Ritchey–Chrétien enjoyers thread

[harsh matrix]

im using a 24 mm canon EFS f/2.8 now, it's not great but it works

[runic violet]

And you would need that more expensive lens anyways

[harsh matrix]

i wouldnt say far but cheaper yes

[runic violet]

It is far far far far far cheaper

[harsh matrix]

i was looking at possibly getting a FF DSLR or mirrorless used

[runic violet]

FF is like a 10k investment

I mean yes that would be better than an aps-c DSLR

I'm talking about mono astrocams

[harsh matrix]

a FF astro cam would be amazing

but yeah it's ridiculously expensive to get one

[runic violet]

If a landscape is not involved imx571 >> any DSLR you would get though

At 14mm though that's landscape

[harsh matrix]

donut isnt terribly obvious in this data

im going to bank on proper back focus fixing it

[runic violet]

Going back to reality (not mono landscape) any half decent DSLR with decent Ha response + something like a sigma 14 or 40 doing mosaics is going to outperform something like a z6 on a rokinon 14mm

[harsh matrix]

okay, interesting.

[runic violet]

Having less sensor size is not much compared to having a much slower and more aberrated lens

Those old sigmas go for $600 used these days

I shoot my sigma 40 on my d5300 at f/1.8 and the stars are fine, on my qhy268m I have to go to f/2.8 but then it's corner perfect

I've migrated to shooting with the qhy268m over the DSLR though

[vapid patio]

Is this your data?

[harsh matrix]

Yeah

[vapid patio]

so the ring of death is gone?

[frosty shard]

So after two nights of dark sky data, I cannot under any circumstances get my HFR below 4.5 or so

[harsh matrix]

No

It was there

But mostly in the red channel only

For some reason...

Also @vapid patio this is my fix for the baffles sliding down the tube

Some clever electrical tape patching around the bottom most baffle

[vapid patio]

so odd

[vapid patio]

haha i did the same

[harsh matrix]

Taped it after pushing all of them forward

[harsh matrix]

Oh really?

This thing isn't going anywhere

[vapid patio]

again same

[harsh matrix]

Quite literally can't move now

[vapid patio]

if it works it works

[harsh matrix]

I just had an idea as to what may be the cause of the ring of death

It's concerning, but not impossible to fix by any means

I'll share my thoughts once I've put this thing back together lmfao

[vapid patio]

haha ok

all im thinking is somehow misaligned somthing in your reducer

[harsh matrix]

Shouldn't be the case since I'm far from the only person with this issue

And HPS was able to recreate it.

[vapid patio]

how?

[vapid patio]

same reducer? or same scope?

[harsh matrix]

Using the same scope and I think the same reducer

Somebody on CN had the exact same thing going on too

Okay

[vapid patio]

oh so its apateuras fault?

[harsh matrix]

I've just confirmed what I suspect

[harsh matrix]

No GSO's

[vapid patio]

newer gso?

[harsh matrix]

What i think could be the issue is something Zegery pointed out to me about my quattro

[harsh matrix]

Age was irrelevant

[vapid patio]

you have link? i would love to readit

[harsh matrix]

They were able to recreate it on a new and old RC6

[harsh matrix]

I don't right now

[vapid patio]

so what is it

[harsh matrix]

Look at my quattro and look at the very front where the white part meets the tube

There's a light leak there

I didnt believe him

I checked, and sure enough there is.

I thought

Well what if this could happen where the primary mirror cell meets the tube on these RC's....

Same thing happens.

I have to put electrical tape all the way around the outside of the tube where the tube meets the primary mirror cell

If this fixes the issue, I finally figured it out.

[vapid patio]

THATS AMAZING

[harsh matrix]

You would think with how these pieces go together that this would be impossible.

[vapid patio]

so even with no reducer would i see it?

[harsh matrix]

Turns out there is still a leak

[harsh matrix]

Not sure tbh

[vapid patio]

yeah it still sounds weird

[harsh matrix]

I think the reducer makes more of the secondary be used, or visible, because of the back focus

And so you're seeing the outline of that leak, maybe.

Thats my running theory.

[vapid patio]

oh well i do have a dew sheild and it covers a good bit of the front end of the scope

[vapid patio]

hm maybe, but you have been able to reduce it, maybe seal off everything

[harsh matrix]

The front end i don't think is a problem, where the 2 pieces meet

Because if your knife edge baffles are positioned correctly, light cannot make it it the primary or secondary from where the 2 meet.

[harsh matrix]

I will try whatever I can think of at this point

I will kill this problem.

[vapid patio]

what if you took like a big peice of cardboard and wraped it around the scope and tape it down. just for a test

maybe thats dumb 🥀

[harsh matrix]

Why do that if I can patch it with electrical tape

[vapid patio]

fair

https://tenor.com/view/pat-patrick-bateman-patrick-spongebob-meme-spongebob-gif-12593993314823291186

[vapid patio]

yurr stars🔥

[frosty shard]

They are not great...I cannot get my HFR any lower

[vapid patio]

hows seeing

[frosty shard]

I think I'm seeing limited

[vapid patio]

and cloud popups

[frosty shard]

Clouds were not an issue last night

[vapid patio]

hm ok yeah cool just be a seeiing thing

what was your hfr

[frosty shard]

It jumped around like crazy but it never went below about 4.6 last night

sometimes it spiked as high as 5.5

[vapid patio]

ouch yeah, when you did auto focus what was your whats it called rc squared?

[frosty shard]

I am focusing manually

[vapid patio]

ah ok

[frosty shard]

I'll get an EAF once I get an extra focuser assembly to go with it

[vapid patio]

what? it comes with it

the little bracket?

[frosty shard]

No an entire extra focuser since I use my RC for visual

[harsh matrix]

Ughhhhhhh

That was NOT the cause of the donut

It really is something to do with the way the mirrors interact with a reducer.

This is the worst.

My flats look slightly better than they ever have, so thats a W.

I guess I'll experiment with back focus on the reducer anyway since I have to.

[vapid patio]

ah ha so we back on reducer

[vapid patio]

ah

[harsh matrix]

it's something to do with the interaction between the mirrors and reducer, yes

i am going to try to calculate a per mm reduction factor to calculate my desired reduction

[vapid patio]

but i thought you took the reducer off and it was still there

[harsh matrix]

and then im going to take a flat when i achieve that spacing

[harsh matrix]

nope

it was gone when i took the reducer off

what was weird is it came back without a reducer when i went to the point of back focus/focus where the scope would focus with a reducer on

so it's back focus dependent, and the reducer amplifies it

but whatever it is, seems to be the mirrors.

having extensive math knowledge is incredibly useful in this hobby

that's the reduction factor per mm of addition back space i add on this reducer

i could have this backwards so i need to think through it rq

NOPE IT'S RIGHT

I graphed it

the actual reduction rn is 0.7814 or 78.14% of native focal length

the graph is approximated, and incredibly accurate

this is 55.5 mm of back focus in the x coordinate, y is the reduction

in % of native focal length remaining

[vapid patio]

Nerd

But Very interesting

[harsh matrix]

how do you think I got nerd LOL

[vapid patio]

So you need more back focus to decrease the amount of this ring?

[harsh matrix]

or to eliminate it entirely, yes

luckily, i need 84.5 mm of back focus to reach my desired 0.67x reduction

and I THINK that's enough to eliminate the problem completely, but I will not know until i try

[vapid patio]

Ok bet well keep me updated

[harsh matrix]

call it 83 mm

my graph was too approximated, i just made it more accurate

the reduction per mm is almost identical to the astrotech reducer

it's slightly different, but not by much

[vapid patio]

Im not gonna be perfect ima just go 75-85mm and get somewhere in there

[harsh matrix]

Throwback to when I was an OSC user still

Very obvious donut here

Shooting reduced too.

This is a strange looking structure but there's not an obvious donut.

I suspect the one sided bias is because most of the light is coming from one side since this room is poorly lit.

If this reaches focus, the issue may be gone.

[vapid patio]

Praying 🙏

Remote desktop is so much better on an iPad

[harsh matrix]

alright here's the control

taken before increasing back focus

this was right after

all 3 versions that i took after vary wildly

dunno why

then there's number 2 after increasing back focus

and number 3

i havent done any ABE on these

in that same order left to right after ABE

clear difference

they all have an STF run on them too

so the back focus theory is gaining traction

again i think the local variance, and extreme variations in illumination across all of these is likely due to how limited i am indoors with taking flats, i suspect sky flats will look way better, but that donut persisted regardless of how well illuminated the sensor was

[vapid patio]

Yeah, these flats look a little rough sky flats will be 1000% better

[harsh matrix]

and ofc, since i disassembled the scope to fix the knife edge baffles, i think collimation could be slightly off too ofc so that may be another factor in illumination evenness.

[vapid patio]

But this theory is definitely getting somewhere

[harsh matrix]

but it's clear the increase in back focus yielded a much flatter field right?

all 3 of my post back focus distance flats were taken using various lighting methods and conditions too btw

[vapid patio]

Do you do star collimation?

[harsh matrix]

yes

[vapid patio]

How long does it take you? I’m nervous to do mine lol

[harsh matrix]

10000000 times easier than doing bench collimation

[vapid patio]

Fair

[harsh matrix]

i can take anywhere from 5 to 10 minute to like 30 minutes depending on how bad it is

when i first got my RC6 it was so bad i didnt know what to do

took me over an hour

but that wasnt really my fault

[vapid patio]

Still, that’s not even too bad

[harsh matrix]

the scope got sent to me being way out

[vapid patio]

You adjust the four screws on the back mirror, right?

Or secondary

[harsh matrix]

no

[harsh matrix]

typically you are adjusting the secondary

the way you can tell is based off of the shape of the defocused disks of the stars

[vapid patio]

Is there a Nina plug-in that helps you?

[harsh matrix]

if theyre flattened out in one direction or another, you adjust the primary to fix it

[harsh matrix]

no i use sharpcap to adjust the primary

and live view on a very bright star

[vapid patio]

Why not Nina?

[harsh matrix]

the instant feedback of sharpcap helps me a lot more

and Nina tends to slow down my mini pc when im pumping in a high volume of frames

[vapid patio]

Yeah, that’s fair

Well, I will defocus on a star next time I want to see how good or bad my collimation is

[harsh matrix]

normally i do pretty short exposure but to gauge smaller movements of either mirror, i bump up the exposure and kill the gain to even out the disk a bit more which gives me a better idea of how close it is

[harsh matrix]

sure

i can probably help with that assuming there are adjustments to be made

[vapid patio]

Good idea

[harsh matrix]

seeing will distort the disk of the star like crazy in weird ways

[vapid patio]

Ok bet i will let you know. Wanna maximize my mono setup you know

[harsh matrix]

things that may look collimation related are often seeing related

[harsh matrix]

ofc

[vapid patio]

Yeah, I could definitely see how that can make a difference

[harsh matrix]

hopefully my calculation is wrong but i calculated my point of focus to be 90 mm from the back of the scope

that means removing at least one spacer and maybe by tilt adapter which could make things worse again

well maybe not we'll see

i forgot theyre both the 25 mm tubes rn and not the 50 mm one

[frosty shard]

oh right I forgor about deconvolution

[frosty shard]

Well it looks like I gotta recollimate my scope

I was wondering why my stars in my Abell 2151 image looked like they had chromatic aberration. I guess I have coma - not enough to be readily visible but enough to cause the stars to become visibily chromatically separated after a meridian flip

[vapid patio]

how does a unfocused star look?

[tight lodge]

Why it looks out of focus? But the difraction spikes look in focus? What's this sorcery?

[frosty shard]

Bad seeing probably

[frosty shard]

Gotta dig through my lights once I'm at my main PC

[vapid patio]

ok no problem

[frosty shard]

This looks bad

[vapid patio]

comet stars 😔

did you recently do anything to your rc?

[tight lodge]

Nightmare fuel

[frosty shard]

I took it out for imaging...

No adjustments or anything

[vapid patio]

weird

did one of your screws leave chat?

[frosty shard]

I'll have to have a look

What bugs me is that the coma isn't uniform throughout the field

[frosty shard]

Oh actually maybe it's the tilt adapter that's the issue? I'm not sure if this is just tilt though

[vapid patio]

could be actually

[frosty shard]

The one thing I will note is that I took the blue subs before a meridian flip and the rest came after

And I had trouble because apparently my mount did not know how to guide after the meridian flip

Here's a raw lum sub before the meridian flip

[vapid patio]

@frosty shard check all your thread adapters and check your tilt plate for sure

[frosty shard]

Oh yeah look here's my tilt after the meridian flip

[frosty shard]

Unfortunately I don't seem to have kept any lights that have defocused stars, but I'll give it a closer look next time I'm out

[frosty shard]

I might have to switch OAGs...the Askar one doesn't thread in and uses set screws instead

Which I'm guessing is causing my imaging train to sag

[vapid patio]

thats odd

[tight lodge]

Can you do this after a session?

I never checked my tilt

[frosty shard]

SIRIL has tilt and aberration inspector tools

[tight lodge]

Siril?

[frosty shard]

Don't tell me you use 🤮 🤮🤮🤮Pixinsight🤮🤮🤮🤮

(I guess I can't strike through emoji? lol never knew that)

[tight lodge]

[vapid patio]

siril?

[tight lodge]

Ours is just fancier

[vapid patio]

is that good or bad

[tight lodge]

Vel told me that this is good

[vapid patio]

haha then its 99% true

[tight lodge]

Very small deviation across the field

[vapid patio]

how can i use it?

[tight lodge]

Facts. I've never seen a dude nitpicking his OTA as he does

[vapid patio]

@harsh matrix we lowkey glazing you rn

[vapid patio]

real

howw can i use that tools whats it called?

[tight lodge]

FWHMEccentricity

[vapid patio]

thanks

[frosty shard]

Hmmm I think I could write a tool to do this

[harsh matrix]

[vapid patio]

@harsh matrix Have you done a mosaic?

I feel like at our fl a mosaic on say m33 would be so so sharp

For me a 3x2 mosaic would go hard

[harsh matrix]

No

[harsh matrix]

It is.

[vapid patio]

What

[vapid patio]

Oh ok

[runic violet]

I've done a 9 panel mosaic of Andromeda and 2 panel of m33

[harsh matrix]

OSC too so mono will be even better

I got TPN on Astrobin with this photo.

[frosty shard]

IC 132 is such a fascinating object

Why it so teal

[vapid patio]

Is this rc6?

533?

I'm confused

[harsh matrix]

RC6 and my 533MC Pro

I shot reduced to fit it in and no mosaic

I can fit the entire galaxy in the frame of a 571 and my reduced RC 8 as well

[coarse shell]

Can’t wait for Triangulum season

[vapid patio]

Ok then I'm gonna cook

[vapid patio]

Real beepbeepbeep

[vapid patio]

@harsh matrix Was this with your rc6

[harsh matrix]

Yes

[vapid patio]

Was it also nir?

@harsh matrix And with your 533mc?

[harsh matrix]

No

I did this after getting my Ares-M

It's NIR + Ha

[vapid patio]

Ah ok sick

[frosty shard]

Just swapped my Dec pins on my Wave 150i from the stock hand bolts to hex bolts. Hopefully that solves my backlash nightmare

[vapid patio]

it fix it?

or waiting to test it

[frosty shard]

It'll probably be Friday when I get to test it

[vapid patio]

ok bet

i will set up my mono and reducer that day

you shoot reduced right?

[harsh matrix]

No

[vapid patio]

thanks vel

@harsh matrix ok so if i have 80mm from the reducer to my sensor ok that's fixed. Does it matter where it is in the compression ring as long as it can reach focus?

[harsh matrix]

Does not matter where in the compression ring, that is correct.

I'll be testing my config tonight as well assuming it isn't magically clouded over.

One weather app said its going to be cloudy all night while the other with satellite data and imagery says it will be clear, with the clouds dissipating right before sundown on the imagery.

Plus it was starting to clear out when I headed to work, looked beautiful about an hour and a half ago.

[vapid patio]

letsa gooooo

[vapid patio]

lets go bro i cant wait to see if it gonna be fixed let me know

also im stupid btw

already with no extra rings i have 112.5mm of spacing

to my sensor.....

so i will be getting hopfully a 863mm focal length heheehha

@tight lodge i will be about your fov with my new setup

[harsh matrix]

How?

I may take the quattro out for a bit tonight as well since thats also ready to image.

I just have to make some final collimation changes between the RC8 and Quattro before everything is finalized and ready for the calm before the "storm" of imaging that will start some time this week or next week whenever this moisture finally clears out.

[vapid patio]

you know the big ring that goes into the back of your rc right before the focuser?

[harsh matrix]

Quite nervous but very excited

[harsh matrix]

Yes

[vapid patio]

haha i feel you

[harsh matrix]

That doesn't count as back focus from the reducer to the camera sensor

[vapid patio]

i don't have it on and found it in a box today lol

so point is to get in focus i had alot more spacers on

[vapid patio]

yeah

[harsh matrix]

Oh so you had too many spacers on?

[vapid patio]

let me send photo

[harsh matrix]

Yeah you have to take out the 50 mm spacer to reach focus with the reducer

[vapid patio]

oh wait i cant

[vapid patio]

the big ring?

[harsh matrix]

The thicker of the 3

Yeah

[vapid patio]

oh i only have one

focuser goes stright into back of rc

[harsh matrix]

Ah

[harsh matrix]

Yeah thats right if you have more than 50 mm of back focus with a reducer on the RC6

[vapid patio]

yeah so i plan to be f/5.7!!!!!! and 0.69 pixel scale

like a redcat on crack

[harsh matrix]

I'm hoping my RC will reach focus without taking one of the spacers out

I think I'm completely screwed if I have to take one out.

[vapid patio]

why?

[harsh matrix]

Because i think that will make the ring of death return

Although i had what I thought was too much back focus at the time when I shot that M33 image

And while the raw data looked pretty bad, I don't think it had the ring of death

There was some calibration or lack of calibration funkiness going on due to the dark current of that camera interacting with the bayer matrix though

That cooked the background so badly that only MSGR could save it after 32 hours of exposure

What may prove it is if I go plate solve my M33 image against my Ghost of Cass image to see what the focal length of both is

Then I can determine when I reduced my back focus, because the ring did appear for that Cass project

[vapid patio]

andd you are also gonna be useing the 571?

[harsh matrix]

I'm going to use my 533 on my RC mainly

To reduce the load on the primary and reduce flexture.

I'll use the 571 from time to time for sure though

[vapid patio]

primary?

[harsh matrix]

Primary mirror

Because the load on the focuser is transferred into the primary mirror which induces mirror flop to a degree

[vapid patio]

571 is gonna cook on the Quattro

[harsh matrix]

Very much so.

[vapid patio]

hm ok never noticed it

[harsh matrix]

Small OSC sensor

[vapid patio]

ohh yeah fair

[harsh matrix]

Especially at native, you would never know

A fully loaded mono set up with a big camera, big wheel, and big filters will be noticeable

Particularly when shooting reduced.

[vapid patio]

uh oh

[harsh matrix]

The effect is minor with my mono 533 rig, and downsizing the wheel and filters will reduce the effect further.

[vapid patio]

oh wait i have not big camera or big filter wheel lol

i have the 5x2

[harsh matrix]

Yeah and the 585 is even narrower

You likely wont even know.

[vapid patio]

plan to buy 1.25 zwo lrgb also to save money and weight haha

i know 1.25 is not future proof but im gonna have 585 for alonggggg time

[harsh matrix]

Thats why if/when I end up sharing screenshots of raw data from my RC8 or RC6, sometimes you can see my stars look almost triangular in nature

The weight of my filter wheel + filters is taking a toll on the mirror.

[harsh matrix]

It's also a great camera

It will pair very well with the redcat too

[vapid patio]

can you not just tighten it down? "may sound domb"

[harsh matrix]

Those filters are horrible but you'll get by

[vapid patio]

im stockedddddddd for nir with my redcat

[harsh matrix]

Since your skies don't suck so much unlike mine.

[vapid patio]

then what?

not doing Croma filters

[harsh matrix]

Doesn't work

[harsh matrix]

Antlia is the best choice by far

[vapid patio]

let me see price

[harsh matrix]

I bought once and I cried once

I love them though

1.25" is much cheaper

Especially if you can find a used set.

[vapid patio]

yeah and im just gonna mess around with my crappy narrow band filters first and use my astromik uv/ir for L data

so i will have some really good L data i feel like

[harsh matrix]

BTW Touptek's filters are way better than ZWO's

At a fraction of the price of Antlia

[harsh matrix]

@vapid patio

[vapid patio]

i have heard they are so trash

sorry i restarted my pc as it decided to not let me click on anything

oh they are 130 wow

they have a transmittance of 98% so much better than zwo loll

[harsh matrix]

Somebody here in AB is testing them

I've seen on Cloudy Nights that the filters other than lum may leak IR, but they perform exceptionally well outside of that.

I think I'm going to ask said reviewer if he can corroborate the IR leak claims to see if they are true or not, or too see how often it happens.

There's some speculation that it could be an issue with older batches of the filters.

Like early production models.

[vapid patio]

yeah and im just gonna use my astromik for L i wish i didnt have to buy one tbh

[harsh matrix]

Normally an IR leak wouldn't be an issue but for a 585 it's way more sensitive than all other sensors available.

[harsh matrix]

Yeah same

[vapid patio]

https://www.highpointscientific.com/astronomik-l-3-uv-ir-blocking-filter-2-round-mounted-l3-2

i have this one

[vapid patio]

nice little flex

[harsh matrix]

It's a good filter

The good news is you can probably sell it for quite a bit if you end up choosing the Lum filter that comes with your mono filters instead

[vapid patio]

i bought a doublet with horrible CA and pinched optics and the dude who i bought it from felt bad and bought me a filter lol haha

[harsh matrix]

Lol

[vapid patio]

eh i dont see a reason to sell it just keep it as a really good lum filter

its some of the best glass if i remeber right

NEVER gonna buy a dublet

buy once cry once. it sucked for the price

[harsh matrix]

I wont either unless I'm using it visually

[vapid patio]

even then i got my rc

@harsh matrix how should i go about hooking up my minipc on my redcat

i just was thinking like where should it go

[harsh matrix]

I didnt get scammed yet

It's clear

[vapid patio]

[harsh matrix]

You could buy a little finder shoe for a guide scope, and attach it to the tube ring for the cat on the right side of the scope

That means finding a bracket that'll work though

[vapid patio]

i have 2 guide scopes

maybe let me look

[harsh matrix]

My scope doesn't reach focus with 2 spacers

[vapid patio]

so you need to take one off or add one

[harsh matrix]

Took one off

Adding more back focus consumes the back focus available in front of the reducer

May need to take another off 😭

[vapid patio]

join the no big ring club

[harsh matrix]

This is bad because I used one of the rings as a solution to my light leak

Light leak from the focuser

Um things just got a whole lot weirder

[vapid patio]

aw man how

[vapid patio]

nothing tape cant fix 🥀 😔

[harsh matrix]

There is no sign of a donut or any broad illumination inconsistency...

But my camera is way closer to the mirror than before.

So the reducer can manipulate the size of it?

[frosty shard]

size of what?

[vapid patio]

size of what?

[vapid patio]

size of the circle of despair i assume

[harsh matrix]

Beautifully collimated once more

[vapid patio]

so then its going good? @harsh matrix

[harsh matrix]

Yeah at the moment I would say it is

Metaguide makes collimating these things so easy.

[vapid patio]

whats that

a software?

seems like it is thats sick

will keep it in mind

[harsh matrix]

A stupidly useful software tool yes

[vapid patio]

should i get it?

[harsh matrix]

It only works on mono cameras as far as I've been able to tell so its a good thing you swapped off OSC

[harsh matrix]

Absolutely

[vapid patio]

i really need to wash both my mirrors like good lord it gets to a point

[vapid patio]

ok bet

and on everones soul it is ok to use dish soap?

[harsh matrix]

I believe so

There's a ton of videos online that show you how to clean a mirror

Okay im just confused at this point.

[vapid patio]

i dont like the idea of useing like dawn haha

[harsh matrix]

How did apertura calculate the proper back focus for this reducer to be 55 mm, and then not realize the math was wrong

[vapid patio]

sales

55 seem easy

[harsh matrix]

I still have to plate solve for the real focal length

[vapid patio]

heheheha

im just too good ig what can i say

@harsh matrix There are 2 different kinds of drivers i can get What did you choose?

hm also a guideing software? looks legit

[harsh matrix]

You need the direct show driver or whatever its called for your camera

[vapid patio]

so you mean just the normal drivers for your camera?

[harsh matrix]

I do not

The ones you are thinking of are the Ascom drivers

There's a direct show version too

I'm assuming you bought a mono 585 from ZWO

They have a direct show driver on their drivers page.

[harsh matrix]

Yo

These broadband subs look better than I've ever seen from an RC

[harsh matrix]

@vapid patio @runic violet @frosty shard @tight lodge DONUT SLAIN

before, for reference

proof is in the pudding

i removed the gradient and there is no sign of a broad structure in the sub

there's now some tilt for me to tune out of it which will hopefully be pretty simple

AND!

no donut here either

after extreme noise reduction

normally if it was here, it shows up after noise reduction

[tight lodge]

Or optolong

[coarse shell]

What

[crisp flower]

Maybe im trippin but looks like its still barely there slightly shifted to the left tho

[vapid patio]

Normal gradient

[vapid patio]

Well this is amazing! You can actually take a photo now

Can't wait to see what you can do now that the circle of despair is gone

[crisp flower]

Then ive said nothing

[harsh matrix]

my AM5N actually averaged less than 0.4 RMS last night LOL

[vapid patio]

yayy good for you smh smh

im getting 3.80ish 😭

tuned up some mount settings and phd2 today so we will see

@harsh matrix you know the Guide Rate on mounts?

mine was 25% for some reason

[vapid patio]

Lower than default settings

[frosty shard]

@tight lodge I was deconvolving my SHO moon image incorrectly. Still having trouble getting the layers aligned though

[harsh matrix]

Yes ish

[vapid patio]

Yo how much back focus you need “all of it”

[harsh matrix]

That doesn't make much sense

[vapid patio]

How i mean i changed it

It will make guiding adjustments 25% the speed of your tracking

Thats what it means

25 is slow

[harsh matrix]

I know what the guide rate is

I just don't know how it was that low

I don't think PHD2 let's you guide if its that low

[vapid patio]

Im confused aswell so i went and brought it up to 75%

Whoever had this mount before me must have been slow

[vapid patio]

@harsh matrix should I just go ahead and knock out my bias and darks?

[tight lodge]

you can do that right now. just put the cap over the camera and you can take them. Just make sure that when you shoot you have the same Gain and Offset and temperature set up

[vapid patio]

Don’t I need to take darks with the reducer?

[tight lodge]

no

[frosty shard]

Darks are mostly for the sensor

[tight lodge]

Same for Bias

[vapid patio]

But if I look it up, it says too

[frosty shard]

I guess it might be helpful to take one to check for light leaks? But darks are about eliminating read noise and thermal noise in the sensor

[vapid patio]

I know

But if I’m shooting reduced pretty sure the pattern wouldn’t lineup

[frosty shard]

What pattern?

[tight lodge]

when you shoot dark and bias frames you want to block all the light from reaching the sensor

[vapid patio]

I know

Wait

[frosty shard]

I'm waiting

[tight lodge]

Interesting

[vapid patio]

Idk

@frosty shard I swear I’ve asked this before, but do you shoot reduced?

[frosty shard]

Nope, native FL

[vapid patio]

Sadly this is a vel question

[harsh matrix]

Yes

[harsh matrix]

Definitely not.

The reducer has no effect on what is effectively quantum behavior in the sensor itself.

Whatever source said you need the optical train to be identical to how it is in shooting conditions to take darks has no idea what they're talking about.

Flats are the only thing that need to be done with the imaging train in the exact same configuration as it was during your imaging time.

Darks are temperature dependent but the temperature does not matter anymore once you add cooling to the equation.

Considering you can almost always hit that -10 or -5 C threshold, depending on what your summer weather allows for you to pull off consistently.

[frosty shard]

heh it's dropping down to 6°C here at night still so my cooler gets to slack

my dew heater does not, humidity is too high

[vapid patio]

ok thanks man

[harsh matrix]

THIS LUM STACK LOOKS EXCELLENT

best green stack from this scope

it appears that i have a primary mirror movement to make

oopsies

dang im still not quite at the calculated focal length either

at about 0.69x reduction

close enough

f/5.5

not bad at all

2.36" stars

really not bad at all

[tight lodge]

This is your FOV uncropped?

[harsh matrix]

yes

[tight lodge]

Well that's just insane

I might have to try the Ring Nebula again. I only saw it once. But never tried to image it properly

[harsh matrix]

i saw it quite a few times

it is one of my favorite visual objects

i can see clear structure and color from my bortle 8 backyard

it's probably insane from bortle 3

CO modulation doing its thing again

[tight lodge]

I saw it trough a cheap 70/900 with a 25mm eyepiece and a 2xbarlow under b4/b3 sky

[harsh matrix]

got some outer shell in the red channel despite no noise reduction

only ~55 minutes per channel except in lum

i did broadband too to strain test the system as best i could

[harsh matrix]

i couldnt find it with my frac like that

i bet that's the same one i have

[tight lodge]

Skywatcher frac on an EQ1 mount?

[harsh matrix]

oh yeah i probably needed to redo my filter offsets cause the focus looks wonky across each channel, whoops

[harsh matrix]

ah no it's not

i have a Celestron Astromaster 70AZ

i can bet it's not any better

awful scope

[tight lodge]

I doubt there are any differences between them. Other than the paint😂

[harsh matrix]

yeah probably

no way

a flat background

for the first time

with an RC

in bortle 8

[tight lodge]

Look at that lil guy

[harsh matrix]

ik

it needs more exposure ofc

[tight lodge]

Is a single RGB combination ?

[harsh matrix]

it's my full integration of RGB

i dont think im going to use the lum i picked up

i only got 11 minutes of that vs the 55 per channel of the rest

[tight lodge]

I know, I meant to say if is a 1xR, 1xG, 1xB

[harsh matrix]

interacting pair in the bottom left

[harsh matrix]

not a single frame

no

unless i am completely misunderstanding

ddint have enough frames to drizzle

[frosty shard]

@harsh matrix do you have a quick list of instructions for fixing the donut of death?

(tbh it would be nice if we could get a mod to pin that in this thread)

I haven't been paying attention much since I'm not currently using a reducer

[harsh matrix]

i do but the issue is that i dont know what reducers have/can cause this issue so i dont know if it would be useful to very many people

[vapid patio]

looks like a halo

[vapid patio]

sharp

[harsh matrix]

noisy as hell though

typical for my skies

[tight lodge]

Did you run BXT on it?

[harsh matrix]

i think that one was correct only

[vapid patio]

@harsh matrix what lrgb set do i get

looking for used bc your boi broke asf right now

[harsh matrix]

aim for antlia LRGB-V Pro, 1.25" ofc

if you cant get those, aim for a touptek set if you can find one

[vapid patio]

well if i get 1.25 then i need adapters

[vapid patio]

ok

[harsh matrix]

well you said you were going to get 1.25" gear, no?

[vapid patio]

like 50 bucks of adapters i saw

[harsh matrix]

filter wheel, filters etc.

[vapid patio]

no my filter wheel is zwo 5x2

[harsh matrix]

i understand that but i got the impression you were going to downsize

if you arent going to downsize, that's going to complicate things

you can still make money back by selling your OSC only filters too btw

[vapid patio]

sold

took 20 min haha

[harsh matrix]

[vapid patio]

but not astronomik l-3

i should keep it right?

[harsh matrix]

if you are being forced to purchase a lum filter with an LRGB set, and you already have an APO frac (redcat 51) and a reflector with no CA, then I dont see a reason to keep it, personally

that's why i sold mine with my doublet.

[vapid patio]

you know your right

im forced to buy a L lol

but its good glass?

[harsh matrix]

I dont think that's justification alone tbh

[vapid patio]

fair

[harsh matrix]

if you get a high quality filter set, that doesnt matter anyway

[vapid patio]

like what?

[harsh matrix]

most likely the glass will be on par or better

antlia or better

[vapid patio]

should i go smaller oag?

i mean filter wheel

filter wheel

filter wheel

or will that make trouble when i go bigger sensor

[harsh matrix]

I think you will get your best bang for your buck by doing that tbh

[harsh matrix]

it will give you trouble

sort of

thing is, you can swap out the filter roulette in the 1.25" filter wheels

I think all of them

to a 31 mm unmounted and 36 mm unmounted roulette

[vapid patio]

can i not swap out the wheel on my 5x2?

[harsh matrix]

so in the long term, it makes the most economical sense, especially for you

[harsh matrix]

i do not believe you can "downgrade" the 2" filter wheels

but you are welcome to research it

[vapid patio]

yeah its a no

oh well

so whats the plan? sell filter wheel and filter buy new filter wheel and filters?

[harsh matrix]

you might be able to get upwards of $200 from the filter wheel

essentially enough to trade it in for a 1.25" filter wheel or one of the 36mm/31mm ones

but like i said, you can always swap the roulettes later

[harsh matrix]

im thinking that

[vapid patio]

oh my firend said if i get a 36mm unmounted filter wheel he will give me his SHO set

[harsh matrix]

it's painful, it's annoying, it's going to slow your plans down

but at the very least

[vapid patio]

its all 7nm

[harsh matrix]

it should cost you less in the long run

[harsh matrix]

what filters are they?

brand

[vapid patio]

zwo haha

[harsh matrix]

oh god 😭

[vapid patio]

but good price 🤑

https://www.highpointscientific.com/zwo-narrowband-filter-set-36mm-unmounted-nbset-36

[harsh matrix]

is he giving them to you for free?

or selling them to you?

[vapid patio]

he says use them for aslong as you want and when you have the spare money pay me back "200"

[harsh matrix]

honestly, that might be the play

i dont think those are great filters, but it means you can do narrowband imaging while you wait for a good deal on LRGB filters to come up

[vapid patio]

so sell 5x2 filter wheel. get 7x36mm. get his filters. OR

wait

@harsh matrix

the lord loves me

[harsh matrix]

you are one lucky mf

hopefully you can sell it at a good price

btw, Nick, the mod here has 1.25" LRGB optolong filters

[vapid patio]

but where do i get the new filter wheel?

[harsh matrix]

i dont know how much he is trying to sell them for though

[harsh matrix]

look for a deal on CN, or look for a good price on a new one

[vapid patio]

ouch

[harsh matrix]

Touptek's arent priced terribly

[vapid patio]

i think they are super cheap

🙏

in stock

@harsh matrix so sell uv/ir? right?

[harsh matrix]

yeah

honestly

if at all possible

try to get the touptek LRGB filters, the 36mm ones since you are going for a 36mm filter wheel

and hopefully you made a decent amount from your other filters to make that happen

[vapid patio]

110 from my crappy dual narrowband filter

100 for my astronomik i hope

and 200 from filter wheel

[harsh matrix]

you may have to get crappy optolong LRGB filters in the meant time

[vapid patio]

sho

hoo

for now

[harsh matrix]

not sure there is any other way to get SHO and LRGB

[vapid patio]

[harsh matrix]

if youre fine with narrowband only

[vapid patio]

at the same time no

[vapid patio]

haha yeah

[harsh matrix]

it's a good thing the summer is about here

[vapid patio]

real

[harsh matrix]

just looking at your options, it seems like this is the only way you get both in a reasonable amount of time

[vapid patio]

your right, thanks bro

still gonna try the cam out tomorrow

[harsh matrix]

ofc

dont let this stop you

[vapid patio]

i really hope my rducer doesnt give me trouble

if it does ima quit astro

[vapid patio]

still get get lum data

[harsh matrix]

assuming your back focus is right, it shouldnt

[frosty shard]

Just want to show y'all an example of what my Bahtinov mask focus looks like - there's no serious issue with this right

[tight lodge]

That focus is sharp

[frosty shard]

Well now I guess I need to figure out what ain't sharp

[tight lodge]

Did you shoot the same star without the bathinov mask?

[frosty shard]

@tight lodge I tested out the new bolts on my mount indoors (it hasn't been clear enough to actually test the guiding) and the OTA feels way, way more rigid

[frosty shard]

Unfortunately I did not

So hopefully I'll be able to resolve the Dec backlash issue. In my M11 image the stars looked elongated along the Dec axis so I hope that's the cause and I don't need to mess with the collimation

After all it looks fine visually

[tight lodge]

Have you ever checked if you are oversampled?

[frosty shard]

I think I am

[harsh matrix]

very most likely

[frosty shard]

The pixel scale is 0.477 arcsec/pixel, and for an FWHM of 2" for the stars in average seeing, I should be able to get just over 4 pixels FWHM?

[tight lodge]

You can test that. Next time do a 2x2 bin, if yours stars get in a better shape then that's your cause

[frosty shard]

This is the best I could manage of any sub I've taken recently

[frosty shard]

I should also add, NINA's Bahtinov analyzer plugin chokes on this and can't tell if it's in critical focus. I'm actually wondering if this might be due to the fainter diffraction spikes from the OTA

[vapid patio]

Is there any wrong backfocus?

Just more back focus more reduction right?

[violet kelp]

damn, that's amazing

[harsh matrix]

no

[harsh matrix]

correct

[harsh matrix]

fr

[vapid patio]

But too much = softness and coma?

[harsh matrix]

idk

possibly

[vapid patio]

https://cdn.discordapp.com/attachments/1133160663271866409/1375929964536397887/togif-1.gif

Ok

[tight lodge]

[tight lodge]

When are you gonna do first light with the new camera?

[vapid patio]

Tonight 🙏🙏🙏

[tight lodge]

Better cook something good

[vapid patio]

Wont be a color photo but plan too 🙏🙏🙏

[harsh matrix]

Guys

Chat has spoken

I'll grab some Ha to pull out more of the outer shell

Tonight

[frosty shard]

Unfortunately this weekend might be ruined by Canada

It's a conspiracy, I tell you. It's not wildfire smoke. It's the Canadian bacon industry trying to cover up their smokers

[vapid patio]

@harsh matrix If you free and bored join vc 🔥🔥🔥

[harsh matrix]

I'm not free

[harsh matrix]

I told my Canadian friend that they need to tax the carbon coming from those fires

He said they already are 💀

[vapid patio]

@harsh matrix

Big problem

Big problem

Big big problem

[vapid patio]

Never mind

[harsh matrix]

[frosty shard]

What did you think happened?

[vapid patio]

for some reason I took some spacers off the end and put them between the reducer and sensor

I must’ve done it without realizing it when taking it apart for the fifth time lol and it made the spacing 100 and something millimeters in no matter what I do I couldn’t reach focus

All good now yippee

[vapid patio]

Its a fun 4am right now

Working on every thing phd2

[harsh matrix]

do you have correction algorithms selected?

those RA oscillations almost look periodic in nature

[vapid patio]

What

My dec is reset switch and ra is predictive pec

[harsh matrix]

what is the predictive weight you are using?

[vapid patio]

50

[harsh matrix]

there's absolutely no reason my EQM-35 should be wiping the floor with your mount unless celestrons are just that bad

[harsh matrix]

try bumping that up iteratively

[vapid patio]

My mount is older than me loll

Ok

[harsh matrix]

but give it some time until you notice changes

[vapid patio]

by intervals of five?

[harsh matrix]

yeah

[vapid patio]

Ok

[harsh matrix]

i do intervals of five

right now my EQM-35 is at 70

[vapid patio]

to be fair, it’s very windy

[vapid patio]

How old is that Mount?

[harsh matrix]

o

maybe you should do it on a less windy night

[vapid patio]

Still had to get out here and just learn a good bit

[harsh matrix]

almost 2 years old?

idk when it was assembled though

[vapid patio]

Mine is from 2007 haha

just a bump up 5% has done good

Going 10

[harsh matrix]

joizuz

[vapid patio]

Now that I have my filters, new mount is probably next on the list

Got it for a great deal could probably sell it

[vapid patio]

@harsh matrix Currently 5am. So all nighter I stopped bc the sun came up lol

Got it down from 4.00+ or error to 1.00-1.50 or error

And I have to get up in a hour lol

[frosty shard]

Got smoked out tonight, RIPperoni

[harsh matrix]

Lagoon in broadband from last night

the data is pretty scuffed and i didnt take flats yet

still, very pretty

[frosty shard]

Just straight RGB? Any lum/IR?

[harsh matrix]

no lum or IR

straight RGB

the H-alpha and H-beta + Oiii is more than strong enough to carry the signal on its own

[tight lodge]

Both

[frosty shard]

Yeah, that's utterly stunning - I gotta give this one a try later

[harsh matrix]

wont do IR until i start getting some clear breaks again and whenever this thing isnt rising after midnight lmao

IR needs a lot of data, and even on Lagoon, that is no exception

[frosty shard]

I gotta wait for these wildfires to calm down sadly

Last night was supposed to be excellent weather, but Vega looked like a 3rd magnitude star

[harsh matrix]

fr

[frosty shard]

I just want to see if I've managed to fix the Dec issue with my mount...it feels like it but I need to see the numbers

btw @harsh matrix are you using ASTAP to plate solve? If so what database do you use?

I've tried seeing if switching from D50 to D80 would help reduce the number of plate solve failures, and it does a bit, but I still have some troublesome images

[harsh matrix]

i switched off of ASTAP

i think im using platesolve 3 now

[vapid patio]

How in the world did you get platesve 3 to work

[frosty shard]

I'd have done this, but one of my goals is to set up an entirely freely licensed software environment to do my processing and AFAIK it's not freely licensed :(

[harsh matrix]

wait really?

maybe im not using plate solve 3 mb

i need to check again

i might be running astap

all i know is that whatever im using never fails to plate solve

[frosty shard]

By freely licensed I mean open source, Platesolve 3 is a free download

[harsh matrix]

ah

[frosty shard]

I write software quite a bit for my research so I like using tools I could contribute back to

[harsh matrix]

holy cow guys

WR136 is actually magenta

we love doing real astronomy

[vapid patio]

What

[frosty shard]

I'm guessing that's due to the overall blue color + H-alpha emission?

[harsh matrix]

strong He II emissions

AND H-alpha emissions

[harsh matrix]

WR136 is magenta

this isnt some kind of color calibration error lol

[frosty shard]

I'm gonna have to figure out how to take a spectrum with my rig

[harsh matrix]

fr

i really want to invest in some spectroscopy equipment

[frosty shard]

lmao if I could get away with just sticking a giant diffraction grating on my aperture

[harsh matrix]

i have to be honest

reflectors do yield much more natural colors right out the gate

doublets screw everything up

[tight lodge]

The doublet murdered those poor stars

[harsh matrix]

it did that and completely baked the color calibration

[tight lodge]

I'm gonna repeat it. This is why Reflectors are the kings. even if you don't color calibrate, you get good colors

[harsh matrix]

every time i color calibrate reflector data, it hits just the right way

[tight lodge]

Right? No histogram adjustments nothing. It's just right

And let's not forget the stars being pinpoints

[vapid patio]

Ah

[tight lodge]

Plus, I want to see some frac dudes resolving these stars on Crescent nebula

Ignore the hot pixel next to them. That don't count

[harsh matrix]

True

[tight lodge]

Bwoah... I need to put some hours on the crescent

[harsh matrix]

My 4" frac split those

They just look like garbage by comparison.

You could park a bus between each of them in the RC pic

Oh yeah there's 5 stars not 4

So the frac didnt split all of them

Raw resolving power at its finest.

[tight lodge]

The advantage of mirrors. Big aperture for not so much money

Even the old DSLR I was using before resolved them better

This is the full image by the way :pepe3:

[harsh matrix]

Ah yeah you can see 5

Reflectors ftw

[tight lodge]

ignore the weird stars... i did a bad SHO with no filter wheel or drawer. i had to manually remove the camera take out one filter an put in another and pray that i put the camera back in the same orientation XD

[frosty shard]

Was the original data taken with an OSC or mono cam?

[harsh matrix]

OSC

[frosty shard]

I feel obliged to link this CN thread:
https://www.cloudynights.com/topic/867680-loss-of-color-diversity-in-lrgb-photography-when-the-filters-do-not-overlap/

Not that you can't get great color results from mono RGB (especially if your goal isn't precise reproduction), but I'm tempted to get overlapping RGB filters to see if it makes any major difference

[tight lodge]

my RGB filters only overlap with Green and Blue

[frosty shard]

Often there's a gap between red and green to avoid the sodium D line. I think this is going to be less important over time as cities transition to LED lighting

Astronomik does make overlapping LRGB filters

[tight lodge]

Yeah, same for LP filters. they are mostly obsolete

[tight lodge]

yes, because they are photometric filters (They have halos because of that)

[frosty shard]

Though not entirely - I've actually had some success with viewing brighter galaxies using an LP filter. Though I wonder if you'll get similar results out of a minus green or minus yellow filter

[frosty shard]

I did not know that that was a thing.

Tbh I actually do like some astrophotos with star halos, so depending on what I want to shoot and how I want to shoot it, maybe I'll get some filters that intentionally introduce them

[tight lodge]

i was looking at Baader photometric filters to get some continuum IR filters

[frosty shard]

Expensive, but maybe I'll get a full set of Baader filters as a graduation gift

UVBRISHO in 1.25" + CMOS optimized H-beta in 2" for visual observing

Honestly at that point...maybe I'd just get a whole 'nother filter wheel

[tight lodge]

Interesting palette

[frosty shard]

Yeah, I feel like it would be really interesting just to shoot UVBRI on nebulae

The CMOS H-beta filters are absolutely crazy though for visual observing. Apparently like 4x more H-beta targets are within its reach compared to a standard 10-12 nm version

The California Nebula may be within reach of the naked eye from my Bortle 7 skies with that filter

[tight lodge]

I never had the chance to try an Hβ filter, nor that I've seen a picture taken with one

[frosty shard]

It's not meaningfully different from H-alpha. Unless you want to quantify dust extinction, in which case it's extremely useful data

You know, now that I think about it, I'm actually a little surprised I haven't seen dual band H-alpha/H-beta filters be produced

[tight lodge]

FireHDn got some really weird filters. He doesn't want to give too much information on those, which I understand... but I'm really curious to see what he got

[frosty shard]

Oh I really want an He-II 468 nm filter...

[frosty shard]

dual band H-alpha/H-beta would be ideal for OSC users who want to maximize H-II SNR, and really that would also help out a mono imager too

[harsh matrix]

My neighborhood and surrounding neighborhoods still use old sodium street lights so this is still very helpful to me

[frosty shard]

Yeah, here in Madison the skyglow is still pretty yellow from sodium lamps

[vapid patio]

@harsh matrix Call?

Got my filters

They are $150 less than everywhere else you can get them

And low-key from a sketchy seller

@frosty shard you too gang 💔

[harsh matrix]

which filters?

[vapid patio]

Lrgb opotolong

I spelled that wrong

They seem to be legit everything is up to spec

[harsh matrix]

nice

theyre not great either but better than ZWO afaik and will serve their purpose until you can get something better down the road

[vapid patio]

for sure

mr pickles has the same ones

my favorite test for L filters is putting it in front of my phones face id and seeing if it stops it from seeing my face

[harsh matrix]

https://www.cloudynights.com/articles/cat/articles/configuring-an-8-rc-telescope-for-astrophotography-r4769

somebody wrote an article on CN about building an RC8 rig

[vapid patio]

same reducer

hehe

[harsh matrix]

honestly

i see one on CN

kind of tempted to gnab it

for 120 bucks

[vapid patio]

good deal

[vapid patio]

@harsh matrix do filters normally come with maybe a little it of dust and maybe tiny smudges?

or mabye me talking to the filter on accident

[harsh matrix]

yes

mine did and they were brand new

💀

antlias

[vapid patio]

ouch

like there was a spot of tiny spit or smude and i was like bruu

Heheeheha

[tight lodge]

What filter is gonna be on the lucky spot?

[vapid patio]

Probably Ha

But I wanna do Hoo so Ima come up with something

[tight lodge]

HαGB

[vapid patio]

Does that work?

I was just thinking

[tight lodge]

Yes.

[vapid patio]

Iike good? Lol I have no clue what the data looks likes

[tight lodge]

It's a good way to go around it. Although, I recommend HαRGB

[vapid patio]

I can do Hargb

[runic violet]

https://www.teleskop-express.de/en/ts-zubehoer-31/adapters-tilting-327/adapter-for-decoupling-the-focuser-from-the-primary-mirror-cell-with-tilt-flange-18760

https://www.teleskop-express.de/en/ts-zubehoer-31/adapters-tilting-327/adapter-for-decoupling-the-focuser-from-the-primary-mirror-cell-with-tilt-flange-18761

The tilt adapters are now being sold

[frosty shard]

Well...hopefully in the US of A here soon 🦅 🇺🇸 🦅

okay actually I do need some clarification: how do those adapters differ from these ones:
https://www.highpointscientific.com/apertura-focuser-tilt-adapter-for-6-and-8-rc-telescopes

I assume it doesn't decouple the focuser from the primary mirror?

I'm just trying to wrap my head around the mechanics

[runic violet]

You can just buy it from TS

It'll probably eventually come to Agena though

[runic violet]

It does not

It's just a tilt adapter

[frosty shard]

What's the mechanical difference, does it attach to a different part of the OTA?

[runic violet]

A tilt adapter doesn't fix anything

It just allows you to tilt the focuser with respect to the primary mirror cell

But the mirror will still flop with the weight on the focuser

The decoupler actually decouples it entirely, and isn't trivial to install

[vapid patio]

@tight lodge found out i have been shooting through smoke for weeks now

Damn Canada

No wonder in no moon the sky is still bright

[harsh matrix]

does this decoupler still permit the collimation of the primary mirror when in use?

i guess it says it is?

although i just noticed the collimation screws on the RC10 are in different positions from the smaller models

the decoupler for the RC8 might be different in design from the RC10 example which is the only one with pictures...

if it's screwing onto the rear threads, im not sure how it's decoupling the focuser from the primary either unless somehow it's transferring all of that weight into the rear of the scope instead somehow

[runic violet]

It probably is