 is better

[frosty shard]

Our physics building has one of those on the rooftop

[slate falcon]

[frosty shard]

Whoa there's actually a special about it on PBS
https://www.pbs.org/video/the-burnham-telescope-wt2d46/

I actually know Jim Lattis too

[harsh matrix]

Im actually jealous

Wtf

[crisp flower]

Xdddd

dont be, u capture some things that are just out ouf my reach

[harsh matrix]

Wrong

That's narrowband almost exclusively

Broadband is basically a lost cause at this rate

[crisp flower]

well yea but nontheless.. m16 for example is sommething im just unable to shoot at my current location

well i think thats not entirely true.. if im lucky i think i have about a 20 minute window in may nights

[frosty shard]

High latitude moment

[crisp flower]

more like a: unfortunately itsa illegal to demolish my neighbours house-moment

[frosty shard]

hey just because something is illegal doesn't mean you can't do it and ask for forgiveness later

[slate falcon]

its easier to beg for forgiveness than ask for permission

[slate falcon]

would

i mean

uhh

cool!

[tight lodge]

https://tenor.com/view/party-rave-glowstick-american-dad-roger-gif-16190476

[frosty shard]

Correct (also congrats on Pulsar, how'd you get it)

[tight lodge]

The laser interferometer that i built a while ago

[frosty shard]

Ohhhh I forgot about that...absolutely deserved

[tight lodge]

#🔨-do-it-yourself message
Also working on this big boy

[frosty shard]

I don't care too much about roles but hopefully working on the Julia packages for image processing is considered extremely biscuity

[slate falcon]

making my own decon isnt extrmely buscut enough :c

[slate falcon]

@sinful sapphire

its always fun to just set the steps to a tiny amount

[sinful sapphire]

askar would do that

[crisp flower]

For once im Not Mad for being photobombed

[slate falcon]

who is it?

im imaging Abell 2218.

[slate falcon]

also which galaxy is this?

[crisp flower]

NGC 6951 still

[slate falcon]

[crisp flower]

Finally getting RGB going on this

[slate falcon]

tbh i want an rct

i would download an rct

[crisp flower]

U have a noot right?

[slate falcon]

yea

[crisp flower]

Those are p great as Well ngl

[slate falcon]

i need the glass gone

bc it effects my ir imagery

[crisp flower]

Yes

[slate falcon]

look the stars

they arent able to fully focus

[sinful sapphire]

the humble IR uncompatible lenses

[slate falcon]

also i have something to tell you about sct's

[crisp flower]

That Star Field tho

[slate falcon]

the bigger issue with the design is that its not made for on axis performance, its made for a corrected field so its not as good in the center as it could be, then obviously theres the ca you get which is unnavoidable, its not particularly a manufacturing issue but more of an inability to solve this like how a maksutov can

manufacturing isnt the issue here

we know how to manufacture an sct

[sinful sapphire]

the issue is manufacturing a good sct which doesnt exist 🗣️

[slate falcon]

yes

not that its difficult to manufacture, just that its impossible

so yea, use these points when you need to argue about sct's again

[sinful sapphire]

i will slander all scts

[slate falcon]

gooood

[plush raptor]

so you listend to me

[slate falcon]

no

fin

[slate falcon]

someone thinks i got an exoplanet

[slate falcon]

oooo

eh

[frosty shard]

This is not true at all. The corrected field of an SCT (at least the most common ones you see, from Celestron and Meade) is not particularly good even if perfectly manufactured due to coma

For simpler optical designs like reflecting telescopes, it's basically never worth sacrificing on-axis spot size for off-axis field

[slate falcon]

the corrector plate very much does sacrifice on axis performance

[slate falcon]

also the entire point i was making is that we can make them well, they just arent a good design

[frosty shard]

Oh do you mean through spherochromatism

I mean that's just par for the course if you have a single zero-power refracting element

[slate falcon]

yea

ayy my guiding settled!

a wind gust anihlated it

[slate falcon]

i got to mess with lokatons data

i gotta finally use the isophote model for astro

[frosty shard]

To get galaxy profiles?

[slate falcon]

yea

used to remove the star glow

like the oval ball that surrounds the galactic core

[frosty shard]

I was actually thinking of using a Sersic profile to explore features in elliptical galaxies

[slate falcon]

the last photo is my shitty attempt at dimmin the core lmao

tbh quite similar to hdr thingy

[slate falcon]

i lov abusing wavelets

[sinful sapphire]

feast your eyes

[harsh matrix]

@crisp flower I keep getting walking noise in my testing

every time ive seen it, my flats dont work

so even had this test been successful in any way, i wouldnt know because i cut corners with dithering to maximize the number of frames i got this night

why?

I was only supposed to have a 3 or 4 hour clear window this night

ended up being clear ALL night

had i known that i wouldve dithered every 2 2 minute frames instead of 3

i also boosted the number of pixels i dither by and that didnt help enough

or at all

i think it made it worse ngl

[crisp flower]

Interesting

[harsh matrix]

Even weirder is you can see the crater

Except it is so much fainter than previous tests

[crisp flower]

Ive noticed Kind of the Same when i uploaded one of the issue-pictures of Mine to the interweb

[harsh matrix]

Its hard to say if that's still due to movement or if that was caused by the walking noise.

[crisp flower]

I think Theres a corelation between movement and Walking noise

Because i think that pretty much all of my Pictures with the issue have Walking noise as well

Thats the one where i noticed it today

[harsh matrix]

Yeah me too

[harsh matrix]

Ohhhhhh what the hell

Wait

[crisp flower]

What surprised menis that U can See it curve

[harsh matrix]

So we both are having the exact same problem triggered under the exact same conditions?

[crisp flower]

Id say so

[harsh matrix]

See what curve? The noise?

[crisp flower]

The Walking noise is curved

[harsh matrix]

Ah I cant tell on my tiny phone screen

Wtf

Hmmmm

It might be in my image too

This is a very odd development

[crisp flower]

I noticed when comparing the upper left Corner with the lower right

[crisp flower]

It is

[harsh matrix]

Oh youre right

HUH

And in your images without walking noise you get no crater, right?

[crisp flower]

I have Not checked If its curving in my other Pictures as Well but thats pretty interesting inthink

[crisp flower]

Jup

[harsh matrix]

It's a detail that's certainly hard to ignore.

[harsh matrix]

Hmmmmmmmm

This just got very interesting.

[crisp flower]

It did indeed

[tight lodge]

Damn bro... you are a train full of troubles 😭

[crisp flower]

Too Bad i Just turned Off the PC, i would Love to Check my issue-data again now lol

[harsh matrix]

Now, how long were your subs and how often did you dither?

[crisp flower]

300 sec subs and i dither every 2 subs by 7pixel

[harsh matrix]

Cause the weird thing is, I can get away with dithering every 2 subs when doing 3 minute broadband subs on my other scopes, but not this one.

[harsh matrix]

Hmmmmmm

I would do every sub at 5 minutes

Is it inefficient? Yes, but i never get walking noise doing it that way.

[crisp flower]

Noted

[harsh matrix]

Just like im thinking I may have to dither every 2 minute sub but dropping the reducer will let me boost my exposure time.

I think im going to go back to my original gain and offset too since I think those just made my problems exponentially worse.

[crisp flower]

Doesnt changing gain and Offset Just Change the extend to which the issues that are there are visable or am i wrong on that one?

[harsh matrix]

I think that's what happened yes.

[harsh matrix]

@crisp flower Something you can try is to do a test stack where you delete every other frame and review the result.

If it is significantly better if not fully resolved, then the issue is how often you dither

If the walking noise either remains a lot or a little then the issue has to do with how much you move by each dither.

Im going to do this once im done with my current task.

[slate falcon]

i hate m94 it blows out too easy

[harsh matrix]

@crisp flower look at this rejection map, youre absolutely right about the noise curving

[crisp flower]

Maybe combining Long and short exposures on it is the way to Go

I cant really Guide on it so i cant really Image it

[harsh matrix]

in my case deleting the 3rd frame of each dither segment didnt help

[crisp flower]

Hmmm

[harsh matrix]

gonna delete more

but something tells me the dither distance is wrong

[crisp flower]

Maybe the Walking noise itself is also caused by movement within the scope?
Because to me, Walking noise caused by Not dithering enough would Not lead to curvature in Walking noise

Or at least i cant explain to myself how it would

[slate falcon]

possibly

@frosty shard yk how you get less signal when you shoot at a slower f ratio, shouldnt you gain some signal and not loose as much as you should due to noise averaging out?

im having a brain ? moment rn im sure

[frosty shard]

You should do a Fourier analysis on this to determine the periodicity of the noise, because that might tell you something about what's causing it

(if you don't know how, send me the raw data and I can try)

[frosty shard]

At the end of the day it's going to be proportional to the total amount of light gathered

[harsh matrix]

that's how i feel as well

it doesnt make much sense

[harsh matrix]

hm

[slate falcon]

[harsh matrix]

I do not know how

but I don't know what exactly that can tell me

because as far as im aware only the camera can cause walking noise

[slate falcon]

also i will like 50% maybe get the rct

[harsh matrix]

just stacking 1/3 of each dither now

the thing is, multiple nights of data will average out/smear out the walking noise of one night

except im not okay with accepting that even a little given my experience with the issue

causing flats to not really work and all

[harsh matrix]

okayyyyy sooooo

the flats just arent really working

still seeing some subtle traces after deleting 2 thirds of the data

and keeping one frame per dither

so this is either camera behavior or not dithering by enough pixels

not due to me not dithering often enough

what a weird problem

[slate falcon]

how much data is this then?

[harsh matrix]

looks really weird still

[slate falcon]

ooof

more data will fix it

[harsh matrix]

much cleaner overall

yet this looks like my small dust mote still

okay this just got really weird

looks like it might be and might not be

uhhhh weird

none of the funky spots like this have anything to do with the flats

the motes dont line up at all

[slate falcon]

crt

[slate falcon]

did you leave your scope out during midday without a cap?

[harsh matrix]

1 hr 52 minutes

[slate falcon]

ooof

[harsh matrix]

no

[slate falcon]

was gunna ask if the sun melted a hole in ur sensor

[frosty flicker]

👀

[harsh matrix]

the sun is in the south not the north

💀

hate to say it but this is by far the cleanest ive seen this thing

it is very very nearly perfect

doesnt seem like it should be but it is

[frosty shard]

@harsh matrix The background of my 4+ hours of NGC 2403 stack is also mottled. It doesn't look terrible if I stretch it compared to the Siril autostretch preview, but I used pretty short L exposures (40 sec) so I wonder if it's due to sensor FPN

[candid flame]

but aren't you dithering?

[frosty shard]

yes, but it won't completely get rid of FPN features that are significantly larger than the dither scale

actually I might have to restack this data now that I think about it

I forgot that I'm using median stacked bias frames and that may be an issue

[candid flame]

i guess that could be it

usually people just choose to dither way too much just to be sure tho. aren't you also?

[frosty shard]

I remember I turned my dither distance down because I was having issues with failed settling at one point, but I should probably turn it back up again

I think it's only like 8 px at image scale

[harsh matrix]

FPN?

[candid flame]

fixed pattern noise

[harsh matrix]

oh

💀

yeah i think it is fixed pattern noise

i just dont understand why it looks curved in the rejection

[frosty shard]

What does your master bias look like, and how old is it?

[harsh matrix]

looks curved in the lights too tbf

[harsh matrix]

brand new

looks normal

i tried 300 gain and 396 offset for this last test

it appears it did remove the crater in the dither every frame stack

mostly

i think i still see it

i just went through and checked the information of each type of frame i stacked and everything matches

temp, offset, and gain

[slate falcon]

got 4 hours of m94 data

next time i shoot it i will either do 4 hours of longer exposures

or shoot it in ha and oiii

[harsh matrix]

@frosty shard is this what you were looking for?

[slate falcon]

that ur noise pattern?

[harsh matrix]

probably not

i ran fourier transform on it

not sure what exactly it is

[slate falcon]

ohhhh

i see

[frosty shard]

Yeah, that's it. It's a map of the frequencies in the noise pattern

I need a little while to take a look at it but this is telling me that what you have may be correctable

[slate falcon]

https://visionbook.mit.edu/image_processing_fourier.html

[harsh matrix]

this was using some different settings

this one and the above one

[slate falcon]

this explains what it is

[slate falcon]

read it all

[harsh matrix]

stinker

[slate falcon]

[harsh matrix]

I do wonder though

can i do an analysis like this to figure out a function to characterize and correct the corners?

[slate falcon]

maybe if you get something from the flat and subtract it from the actual image then recombine maybe

like the dft phase

add the phase from the flats only having the edge in it maybe

so cut out all the rest, get the phase then (invert) then add to the phase of the actual image

[harsh matrix]

uhhhhhhhh

https://tenor.com/view/monster-versus-vs-alien-monster-vs-alien-gif-16037253809360562033

DFT phase of the flats on the left and DFT phase of the full 5.5 hour stack or whatever it was on the right

same order for the magnitude here

wtf

i dont understand any of this

[slate falcon]

[slate falcon]

now subtract the magnitude of the flats from the magnitude of the image and recombine

trust

[harsh matrix]

didn't do much other than add this

[digital nexus]

Hey RC guys

Anyone want to buy my rc6?

I need funds to replace my mini oc

[frosty flicker]

rc6 needs you

[digital nexus]

I think the rc6 cursed me

[slate falcon]

rc6 is your wife

[harsh matrix]

@frosty shard I figured out another way to sniff around for flexture in my system

Put a laser in a compression ring and push around on the back of the scope.

I found movement in the decoupler.

[slate falcon]

[frosty shard]

THE ONE ACCEPTABLE USE OF A LASER COLLIMATOR

Anyway, if you want to understand the Fourier transform, watch the 3Blue1Brown video about it

It's one of my favorite videos on all of YouTube

[harsh matrix]

I didn't tighten the tilt adapter enough again. 🤦‍♂️

[slate falcon]

you gotta start making everything tight

almost lost my cam the other night

because i didnt thread it on well

[harsh matrix]

Of course now im just being a child and im making diffraction patterns with the laser.

[slate falcon]

(lost as in lost rotation )

[slate falcon]

reasonable

[harsh matrix]

I get everything as tight as I can and I try not to get it so tight that everything wants to weld together but it can be a hard balance to strike.

[slate falcon]

i welded my dualband to another filter

still cant get it off

[harsh matrix]

Good job

[crisp flower]

I Had my main-guidecam and Filterwheel having a Not so nice Meeting with the ground because Something Like this once

[harsh matrix]

@frosty shard I just reset my RC8's collimation because it seemed so far off and now I have like near infinite hall of mirrors going on around all sides of the secondary, dang near perfectly.

[slate falcon]

thank you, im very proud (deeply pissed off) that i lost one of my spare 1.25" filter holders for exotic filters :D

[harsh matrix]

Das pretty bad

They must be aluminum and poorly coated or something.

Rotator installed.

This is hot ngl

[slate falcon]

why does this guy have such a bright ring

[slate falcon]

@harsh matrix this is the raw stack, dark circle around the target

[slate falcon]

bg correction cant correct it

[harsh matrix]

That appears to be light leaking into one of the mirrors

Im assuming you have put something over the back of the scope to stop light from leaking through the primary mirror, but have you painted and/or covered the back and the sides of the secondary mirror?

[slate falcon]

yup

[slate falcon]

oh i havent done anything to my secondary

[harsh matrix]

That's what is causing that.

[slate falcon]

beh

[crisp flower]

Its as If u have ripples of light and dark across this

[slate falcon]

thx for the help

[harsh matrix]

i did just finish up setting up the RC and testing out the rotator

reset the autofocuser position as well

everything is working in harmony once again

now the weird thing is, despite messing with the collimation, the position of the ring that causes the crater is still offset to the right

almost in the exact same spot as with the reducer except i changed collimation and the point of focus by a lot

very strange

[harsh matrix]

@slate falcon @frosty shard we got new test flats, this is with the rotator installed and all of the accessories needed to install it.

luckily the tubes I got and the BDS adapter came pre darkened already

basically incredibly small reflection risk

and if you notice, i have no ringing

no reducer

ironically there's very little actual vignetting taking place

[slate falcon]

nice circle

[harsh matrix]

yup

my only concern is how offset that is

also the donuts are showing coma

so collimation either could be better or i have to adjust the tilt

probably wont know until i get another night under the stars

I am using M 54 accessories all the way through so im able to capture then entire image circle with the 571

im losing maybe only about 25% of the light from center to corner lol

and i mean to the extreme corners that are showing the slightest bit of darkening

that's actually a huge difference from before and totally ignoring the drop off caused by the reducer before

[frosty shard]

🇧 🇷 🇺 🇭

[crisp flower]

My new focusser is on its way

I think i'll wait to Install it until im finished with NGC 6951 tho

[harsh matrix]

what focuser did you end up getting?

[crisp flower]

The exact Same one u are running

[harsh matrix]

based

[crisp flower]

well the ones i saw were all basically the same of what i have and i didnt want the possibilty of it moving around randomly if i touch it the wrong way lol

[harsh matrix]

yeah that was the same problem i ran into

another choice is to buy one off of Teleskop Express but they are in Europe which may make them cost a fortune, and there's no guarantee that they will be any more rigid than the stock GSO focusers

although maybe not as much as you

but same problem exists for rigidity

[crisp flower]

I was Not really convinced of the ones they have tbh

[harsh matrix]

neither was I

[crisp flower]

Well i think There was one i thought might do it but it was for 10" RCs and thats Something i die Not want to mess wirh

[crisp flower]

I Like my autocorrection changing do to die lol

[harsh matrix]

that would be annoying to make work on a not truss tube

[frosty shard]

Those are 3.3" focusers IIRC so good call

I might have to join you for a focuser upgrade in the future, though at the moment I'm not seeing the flat frame issues you are

[harsh matrix]

It seems like its more likely to occur if walking noise develops, even just a little bit.

It is still happening to me even when it doesnt develop though and that's what has me concerned.

[haughty steppe]

not gonna fix the problem. But you can try out sas walking noise denoiser 😄

[harsh matrix]

Not going to do that

[slate falcon]

hell yea

[slate falcon]

have you tried stacking using biases?

biases should take away some pattern noise

[slate falcon]

yk what i mean

stacking with biases

should maybe sleep

[harsh matrix]

I only stack using biases

[slate falcon]

oh

uhhhhh

idk then

ik some people dont do biases

[harsh matrix]

Correct but I'm not one of those people.

[slate falcon]

[crisp flower]

My guiding is absolutely Not managing this but its giving its best xD

[harsh matrix]

Lol hell yeah

Man everyone but me is getting clear skies.

[crisp flower]

Thats because we Had Clouds only here from September until mid November

[tight lodge]

@slate falcon can I ask you for a favor in your fancy optics software? Can you make a reflective null corector from am RC8 and an RC6 primary mirror?

[slate falcon]

potentiallly

what is a reflective null corrector?

[tight lodge]

The thing that said that hubble's primary mirror was perfect

[slate falcon]

i see

[tight lodge]

I'm asking specifically about RC8 and RC6 because you probably have them saved somewhere

[slate falcon]

funny enough i dont

[tight lodge]

[slate falcon]

i do have 70 gregorian designs though

[tight lodge]

I mean... this is somewhat a cursed gregorian🤣

[slate falcon]

[crisp flower]

Now thats slowly getting there

[waxen mountain]

How much int

[crisp flower]

8,5hours Lum and about 9 rgb

[waxen mountain]

Noice good Job

[crisp flower]

ty man

[waxen mountain]

How much do you have in mind ?

[crisp flower]

getting the colors in the dut was pretty hard but 3rd time was the charme

[crisp flower]

not too sure tbh

maybe ill double everything, maybe thatll be it

[frosty shard]

What's the target?

[crisp flower]

NGC 6951 in Cepheus

[slate falcon]

onion

[plush raptor]

I was gonna shoot that at one point lol

[stiff mason]

Purple and blue? What was bro doing

I mean it looks cool

[harsh matrix]

did a magma palette style SHO image with a subtle Adam Block flair

[crisp flower]

Damn i really need to Image that sometime

[tight lodge]

@harsh matrix What did I tell you?

[harsh matrix]

dang wtf

[tight lodge]

Do you remember this?
We were fighting over who wad sharpervand such but we ignored the level of detail we were comparing. Most people don't even know those features exist in the nebula

[harsh matrix]

I wasnt ignoring the level of detail lmfao

[tight lodge]

Still... the scale is quite extreme for an average astrophotographer😂

[harsh matrix]

yeah true

but mine is sharper (right)

[tight lodge]

No doubt. Also unfair match in integration time

[quartz meadow]

Wait until they find out what features can be revealed with a Ar III filter (dont know about this target tho)

[tight lodge]

Tell me where I can buy a 2" Ar-III filter

[quartz meadow]

best I can give you is a 7nm from QHY

[tight lodge]

The smol square one?😭

[quartz meadow]

yup that you can exclusively use with the Minicam 8

[tight lodge]

I could design an adapter from 2" to whatever size that filter is... but the vignetting is gonna be horrible and probably not worth the hassle

[quartz meadow]

absolutely not worth it

[tight lodge]

How many kidneys would Optolong ask for to make a custom Ar-III filter?

[quartz meadow]

I really wonder when other manufacturers will cling on to that

[slate falcon]

maybe do it without bxt

[sinful sapphire]

Yk.. it may just be worth asking QHY for one.

[tight lodge]

I doubt they will do it

[sinful sapphire]

asking doesnt hurt

[tight lodge]

There are 2 outcomes

1. They say no because otherwise they won't be making money with the minicam 8.
2. They throw an insane price so they make sure to discourage you from buying an individual filter and make it seem like the minicam 8 is a better choice

[sinful sapphire]

https://cdn.discordapp.com/attachments/1454583948943298692/1490457666651422720/togif.gif

[slate falcon]

oh yea no 100%

[crisp flower]

Would u people think a Carbon Filter would be an Idea?

[slate falcon]

like Cii?

[crisp flower]

Cii i mean basically a comet Filter but i think it sounds interesting

[slate falcon]

i will say good luck

[slate falcon]

swan lines?

[crisp flower]

Yess

[slate falcon]

oh then you will be ok

theres some stuff

pne's mainly i thibk

[crisp flower]

Its Just an Idea for now

[slate falcon]

isee

[slate falcon]

its kinda like how i will be getting the solar 2nm filter (non solar continuum) as it lands on an Fe line

i also want it for solar

but other than that

[crisp flower]

Solar Sounds pretty cool ngl

[frosty shard]

Baader already makes one of those. I don't think the Swan bands are particularly prominent in emission nebulae though

[slate falcon]

the ir lines are more prominent yea

(afaik)

i wish i could get cmy filters instead of rgb

some random Fe line lands here

[harsh matrix]

Iron?

Really?

[harsh matrix]

What about molecular clouds?

[slate falcon]

theres a few absorbtion and emission lines on this

(1 absorb and 1 emit)

[harsh matrix]

@frosty shard new strat

If you ever lose your collimation and you cant get it back

Reset it using hall of mirrors

It was almost dead on lmao

[frosty shard]

New meta just dropped

[harsh matrix]

I think i need to adjust tilt again 💀

[slate falcon]

[crisp flower]

What that?

[harsh matrix]

When you look down the tube at the primary mirror toward the inside of the baffle, with your head close to the secondary mirror, you should see near limitless reflections.

Limitless is an exaggeration, should be more like 10 or so.

All the way around the secondary.

[crisp flower]

And then U adjust the screws to have as many reflections as possible or how do u Go about it

[harsh matrix]

Yes

Mainly with the primary but the secondary plays a role too, very minor.

[tight lodge]

When I look down my OTA I see a magnified dummie

[crisp flower]

Got it

[harsh matrix]

Shouldn't get walking noise tonight

If i get any good frames

Its been clear when it wasnt supposed to be and now clouds rolled in.

No idea whats going to happen.

[harsh matrix]

dont see any strong vignetting until the veeeeerrrry upper left corner

the circle is still offset to the right but not as bad

collimation or tilt or focus or something is weird af

[harsh matrix]

moment of truth shortly

[harsh matrix]

@crisp flower hey for you when your BDS arrives, you only need one 50 mm M90 extension tube and one 25 mm M90 extension tube to reach focus, and the focuser will rack all the way in no problem

just be aware that with the M 90 adapter, the drawtube lets light in around it so you will want to have a plan at the ready to address that asap

@slate falcon or @tight lodge do either of you have any idea what would cause these chains of black spots in my flats?

whatever they are, they were not visible during image acquisition last night

regarding last night, i have incredible news

can see that a little bit better here

anyway

this is small fries

[slate falcon]

what theee

[harsh matrix]

that kind of looks like when there's hair on a filter with a refractor

but this is an RC

could it be hair on the lum filter or my sensor?

[slate falcon]

are you even running any glass in this

[harsh matrix]

no

[slate falcon]

maybe?

could be some cotton or something

[harsh matrix]

yeah cause those caused splotches

in the lights

which makes no sense

why did that stuff show up in the flats but wasnt present in the lights?

[slate falcon]

did it overcorrect in those spots though

[harsh matrix]

yes

I was working on it

you can see it clearly

like wtf

but

[slate falcon]

oh

thats very clear

[harsh matrix]

im not even really worried about that atm

[harsh matrix]

yes

maybe dew spots?

i dont think that's terribly likely either

i had the dew heater on the sensor on

wait

do you think it could be junk on the flat panel?

[slate falcon]

i was thinking that

[harsh matrix]

or wouldnt that be way too beyond the focal plane?

[slate falcon]

but surely it would have to be big

[harsh matrix]

hmmmmmmmm

[slate falcon]

like a massive obstruction

[harsh matrix]

right?

maybe i can clean that off or something and give this another go?

alright well, no crater

[slate falcon]

could do that

[harsh matrix]

oh shoot

this does look like dew

hmmmmmmm

maybe it's dew on the secondary

cause it was humid af

FUDGE

[slate falcon]

im so glad ive had no dew issues yet

[harsh matrix]

!JBN@IKOEWOIKLWNA

[slate falcon]

reasonable

[harsh matrix]

but

see

no crater

at all

not even a ghost

the saga is FINALLY over

it WAS the compression ring after all

also

that was the laziest possible DBE

so let me give it a real shot lmao

[slate falcon]

heres my final process of m94 btw

[harsh matrix]

yeah i am impressed with that

that's a very nice result

[slate falcon]

whcihc targer is this btw?

[harsh matrix]

M 94 as well

[slate falcon]

(ignore the spelling)

[slate falcon]

ooo nice

[harsh matrix]

kind of hard to tell with the spots all over

[slate falcon]

wont you be able to take flats now

if the dew is gone

[harsh matrix]

yes

[slate falcon]

[harsh matrix]

as long as me bringing in the scope didnt cause any changes and usually it doesnt

i want to go try again in a sec

if it remains, then something weird happened between the completion of the night and me taking flats

honestly

beautiful

holy

i wondered if this day would ever come and here it is

now it is time to go crazy crazy

[slate falcon]

delectable

[harsh matrix]

im honestly shocked

at just how bad the reduced image was

honestly at this point

screw glass

jfc

stuff sucks

@crisp flower the crater is completely gone

not even a slight trace of it exists now

it is finally over

okay TLDR here

you need a very rigid focuser, and a direct threaded connection

if you have both, the problem doesnt manifest but if you have one or the other, it isnt enough

a connection that is not robust enough is the cause of the crater

@slate falcon what's the raw core of your M 94 look like?

my data was booty cheeks

like 3 - 3.5" FWHM

[harsh matrix]

@frosty shard it is over

I won

now for this, id like all hands on deck

does this look like collimation adjustments need to happen, or tilt, or both, what do you think?

the stars appear to be astigmatic across the entire field yet the primary and secondary are matching position to the best that I am able to tell given the really bad seeing last night

that top right corner is always bad too

so id like suggestions about how to fix that one

the worst thing about this is that the top left and bottom right corners appear to match but the bottom left and top right are similar yet different to two different extremes

that's what makes this hard for me to wrap my pea brain around

tilt is a major factor according to ASTAP

I desperately need good weather again

on axis looks pretty good

[slate falcon]

good question

[frosty shard]

https://tenor.com/view/crab-rave-dancing-dancing-crab-gif-16543314

[frosty shard]

Collimation it seems.

[harsh matrix]

Hmmmm okay

There's no on axis coma

[slate falcon]

looks funky af

[frosty shard]

There's definitely some tilt to it as well, but the astigmatic stars should point to the center

[harsh matrix]

Which obv they do not

They point straight up and down

💀

[frosty shard]

Also some tilt can be induced because bad collimation actually changes the angle of the focal plane

[harsh matrix]

Yeah

So

Question

Do you think I should reset the tilt of the focuser?

I think this might be making it harder

If the plane of the focuser is parallel with the secondary mirror, then I should be able to get somewhere with this, no?

Otherwise it's extremely difficult to diagnose ngl.

[frosty shard]

I probably would, but I haven't really done any focuser tilt adjustments so take what I say with a grain of salt

[frosty shard]

That's what I'd think

[slate falcon]

some of them go to the cemter!

[frosty shard]

That's often the case

Also the DSI manual may cover focuser tilt adjustments?

I'm not entirely sure though

That's the stage you're at

[harsh matrix]

Yeah but in opposite corners 💀

That makes no sense.

[slate falcon]

[frosty shard]

Who wants a face reveal

https://www.youtube.com/watch?v=SI7cxHbJ3No

[harsh matrix]

@slate falcon I took new flats and I still see SOMETHIMG but not a widespread pattern and not obvious.

It doesnt look anything like my flats from this morning.

[slate falcon]

thats good

[harsh matrix]

yeah

gonna test the stack with them next

[harsh matrix]

alright new flats show no crater still

i think there are affected frames from the dew ofc

but there's no way i can tell without blinking through the calibrated ones

there's nothing immediately apparent with the raw ones

could just be clouds too

some number of these had passing clouds

very hard to see

[frosty shard]

honestly I think you'll be at the point where your data is going to reliably capture small variations in things like transparency and atmospheric extinction that otherwise wouldn't have a noticeable effect

[harsh matrix]

what the hell

i mean

that may certainly explain the weird variations in the background there lmao

they dont match up with anything in the flats

not even remotely

i thought for a sec it was the crater because that dark line does almost line up with the inner ring of the crater, but it doesnt match the shape at all

it's too straight

ohhhhhh yeah that could very well be it

high altitude cirrus i wouldnt otherwise see or something

there's like nothing holding this thing back now

[frosty shard]

Remove the atmosphere

[harsh matrix]

true

[plush raptor]

whats that

[harsh matrix]

this

i swapped that out for an M 54 adapter and put my rotator on and suddenly my problems are gone

[quartz meadow]

I've had horrific experience with those compression thingies

[frosty shard]

@harsh matrix one thing I forgot to tell you earlier: if you keep seeing weird patterns in your data, you can try doing an FFT analysis of your flats as well to see if there's any wave pattern in it

Actually, flats and the log of your flats

[harsh matrix]

hmmmmm

[harsh matrix]

alright

[frosty shard]

log(flat) because it's a multiplicative contributor to the calibration, but if there's a pattern you should see it in both tbh

[harsh matrix]

what kind of patterns/issues are we talking about here?

[frosty shard]

That kind of waviness that you did the FFT analysis on before

[harsh matrix]

ah

okay

i can kind of avoid that now since i can do 5 minute subs at native focal length luckily

my subs last night were all 5 minute lum subs

the histogram reached maybe only 10% illumination

[frosty shard]

You're giving me the itch to just get a larger sensor

[harsh matrix]

not half bad for bortle 8 imo

i mean

it does make it a little easier to collimate and find tilt ngl

[slate falcon]

my 3x barlow has horrendous tilt due to these

[harsh matrix]

I have too

when i started with my RC6, my collimation was always different if i removed the camera from the focuser

the sad thing is that i had no choice if i wanted to use the reducer i have

there is no way i can use it with a direct threaded connection

it's simply not possible to rack the focuser far enough in to reach focus

i was screwed or i was screwed and because id rather not have calibration issues at all, i dropped the reducer for a more stable connection

https://cdn.discordapp.com/attachments/1325030460409249867/1494801014107406508/image.png?ex=69e3ed6d&is=69e29bed&hm=d63fe5d218fb3a393fbf7ccc43baffa91d039c57f1c9c228f38c8d5bfd7de53e&

Stack without the flats doesnt show the ridges

Weird.

Thats why I like to take my flats before the sun comes up

There's always something weird.

Can't normally see it either

[slate falcon]

@harsh matrix how the core details looked before wavelets

[harsh matrix]

Probably slightly sharper than mine

Makes sense

Mine is super soft.

[slate falcon]

ouch :(

i thought mine was kinda bad bc due to my correctors tendency to cause star bloat i cant get an accurate fwhm

[harsh matrix]

Yeah that was my issue with the reducer i use

It causes the stars to puff up so you cant get an accurate FWHM

That's why my M 16 image has details only visible in sub 2" images but the FWHM is over 2.1"

[slate falcon]

says mine is over 3.5 when its 3 and below

my fwhm is definately not 4

aaanyways thats why wavelets works so good

any possible fuzziness it just nukes it

[frosty shard]

Try using HFRs instead of FWHMs if your software supports it.

FWHM is not robust enough

[slate falcon]

my hfr is usually 2.8-3.5

idk if siril supports

it

but the raw sub hfr

is usually 2.8-3.5

went to 2.5 once

[frosty shard]

Pixels or arcseconds?

[slate falcon]

pixels

idk how nina measures it but im pretty sure its pixels

[frosty shard]

Yeah it's pixels

Honestly they should give you an option for measuring the HFR in arcseconds

If you have the right focal length entered that information is easy to calculate

[slate falcon]

archours

we should rename degrees to archours

[harsh matrix]

interesting

this is the difference between the flats from this morning and this afternoon

ahhhhhhh so this is dew on the camera sensor

this gives it away

i need to bump the dew heater strength up by a lot

the new flats did add some of the weird lines im seeing so that's probably due to whatever light is getting around the focuser drawtube

i should make a sleeve to stop that

[frosty shard]

Well, there's more than 24 archours in a circle then...

[slate falcon]

360 archours

[slate falcon]

ouch

[harsh matrix]

oh nvm

whatever weirdness there is is in the lights

i was able to cancel it out and using flats on the resulting image didnt introduce anything new

weird

[frosty shard]

What are the available dew heater settings for your camera and which one are you currently using?

[harsh matrix]

1 through 4 and I had it on 1

25% strength.

it was probably not warmer than ambient

[harsh matrix]

you are slightly more cropped in than I

I guess 585 powers lol

but also me using a 571 on the RC is making me wider

[slate falcon]

how many hours of data and what bortle btw?

[crisp flower]

Got it
It did arrive already, im Just gonna wait Till im finished with m ycurrent Project before i install it

[harsh matrix]

YEAAAAAAAH

also are you going to go for a fully threaded connection to the focuser for your imaging train?

[slate falcon]

ehats a bds

[crisp flower]

Yes

[harsh matrix]

good

good good

yeah then

you shouldnt really see another issue

[crisp flower]

Baader Diamond steeltrack

[slate falcon]

aaa

[harsh matrix]

the mirror flop might pose a problem still

maybe

on some nights

but i dont think it will be a regular occurance

for you

mine might be totally finished beyond when the moon is out

[crisp flower]

Thats good to know
Im Just gonna be relieved that i dont need to worry about fov shifting anymore tbh

[harsh matrix]

real

that was driving me nuts as well

like why tf can i see my image plane shifting throughout the night

[crisp flower]

Ive never Had it Shift During nights, but between imaging sessions

[harsh matrix]

oh yeah that too

do you take the imaging train off every night?

[crisp flower]

Which was really confusing

[crisp flower]

Nope

[harsh matrix]

and/or time letting it settle would make it shift

yeaaaaaaaaaaahhhhhhh

that's garbo GSO focusers for you

[crisp flower]

Real

[harsh matrix]

I can give you a time answer in a sec but bortle 8

[crisp flower]

Im letting my scope assembled all the time and then all of the sudden fov Changed
And i thought im going crazy or smth

[harsh matrix]

i think this stack is 2 hours and 55 minutes

[harsh matrix]

very very weird

even for a bad night this is such a ridiculous amount of improvement

I cant even believe it

I want to experiment with resampling it too

[harsh matrix]

this is correct

i lost an hour to clouds

actually 2 hours

[slate falcon]

ahh i was wondering why so much lower snr, b8 + 3 hours of data

[harsh matrix]

yes

and f/8

youre probably f/4 or f/5

[slate falcon]

yea

[slate falcon]

im f4.5

[harsh matrix]

yeah see