Ritchey–Chrétien enjoyers thread

[harsh matrix]

I think my possible fears of the tube being another source of flexture may not be unfounded as well

like slight tube flex over the course of a night causing it

but because i have reinforced every single axis in the scope, i havent observed the issue on any nights beyond those around the full moon, in broadband

so a solid focuser + threaded connection, and avoiding the moon at all costs will go a long ways towards solving the issue entirely

[plush raptor]

[harsh matrix]

making sure the primary mirror and secondary mirrors are tight is another good step

[plush raptor]

holy info

[harsh matrix]

you cant get rid of it 100% i dont think, but you can get about 98% of the way there

[harsh matrix]

due I have been working on this flaw of the RC's for like 8 months

ive been hunting for the cause like a rabid dog hunts for food

[plush raptor]

lol, why I own a newt

[harsh matrix]

found nothing until this random post on CN

[harsh matrix]

oh no

this issue pertains to noots too

i saw it on my quattro

[plush raptor]

what if its a good newt

like good mirrors

[harsh matrix]

part of what made me so desparate for answers

[harsh matrix]

nope

[plush raptor]

im gonna have to deal with elatoing soon

[harsh matrix]

somebody in this thread still observed the artifact in question on an OOUK noot

[plush raptor]

https://tenor.com/view/don't-grab-me-aibitedoj-imma-bite-you-ai-gif-9055272973576911085

[harsh matrix]

this is the issue in question

this ring of death

this

[plush raptor]

how do you stop it

[harsh matrix]

cancer

[plush raptor]

on an oouk?

[harsh matrix]

you must try to eliminate any and all sources of flexture in the system

i think it's much harder to do on a noot since the imaging train sticks off the tube at an angle

that puts unusual stress on the focuser

your focuser needs to be exceptional at worst

[plush raptor]

this focuser any good or naw https://antares.space/products/focusers/focuser-newtonian-2-rackpinion-micro-focus'

its r&p

[harsh matrix]

this is the OP

I dont believe the OP states what noot it is other than a 12"

[plush raptor]

prolly a gso or smt

[harsh matrix]

this was the OOUK

basically this is what is happening

you can correct it by using a phyiscal offset when applyuing the flat

that does cause other issues yes, but it does prove that the imaging train moving is the reason it shows up

imaging train or a mirror

most likely the imaging train though

[harsh matrix]

I know people use this focuser but I don't have any idea if it is any good

normally noot people's goto is the Baader Diamond Steeltrack

[plush raptor]

im gonna have a decenly light imaging train ftr

[crisp flower]

Daaaaamn so flexture all along
I think its eliminated for me as far as it goes (apart from me Being dumb the other night and loosening the focuser accidently one night)

But very good to know im Not gonna lie
That Info will definetely be able to Help many people going forward

[harsh matrix]

https://www.vxinstagram.com/p/DYOca-KGzpC/?igsh=eHBqM2N0ZXBtcDdi

@[email protected]

❤️ 0   💬 0

vxinstagram · May 31, 2026, 9:33 AM

I spy Touptek advertising their SWIR cam

[sinful sapphire]

is the touptek in the room with us

[slate falcon]

gimme

[pine path]

I got a peak at the biggest RC as well last night

[tulip moon]

you're in La Palma ?

[distant field]

i want swir

gimi

[sinful sapphire]

ai

🗣️

[keen agate]

Yeah I removed the screws first but it just doesn't move. 😅

Yes I did😅

[slate falcon]

qhy are that lazy huh :/

[harsh matrix]

Then it's really stuck on.

The tube does like to hold on to it.

If they got the tolerqnce too tight, that will happen.

[keen agate]

Yes it really is. It seems to be a very common problem with this telescope because the seller I've bought it from states in the description that it can be hard to remove the primary mirror cell. I hoped you had the same problem and found a fix but I guess I'm out of luck. 😅

[tulip moon]

wd40

I'm joking, don't do that

[stiff mason]

You need to remove the clamps but first you gotta remove the mirror assembly from the tube its like 4 black screws at the bottom of the telescope

[stiff mason]

You gotta wiggle it like lift one side up then the other and repeat until it's off

[slate falcon]

i have to pry my cell of with the explorer 150p

then hammer it back in

[harsh matrix]

I was going to say it probably needs to be pried out.

[stiff mason]

I'm sure thats healthy for the mirror

[sinful sapphire]

what do you think will happen to it

[stiff mason]

Well idk microstresses and

[sinful sapphire]

its a pyrex mirror

a friend dropped one and nothing happened to it

[slate falcon]

i stepped on mine and not a single chip or crack

[shut egret]

Amy stop typing RIGHT NOW

[slate falcon]

[stiff mason]

I mean if you use a lead hammer i think it will be healthier

[harsh matrix]

Dafuq

[slate falcon]

i hammer it in with a screwdriver

[sinful sapphire]

yuh

[stiff mason]

Ig that works i though you went all out with a metal hammer lmao

[slate falcon]

time to make a pasta bake on my mirror

[slate falcon]

i would if i didnt care about the paint flaking

[stiff mason]

Could buy a lead hammer

[slate falcon]

nah

[slate falcon]

i should buy a dead blow

[harsh matrix]

Diesofcringe

[harsh matrix]

Same

[slate falcon]

i totally dont want swir

[distant field]

😭

[harsh matrix]

It is way too expensive

[distant field]

swir hater amy

[harsh matrix]

I would get it in a heartbeat if money was no object

[distant field]

yupp

one day theyll be affordable

one day

[slate falcon]

already found an affordable swir cam

[distant field]

i dont think the tech is really that crazy hard to produce, it just doesnt have a killer application that would spark production at scale

[distant field]

lies

[slate falcon]

now i just need a mwir cam to match

[slate falcon]

its £4000

[distant field]

how expensive

i mean ok that is afforable for swir

[stiff mason]

Wait but wouldn't you need to cool your entire telescope for MWIR

Since the walls of your scope would be a major source of radiation

[slate falcon]

no!!

[stiff mason]

Explain

[slate falcon]

narrowband

it eliminates most of the thermal noise

[stiff mason]

Where can you even find infrared narrowband

[slate falcon]

i got a quote and they said a 3nm gernanium nb filter would be arround 10k depending on the wavelength

[stiff mason]

https://tenor.com/view/monsters-inc-big-eyes-gif-14567916

I think it will be easier to cool the telescope walls

[slate falcon]

i corrected my filters bandpass shift

[stiff mason]

The mirror itself wont be emitting infrared since it's a white body not a black body so that only leaves the walls

[stiff mason]

What am i looking at

[slate falcon]

Niii filter

[stiff mason]

What was the issue again like the cause of the bandpass shift

[slate falcon]

manufacturer error

[stiff mason]

How did you fix it

[slate falcon]

secret

[stiff mason]

You bought a new one didn't you or maybe reduced your f stop

[slate falcon]

increasing f stop would have fixed it

sadly i dont have an f1 scope

[slate falcon]

and no, i didnt buy a new one

[stiff mason]

Damn uhh no idea then

[slate falcon]

Observatories do it when their filters dont fit for distant galaxies

[stiff mason]

Still clueless

[slate falcon]

i physically tilted the filter

[stiff mason]

Oh right forgot that also causes bandpass shift

[slate falcon]

if you have a fast system it creates issues tho sadly

[stiff mason]

Like what

[slate falcon]

gradient

its not a perfectly even shift across the whole filter

but at f4.5 theres no issue

[stiff mason]

Right

[slate falcon]

light is such an ah

[stiff mason]

There are no perfect solution you'll always have to lose something to gain something

[slate falcon]

exactly

[sinful sapphire]

unless you steal

[stiff mason]

Nope I'm talking about solutions to problems in general

[candid flame]

no linux is completely free

[stiff mason]

So is windows

[slate falcon]

[stiff mason]

If you don't mind the watermark

[slate falcon]

windows is not free, they collect your data as payment instead

[stiff mason]

They do that either way

[slate falcon]

yea so its not free

meanwhile my linux system is free of any trackers

[stiff mason]

You could technically remove all the bloat ware on windows

[stiff mason]

But with linux is a prime example of my previous statement

[slate falcon]

how?

[stiff mason]

You get software with no tracker and it's free but you lose window's compatibility

[slate falcon]

i gain compatability

[stiff mason]

How

[slate falcon]

i can use all windows apps and all Linux apps

[stiff mason]

Yeah but you cant use nina for example

You also cant run java

[slate falcon]

i can use nina

[slate falcon]

say that again but slower

[stiff mason]

Can you?

Idk

Then why is minecraft java only on windows

[slate falcon]

java has an almost 30% performance boost on linux

[slate falcon]

yk java is a WORA language right...

[plush raptor]

nina is old news, kstars is meta now

[slate falcon]

nina is runnable on linux natively

[plush raptor]

im just sad that I cant run nina

[slate falcon]

ah

[stiff mason]

Nina is the goat

[frosty shard]

Java has native Linux support

[stiff mason]

Right

[slate falcon]

i beat uupo stacking with installing arch

im apparently quicker at installing arch than someone is at stacking

idk if thats good or not

[pine path]

toured another big RC tonight

[pine path]

yup, though this is our last night

[slate falcon]

take it, they wont notice

[digital nexus]

my first good RC6 image

[harsh matrix]

@frosty shard ive slightly loosened the primary mirror so we shall see what collimation says later.

[bleak solar]

Just a very quick edit… but we are getting somewhere. Now I just need a lot more Oiii data 😂

[harsh matrix]

The astigmatism appears to be much better controlled now

[harsh matrix]

Yes I fixed it

Finally

😩

[tulip moon]

Nice how's the weather up there these days? I'm landing in 2 weeks

[harsh matrix]

Uh

RC has the best collimation ive seen since august

Holy

[sinful sapphire]

Pillars of Creation part 2?

[harsh matrix]

not yet

the moon is chilling like right in front of M16 rn

i will be adding onto my existing data though

im hoping that by combining the different data, i dont make it completely unusable though

I honestly want to order a corrector now

just to make the most of the scope

[tulip moon]

you need a corrector with a RC ? is that because you're using a reducer?

[harsh matrix]

correct

im not using a reducer and using APS-C on an 8" RC

if i had a 10" RC i probably wouldnt need a corrector or if i used my 533 on here instead, i also wouldnt need a corrector

but the 8" is in a weird spot where it does rather well at APS-C but it does leave a little bit for wanting

even a field flattener with a reducer wasn't perfect tbh

i think a flattener at native or 0.8x would be far better

i also just want something to be in front of the filters to catch dust

[harsh matrix]

based

funky spider vanes

I am seeing some chromatic aberration in the one Ben linked some time ago

🤔

im seeing a lot with CA

now that could be from bad offsets

or it is from the corrector lacking any high dispersion glass

[sinful sapphire]

Which corrector

[harsh matrix]

https://www.teleskop-express.de/en/astrophotography-and-photography-15/imaging-correctors-for-telescopes-138/ts-optics-rc-1-0x-corrector-for-ritchey-chretien-2-inch-connection-4006

[distant field]

Stack with drizzle scale 2, pixfrac 1, rgb align, bin. Thank me later

Ok more of a bandage solution but it works extremely well

Idk why im in the rc thread

[sinful sapphire]

Yikes very likely

[pine path]

has been really good this trip, summer is usually good weather other than maybe some calima

[harsh matrix]

@frosty shard been sub 3.0 HFR all night tonight

regularly seeing below 2.5 as long as there isn't a sudden disturbance in the air

[stiff mason]

How big

I'm guessing 1 or 2m from the image

[tulip moon]

Fingers crossed

[gloomy hawk]

holyyyy

apperture fever

[pine path]

just under 3.6 metres

me for scale

[tight lodge]

Finally someone wo can compete with Tom in aperture

[prisma summit]

big

[pine path]

it’s a cool telescope, they do a lot of exoplanet discoveries and characterisation, and very good IR/Optical spectroscopy

they also have an imager which can do like nanosecond readout

[slate falcon]

@tight lodge decided to start designing a logo

gotta love orange lights

[slate falcon]

-# (this does spell something out btw, its not just random lines)

[tight lodge]

What you think of my logo?

[slate falcon]

very minimalist, very tech

[stiff mason]

https://tenor.com/view/patrick-patrick-star-peak-cinema-absolute-cinema-gif-2419960068189387292

[stiff mason]

Very nice

[harsh matrix]

2.27" FWHM here @frosty shard

i get cracked collimation and everything is over

[frosty shard]

Okay I'm actually tilted at your HFRs

But not your FWHMs

Because I've achieved similar with my IC 10 data

It's making me very curious about how kurtosis affects star profile measurements

[harsh matrix]

I wasnt convinced the HFRs were all that good

I have already found some neat features in this region

some bok globules and some evaporating globules that will eventually manifest into well defined structure with enough data

DSNR is cheating holy

[waxen mountain]

How much Int

[harsh matrix]

1 hour per SHO

with some clouds

[waxen mountain]

Ahh not bad

I'm so excited for NB filters

But they are damn expensive

[harsh matrix]

I had to save for months to get these

but it's looking like it will pay off

these ones arent producing halos

[waxen mountain]

Yee I'm doing this rn

[harsh matrix]

just know as long as you arent impatient and buy something else instead, it's worth the wait

that's even more true for dark skies

[waxen mountain]

I only have the camera + lum and a filter holder that i used with my first astro cam

So I need EFW RGB+NB and Focuser

My Gemini is broken in the truest sense of the word

[waxen mountain]

That will cost more than 1.2k

[harsh matrix]

well i do have to say

good filters are worth it

it hurts

[waxen mountain]

Yea

[harsh matrix]

but they are the kinds of things that will last years with good care

[waxen mountain]

I want good filters

[harsh matrix]

the ones i bought i intend to use for the next 5 or 10 years

easy

[waxen mountain]

Goood

If no accident happens then you could do it

[harsh matrix]

yeah

[waxen mountain]

Oh and I still have to upgrade my Planetery Setup

damn

That will also be expensive

Oh god this hobby is so bad

When it comes to the cost

[harsh matrix]

yes it is

[waxen mountain]

https://tenor.com/view/megan-soo-dog-meme-funny-dog-meme-gif-14413441628212659223

Me rn

[harsh matrix]

if kurtosis is the analysis of outliers, then I think mine should be worse by far

since I have an APS-C camera and the corners are not corrected

cropping to just the middle does always yield an even better FWHM and HFR

sometimes by not much, sometimes by a whole lot

[frosty shard]

Not the kurtosis of the FWHM/HFR values, the kurtosis of the star profiles in ADU

The normal distribution (black) is the most platykurtic (goes to zero most quickly) of the three

The Cauchy distribution is the most leptokurtic

The star profile of an obstructed aperture is more leptokurtic than that of a clear aperture

This is a good way of quantifying the difference in star profiles when the FWHM appears to be the same

[prisma summit]

i was literally today revising this for my statistics exam in 10 days lmfao

[slate falcon]

digitized it

i really need to not write on lined paper

[gloomy hawk]

hubble is an rc right?

[frosty shard]

Almost, then Perkin-Elmer screwed it up

[gloomy hawk]

what happened?

[tight lodge]

The primary mirror was perfectly shaped wrong

[tight lodge]

A bit more work and you got yourself a grind core band logo

[gloomy hawk]

https://tenor.com/view/robert-downey-jr-huh-what-iron-man-surprised-gif-17639389346286804402

[tight lodge]

No for real, the error on the mirror was so perfect that they literally made a tertiary mirror with the inverse error of the primary

[gloomy hawk]

how can an error be perfect?

[tight lodge]

This is a good example. See the big spike? Thats the mount periodic error. It's actually happening so consistent that you can predict exactly when is gonna happe so you can correct. That's what perfect error means. It means you can reliably correct it

[gloomy hawk]

ohhhh

makes sense

thanks

[harsh matrix]

this is what a bad harmonic drive looks like in case you wanted to know

this is known good

periodic error is like +/-4"

very good

[slate falcon]

its definitely harmonic!

[tight lodge]

I think my guitar makes a similar sinewave😂

[slate falcon]

this still gets more photons than ur rct

[silver ibex]

How's Arch? (totally not related)

[slate falcon]

it works

ive been practicing fry screaming a bit

[silver ibex]

But like, would you suggest it to someone that never used Linux? I've been wanting to switch for a while now

[silver ibex]

Peak

[slate falcon]

if you know how to read and how to problem solve you will be able to use it :D

[slate falcon]

i dont think im doing it right still :(

[silver ibex]

Read? That seems complicated

[silver ibex]

Just don't destroy your voice trying

[slate falcon]

thats waht im planning

it didnt hurt at all

so maybe im doing it right

i still got my vocal range

[silver ibex]

No idea, I'm not good at screaming tbh, I should practice

[slate falcon]

do you wanna hear what i can make

it sounds like a deranged parrot

[tight lodge]

Oooo, please do say more

[slate falcon]

mainly bc im too scared to go too loud

[slate falcon]

idk what to say tbh :(

[silver ibex]

Sure

[slate falcon]

you can see where the clouds left the sun alone

ignore the light leak speckles

[slate falcon]

ill dm like 1 audio recording

[frosty shard]

Arch is not a beginner distro unless you are big on the DIY mindset. Literally just like recommending an RC to a beginner – not a good idea for most, but for some dedicated beginners it can be fantastic.

If you want an easier first time experience, try CachyOS, which is pacman based so you can use much of the Arch Wiki for help.

[distant field]

First experience with linux was arch+i3

[frosty shard]

Perfect shot in tonight's time lapse

[tulip moon]

hey

Why RC are so slow? Real question.

They're often F/8 or something

[frosty flicker]

By design. Slower they are, sharper they are

[sinful sapphire]

Their CO is already huge natively at F/8

Imagine that but faster. Absolute pain with collimation too,

And the native correction of the 2 mirrors substantially reduces

Making a CDK or HW just better for faster FR because they’re diffraction limited throughout the field without using complex surfaces

[silver ibex]

I see, I'll def look into CachyOS then